2023 Vol. 48, No. 11
Display Method:
2023, 48(11): 3965-3977.
doi: 10.3799/dqkx.2022.063
PDF 4621KB
Abstract:
Clinozoisite in garnet amphibolite from Hong'an area of Dabie Mountain contains a large amount of oriented needle-like and rod-like rutile inclusions. Clinozoisite (Ca2Al2.57Si0.46[Si3O11]O(OH)) is formed during the eclogite retrograde process, and the observed spacial relationships between inclusion and host are not fixed. Electron backscatter diffraction (EBSD) analysis demonstrates complex crystallographic orientations relationships (CORs) between rutile inclusions and host clinozoisite. Among them, CORs < 001 > Rt // < 010 > Czo, < 100 > Rt // < 001 > Czo, < 110 > Rt // < 001 > Czo, < 101 > Rt // < 001 > Czo occurred frequently, with occurrence probability of 17.7%, 14.9%, 14.2% and 25.0%, respectively. The parallel axis of each COR is in high lattice coherency. The rutile needles/rods are distributed and rotated around the directions of high lattice coherency in clinozoisite. The unique morphological distribution makes it difficult to visualize inclusion distribution inside a single or a few host minerals, and crystallographic orientation relationships analysis using a larger database is necessary for the qualitative description of the morphology distribution of inclusions. The exsolution origin is excluded based on the chemical distribution and topotaxial relationships between clinozoisite and rutile.
Clinozoisite in garnet amphibolite from Hong'an area of Dabie Mountain contains a large amount of oriented needle-like and rod-like rutile inclusions. Clinozoisite (Ca2Al2.57Si0.46[Si3O11]O(OH)) is formed during the eclogite retrograde process, and the observed spacial relationships between inclusion and host are not fixed. Electron backscatter diffraction (EBSD) analysis demonstrates complex crystallographic orientations relationships (CORs) between rutile inclusions and host clinozoisite. Among them, CORs < 001 > Rt // < 010 > Czo, < 100 > Rt // < 001 > Czo, < 110 > Rt // < 001 > Czo, < 101 > Rt // < 001 > Czo occurred frequently, with occurrence probability of 17.7%, 14.9%, 14.2% and 25.0%, respectively. The parallel axis of each COR is in high lattice coherency. The rutile needles/rods are distributed and rotated around the directions of high lattice coherency in clinozoisite. The unique morphological distribution makes it difficult to visualize inclusion distribution inside a single or a few host minerals, and crystallographic orientation relationships analysis using a larger database is necessary for the qualitative description of the morphology distribution of inclusions. The exsolution origin is excluded based on the chemical distribution and topotaxial relationships between clinozoisite and rutile.
2023, 48(11): 3978-3994.
doi: 10.3799/dqkx.2022.027
Abstract:
To find out the genetic linking between the Dichishan highly differentiated granite and pegmatite vein molybdenum deposit in West Sichuan, the petrogeochemistry, zircon U-Pb and molybdenite Re-Os isotopic age were studied in this paper. Samples from the Dichishan granite show variable SiO2 of 72.95%-75.44% and are characterized by Al2O3(13.93%- 14.99%) and high aluminum saturation index (A/CNK=1.11-1.25). They are high K calc-alkaline and peraluminous series, enriched in high field strength elements Th, Ce, Zr, Sm and large ion lithophile element Rb, depleted in high field strength elements Hf, Yb and large ion lithophile element Ba. The molybdenite Re-Os weighted mean age is 188.6±4.8 Ma (MSWD=0.90), which is consistent with LA-ICP-MS zircon U-Pb dating results of the granite yielded 206Pb/238U ages of 201.9±0.8 Ma. The oxygen fugacity parameter of zircon shows its low oxygen fugacity (log fO2=-15.40±2.89, △FMQ=-0.403±2.89). It proposes that the Dichishan granite batholith was emplaced in a syn-collisional setting, formed in early Yanshannian highly fractionated S-type granite. It represents the transition period of tectonic system from lithospheric compression to extensional in the southern margin of the Songpan-Garze Block. The discovery broadens the perspectives about mineral exploration in Jiulong region and its surrounding areas in West Sichuan.
