2025 Vol. 50, No. 2
Display Method:
2025, 50(2): 363-376.
doi: 10.3799/dqkx.2025.011
PDF 8512KB
Abstract:
Volcanic oil and gas reservoirs in the deep part of basins are important exploration targets and have received worldwide attention. The exploration results show that there are high daily production wells of all lithologies, and rhyolite wells have the highest daily production. China has grown into the main body of global volcanic exploration in terms of reserves. The breakthrough of volcanic exploration requires decades of exploration and research accumulation, and the exploration findings show a spiral rise. The reserves of Circum-Pacific tectonic domain, Tethys tectonic domain and Central Asian orogenic belt are 44%, 33% and 16%, respectively; and other areas accounted for 7%. The proved reserves of volcanic rocks in Mesozoic, Cenozoic and Paleozoic strata are 43%, 38% and 19%, respectively. In terms of reserves, the proportion of lava, volcaniclastic lava and pyroclastic rock is 61%, 31% and 8%, respectively, and the proportion of reserves in basalt, rhyolite and trachyte reservoirs is 41%, 13% and 6%, respectively. The understanding of volcanic rock reservoir distribution can be roughly divided into the stage of reference to sedimentary rock research methods and the stage of volcanostratigraphy theory. The main controlling factors of volcanic rock reservoir are as follows: Deposition unit controls reservoir quality, tectonic process and weathering are catalysts for secondary porosity formation, deep fluid dissolution is the key to increasing pores, and formation overpressure and weak cementation are the key to preserving pores in volcaniclastic rocks. The superposition of many factors promotes the formation of multi-layer connected large-scale composite reservoir. Volcanic reservoirs can be divided into three main types: structural reservoirs, structural lithological reservoirs, and lithological reservoirs. The techniques of identifying volcanic edifices and predicting favorable lithofacies, the study of reservoir genesis as well as reservoir prediction technology provide strong support for the target locating of volcanic exploration.
Volcanic oil and gas reservoirs in the deep part of basins are important exploration targets and have received worldwide attention. The exploration results show that there are high daily production wells of all lithologies, and rhyolite wells have the highest daily production. China has grown into the main body of global volcanic exploration in terms of reserves. The breakthrough of volcanic exploration requires decades of exploration and research accumulation, and the exploration findings show a spiral rise. The reserves of Circum-Pacific tectonic domain, Tethys tectonic domain and Central Asian orogenic belt are 44%, 33% and 16%, respectively; and other areas accounted for 7%. The proved reserves of volcanic rocks in Mesozoic, Cenozoic and Paleozoic strata are 43%, 38% and 19%, respectively. In terms of reserves, the proportion of lava, volcaniclastic lava and pyroclastic rock is 61%, 31% and 8%, respectively, and the proportion of reserves in basalt, rhyolite and trachyte reservoirs is 41%, 13% and 6%, respectively. The understanding of volcanic rock reservoir distribution can be roughly divided into the stage of reference to sedimentary rock research methods and the stage of volcanostratigraphy theory. The main controlling factors of volcanic rock reservoir are as follows: Deposition unit controls reservoir quality, tectonic process and weathering are catalysts for secondary porosity formation, deep fluid dissolution is the key to increasing pores, and formation overpressure and weak cementation are the key to preserving pores in volcaniclastic rocks. The superposition of many factors promotes the formation of multi-layer connected large-scale composite reservoir. Volcanic reservoirs can be divided into three main types: structural reservoirs, structural lithological reservoirs, and lithological reservoirs. The techniques of identifying volcanic edifices and predicting favorable lithofacies, the study of reservoir genesis as well as reservoir prediction technology provide strong support for the target locating of volcanic exploration.
2025, 50(2): 377-387.
doi: 10.3799/dqkx.2024.013
Abstract:
In recent years, multiple large gas reservoirs have been discovered in the oil-prone Bohai Bay Basin, among which the natural gas reserves of the Bozhong 19-6 structure exceed 100 billion cubic meters, breaking the traditional understanding that large gas reservoirs cannot be found in oil-prone basins.This article comprehensively applies oil and gas components, natural gas isotopes, fluid inclusions, and PVT analysis data to analyze the formation process and phase control factors of large-scale gas reservoirs in the Bohai Bay oil type basin. The research results indicate that large gas reservoirs have been discovered in the Bohai Bay oil-bearing basin, and have generally undergone the process of "early oil and late gas" accumulation. CO2 is influenced by both mantle and crust sources, resulting in a mixed crust mantle origin; The CO2 content affects the fluid phase state, manifested as a decrease in the critical temperature of the system as the content increases, making it more prone to gas phase. High CO2 content Paleozoic carbonate buried hills are gas reservoirs, while low CO2 content Archean buried hills are mostly condensate gas reservoirs or high volatility oil reservoirs. Therefore, the search for large condensate gas reservoirs should be considered as the exploration direction for natural gas reservoirs in oil bearing basins.
In recent years, multiple large gas reservoirs have been discovered in the oil-prone Bohai Bay Basin, among which the natural gas reserves of the Bozhong 19-6 structure exceed 100 billion cubic meters, breaking the traditional understanding that large gas reservoirs cannot be found in oil-prone basins.This article comprehensively applies oil and gas components, natural gas isotopes, fluid inclusions, and PVT analysis data to analyze the formation process and phase control factors of large-scale gas reservoirs in the Bohai Bay oil type basin. The research results indicate that large gas reservoirs have been discovered in the Bohai Bay oil-bearing basin, and have generally undergone the process of "early oil and late gas" accumulation. CO2 is influenced by both mantle and crust sources, resulting in a mixed crust mantle origin; The CO2 content affects the fluid phase state, manifested as a decrease in the critical temperature of the system as the content increases, making it more prone to gas phase. High CO2 content Paleozoic carbonate buried hills are gas reservoirs, while low CO2 content Archean buried hills are mostly condensate gas reservoirs or high volatility oil reservoirs. Therefore, the search for large condensate gas reservoirs should be considered as the exploration direction for natural gas reservoirs in oil bearing basins.
2025, 50(2): 388-404.
doi: 10.3799/dqkx.2024.026
Abstract:
In order to solve the problem of finding large-scale volcanic reservoirs in the Mesozoic of Bozhong Depression, Bohai Bay Basin, this paper takes BZ8-3S large volcanic trap and BZ8-3S-A high-yield volcanic exploration well drilled in this structure as the research object, and studies the lithology, lithofacies and reservoir characteristics of volcanic rocks in this structure in detail. The development conditions of the large volcanic trap model reservoir close to the source rock are discussed and the development model of the reservoir is established. The results show that the BZ8-3S structure is composed of several large and medium-sized acid lava volcanic structures and mainly develops three lithological lithofacies, namely porous rhyolite of the upper subfacies of the intermediate effusive facies, massive rhyolite of the lower subfacies and the crypto-explosive breccia subfacies of the volcanic vent facies, forming three types of volcanic reservoirs: high porosity and low permeability, medium porosity and low porosity and low permeability. The medium and large acid lavas with multiple eruption centres, rich upper subfacies of the effusive facies, as well as the upper subfacies of the effusive facies and the crypto-explosive breccia subfacies developed near the source facies of the volcanic mechanism are the basis for the formation of regular model volcanic rock reservoirs. Weathering promoted the formation of pores and fractures in the upper subfacies of the intermediate effusive facies and the crypto-explosive breccia subfacies, improved reservoir physical properties and was key to the formation of favourable reservoirs in the weathered crust. Tectonism transformed the massive lava of the lower subfacies of the effusive facies and formed the fracture and dissolution pore development zone in the parent rock of the lower part of the weathered crust, which formed the weathered crust-internal two-layer reservoir structure. Based on BZ8-3S, the reservoir development model of large-scale volcanic structure is established, which is based on the favourable lithology and lithofacies of large acid lava volcanic institutions and is controlled by weathering and tectonic transformation.
In order to solve the problem of finding large-scale volcanic reservoirs in the Mesozoic of Bozhong Depression, Bohai Bay Basin, this paper takes BZ8-3S large volcanic trap and BZ8-3S-A high-yield volcanic exploration well drilled in this structure as the research object, and studies the lithology, lithofacies and reservoir characteristics of volcanic rocks in this structure in detail. The development conditions of the large volcanic trap model reservoir close to the source rock are discussed and the development model of the reservoir is established. The results show that the BZ8-3S structure is composed of several large and medium-sized acid lava volcanic structures and mainly develops three lithological lithofacies, namely porous rhyolite of the upper subfacies of the intermediate effusive facies, massive rhyolite of the lower subfacies and the crypto-explosive breccia subfacies of the volcanic vent facies, forming three types of volcanic reservoirs: high porosity and low permeability, medium porosity and low porosity and low permeability. The medium and large acid lavas with multiple eruption centres, rich upper subfacies of the effusive facies, as well as the upper subfacies of the effusive facies and the crypto-explosive breccia subfacies developed near the source facies of the volcanic mechanism are the basis for the formation of regular model volcanic rock reservoirs. Weathering promoted the formation of pores and fractures in the upper subfacies of the intermediate effusive facies and the crypto-explosive breccia subfacies, improved reservoir physical properties and was key to the formation of favourable reservoirs in the weathered crust. Tectonism transformed the massive lava of the lower subfacies of the effusive facies and formed the fracture and dissolution pore development zone in the parent rock of the lower part of the weathered crust, which formed the weathered crust-internal two-layer reservoir structure. Based on BZ8-3S, the reservoir development model of large-scale volcanic structure is established, which is based on the favourable lithology and lithofacies of large acid lava volcanic institutions and is controlled by weathering and tectonic transformation.
2025, 50(2): 405-418.
doi: 10.3799/dqkx.2023.187
Abstract:
The buried hill in the Baiyun Sag is one of the deep-water oils and gas exploration fields in the Pearl River Mouth Basin in the northern South China Sea. However, research on the origin and classification of buried hills is relatively weak, which restricts the evaluation of the oil and gas exploration potential of buried hills. Structural analysis of buried hills in the Baiyun Sag from the perspective of inherited continental margin tectonic background using large-scale 3D seismic data. Mesozoic preexisting structures, Cenozoic detachment fault systems and multiple phases of magmatism, and strike-slip fault systems are identified. The buried hill in the Baiyun Sag is affected by three main controlling factors: pre-existing basement structure, detachment fault and late magmatic transformation. The buried hills in this area can be divided into three types and six subtypes: the geomorphic residual hill dominated by the Mesozoic structure, the extensional fault block dominated by the early Cenozoic structure, and the later modified buried hills. Among them, the thrust residual hill in the northern Baiyun sag, the tilting fault block in the eastern Baiyun sag and the horst and fault blockformed by normal and strike-slip faults of different orientations in the southwestern Baiyun sag have good granite reservoir development conditions, and is the favorable area to search for traps.