To find out the genetic linking between the Dichishan highly differentiated granite and pegmatite vein molybdenum deposit in West Sichuan, the petrogeochemistry, zircon U-Pb and molybdenite Re-Os isotopic age were studied in this paper. Samples from the Dichishan granite show variable SiO2 of 72.95%-75.44% and are characterized by Al2O3(13.93%- 14.99%) and high aluminum saturation index (A/CNK=1.11-1.25). They are high K calc-alkaline and peraluminous series, enriched in high field strength elements Th, Ce, Zr, Sm and large ion lithophile element Rb, depleted in high field strength elements Hf, Yb and large ion lithophile element Ba. The molybdenite Re-Os weighted mean age is 188.6±4.8 Ma (MSWD=0.90), which is consistent with LA-ICP-MS zircon U-Pb dating results of the granite yielded 206Pb/238U ages of 201.9±0.8 Ma. The oxygen fugacity parameter of zircon shows its low oxygen fugacity (log fO2=-15.40±2.89, △FMQ=-0.403±2.89). It proposes that the Dichishan granite batholith was emplaced in a syn-collisional setting, formed in early Yanshannian highly fractionated S-type granite. It represents the transition period of tectonic system from lithospheric compression to extensional in the southern margin of the Songpan-Garze Block. The discovery broadens the perspectives about mineral exploration in Jiulong region and its surrounding areas in West Sichuan.
2023, 48(11): 3995-4016.
doi: 10.3799/dqkx.2022.012
Abstract:
In order to find out the genesis of the gray sandstones of the Lower Cretaceous Luohe Formation in the southwestern Ordos basin, deepen the understanding of the law for uranium mineral enrichment, and locate the occurrence area of sandstone type uranium ore body, the gray sandstone of Luohe Formation is studied by means of rock and mineral identification, XRD analysis and element geochemical analysis. The results show that there are two different genetic types of gray sandstone in the study area. (1) The sandstone in the lower part of Luohe Formation has typical aeolian sedimentary characteristics, with good separation and roundness of clastic particles, high quartz content, low total clay minerals content, the inter-particle porosity is large, indicating that it has a better fluid migration channel, and it has undergone a higher degree of transformation by the later reducing fluid. Meanwhile, this type of sandstone is also the most important uranium rich sand body. (2) The sedimentary types of the upper part of Luohe Formation are mainly braided river channel, channel edge and flooding basin. with medium-poor separation and roundness of clastic particles, low quartz content, high total clay mineral content, the inter-particle porosity is slightly low, and the reduction transformation degree of sandstone is weak or even basically not transformed. The geochemical characteristics of the two genetic gray sandstones are generally consistent, and some elements are different. When the content of U is higher, the contents of Cao, P2O5 and MnO in the major elements increase obviously, while the ratio of Fe2O3/FeO decreases obviously.The δEu has both positive and negative anomalies and δCe shows mainly negative anomaly in the gray sandstone of aeolian deposition, while both δEu and δCe show negative anomalies in the gray sandstone of fluvial sedimentation. It is concluded that the fluvial sedimentary sandstone of the Luohe Formation is dominated by a reduction environment, which is primary sedimentary sandstone, while aeolian sedimentary sandstone may have undergone the transformation from oxidation to reduction environment, which is altered sandstone. Uranium ore bodies are mostly produced in gray sandstones of eolian deposits. The increase in U content is accompanied by the relative enrichment of P, Ca and ΣREE, the generation of aeolian sedimentary gray sandstone and the enrichment of uranium ore are closely related to the alteration of hydrocarbon fluids.