The buried hill in the Baiyun Sag is one of the deep-water oils and gas exploration fields in the Pearl River Mouth Basin in the northern South China Sea. However, research on the origin and classification of buried hills is relatively weak, which restricts the evaluation of the oil and gas exploration potential of buried hills. Structural analysis of buried hills in the Baiyun Sag from the perspective of inherited continental margin tectonic background using large-scale 3D seismic data. Mesozoic preexisting structures, Cenozoic detachment fault systems and multiple phases of magmatism, and strike-slip fault systems are identified. The buried hill in the Baiyun Sag is affected by three main controlling factors: pre-existing basement structure, detachment fault and late magmatic transformation. The buried hills in this area can be divided into three types and six subtypes: the geomorphic residual hill dominated by the Mesozoic structure, the extensional fault block dominated by the early Cenozoic structure, and the later modified buried hills. Among them, the thrust residual hill in the northern Baiyun sag, the tilting fault block in the eastern Baiyun sag and the horst and fault blockformed by normal and strike-slip faults of different orientations in the southwestern Baiyun sag have good granite reservoir development conditions, and is the favorable area to search for traps.
2025, 50(2): 419-432.
doi: 10.3799/dqkx.2024.010
Abstract:
The composite igneous rock buried hill in Huizhou Sag of the Pearl River Mouth Basin, experienced multi-stage tectonic evolution from Yanshanian to Himalayan, and developed fracture dissolution type reservoirs. In order to clarify the mechanism of buried hill reservoirs, the author conducted a detailed study on the fracture cause, phase and diagenetic evolution of Huizhou 26-6 buried-hill reservoir with zircon U-Pb dating and casting thin section observation. Huizhou 26-6 buried-hill is composed of granite, diorite and basaltic andesite, which have undergone at least six stages of tectonic magmatic activity.Granites suffered cataclastic, diorite and basaltic andesite are schistotized. At 166 to 145 Ma, basaltic volcanic rocks erupted. At 145 to 134 Ma, regional metamorphism occurred under the influence of the mid-Yanshan tectonic movement, resulting in gneissic and gneissic mineralization of basaltic volcanic rocksand early fractures. At ~134 Ma and 120 to 110 Ma, acidic magma invaded of basaltic volcanic rocks in two stages with extension, and granite, siliceous and carbonate veins developed. Actinization, epidotization and chlorite occurred at the volcanic passage.A first phase of tensile fissure developed between 110 and 100 Ma, and magmatic hydrothermal upwelling between 102 and 87 Ma, and the fissure was half-filled with dolomite and turbidite. Large scale uplift of the area affected by Late Cretaceous tectonic transfor Mation, strong weathering, and developed weathering cracks and dissolution cracks; During the rifting period, there were two periods of Mag Matic hydrother Mal activity influenced by the movements of the first and second episodes of Zhuqiong, and the cracks were filled with chlorite and turbidite; During the South China Sea Movement and neotectonics, micro fractures were generated to connect Source rock. Organic acids entered the reservoir for further dissolution and transfor Mation. The fractures were not filled or half filled. Large scale oil and gas filling and accumulation took place at 5 to 13 Ma. This study provides a basis for comprehensive evaluation of reservoir characteristics and clarification of natural gas enrichment patterns in the study area.
The composite igneous rock buried hill in Huizhou Sag of the Pearl River Mouth Basin, experienced multi-stage tectonic evolution from Yanshanian to Himalayan, and developed fracture dissolution type reservoirs. In order to clarify the mechanism of buried hill reservoirs, the author conducted a detailed study on the fracture cause, phase and diagenetic evolution of Huizhou 26-6 buried-hill reservoir with zircon U-Pb dating and casting thin section observation. Huizhou 26-6 buried-hill is composed of granite, diorite and basaltic andesite, which have undergone at least six stages of tectonic magmatic activity.Granites suffered cataclastic, diorite and basaltic andesite are schistotized. At 166 to 145 Ma, basaltic volcanic rocks erupted. At 145 to 134 Ma, regional metamorphism occurred under the influence of the mid-Yanshan tectonic movement, resulting in gneissic and gneissic mineralization of basaltic volcanic rocksand early fractures. At ~134 Ma and 120 to 110 Ma, acidic magma invaded of basaltic volcanic rocks in two stages with extension, and granite, siliceous and carbonate veins developed. Actinization, epidotization and chlorite occurred at the volcanic passage.A first phase of tensile fissure developed between 110 and 100 Ma, and magmatic hydrothermal upwelling between 102 and 87 Ma, and the fissure was half-filled with dolomite and turbidite. Large scale uplift of the area affected by Late Cretaceous tectonic transfor Mation, strong weathering, and developed weathering cracks and dissolution cracks; During the rifting period, there were two periods of Mag Matic hydrother Mal activity influenced by the movements of the first and second episodes of Zhuqiong, and the cracks were filled with chlorite and turbidite; During the South China Sea Movement and neotectonics, micro fractures were generated to connect Source rock. Organic acids entered the reservoir for further dissolution and transfor Mation. The fractures were not filled or half filled. Large scale oil and gas filling and accumulation took place at 5 to 13 Ma. This study provides a basis for comprehensive evaluation of reservoir characteristics and clarification of natural gas enrichment patterns in the study area.
2025, 50(2): 433-452.
doi: 10.3799/dqkx.2023.199
Abstract:
Deepwater reservoirs are the hotspot of global oil and gas exploration. With the continuous development of deepwater exploration, overpressure bedrock buried hills have gradually become an important successor field. The breakthrough of Lingshui 32-1 buried hill gas reservoir in the western deepwater area of the Qiongdongnan Basin reveals the insider fracture reservoir as well as the formation of large gas fields, and demonstrates the exploration potential of Lingnan Low Uplift buried-hills. However, overpressures are prevalent in buried hills, and how overpressure affects gas reservoir accumulation is a vital issue that needs to be solved urgently. To explore the overpressure characteristics, development mechanism of overpressure, and the relationship between overpressure and hydrocarbon accumulation, the drilled cores, thin-section observation, numerical simulation, and fluid inclusions analyses were utilized, revealed the two pressure systems, with an upper pressure coefficient of 1.68 and a lower pressure coefficient of 1.76 to 1.85, and two phases of gas filling from 3.0 to 1.9 Ma and from 1.8 Ma to the present day, respectively, and the gas filling process is consistent with the overpressure formation. Lingshui 32-1 buried hill consists of gravelly reservoirs, weathered crust reservoirs, tight interval, and internal fracture reservoirs. The fracture, basement fault, and vertical microfracture are the main channels for natural gas migration. The overpressure mechanism of Lingshui 32-1 buried hill is mainly due to disequilibrium compaction and hydrocarbon pressurization in the early stage, and lately controlled by lateral transmission of fluids pressure. The timing of strong overpressure formation matches well with the gas filling. The overpressure within the depression and the gas filling process into the buried hills control the gas reservoir accumulation. Eventually, an accumulation model of overpressure-controlled hydrocarbon generation, transmission, filling, and preservation developed. This study provides an important basis for further exploration of bedrock buried hill reservoirs in the deepwater area of the Qiongdongnan Basin.
Deepwater reservoirs are the hotspot of global oil and gas exploration. With the continuous development of deepwater exploration, overpressure bedrock buried hills have gradually become an important successor field. The breakthrough of Lingshui 32-1 buried hill gas reservoir in the western deepwater area of the Qiongdongnan Basin reveals the insider fracture reservoir as well as the formation of large gas fields, and demonstrates the exploration potential of Lingnan Low Uplift buried-hills. However, overpressures are prevalent in buried hills, and how overpressure affects gas reservoir accumulation is a vital issue that needs to be solved urgently. To explore the overpressure characteristics, development mechanism of overpressure, and the relationship between overpressure and hydrocarbon accumulation, the drilled cores, thin-section observation, numerical simulation, and fluid inclusions analyses were utilized, revealed the two pressure systems, with an upper pressure coefficient of 1.68 and a lower pressure coefficient of 1.76 to 1.85, and two phases of gas filling from 3.0 to 1.9 Ma and from 1.8 Ma to the present day, respectively, and the gas filling process is consistent with the overpressure formation. Lingshui 32-1 buried hill consists of gravelly reservoirs, weathered crust reservoirs, tight interval, and internal fracture reservoirs. The fracture, basement fault, and vertical microfracture are the main channels for natural gas migration. The overpressure mechanism of Lingshui 32-1 buried hill is mainly due to disequilibrium compaction and hydrocarbon pressurization in the early stage, and lately controlled by lateral transmission of fluids pressure. The timing of strong overpressure formation matches well with the gas filling. The overpressure within the depression and the gas filling process into the buried hills control the gas reservoir accumulation. Eventually, an accumulation model of overpressure-controlled hydrocarbon generation, transmission, filling, and preservation developed. This study provides an important basis for further exploration of bedrock buried hill reservoirs in the deepwater area of the Qiongdongnan Basin.
2025, 50(2): 453-465.
doi: 10.3799/dqkx.2025.010
Abstract:
In recent years, multiple billion ton oil and gas fields have been discovered in the Precambrian metamorphic rocks of the Bozhong Depression and Liaodong Bay area, with height of oil and gas column exceeding 1 000 m, demonstrating the exploration potential of the Archean buried hills. Research has shown that the degree of reservoir development determines the oil reservoir scale of the Archean buried hill, and fractures plays a key controlling role in the reservoir. The lithology has a significant impact on the development degree of fractured reservoirs, The reservoirs with high content of plastic minerals such as biotite and hornblende are not well-developed, while fractures are developed with high content of feldspar and quartz minerals. The weathering and leaching during the epigenetic stage reduce the compressive strength of rocks, and the degree of crack development and recorded stages in the weathering crust are much higher than those in the inner zone. Experiments and thin section analysis have shown that samples with early developed fractures, although filled with minerals, have significantly reduced compressive strength, laying the foundation for later crack development. The later fractures will choose to reactivate the original crack zone, and fractures filled with clay minerals, carbonate minerals, and iron minerals are more susceptible to reactivation under the influence of later stress and fluid.Macroscopically, the Indosinian period was a critical period for the formation of fractured reservoirs due to thrust and overturning. The superimposed transformation of faults during the Yanshan and Himalayan periods played an important role in activating early fractures. The distribution of thick reservoirs was controlled by the overlapping of faults during the Indosinian, Yanshan, and Himalayan periods.
In recent years, multiple billion ton oil and gas fields have been discovered in the Precambrian metamorphic rocks of the Bozhong Depression and Liaodong Bay area, with height of oil and gas column exceeding 1 000 m, demonstrating the exploration potential of the Archean buried hills. Research has shown that the degree of reservoir development determines the oil reservoir scale of the Archean buried hill, and fractures plays a key controlling role in the reservoir. The lithology has a significant impact on the development degree of fractured reservoirs, The reservoirs with high content of plastic minerals such as biotite and hornblende are not well-developed, while fractures are developed with high content of feldspar and quartz minerals. The weathering and leaching during the epigenetic stage reduce the compressive strength of rocks, and the degree of crack development and recorded stages in the weathering crust are much higher than those in the inner zone. Experiments and thin section analysis have shown that samples with early developed fractures, although filled with minerals, have significantly reduced compressive strength, laying the foundation for later crack development. The later fractures will choose to reactivate the original crack zone, and fractures filled with clay minerals, carbonate minerals, and iron minerals are more susceptible to reactivation under the influence of later stress and fluid.Macroscopically, the Indosinian period was a critical period for the formation of fractured reservoirs due to thrust and overturning. The superimposed transformation of faults during the Yanshan and Himalayan periods played an important role in activating early fractures. The distribution of thick reservoirs was controlled by the overlapping of faults during the Indosinian, Yanshan, and Himalayan periods.
2025, 50(2): 478-493.
doi: 10.3799/dqkx.2024.041
Abstract:
Bozhong 26-6 Oilfield is located in the west section of Bonan Low Uplift, Bozhong Depression, Bohai Bay Basin.It is an another buried hill oil field newly discovered in Bohai Sea area with 100 million ton reserves after the exploration breakthrough of Bozhong 19-6 buried hill condensate gas field, is also the largest oil and gas discovery in China's offshore waters in recent years. In response to solve unclear reservoir formation laws in the research area, especially the unclear source and accumulation process of oil and gas, this paper comprehensively uses the methods of crude oil physical property analysis, biomarkers, inclusion Petrography, homogenization temperature-paleosalinity and hydrocarbon generation simulation of source rocks, a systematic analysis was conducted, the results have shown that: (1) Bozhong 26-6 structure has different oil and gas sources, the characteristics of biomarker compounds indicate that crude oil mainly comes from the third member of the Shahejie Formation in the Huanghekou sag, however, condensate gas mainly comes from the third member of the Shahejie Formation in the southern subsag of the Bozhong Depression; (2) The Bozhong 26-6 oilfield has gone through three stages of oil and gas injection: early normal mature crude oil, middle condensate oil and gas (natural gas), and late light oil, The large scale of fluid filling in the middle and late stages plays a decisive role in the formation of reservoirs in the Bozhong 26-6 oilfield; (3)There are differences in hydrocarbon generation evolution between the source rocks in the Small sub depression in the southern part of Bozhong Depression and the Huanghekou Depression, and the contact relationship between the source rocks and the Bozhong 26-6 buried hill is different.therefore, this leads to differences in reservoir formation patterns and fluid phase states between different blocks in Bozhong 26-6.The above understanding and inspiration are of great significance for enriching the rules of buried hill oil and gas accumulation and guiding oil and gas exploration.
Bozhong 26-6 Oilfield is located in the west section of Bonan Low Uplift, Bozhong Depression, Bohai Bay Basin.It is an another buried hill oil field newly discovered in Bohai Sea area with 100 million ton reserves after the exploration breakthrough of Bozhong 19-6 buried hill condensate gas field, is also the largest oil and gas discovery in China's offshore waters in recent years. In response to solve unclear reservoir formation laws in the research area, especially the unclear source and accumulation process of oil and gas, this paper comprehensively uses the methods of crude oil physical property analysis, biomarkers, inclusion Petrography, homogenization temperature-paleosalinity and hydrocarbon generation simulation of source rocks, a systematic analysis was conducted, the results have shown that: (1) Bozhong 26-6 structure has different oil and gas sources, the characteristics of biomarker compounds indicate that crude oil mainly comes from the third member of the Shahejie Formation in the Huanghekou sag, however, condensate gas mainly comes from the third member of the Shahejie Formation in the southern subsag of the Bozhong Depression; (2) The Bozhong 26-6 oilfield has gone through three stages of oil and gas injection: early normal mature crude oil, middle condensate oil and gas (natural gas), and late light oil, The large scale of fluid filling in the middle and late stages plays a decisive role in the formation of reservoirs in the Bozhong 26-6 oilfield; (3)There are differences in hydrocarbon generation evolution between the source rocks in the Small sub depression in the southern part of Bozhong Depression and the Huanghekou Depression, and the contact relationship between the source rocks and the Bozhong 26-6 buried hill is different.therefore, this leads to differences in reservoir formation patterns and fluid phase states between different blocks in Bozhong 26-6.The above understanding and inspiration are of great significance for enriching the rules of buried hill oil and gas accumulation and guiding oil and gas exploration.
2025, 50(2): 494-503.
doi: 10.3799/dqkx.2024.050
Abstract:
Drilling of carbonate buried hills in the Lower Paleozoic in the western Bohai Sea has confirmed that finding thick and high-quality reservoirs is the key to buried hill exploration. According to drilling, there are great differences in the characteristics and distribution of the Lower Paleozoic reservoirs, which reflects the essential differences in the genesis of the reservoirs. Based on the analysis of fault development and tectonic evolution, two types of carbonate buried hills in the western Bohai Sea, denudation residual hill type and denudation fault block type, are established for the first time in this paper. The results show that the residual hill type buried hills form karst reservoirs. The more developed the karst paleo-water system is under the control of micro-paleomorphology, the greater the degree of development of karst reservoirs, and the development pattern of dendritic reservoirs is formed; Fault-block buried hills form fracture-melt reservoirs. In the multi-phase tectonic stress superposition area, effective fractures are more developed and the reservoir thickness is larger, forming a fractured reservoir development model. Identifying the different genesis and patterns of carbonate reservoirs of different buried hill types in the western Bohai Sea has certain guiding significance for the next step of hydrocarbon exploration in carbonate rock areas.
Drilling of carbonate buried hills in the Lower Paleozoic in the western Bohai Sea has confirmed that finding thick and high-quality reservoirs is the key to buried hill exploration. According to drilling, there are great differences in the characteristics and distribution of the Lower Paleozoic reservoirs, which reflects the essential differences in the genesis of the reservoirs. Based on the analysis of fault development and tectonic evolution, two types of carbonate buried hills in the western Bohai Sea, denudation residual hill type and denudation fault block type, are established for the first time in this paper. The results show that the residual hill type buried hills form karst reservoirs. The more developed the karst paleo-water system is under the control of micro-paleomorphology, the greater the degree of development of karst reservoirs, and the development pattern of dendritic reservoirs is formed; Fault-block buried hills form fracture-melt reservoirs. In the multi-phase tectonic stress superposition area, effective fractures are more developed and the reservoir thickness is larger, forming a fractured reservoir development model. Identifying the different genesis and patterns of carbonate reservoirs of different buried hill types in the western Bohai Sea has certain guiding significance for the next step of hydrocarbon exploration in carbonate rock areas.
2025, 50(2): 504-520.
doi: 10.3799/dqkx.2023.104
Abstract:
Bozhong A condensate gas field is a typical large Archean metamorphic buried hill gas field. Its reservoir lithology is mainly composed of gneiss, metamorphic monzogranite, metamorphic granodiorite and cataclastic monzogranite. The reservoir space is dominated by fracture⁃pore and pore⁃fracture combination types. Vertically, the buried hill is divided into semi⁃weathered zone and buried hill interior. The semi⁃weathered zone is generally developed with network fractures and intragranular dissolution pores, forming a massive reservoir with good reservoir guality. The buried hill interior is highly heterogeneous, and the reservoir guality is worse than that of the semi⁃weathered zone; Fracture system are both effective reservoir space and good seepage channel. The fracture is relatively rich near the major fracture. The reservoir space of porous reservoirs is mainly intergranular pores and dissolution pores, which are mainly developed at the top of the buried hill or near the fault inside the buried hill; The physical properties of the reservoir and the distribution of its dissolution pores in the semi⁃weathered zone are closely related to the faults; The density and opening of the fractures have an important impact on the open flow and production of the gas well.
Bozhong A condensate gas field is a typical large Archean metamorphic buried hill gas field. Its reservoir lithology is mainly composed of gneiss, metamorphic monzogranite, metamorphic granodiorite and cataclastic monzogranite. The reservoir space is dominated by fracture⁃pore and pore⁃fracture combination types. Vertically, the buried hill is divided into semi⁃weathered zone and buried hill interior. The semi⁃weathered zone is generally developed with network fractures and intragranular dissolution pores, forming a massive reservoir with good reservoir guality. The buried hill interior is highly heterogeneous, and the reservoir guality is worse than that of the semi⁃weathered zone; Fracture system are both effective reservoir space and good seepage channel. The fracture is relatively rich near the major fracture. The reservoir space of porous reservoirs is mainly intergranular pores and dissolution pores, which are mainly developed at the top of the buried hill or near the fault inside the buried hill; The physical properties of the reservoir and the distribution of its dissolution pores in the semi⁃weathered zone are closely related to the faults; The density and opening of the fractures have an important impact on the open flow and production of the gas well.
2025, 50(2): 521-534.
doi: 10.3799/dqkx.2023.175
Abstract:
Igneous buried⁃hill oil and gas reservoir has become a new field for increasing reserves and production, which has broad exploration and development prospects. The burial⁃hill gas reservoir in Qiongdongnan Basin is affected by multi⁃stage magma intrusion, the rock structure is complex and varied, the reservoir space distribution is highly heterogeneous, and it is difficult to identify fractures by logging curves.In view of the difficult problem of identifying fractures in igneous rock buried hill logging, the fracture characteristics and logging response rules are analyzed by using the data of core, thin section, imaging logging and conventional logging. The classical rock elastic parameter calculation model is used to establish the rock mechanics section, and the rock mechanics layer is divided according to the difference of the longitudinal mechanical properties of the well section. The rock mechanics evaluation model reflecting rock stability is introduced, and the fractal dimension principle of curve fluctuation is adopted to identify the fractures in buried hills of igneous rocks by the constraint of mechanical layer division to eliminate the interference of lithology change. The results show that the development of fractures in buriedhill has obvious lithology selection bias, and the fractures developed in monzonitic granite have the largest opening degree and retain more open fractures. The change of rock properties is easy to cause the difference of fracture distribution, which leads to the change of density and wave velocity. The cross analysis of the ratio of P⁃wave to S⁃wave time difference and photoelectric absorption cross section can distinguish most of the more developed cracks and most of the more developed fractures to the greatest extent. On the basis of mechanical interval division, segmented identification of natural fractures can improve the identification effect of buried hill fractures, and the identification coincidence rate is 85% with that of dissolution fractures + high conductivity fractures in imaging logging, which can meet the research needs and provide guidance for the effective development of buried hill gas reservoirs.