In order to find out the genesis of the gray sandstones of the Lower Cretaceous Luohe Formation in the southwestern Ordos basin, deepen the understanding of the law for uranium mineral enrichment, and locate the occurrence area of sandstone type uranium ore body, the gray sandstone of Luohe Formation is studied by means of rock and mineral identification, XRD analysis and element geochemical analysis. The results show that there are two different genetic types of gray sandstone in the study area. (1) The sandstone in the lower part of Luohe Formation has typical aeolian sedimentary characteristics, with good separation and roundness of clastic particles, high quartz content, low total clay minerals content, the inter-particle porosity is large, indicating that it has a better fluid migration channel, and it has undergone a higher degree of transformation by the later reducing fluid. Meanwhile, this type of sandstone is also the most important uranium rich sand body. (2) The sedimentary types of the upper part of Luohe Formation are mainly braided river channel, channel edge and flooding basin. with medium-poor separation and roundness of clastic particles, low quartz content, high total clay mineral content, the inter-particle porosity is slightly low, and the reduction transformation degree of sandstone is weak or even basically not transformed. The geochemical characteristics of the two genetic gray sandstones are generally consistent, and some elements are different. When the content of U is higher, the contents of Cao, P2O5 and MnO in the major elements increase obviously, while the ratio of Fe2O3/FeO decreases obviously.The δEu has both positive and negative anomalies and δCe shows mainly negative anomaly in the gray sandstone of aeolian deposition, while both δEu and δCe show negative anomalies in the gray sandstone of fluvial sedimentation. It is concluded that the fluvial sedimentary sandstone of the Luohe Formation is dominated by a reduction environment, which is primary sedimentary sandstone, while aeolian sedimentary sandstone may have undergone the transformation from oxidation to reduction environment, which is altered sandstone. Uranium ore bodies are mostly produced in gray sandstones of eolian deposits. The increase in U content is accompanied by the relative enrichment of P, Ca and ΣREE, the generation of aeolian sedimentary gray sandstone and the enrichment of uranium ore are closely related to the alteration of hydrocarbon fluids.
2023, 48(11): 4017-4033.
doi: 10.3799/dqkx.2022.095
Abstract:
Zhexiang gold deposit is one of the typical Carlin-type gold deposits in Southwest Guizhou Province. However, the characteristics of ore-controlling faults, laws of ore-bodies orientation, and directions for further prospecting are still unclear, since the ore bodies are deep buried, with complicated shapes. In this paper it employs QuantyPES 3D modeling software for the fine 3D visualization modeling of deep strata, faults and ore-bodies in the mining area, to characterize the ore-controlling faults and relevant ore-bodies, to evaluate its deep metallogenic capacity, and to estimate the potential mineral resources. Based on the 3D visualization, and data of the characteristics of geochemical anomaly and field drilling exposure, it is revealed that the F20 fault is main ore-leading and controlling fault in the mining area. The structural ore-controlling model in the mining area is constructed, suggesting that there is great metallogenic and prospecting potential in the direction of deep NNE-striking F20 at the periphery of Zhexiang deposit. The calculated gold resources of mining area are 15 550 kg with the average grade of 3.59 g/t according to the 3D ore-bodies model, which is comparable to the results of traditional geological block method, indicating that the gold resources calculated by Kriging method are reliable. This study provides a new approach to characterize and prospect for the Carlin-type gold deposit, and a demonstration of the optimization of prospecting target areas in the depth and periphery of the Zhexiang gold deposit, which can be further used to guide the regional mineral exploration in the Huijiabao anticline.
Zhexiang gold deposit is one of the typical Carlin-type gold deposits in Southwest Guizhou Province. However, the characteristics of ore-controlling faults, laws of ore-bodies orientation, and directions for further prospecting are still unclear, since the ore bodies are deep buried, with complicated shapes. In this paper it employs QuantyPES 3D modeling software for the fine 3D visualization modeling of deep strata, faults and ore-bodies in the mining area, to characterize the ore-controlling faults and relevant ore-bodies, to evaluate its deep metallogenic capacity, and to estimate the potential mineral resources. Based on the 3D visualization, and data of the characteristics of geochemical anomaly and field drilling exposure, it is revealed that the F20 fault is main ore-leading and controlling fault in the mining area. The structural ore-controlling model in the mining area is constructed, suggesting that there is great metallogenic and prospecting potential in the direction of deep NNE-striking F20 at the periphery of Zhexiang deposit. The calculated gold resources of mining area are 15 550 kg with the average grade of 3.59 g/t according to the 3D ore-bodies model, which is comparable to the results of traditional geological block method, indicating that the gold resources calculated by Kriging method are reliable. This study provides a new approach to characterize and prospect for the Carlin-type gold deposit, and a demonstration of the optimization of prospecting target areas in the depth and periphery of the Zhexiang gold deposit, which can be further used to guide the regional mineral exploration in the Huijiabao anticline.