Igneous buried⁃hill oil and gas reservoir has become a new field for increasing reserves and production, which has broad exploration and development prospects. The burial⁃hill gas reservoir in Qiongdongnan Basin is affected by multi⁃stage magma intrusion, the rock structure is complex and varied, the reservoir space distribution is highly heterogeneous, and it is difficult to identify fractures by logging curves.In view of the difficult problem of identifying fractures in igneous rock buried hill logging, the fracture characteristics and logging response rules are analyzed by using the data of core, thin section, imaging logging and conventional logging. The classical rock elastic parameter calculation model is used to establish the rock mechanics section, and the rock mechanics layer is divided according to the difference of the longitudinal mechanical properties of the well section. The rock mechanics evaluation model reflecting rock stability is introduced, and the fractal dimension principle of curve fluctuation is adopted to identify the fractures in buried hills of igneous rocks by the constraint of mechanical layer division to eliminate the interference of lithology change. The results show that the development of fractures in buriedhill has obvious lithology selection bias, and the fractures developed in monzonitic granite have the largest opening degree and retain more open fractures. The change of rock properties is easy to cause the difference of fracture distribution, which leads to the change of density and wave velocity. The cross analysis of the ratio of P⁃wave to S⁃wave time difference and photoelectric absorption cross section can distinguish most of the more developed cracks and most of the more developed fractures to the greatest extent. On the basis of mechanical interval division, segmented identification of natural fractures can improve the identification effect of buried hill fractures, and the identification coincidence rate is 85% with that of dissolution fractures + high conductivity fractures in imaging logging, which can meet the research needs and provide guidance for the effective development of buried hill gas reservoirs.
2025, 50(2): 535-550.
doi: 10.3799/dqkx.2023.207
Abstract:
High⁃resolution seabed multibeam bathymetric data is widely used in marine research and resource exploration, as marine surveying and seafloor mapping and exploration. The multibeam echo⁃sounder system is disturbed by the complexity of sea condition, ocean noise and other factors, which seriously affect the data quality. Removing various anomalies in the multibeam bathymetric data can recover the real seabed topography and it will be greatly useful for study and interpretation of the fine submarine geomorphological features. Based on the EM122 multibeam echo⁃sounder system who hull⁃mounded at the vessel "Dongfanghong 3", the high⁃resolution bathymetric data have been acquired in the northern continental margin of the South China Sea in recent years. We identify and find five types of bathymetric outlier data by fine process and analysis of the bathymetric data in this study. Based on the geometric forms of the anomaly in the topographic map and the discrete characteristics of the anomaly points in the two⁃dimensional bathymetric point cloud data, we interpret and name the topography fold anomaly, the point anomaly, the linear anomaly, the radial anomaly and the blank anomaly, respectively. Using different filtering methods, the five types of bathymetric outlier data in the multibeam bathymetric data are well removed and processed. The linear anomaly is processed well by swath filtering or subset filtering, the point anomaly and the radial anomaly are removed by the common subset filtering. The topography fold anomaly is corrected by the refraction editor and the blank area anomaly is resolved by interpolation method. By the manually filtering to the acquired bathymetric data, the outlier data are well removed and corrected. These post⁃processed bathymetric data are able to greatly support the further interpretation and analysis of seafloor geomorphological features.
High⁃resolution seabed multibeam bathymetric data is widely used in marine research and resource exploration, as marine surveying and seafloor mapping and exploration. The multibeam echo⁃sounder system is disturbed by the complexity of sea condition, ocean noise and other factors, which seriously affect the data quality. Removing various anomalies in the multibeam bathymetric data can recover the real seabed topography and it will be greatly useful for study and interpretation of the fine submarine geomorphological features. Based on the EM122 multibeam echo⁃sounder system who hull⁃mounded at the vessel "Dongfanghong 3", the high⁃resolution bathymetric data have been acquired in the northern continental margin of the South China Sea in recent years. We identify and find five types of bathymetric outlier data by fine process and analysis of the bathymetric data in this study. Based on the geometric forms of the anomaly in the topographic map and the discrete characteristics of the anomaly points in the two⁃dimensional bathymetric point cloud data, we interpret and name the topography fold anomaly, the point anomaly, the linear anomaly, the radial anomaly and the blank anomaly, respectively. Using different filtering methods, the five types of bathymetric outlier data in the multibeam bathymetric data are well removed and processed. The linear anomaly is processed well by swath filtering or subset filtering, the point anomaly and the radial anomaly are removed by the common subset filtering. The topography fold anomaly is corrected by the refraction editor and the blank area anomaly is resolved by interpolation method. By the manually filtering to the acquired bathymetric data, the outlier data are well removed and corrected. These post⁃processed bathymetric data are able to greatly support the further interpretation and analysis of seafloor geomorphological features.
2025, 50(2): 551-568.
doi: 10.3799/dqkx.2023.195
Abstract:
Triaxial compaction test, Brazilian test, and triaxial shear test were conducted to characterize the rock mechanical parameters of buried⁃hill reservoirs in the metamorphic rocks of Bozhong 19⁃6 gas field in Bohai Bay Basin and to provide reliable basic data for subsequent numerical simulation of ground stress field and reservoir fractures in this region. Single⁃well dynamic rock mechanical parameters were computed using array acoustic curves, and the single⁃well distributions of static rock mechanical parameters were determined via dynamic⁃static calibration; Prestack seismic multiattribute detection was adopted to deterministically inverse 3D heterogeneous rock mechanical fields and clarify the spatial distribution of rock mechanical parameters. On this basis, physical property test, whole⁃rock mineral analysis and mercury intrusion testing data were used to analyze the main control factors on the rock mechanical parameters. Then the fracture development index and lithological identification charts were built using static rock mechanical parameters. It was found the metamorphic buried⁃hill reservoirs in Bozhong 19⁃6 gas field of Bohai Bay Basin had Young's modulus within 20 to 60 GPa, Poisson's ratio within 0.15 to 0.25, tensile strength within 5 to 15 MPa, and internal friction angle within 30° to 50°. The horizontal distributions of the rock mechanical parameters were highly heterogeneous, and their vertical distributions were mainly related to tectonic properties and the weathering effect, and reflected the physical properties of reservoirs to some extent. Reservoir physical properties, concentrations of different minerals, and pore radius were the main controlling factors of the rock mechanical parameters. The metamorphic buried⁃hill reservoirs were featured by well⁃developed fractures, and complex lithology, and the reservoir fractures and lithology cannot be accurately identified using routine methods. In comparison, the fracture development index, and lithological identification charts built on basis of static rock mechanical parameters are significant in guiding the evaluation of fracture development degree and complex lithologic division in metamorphic buried⁃hill reservoirs.
Triaxial compaction test, Brazilian test, and triaxial shear test were conducted to characterize the rock mechanical parameters of buried⁃hill reservoirs in the metamorphic rocks of Bozhong 19⁃6 gas field in Bohai Bay Basin and to provide reliable basic data for subsequent numerical simulation of ground stress field and reservoir fractures in this region. Single⁃well dynamic rock mechanical parameters were computed using array acoustic curves, and the single⁃well distributions of static rock mechanical parameters were determined via dynamic⁃static calibration; Prestack seismic multiattribute detection was adopted to deterministically inverse 3D heterogeneous rock mechanical fields and clarify the spatial distribution of rock mechanical parameters. On this basis, physical property test, whole⁃rock mineral analysis and mercury intrusion testing data were used to analyze the main control factors on the rock mechanical parameters. Then the fracture development index and lithological identification charts were built using static rock mechanical parameters. It was found the metamorphic buried⁃hill reservoirs in Bozhong 19⁃6 gas field of Bohai Bay Basin had Young's modulus within 20 to 60 GPa, Poisson's ratio within 0.15 to 0.25, tensile strength within 5 to 15 MPa, and internal friction angle within 30° to 50°. The horizontal distributions of the rock mechanical parameters were highly heterogeneous, and their vertical distributions were mainly related to tectonic properties and the weathering effect, and reflected the physical properties of reservoirs to some extent. Reservoir physical properties, concentrations of different minerals, and pore radius were the main controlling factors of the rock mechanical parameters. The metamorphic buried⁃hill reservoirs were featured by well⁃developed fractures, and complex lithology, and the reservoir fractures and lithology cannot be accurately identified using routine methods. In comparison, the fracture development index, and lithological identification charts built on basis of static rock mechanical parameters are significant in guiding the evaluation of fracture development degree and complex lithologic division in metamorphic buried⁃hill reservoirs.
2025, 50(2): 466-477.
doi: 10.3799/dqkx.2024.004
Abstract:
The paper aims to analysis the accommodation feature, basin boundaries and basement properties of the Taiwan forearc basin, and probe into the sequence basic configuration, main controlling factors and evolution stage of the Taiwan forearc basin. Based on the orogenic events, such as the initial and normal subduction of the South China Sea Plate, slabs under plating, accretion, exhumation, uplift and denudation of the accretionary prism and the series of volcanic activities of the North Luzon Island Arc, combined with the sequence configuration analysis of the seismic profiles, this paper will study the basin character, boundary nature and evolutionary stages of the Taiwan forearc basin in more depth. The evolution history of Taiwan forearc basin can be divided into three stages: "rectangular rift basin in the spreading period", "wedge-shaped forearc basin in the initial collision period" and "sheet (residual) forearc basin stage in the arc-continental collision period". The initially eastern boundary of the rectangular rift basin is the South China Sea oceanic crust and later the North Luzon Island Arc, the western boundary is the Philippine Sea oceanic crust, and the basement is forearc split mantle. The eastern and western boundaries of the wedge-shaped forearc basin are the North Luzon Arc and the subducted South China Sea Plate margin which is thickened by the under platings labs respectively, and part of the north Luzon Island Arc gradually evolved into the basement of the forearc basin. The eastern boundary of the deformed residual forearc basin is the North Luzon Island Arc, and the western boundary is the Taiwan accretionary wedge that has been exhumed and continuously uplifted this period.
The paper aims to analysis the accommodation feature, basin boundaries and basement properties of the Taiwan forearc basin, and probe into the sequence basic configuration, main controlling factors and evolution stage of the Taiwan forearc basin. Based on the orogenic events, such as the initial and normal subduction of the South China Sea Plate, slabs under plating, accretion, exhumation, uplift and denudation of the accretionary prism and the series of volcanic activities of the North Luzon Island Arc, combined with the sequence configuration analysis of the seismic profiles, this paper will study the basin character, boundary nature and evolutionary stages of the Taiwan forearc basin in more depth. The evolution history of Taiwan forearc basin can be divided into three stages: "rectangular rift basin in the spreading period", "wedge-shaped forearc basin in the initial collision period" and "sheet (residual) forearc basin stage in the arc-continental collision period". The initially eastern boundary of the rectangular rift basin is the South China Sea oceanic crust and later the North Luzon Island Arc, the western boundary is the Philippine Sea oceanic crust, and the basement is forearc split mantle. The eastern and western boundaries of the wedge-shaped forearc basin are the North Luzon Arc and the subducted South China Sea Plate margin which is thickened by the under platings labs respectively, and part of the north Luzon Island Arc gradually evolved into the basement of the forearc basin. The eastern boundary of the deformed residual forearc basin is the North Luzon Island Arc, and the western boundary is the Taiwan accretionary wedge that has been exhumed and continuously uplifted this period.