2023, 48(11): 4034-4052.
doi: 10.3799/dqkx.2022.435
Abstract:
The Alxa block is located in the southwestern margin of the North China craton. The Early Precambrian tectonic evolution and tectonic affinity of the block remain unknown or controversial, which restricts the study of the tectonic framework and evolution of the North China craton. The Longshoushan complex is one of the few Early Precambrian metamorphic basement rocks in the Alxa block, and records multiple Paleoproterozoic metamorphic events. Hence, which makes it possible to solve the above problems. It presents petrography, whole-rock geochemistry, and mineralogy, mineral geochemistry and chronology of zircon for the granitic pegmatite and zoisite amphibolite in the Longshoushan complex from the Jinchuan mining area in the central part of the Longshoushan area. The granitic pegmatite is characterized by SiO2 contents of 69.70%-73.08%, belongs to weak peraluminous and shoshonite series, and formed from low degree partial melting of crustal rocks during migmatisation. The intersection ages of 1 892±7 Ma (MSWD=0.76) were obtained from the core of zircon in granitic pegmatite, representing the formation age of the granitic pegmatite. The zoisite amphibolite is characterized by SiO2 contents of 41.51%-48.92%, and is the metamorphic product of tholeiitic diabase. Zircons in the zoisite amphibolite are amphibolite facies metamorphic zircons. The weighted average age of 1 830±8 Ma (MSWD=0.61) represents an amphibolite facies metamorphic event in the Longshoushan area. Combined with previous studies, there was a strong metamorphic-anatexis event in the Late Paleoproterozoic in the Longshoushan area, which is most likely related to a collisional orogeny. Through the comparison of tectonic-thermal events, it suggests that the Alxa block and the Khondalite belt of the North China craton have affinity in the Early Precambrian.
The Alxa block is located in the southwestern margin of the North China craton. The Early Precambrian tectonic evolution and tectonic affinity of the block remain unknown or controversial, which restricts the study of the tectonic framework and evolution of the North China craton. The Longshoushan complex is one of the few Early Precambrian metamorphic basement rocks in the Alxa block, and records multiple Paleoproterozoic metamorphic events. Hence, which makes it possible to solve the above problems. It presents petrography, whole-rock geochemistry, and mineralogy, mineral geochemistry and chronology of zircon for the granitic pegmatite and zoisite amphibolite in the Longshoushan complex from the Jinchuan mining area in the central part of the Longshoushan area. The granitic pegmatite is characterized by SiO2 contents of 69.70%-73.08%, belongs to weak peraluminous and shoshonite series, and formed from low degree partial melting of crustal rocks during migmatisation. The intersection ages of 1 892±7 Ma (MSWD=0.76) were obtained from the core of zircon in granitic pegmatite, representing the formation age of the granitic pegmatite. The zoisite amphibolite is characterized by SiO2 contents of 41.51%-48.92%, and is the metamorphic product of tholeiitic diabase. Zircons in the zoisite amphibolite are amphibolite facies metamorphic zircons. The weighted average age of 1 830±8 Ma (MSWD=0.61) represents an amphibolite facies metamorphic event in the Longshoushan area. Combined with previous studies, there was a strong metamorphic-anatexis event in the Late Paleoproterozoic in the Longshoushan area, which is most likely related to a collisional orogeny. Through the comparison of tectonic-thermal events, it suggests that the Alxa block and the Khondalite belt of the North China craton have affinity in the Early Precambrian.
2023, 48(11): 4053-4071.
doi: 10.3799/dqkx.2022.500
Abstract:
Mengshan, located in the middle of the western Pingxiang-Leping depression zone, have experienced complex tectono-magmatic processes during the Triassic, forming the Shizhushan giant wollastonite deposit. In order to reveal the structural ore-controlling mechanism of wollastonite deposit, in this study it probes into the rock deformation characteristics of different periods in detail based on the structural analysis of macroscopic and microscopic structural and the electron backscatter diffraction (EBSD) analysis of calcite. The results show that Mengshan experienced two tectonic deformation events during Triassic, indicating a tectonic regime transition from compression to extension. The D1 event is characterized by low angle ductile thrust with top-to-the-SE, accompanied by intense calci-mylonitization. The D2 event is a top-to-the-SSW extensional detachment related to the intrusion of the Mengshan granite. The deformed limestone is marmarosis and wollastonite mineralization. The microstructure analysis shows that the grain size and shape preferred orientation of calcite in the two deformed stages have different characteristics. EBSD results show that the D1 deformed calcite displays a wide c-axis maximum close to Z, indicating monoclinic symmetry and a top-to-the-SE thrust shearing. The calcite of D2 event developed randomly oriented c-axis poles, and underwent syn-tectonic recrystallization which resulted in resetting the microstructures of D1 event. The Late Triassic Mengshan granite intruded into the first deformation zone as a post-kinematic product in an extensional tectonic background that provides time constraints for the deformations. The D2 ductile detachment and wollastonite mineralization were both controlled by the extensional tectono-thermal system of the Mengshan granite. The extensional detachment leads to layered rich mineralization. The D1 deformation can be related to the strong NW-SE compression widely developed in the Northwest Jiangxi Province, which was controlled by the collision of the South China block and North China block during the Middle Triassic. The D2 deformation is the result of lithospheric extension adjustment in the Late Triassic on the basis of previous compressional deformation.