2025, 50(2): 752-762.
doi: 10.3799/dqkx.2024.011
Abstract:
Glacial debris flows occur frequently in the Rangdaqu River Basin, posing a serious threat to local safety. Reconstructing the eruption history, flow range, and causes of debris flows can provide disaster prevention and mitigation parameters for engineering construction. Based on the cambial injury tissue and growth inhibition response of trees, this study provides a new calculation method for the evaluation threshold of growth inhibition in tree rings and the Wit index of debrisflow identification in tree rings, and reconstructs the outbreak time and flow range of debris flows from 1890 to 2021. The results show that: (1) the threshold for growth inhibition in the active zone of glaciers has been revised to 25%; (2) the calculation of the Wit index needs to exclude growth release factors, and the use of traumatic tissue and growth inhibition in tree rings can improve the accuracy of dating debris flow events.
Glacial debris flows occur frequently in the Rangdaqu River Basin, posing a serious threat to local safety. Reconstructing the eruption history, flow range, and causes of debris flows can provide disaster prevention and mitigation parameters for engineering construction. Based on the cambial injury tissue and growth inhibition response of trees, this study provides a new calculation method for the evaluation threshold of growth inhibition in tree rings and the Wit index of debrisflow identification in tree rings, and reconstructs the outbreak time and flow range of debris flows from 1890 to 2021. The results show that: (1) the threshold for growth inhibition in the active zone of glaciers has been revised to 25%; (2) the calculation of the Wit index needs to exclude growth release factors, and the use of traumatic tissue and growth inhibition in tree rings can improve the accuracy of dating debris flow events.
2025, 50(2): 763-781.
doi: 10.3799/dqkx.2022.384
Abstract:
Terrestrial heat flow is an important parameter to characterize the heat transfer from the earth's interior to the surface. The distribution of terrestrial heat flow is the basic work in geothermal research. The data quality of terrestrial heat flow varies greatly and the spatial distribution of heat flow data in China is uneven. The scientific prediction of continental heat flow is an essential basis for the development of continental heat flow and related research. Based on the relationship between geologic age and heat flow, this paper uses geographic information system (GIS) technology to define heat flow values in different geological regions by using digital geological map of the Chinacontinentalarea, and assigns statistical values to geologic age with large heat flow dispersion combined with tectonic subdivision, so that heat flow prediction is more in line with Chinese tectonic-thermal background. Heat flow prediction is based on 1×1 degree equal longitude grid to restrict the influence range of heat flow in grid cell. The predicted mean value of terrestrial heat flow in China continental area is 63.54 mW/m2, and the median value is 62.32 mW/m2, with small discreteness of heat flow distribution. The prediction results in this paper are close to the tectonic-thermal background in China, which provides a scientific basis for the prediction of heat flow in the blank area of heat flow data.
Terrestrial heat flow is an important parameter to characterize the heat transfer from the earth's interior to the surface. The distribution of terrestrial heat flow is the basic work in geothermal research. The data quality of terrestrial heat flow varies greatly and the spatial distribution of heat flow data in China is uneven. The scientific prediction of continental heat flow is an essential basis for the development of continental heat flow and related research. Based on the relationship between geologic age and heat flow, this paper uses geographic information system (GIS) technology to define heat flow values in different geological regions by using digital geological map of the Chinacontinentalarea, and assigns statistical values to geologic age with large heat flow dispersion combined with tectonic subdivision, so that heat flow prediction is more in line with Chinese tectonic-thermal background. Heat flow prediction is based on 1×1 degree equal longitude grid to restrict the influence range of heat flow in grid cell. The predicted mean value of terrestrial heat flow in China continental area is 63.54 mW/m2, and the median value is 62.32 mW/m2, with small discreteness of heat flow distribution. The prediction results in this paper are close to the tectonic-thermal background in China, which provides a scientific basis for the prediction of heat flow in the blank area of heat flow data.
2025, 50(2): 782-797.
doi: 10.3799/dqkx.2023.050
Abstract:
Quantitative research of geomorphic evolution is of great significance to further study the theorical research and multi-disciplinary integration of Danxia landscape. Geomorphic indices, which play an important role on evaluating regional tectonic activity and geomorphic evolution as well as quantitatively indicating landscape maturity, are advantageous to understand the evolution process and controlling factors of Danxia landscape. Therefore, in this study, the Mount Danxiashan, located in Shaoguan, Guangdong Province, was taken as study area, and suitable moving window sizes as well as three geomorphic which are Hypsometric Integral (HI), Surface Roughness (SR) and Surface Index (SI) were calculated based on the open-source TecDEM toolbox. The 900 meters was chosen as moving window size for calculating geomorphic indices. The HI values distribution of Danxia Formation concentrates in 0.22 to 0.47, as well as the ones of SR values and SI values concentrate in 1.04 to 1.14 and -0.37 to -0.11, respectively. There is an apparent negative correlation between SR values and SI values, and high SR values with low SI values usually distribute around Danxia redcliff landscape. The relatively high landscape maturity indicated by this study is compatible with scholars' views about the evolution stage of Mount Danxiashan. The quantitative relation between geomorphic indices and fault activities, lithology and fluvial erosion shows that HI and SR values decrease with the increasing distance from faults. The HI values of Jinshiyan Member concentrates in 0.29to 0.48, which is the highest of ones in Danxia Formation, in contrast to relatively low values of Bazhai Member and Baizhaiding Member. Moreover, the relatively high HI values (> 0.24) appears in Baizhaiding Member while the relatively low HI values appears in Bazhai Member located on sides of stream, indicating distinct lateral erosion with the combined action of tectonic condition and fluvial process.
Quantitative research of geomorphic evolution is of great significance to further study the theorical research and multi-disciplinary integration of Danxia landscape. Geomorphic indices, which play an important role on evaluating regional tectonic activity and geomorphic evolution as well as quantitatively indicating landscape maturity, are advantageous to understand the evolution process and controlling factors of Danxia landscape. Therefore, in this study, the Mount Danxiashan, located in Shaoguan, Guangdong Province, was taken as study area, and suitable moving window sizes as well as three geomorphic which are Hypsometric Integral (HI), Surface Roughness (SR) and Surface Index (SI) were calculated based on the open-source TecDEM toolbox. The 900 meters was chosen as moving window size for calculating geomorphic indices. The HI values distribution of Danxia Formation concentrates in 0.22 to 0.47, as well as the ones of SR values and SI values concentrate in 1.04 to 1.14 and -0.37 to -0.11, respectively. There is an apparent negative correlation between SR values and SI values, and high SR values with low SI values usually distribute around Danxia redcliff landscape. The relatively high landscape maturity indicated by this study is compatible with scholars' views about the evolution stage of Mount Danxiashan. The quantitative relation between geomorphic indices and fault activities, lithology and fluvial erosion shows that HI and SR values decrease with the increasing distance from faults. The HI values of Jinshiyan Member concentrates in 0.29to 0.48, which is the highest of ones in Danxia Formation, in contrast to relatively low values of Bazhai Member and Baizhaiding Member. Moreover, the relatively high HI values (> 0.24) appears in Baizhaiding Member while the relatively low HI values appears in Bazhai Member located on sides of stream, indicating distinct lateral erosion with the combined action of tectonic condition and fluvial process.
2025, 50(2): 798-804.
doi: 10.3799/dqkx.2025.009
Abstract:
On January 7, 2025, a magnitude MS6.8 earthquake occurred in Dingri County, Shigatse City, Xizang, China, causing severe damage near the epicenter. The affected area is located on a plateau at over 4, 000 meters above sea level, where seismic stations are sparsely distributed. There is a lack of comprehensive reference data or basic seismic records within a 100 km radius, which are essential for quickly assessing the extent of earthquake damage and guiding post-earthquake reconstruction efforts. The high mountain region affected by this earthquake is mostly covered with permanent glaciers, such as those on Mount Everest, and contains numerous potential landslide sites. Studying the impact of earthquakes on the stability of glaciers and landslides is an important scientific concern. Given this context, this article focuses on an MS3.9 small earthquake recorded at the XZ-ZHF seismic station, located 55 km from the epicenter. Using the empirical Green's function method, the study considers parameter uncertainty to synthesize the acceleration waveform of the earthquake at this station. The research results indicate that the horizontal peak ground acceleration (PGA) at Zhufeng seismic station ranged from 70 to 190 cm/s2, while the vertical PGA ranged from 40 to 140 cm/s2. This corresponds to an instrument seismic intensity of Ⅵ-Ⅶ. These findings reflect the seismic intensity at the Zhufeng Seismic Station. When compared with the seismic response spectra of various probability levels in the fifth-generation Seismic ground motion parameters zonation map of China, and taking into account the structural integrity of local buildings, it is analyzed that the seismic intensity could cause more severe damage to general civil structures near the Zhufeng seismic station. Furthermore, it is expected that the earthquake damage near the epicenter is likely to be even more severe. Additionally, the earthquake may have implications for the stability of high-altitude glaciers and potential landslide bodies, and it is recommended that special attention be paid to these issues.
On January 7, 2025, a magnitude MS6.8 earthquake occurred in Dingri County, Shigatse City, Xizang, China, causing severe damage near the epicenter. The affected area is located on a plateau at over 4, 000 meters above sea level, where seismic stations are sparsely distributed. There is a lack of comprehensive reference data or basic seismic records within a 100 km radius, which are essential for quickly assessing the extent of earthquake damage and guiding post-earthquake reconstruction efforts. The high mountain region affected by this earthquake is mostly covered with permanent glaciers, such as those on Mount Everest, and contains numerous potential landslide sites. Studying the impact of earthquakes on the stability of glaciers and landslides is an important scientific concern. Given this context, this article focuses on an MS3.9 small earthquake recorded at the XZ-ZHF seismic station, located 55 km from the epicenter. Using the empirical Green's function method, the study considers parameter uncertainty to synthesize the acceleration waveform of the earthquake at this station. The research results indicate that the horizontal peak ground acceleration (PGA) at Zhufeng seismic station ranged from 70 to 190 cm/s2, while the vertical PGA ranged from 40 to 140 cm/s2. This corresponds to an instrument seismic intensity of Ⅵ-Ⅶ. These findings reflect the seismic intensity at the Zhufeng Seismic Station. When compared with the seismic response spectra of various probability levels in the fifth-generation Seismic ground motion parameters zonation map of China, and taking into account the structural integrity of local buildings, it is analyzed that the seismic intensity could cause more severe damage to general civil structures near the Zhufeng seismic station. Furthermore, it is expected that the earthquake damage near the epicenter is likely to be even more severe. Additionally, the earthquake may have implications for the stability of high-altitude glaciers and potential landslide bodies, and it is recommended that special attention be paid to these issues.
2025, 50(2): 569-584.
doi: 10.3799/dqkx.2024.103
Abstract:
CO2 mineralization storage in basaltis a new CCUS technique that enables the sequestration of CO2 in basaltic areas for carbon reduction. The Leizhou Peninsula in the Guangdong Province of South China boasts a vast area covered by basalt, exceeding 3 000 km2.The basaltic formations on the Leizhou Peninsula consist primarily of tholeiite and alkali olivine basalts, making it a promising candidate for CO2 mineralization storage. This paper analyzed the geological and hydrological conditions of the Leizhou Peninsular and pointed out that the Carbfix technology, which allows safe storage of CO2 without caprocks, is applicable to the area, However, the basalts in the peninsular are mostly shallowly buried, and only volcanic crater basalts and deeply buried Tertiary basalts might meet the minimum depth requirements of the Carbfix technology. Currently, Xuwun County's Tianyang Quaternary caldera basalts and the Yongshi Farmland's Tertiary basalts have been identified as potential pilot project sites. The geological and hydrological conditions at these two sites are reviewed, and favorable and unfavorable factors and potential for CO2 storage are analyzed. The primary challenges currently faced are to investigate the safety issues of large⁃quantity water injection into the caldera basalts, and to detect the deep basal interface and lateral extension of the basalts. Additionally, the potential impacts of injected CO2⁃changed water on underground water resources need to be monitored and investigated. The article proposes to develop techniques of storing CO2 in shallower (e.g. < 150 m) basalts, and suggests to conduct necessary experiments at a shore site to explore the feasibility and techniques of using seawater for basalt CO2 storage. These actions will benefit not only expanding the potential of basalt mineralization storage on the Leizhou Peninsula, but also contributing to the study of utilizing global submarine basaltic carbon storage resources.
CO2 mineralization storage in basaltis a new CCUS technique that enables the sequestration of CO2 in basaltic areas for carbon reduction. The Leizhou Peninsula in the Guangdong Province of South China boasts a vast area covered by basalt, exceeding 3 000 km2.The basaltic formations on the Leizhou Peninsula consist primarily of tholeiite and alkali olivine basalts, making it a promising candidate for CO2 mineralization storage. This paper analyzed the geological and hydrological conditions of the Leizhou Peninsular and pointed out that the Carbfix technology, which allows safe storage of CO2 without caprocks, is applicable to the area, However, the basalts in the peninsular are mostly shallowly buried, and only volcanic crater basalts and deeply buried Tertiary basalts might meet the minimum depth requirements of the Carbfix technology. Currently, Xuwun County's Tianyang Quaternary caldera basalts and the Yongshi Farmland's Tertiary basalts have been identified as potential pilot project sites. The geological and hydrological conditions at these two sites are reviewed, and favorable and unfavorable factors and potential for CO2 storage are analyzed. The primary challenges currently faced are to investigate the safety issues of large⁃quantity water injection into the caldera basalts, and to detect the deep basal interface and lateral extension of the basalts. Additionally, the potential impacts of injected CO2⁃changed water on underground water resources need to be monitored and investigated. The article proposes to develop techniques of storing CO2 in shallower (e.g. < 150 m) basalts, and suggests to conduct necessary experiments at a shore site to explore the feasibility and techniques of using seawater for basalt CO2 storage. These actions will benefit not only expanding the potential of basalt mineralization storage on the Leizhou Peninsula, but also contributing to the study of utilizing global submarine basaltic carbon storage resources.
2025, 50(2): 585-595.
doi: 10.3799/dqkx.2024.045
Abstract:
Xinjiang is an important lithium province in China. The ever-known deposits are dominated by pegmatite and brine type. Recently, a clay-type lithium deposit has been discovered in the Ertanggou area, East Tianshan. In order to determine the occurrence of lithium in the Ertanggou deposit, we carried out detailed deposit geology, whole-rock chemical composition, X-ray diffraction, automatic mineral Quantitative analysis (TIMA), electron probe microanalysis (EPMA), LA-ICPMS trace element analysis as well as soaking immersion experiments. The results show that, the lithium orebodies are mainly hosted by bioclasts-rich carbonate rocks of the Upper Carboniferous Qijiagou Formation. The ore mainly consists of calcite, quartz and sepiolite, with Li2O content of 0.10% to 0.27%. Sepiolite is the main Li-bearing phase (with Li content up to 9 519×10-6), and there is a good positive relationship between Li and F. Collectively, we propose that the Ertanggou deposit is the first clay-type lithium deposit discovered in Xinjiang. The occurrence of lithium in Ertanggou is significantly different from other clay-type deposits.It has important value of scientific research and practical significance of prospecting.
Xinjiang is an important lithium province in China. The ever-known deposits are dominated by pegmatite and brine type. Recently, a clay-type lithium deposit has been discovered in the Ertanggou area, East Tianshan. In order to determine the occurrence of lithium in the Ertanggou deposit, we carried out detailed deposit geology, whole-rock chemical composition, X-ray diffraction, automatic mineral Quantitative analysis (TIMA), electron probe microanalysis (EPMA), LA-ICPMS trace element analysis as well as soaking immersion experiments. The results show that, the lithium orebodies are mainly hosted by bioclasts-rich carbonate rocks of the Upper Carboniferous Qijiagou Formation. The ore mainly consists of calcite, quartz and sepiolite, with Li2O content of 0.10% to 0.27%. Sepiolite is the main Li-bearing phase (with Li content up to 9 519×10-6), and there is a good positive relationship between Li and F. Collectively, we propose that the Ertanggou deposit is the first clay-type lithium deposit discovered in Xinjiang. The occurrence of lithium in Ertanggou is significantly different from other clay-type deposits.It has important value of scientific research and practical significance of prospecting.
2025, 50(2): 596-608.
doi: 10.3799/dqkx.2023.203
Abstract:
In the purpose of understanding formation time and physical-chemical conditions of skarn in Chengmenshan Cu deposit of northwestern Jiangxi Province, we use garnet to do U-Pb isotopic dating, EPMA major elements analyze and LA-ICPMS trace elements analyze, combined with TIMA automated mineral analyze, the skarn forming age of 146.2±1.1 Ma is acquired, and the mineral composition is mainly garnet (Andradite with And value average 95%), LREE elements are enriched and HREE elements are depleted, and Eu show obviously positive anomalies. Therefore we conclude that Chengmenshan Cu deposit own two times of skarn forming respectively corresponding to the formation of granodiorite porphyry and quartz porphyry. Strong oxidized, acidic, high salinity and advective metasomatism conditions are the environment of skarn forming, and magmatic fluids is the major source of these skarns. The physical-chemical conditions like fO2, pH, Cl- concentration varied systematically with the change of W/R ratio during the formation process of Chengmenshan skarns.
In the purpose of understanding formation time and physical-chemical conditions of skarn in Chengmenshan Cu deposit of northwestern Jiangxi Province, we use garnet to do U-Pb isotopic dating, EPMA major elements analyze and LA-ICPMS trace elements analyze, combined with TIMA automated mineral analyze, the skarn forming age of 146.2±1.1 Ma is acquired, and the mineral composition is mainly garnet (Andradite with And value average 95%), LREE elements are enriched and HREE elements are depleted, and Eu show obviously positive anomalies. Therefore we conclude that Chengmenshan Cu deposit own two times of skarn forming respectively corresponding to the formation of granodiorite porphyry and quartz porphyry. Strong oxidized, acidic, high salinity and advective metasomatism conditions are the environment of skarn forming, and magmatic fluids is the major source of these skarns. The physical-chemical conditions like fO2, pH, Cl- concentration varied systematically with the change of W/R ratio during the formation process of Chengmenshan skarns.
2025, 50(2): 609-620.
doi: 10.3799/dqkx.2025.005
Abstract:
In order to thoroughly investigate the tectonic evolution, magmatic activities, and their effects on mineral resource formation during the Early Paleozoic and Early Mesozoic eras in South China, systematic field investigations were conducted in the Baimashan complex located in the central Hunan region. Additionally, zircon geochronological analysis, Hf isotope studies, and geochemical assessments were performed. Zircon LA-ICP-MS U-Pb dating illustrates that the weighted mean ages of the Shuiche mylonitized granite and the Longtan-Xiaoshajiang biotite granodiorite within the Baimashan granitic complex are 409±2 Ma and 211±1 Ma, respectively. These ages correspond to the Late Caledonian and Indosinian magmatic events, respectively. The Caledonian mylonitized granite is characterized by high silica, high alkali and strong peraluminosity, accompanied by a pronounced negative Eu anomaly. This, combined with its enriched Hf isotopic composition [εHf(t)=-13.4 to -5.4], indicates that it is likely a S-type granite formed through partial melting of Paleoproterozoic sedimentary rocks. In contrast, the Indosinian biotite granodiorite exhibits low-silica, high-alkalinity and aluminous, displaying a moderate Eu-negative anomaly with a relatively negative εHf(t) value (-10.3 to -7.4) and an ancient modal age (1.71 to 1.89 Ga). This granodiorite can be categorised as a Paleoproterozoic meta-igneous mixing of partially metasomatised sedimentary rocks remelted to form Ⅰ type granites. The Caledonian and Indosinian superunits of the Baimashan complex may have been formed in a tectonic environment of intra-plate orogeny. There is a strong genetic connection between the Caledonian rocks and the regional W mineralization, as well as between the Indosinian granitic rocks and the Au-Sb-W mineralization in the area. These rocks exhibit significant potential for Au-Sb-W mineralization.
In order to thoroughly investigate the tectonic evolution, magmatic activities, and their effects on mineral resource formation during the Early Paleozoic and Early Mesozoic eras in South China, systematic field investigations were conducted in the Baimashan complex located in the central Hunan region. Additionally, zircon geochronological analysis, Hf isotope studies, and geochemical assessments were performed. Zircon LA-ICP-MS U-Pb dating illustrates that the weighted mean ages of the Shuiche mylonitized granite and the Longtan-Xiaoshajiang biotite granodiorite within the Baimashan granitic complex are 409±2 Ma and 211±1 Ma, respectively. These ages correspond to the Late Caledonian and Indosinian magmatic events, respectively. The Caledonian mylonitized granite is characterized by high silica, high alkali and strong peraluminosity, accompanied by a pronounced negative Eu anomaly. This, combined with its enriched Hf isotopic composition [εHf(t)=-13.4 to -5.4], indicates that it is likely a S-type granite formed through partial melting of Paleoproterozoic sedimentary rocks. In contrast, the Indosinian biotite granodiorite exhibits low-silica, high-alkalinity and aluminous, displaying a moderate Eu-negative anomaly with a relatively negative εHf(t) value (-10.3 to -7.4) and an ancient modal age (1.71 to 1.89 Ga). This granodiorite can be categorised as a Paleoproterozoic meta-igneous mixing of partially metasomatised sedimentary rocks remelted to form Ⅰ type granites. The Caledonian and Indosinian superunits of the Baimashan complex may have been formed in a tectonic environment of intra-plate orogeny. There is a strong genetic connection between the Caledonian rocks and the regional W mineralization, as well as between the Indosinian granitic rocks and the Au-Sb-W mineralization in the area. These rocks exhibit significant potential for Au-Sb-W mineralization.
2025, 50(2): 621-638.
doi: 10.3799/dqkx.2024.017
Abstract:
In-situ U-Pb dating of garnet is a newly developed isotope dating method for low-U minerals recently, which has been widely used in skarn deposits study. In this paper, the LA-ICP-MS U-Pb age and trace element compositions of garnet are reported for the first time in the Tangge skarn-type copper-lead-zinc deposit in Xizang. Combining with the results of zircon U-Pb dating of quartz porphyry, this study investigates the timing of magmatism and related mineralization and the ore-forming processes of the Tangge deposit. The garnet U-Pb age is 65.5±3.9 Ma, and the zircon U-Pb age of quartz porphyry is 68.1±0.9 Ma. These ages indicate both the granitic rocks and mineralization of the Tangge deposit were formed at Late Cretaceous-Palaeocene. The rare earth distribution patterns of garnet show an enrichment in light rare earth elements and depleted in heavy rare earth elements in the Tangge deposit with a LREE/HREE ratio is 0.01 to 12.68.Thegarnet can be further divided into two stages (Grt Ⅰ and Grt Ⅱ). The different Eu anomalies and average U contents in Grt Ⅰ and Grt Ⅱ indicate that the oxygen fugacity increases at first and then decreases. The average contents of Hf and Ta in the core of the first-stage garnet(GrtI-1) (8.84×10-6 and 0.52×10-6) are higher than those in the rim (GrtI-2:1.60×10-6 and 0.23×10-6), and in the second-stage garnet (GrtII: 1.47×10-6 and 0.37×10-6), indicating that the metallogenic environment changes from a relatively closed system to an open and oscillating one. The ore-forming age of the skarn-type deposits in the syn-collisional Gangdese metallogenic belt is gradually getting older from east to west, which reveals the diachronous volcanic activity and reflects the characteristics of uneven collision between the Indian continent and the Asia continent. The Tangge deposit is a newly discovered syn-collisional skarn-type copper polymetallic deposit in the South Gangdese, which will provide a new direction for mineral prospecting in the Zhunuo ore concentration area and its surrounding areas, and even in the entire South Gangdese.
In-situ U-Pb dating of garnet is a newly developed isotope dating method for low-U minerals recently, which has been widely used in skarn deposits study. In this paper, the LA-ICP-MS U-Pb age and trace element compositions of garnet are reported for the first time in the Tangge skarn-type copper-lead-zinc deposit in Xizang. Combining with the results of zircon U-Pb dating of quartz porphyry, this study investigates the timing of magmatism and related mineralization and the ore-forming processes of the Tangge deposit. The garnet U-Pb age is 65.5±3.9 Ma, and the zircon U-Pb age of quartz porphyry is 68.1±0.9 Ma. These ages indicate both the granitic rocks and mineralization of the Tangge deposit were formed at Late Cretaceous-Palaeocene. The rare earth distribution patterns of garnet show an enrichment in light rare earth elements and depleted in heavy rare earth elements in the Tangge deposit with a LREE/HREE ratio is 0.01 to 12.68.Thegarnet can be further divided into two stages (Grt Ⅰ and Grt Ⅱ). The different Eu anomalies and average U contents in Grt Ⅰ and Grt Ⅱ indicate that the oxygen fugacity increases at first and then decreases. The average contents of Hf and Ta in the core of the first-stage garnet(GrtI-1) (8.84×10-6 and 0.52×10-6) are higher than those in the rim (GrtI-2:1.60×10-6 and 0.23×10-6), and in the second-stage garnet (GrtII: 1.47×10-6 and 0.37×10-6), indicating that the metallogenic environment changes from a relatively closed system to an open and oscillating one. The ore-forming age of the skarn-type deposits in the syn-collisional Gangdese metallogenic belt is gradually getting older from east to west, which reveals the diachronous volcanic activity and reflects the characteristics of uneven collision between the Indian continent and the Asia continent. The Tangge deposit is a newly discovered syn-collisional skarn-type copper polymetallic deposit in the South Gangdese, which will provide a new direction for mineral prospecting in the Zhunuo ore concentration area and its surrounding areas, and even in the entire South Gangdese.
2025, 50(2): 639-666.
doi: 10.3799/dqkx.2024.014
Abstract:
The Precambrian geological bodies in the orogenic belts are important for the division of tectonic units and also provide important information for understanding the amalgamation and fragmentation of early supercontinents. The understanding of their formation ages, distribution ranges, material compositions, etc. affects the view on the tectonics, evolution, and orogenic models of the different orogenic belts. It is the basis of many scientific issues and has important research values. However, due to structural deformation and replacement, it is difficult to differentiate some Phanerozoic and Precambrian geological bodies in ancient orogenic belts around the world. In addition, different research levels and testing methods in different periods have led to several changes in the classifications, nomenclatures, distribution ranges, and geotectonic attributes of some Precambrian geological bodies, affecting the understanding of the topics above. This study focuses on the Beishan Complex in the middle segment of the southern Central Asian Orogenic Belt (CAOB) to discuss the influence of the complicated and arbitrary classifications, divisions, and distribution of a Precambrian geological body on the tectonics and evolution of the orogenic belt. The Beishan Complex has long been regarded as the Precambrian basement of the microcontinents in the Beishan Orogenic Blet (BOB) in the middle section of the southern CAOB. In recent years, numerous advances have been made in its distribution ranges, ages, and basement affinities, which affect the tectonics and evolution of the BOB. This study reviews the classification history of the Beishan Complex, summarizes the previous views on the differences in the basement rocks between the southern and northern zones of the BOB, compares the Beishan Complex of the BOB with the Precambrian geological bodies of northern Alxa and the Central Tianshan blocks, and elaborates the understanding of the basement attribution of the tectonic units to which the Beishan Complex belongs. Based on the comprehensive comparison of rock assemblages, the Precambrian detrital zircon peak characteristics, magmatic event sequences, and zircon Hf isotope characteristics of the microcontinents in the middle section of the southern margin of the CAOB, it is considered that these microcontinents might experience a similar Precambrian evolution history. Integrated with previous data, it is proposed that these microcontinents may originate from the breakup of the Columbia Supercontinent, participate in the evolution of the Rodinia Supercontinent amalgamation, and finally break up into several microcontinent blocks. In view of the importance of geological bodies with Precambrian basement attributes and the various differences caused by the constantly changing connotation and distribution ranges, this paper calls for strengthening the research on the division and evolution of Precambrian geological bodies in the middle section of the southern CAOB and attaching importance to the compilation of regional geologic maps.
The Precambrian geological bodies in the orogenic belts are important for the division of tectonic units and also provide important information for understanding the amalgamation and fragmentation of early supercontinents. The understanding of their formation ages, distribution ranges, material compositions, etc. affects the view on the tectonics, evolution, and orogenic models of the different orogenic belts. It is the basis of many scientific issues and has important research values. However, due to structural deformation and replacement, it is difficult to differentiate some Phanerozoic and Precambrian geological bodies in ancient orogenic belts around the world. In addition, different research levels and testing methods in different periods have led to several changes in the classifications, nomenclatures, distribution ranges, and geotectonic attributes of some Precambrian geological bodies, affecting the understanding of the topics above. This study focuses on the Beishan Complex in the middle segment of the southern Central Asian Orogenic Belt (CAOB) to discuss the influence of the complicated and arbitrary classifications, divisions, and distribution of a Precambrian geological body on the tectonics and evolution of the orogenic belt. The Beishan Complex has long been regarded as the Precambrian basement of the microcontinents in the Beishan Orogenic Blet (BOB) in the middle section of the southern CAOB. In recent years, numerous advances have been made in its distribution ranges, ages, and basement affinities, which affect the tectonics and evolution of the BOB. This study reviews the classification history of the Beishan Complex, summarizes the previous views on the differences in the basement rocks between the southern and northern zones of the BOB, compares the Beishan Complex of the BOB with the Precambrian geological bodies of northern Alxa and the Central Tianshan blocks, and elaborates the understanding of the basement attribution of the tectonic units to which the Beishan Complex belongs. Based on the comprehensive comparison of rock assemblages, the Precambrian detrital zircon peak characteristics, magmatic event sequences, and zircon Hf isotope characteristics of the microcontinents in the middle section of the southern margin of the CAOB, it is considered that these microcontinents might experience a similar Precambrian evolution history. Integrated with previous data, it is proposed that these microcontinents may originate from the breakup of the Columbia Supercontinent, participate in the evolution of the Rodinia Supercontinent amalgamation, and finally break up into several microcontinent blocks. In view of the importance of geological bodies with Precambrian basement attributes and the various differences caused by the constantly changing connotation and distribution ranges, this paper calls for strengthening the research on the division and evolution of Precambrian geological bodies in the middle section of the southern CAOB and attaching importance to the compilation of regional geologic maps.
2025, 50(2): 667-686.
doi: 10.3799/dqkx.2024.019
Abstract:
The ancient rocks exposed along the southern margin of the North China Craton primarily comprise a suite of rocks known as TTG (Tonalite-Trondhjemite-Granodiorite) and K-rich granites. This suite represents a critical target for the study of granite genesis and the evolution of continental crust. This paper focuses on the Xiong'ershan region and employs zircon microanalysis of Hf-O isotopes and trace elements to trace the evolution of magma. It explores the geochemical characteristics of granites at different stages, the nature of their source regions, and the mechanisms behind their formation. This study identifies two significant magmatic-tectonic events around 2.5 to 2.4 Ga and ~2.3 Ga. The research reveals that in the Xiaonangou region, trondhjemite from 2.51 to 2.43 Ga contain rich titanium oxides, with low εHf(t) values ranging from -6.9 to +5.0. The zircon oxygen isotope values average 6.03‰ and 5.18‰, suggesting potential associations with partial crustal melting and the incorporation of sedimentary material. In the Huanggou and Muce regions, ~2.3 Ga potassic granites exhibit zircon oxygen isotope values averaging 3.98‰ and 3.10‰, with enriched εHf(t) values ranging from -5.8 to -3.5, respectively. The significant decrease in zircon δ18O values may be linked to high-temperature hydrothermal-magmatic interactions caused by upwelling mantle material. Zircon trace element compositions of different types in granites from different eras exhibit characteristics of continental arc environments. Combined with continuously low εHf(t) and reducing δ18O isotopic composition, the Xiong'ershan region likely formed in an active continental margin arc environment on the eve of the magmatic quiet period.
The ancient rocks exposed along the southern margin of the North China Craton primarily comprise a suite of rocks known as TTG (Tonalite-Trondhjemite-Granodiorite) and K-rich granites. This suite represents a critical target for the study of granite genesis and the evolution of continental crust. This paper focuses on the Xiong'ershan region and employs zircon microanalysis of Hf-O isotopes and trace elements to trace the evolution of magma. It explores the geochemical characteristics of granites at different stages, the nature of their source regions, and the mechanisms behind their formation. This study identifies two significant magmatic-tectonic events around 2.5 to 2.4 Ga and ~2.3 Ga. The research reveals that in the Xiaonangou region, trondhjemite from 2.51 to 2.43 Ga contain rich titanium oxides, with low εHf(t) values ranging from -6.9 to +5.0. The zircon oxygen isotope values average 6.03‰ and 5.18‰, suggesting potential associations with partial crustal melting and the incorporation of sedimentary material. In the Huanggou and Muce regions, ~2.3 Ga potassic granites exhibit zircon oxygen isotope values averaging 3.98‰ and 3.10‰, with enriched εHf(t) values ranging from -5.8 to -3.5, respectively. The significant decrease in zircon δ18O values may be linked to high-temperature hydrothermal-magmatic interactions caused by upwelling mantle material. Zircon trace element compositions of different types in granites from different eras exhibit characteristics of continental arc environments. Combined with continuously low εHf(t) and reducing δ18O isotopic composition, the Xiong'ershan region likely formed in an active continental margin arc environment on the eve of the magmatic quiet period.
2025, 50(2): 687-698.
doi: 10.3799/dqkx.2023.072
Abstract:
Conventional methods such as differential flow gauging, one-dimensional heat transport equations, and environmental isotopic and geochemical tracers are often used to study the interaction mechanism between groundwater and surface water in alpine watersheds. However, they can not accurately describe this mechanism on a small scale, such as the complex stream stretches of a piedmont fluvial-alluvial fan. Therefore, the piedmont fluvial-alluvial fan in the Hulugou Valley in the headwaters of the Heihe River was chosen as our study site. Discrete zones of groundwater discharge along the stream stretches from the east tributary to the mainstream were identified on the basis of variations in streambed temperature using a distributed temperature sensor (DTS). The DTS gives measurements of the spatial (±1 m) and temporal (10 min) variation of streambed temperature over a much larger reach of stream (~883 m) than previous methods. Results show that focused groundwater discharge has been identified in twelve points along the east tributary, and groundwater discharge in the mainstream has been dominated by diffuse flow. Combining the hydrogeology of this catchment, we build the conceptual model of interactions between groundwater and surface water in a piedmont fluvial-alluvial fan. The heterogeneity of fluvial-alluvial aquifers in the alpine watershed controls and impacts groundwater flow and its interaction with surface water. Furthermore, the impact's space-time scope will gradually increase with climate warming.
Conventional methods such as differential flow gauging, one-dimensional heat transport equations, and environmental isotopic and geochemical tracers are often used to study the interaction mechanism between groundwater and surface water in alpine watersheds. However, they can not accurately describe this mechanism on a small scale, such as the complex stream stretches of a piedmont fluvial-alluvial fan. Therefore, the piedmont fluvial-alluvial fan in the Hulugou Valley in the headwaters of the Heihe River was chosen as our study site. Discrete zones of groundwater discharge along the stream stretches from the east tributary to the mainstream were identified on the basis of variations in streambed temperature using a distributed temperature sensor (DTS). The DTS gives measurements of the spatial (±1 m) and temporal (10 min) variation of streambed temperature over a much larger reach of stream (~883 m) than previous methods. Results show that focused groundwater discharge has been identified in twelve points along the east tributary, and groundwater discharge in the mainstream has been dominated by diffuse flow. Combining the hydrogeology of this catchment, we build the conceptual model of interactions between groundwater and surface water in a piedmont fluvial-alluvial fan. The heterogeneity of fluvial-alluvial aquifers in the alpine watershed controls and impacts groundwater flow and its interaction with surface water. Furthermore, the impact's space-time scope will gradually increase with climate warming.
2025, 50(2): 699-717.
doi: 10.3799/dqkx.2023.214
Abstract:
In order to reconcile the contradictions among the Holocene precipitation records retrieved from different nature archives in the middle and lower reaches of the Yangtze River (MLRYR), this study analyzed 12 Holocene precipitation records in the middle reaches of the Yangtze River and 18 Holocene precipitation records in the lower reaches of the Yangtze River. The results show that the precipitation in the MLRYR has gradually increased since the onset of the Holocene, and then decreased after the middle Holocene. During the late Holocene, the precipitation evolution pattern in the MLRYR was decoupled: the precipitation in the middle reaches of the Yangtze River increased again, while the precipitation in the lower reaches of the Yangtze River tended to decrease with fluctuations. In terms of mechanisms, the Holocene precipitation evolution in the MLRYR was generally controlled by the Northern Hemisphere summer insolation (NHSI). During the late Holocene, the ENSO activity increased significantly, and the position of the Asian westerly jet was shifted to the south, superimposed on the anomalies of the Indian summer monsoon circulation, which not only led to the deviation of the precipitation pattern in the MLRYR from the variation trend of NHSI, but also resulted in the formation of a more wet climate in the middle reaches of the Yangtze River relative to the lower reaches of the Yangtze River.
In order to reconcile the contradictions among the Holocene precipitation records retrieved from different nature archives in the middle and lower reaches of the Yangtze River (MLRYR), this study analyzed 12 Holocene precipitation records in the middle reaches of the Yangtze River and 18 Holocene precipitation records in the lower reaches of the Yangtze River. The results show that the precipitation in the MLRYR has gradually increased since the onset of the Holocene, and then decreased after the middle Holocene. During the late Holocene, the precipitation evolution pattern in the MLRYR was decoupled: the precipitation in the middle reaches of the Yangtze River increased again, while the precipitation in the lower reaches of the Yangtze River tended to decrease with fluctuations. In terms of mechanisms, the Holocene precipitation evolution in the MLRYR was generally controlled by the Northern Hemisphere summer insolation (NHSI). During the late Holocene, the ENSO activity increased significantly, and the position of the Asian westerly jet was shifted to the south, superimposed on the anomalies of the Indian summer monsoon circulation, which not only led to the deviation of the precipitation pattern in the MLRYR from the variation trend of NHSI, but also resulted in the formation of a more wet climate in the middle reaches of the Yangtze River relative to the lower reaches of the Yangtze River.
2025, 50(2): 718-736.
doi: 10.3799/dqkx.2024.009
Abstract:
As an extreme surface event of high magnitude and low frequency, high-energy outburst flood has strong erosion and remodeling ability, which greatly affects the evolution of surface topography. In recent years, studies on high-energy outburst floods have gradually increased, however, the related erosion mechanisms and geomorphic effects still lack systematic understanding. We sorted out systematically of the relevant progresses of high-energy outburst floods at domestic and abroad, summarized three forms of erosion landforms and their features formed by high-energy outburst floods: large, medium and small, analyzed the erosion patterns and occurrence conditions of four types of high-energy outburst floods, including plucking, cavitation, eddy erosion and abrasion, and further integrated the typical erosion effects of outburst floods. Lastly, the study is combined with domestic and international research interests to reveal the mechanism and driving factors of flood erosion in terms of multi-methods, the "tool effect" and "cover effect" under the erosion and transport, the power and energy relationship between high-energy outburst flood and particle comminution, and the coupling effect of erosion and tectonic uplift.The aim is to provide an in-depth understanding of the occurrence patterns of high-energy outburst floods and their erosion processes, and to deepen the understanding of the links between such catastrophic extreme surface events and the evolution of the landscape.
As an extreme surface event of high magnitude and low frequency, high-energy outburst flood has strong erosion and remodeling ability, which greatly affects the evolution of surface topography. In recent years, studies on high-energy outburst floods have gradually increased, however, the related erosion mechanisms and geomorphic effects still lack systematic understanding. We sorted out systematically of the relevant progresses of high-energy outburst floods at domestic and abroad, summarized three forms of erosion landforms and their features formed by high-energy outburst floods: large, medium and small, analyzed the erosion patterns and occurrence conditions of four types of high-energy outburst floods, including plucking, cavitation, eddy erosion and abrasion, and further integrated the typical erosion effects of outburst floods. Lastly, the study is combined with domestic and international research interests to reveal the mechanism and driving factors of flood erosion in terms of multi-methods, the "tool effect" and "cover effect" under the erosion and transport, the power and energy relationship between high-energy outburst flood and particle comminution, and the coupling effect of erosion and tectonic uplift.The aim is to provide an in-depth understanding of the occurrence patterns of high-energy outburst floods and their erosion processes, and to deepen the understanding of the links between such catastrophic extreme surface events and the evolution of the landscape.
2025, 50(2): 737-751.
doi: 10.3799/dqkx.2023.212
Abstract:
The occurrence and development of land subsidence has become a global geological disaster. Based on the monitoring data of groundwater level, groundwater quality and land subsidence for years, the relationship between groundwater level dynamics and land subsidence was explored from the perspective of spatial horizontal-vertical-point by using GIS technology, Logistic curve model, linear trend analysis and grey correlation analysis. Finally, the influence of land subsidence on groundwater quality was discussed. The groundwater dynamic types in the study area included exploitation type, hydrologic-irrigation type and irrigation type, and the groundwater level showed a rapid and slow decline trend from 2019 to 2022, the average annual rate ranges from -0.97 m·a-1 to -0.25 m·a-1. By 2021, the amount and rate of land subsidence in the center of large land subsidence cone in the southeast direction of Gaochang district in the South Turpan Basin were -366 mm and -140 mm·a-1, respectively. There was a good coupling between the confined groundwater level depression cone and land subsidence cone, and there was a significant positive correlation between the deep confined groundwater level and the land subsidence (r=1.00), and the relationship was approximately linear in the Logical curve model. There was a significant positive correlation between the land subsidence and SO42- content in groundwater (r=0.95). Long-term over-exploitation of deep confined groundwater for agriculture irrigation results in compaction and consolidation of clay resulting in the land subsidence cone, and part of the released SO42- may enter deep confined aquifers.
The occurrence and development of land subsidence has become a global geological disaster. Based on the monitoring data of groundwater level, groundwater quality and land subsidence for years, the relationship between groundwater level dynamics and land subsidence was explored from the perspective of spatial horizontal-vertical-point by using GIS technology, Logistic curve model, linear trend analysis and grey correlation analysis. Finally, the influence of land subsidence on groundwater quality was discussed. The groundwater dynamic types in the study area included exploitation type, hydrologic-irrigation type and irrigation type, and the groundwater level showed a rapid and slow decline trend from 2019 to 2022, the average annual rate ranges from -0.97 m·a-1 to -0.25 m·a-1. By 2021, the amount and rate of land subsidence in the center of large land subsidence cone in the southeast direction of Gaochang district in the South Turpan Basin were -366 mm and -140 mm·a-1, respectively. There was a good coupling between the confined groundwater level depression cone and land subsidence cone, and there was a significant positive correlation between the deep confined groundwater level and the land subsidence (r=1.00), and the relationship was approximately linear in the Logical curve model. There was a significant positive correlation between the land subsidence and SO42- content in groundwater (r=0.95). Long-term over-exploitation of deep confined groundwater for agriculture irrigation results in compaction and consolidation of clay resulting in the land subsidence cone, and part of the released SO42- may enter deep confined aquifers.