Mengshan, located in the middle of the western Pingxiang-Leping depression zone, have experienced complex tectono-magmatic processes during the Triassic, forming the Shizhushan giant wollastonite deposit. In order to reveal the structural ore-controlling mechanism of wollastonite deposit, in this study it probes into the rock deformation characteristics of different periods in detail based on the structural analysis of macroscopic and microscopic structural and the electron backscatter diffraction (EBSD) analysis of calcite. The results show that Mengshan experienced two tectonic deformation events during Triassic, indicating a tectonic regime transition from compression to extension. The D1 event is characterized by low angle ductile thrust with top-to-the-SE, accompanied by intense calci-mylonitization. The D2 event is a top-to-the-SSW extensional detachment related to the intrusion of the Mengshan granite. The deformed limestone is marmarosis and wollastonite mineralization. The microstructure analysis shows that the grain size and shape preferred orientation of calcite in the two deformed stages have different characteristics. EBSD results show that the D1 deformed calcite displays a wide c-axis maximum close to Z, indicating monoclinic symmetry and a top-to-the-SE thrust shearing. The calcite of D2 event developed randomly oriented c-axis poles, and underwent syn-tectonic recrystallization which resulted in resetting the microstructures of D1 event. The Late Triassic Mengshan granite intruded into the first deformation zone as a post-kinematic product in an extensional tectonic background that provides time constraints for the deformations. The D2 ductile detachment and wollastonite mineralization were both controlled by the extensional tectono-thermal system of the Mengshan granite. The extensional detachment leads to layered rich mineralization. The D1 deformation can be related to the strong NW-SE compression widely developed in the Northwest Jiangxi Province, which was controlled by the collision of the South China block and North China block during the Middle Triassic. The D2 deformation is the result of lithospheric extension adjustment in the Late Triassic on the basis of previous compressional deformation.
2023, 48(11): 4072-4087.
doi: 10.3799/dqkx.2023.042
Abstract:
The Wengmen complex, a newly identified Early Precambrian metamorphic basement with shallow metamorphism, opens a fresh avenue for future research on the formation and evolution of the early continental crust of the Dabie orogen on the northern Yangtze Block. In this paper, it presents a comprehensive study of in situ zircon U-Pb geochronology and Hf isotopes of representative meta-granitic rocks from the Wengmen complex. The results show that two meta-tonalite gneisses were formed at 2 914±24.5 Ma and 2 874±6.6 Ma respectively, two monzonitic granitic gneisses were formed at 2 669±10.7 Ma and 2 644±7.1 Ma respectively, and one mylonitized monzonitic granite was formed at 2 454±6.5 Ma, which confirms the existence of Archean to Early Paleoproterozoic continental crust basement in the southern Dabie orogen. The dating results also show that the formation ages of the two eyeball-like granitic gneisses are 2 011±6.3 Ma and 2 010±5.4 Ma, respectively. Moreover, ca. 2.0 Ga metamorphic zircon age has been obtained from the Wengmen Archean rocks, indicating that the complex may have been involved in the Paleoproterozoic orogenic event. The available data indicate that the newly discovered Wengmen complex in the southern Dabie orogen and the Kongling complex in the Yangtze continental core have synchronous tectono-magmatic thermal events and crustal accretion history during the Archean to Early Paleoproterozoic. However, the periphery of the Dabie orogen shows uniqueness due to its well-developed ~2.5 Ga tectono-magmatic thermal event, which is consistent with those of the ancient continental blocks in the world and may be the record of the final maturation and stabilization during the end of the Archean. Integrating the new and published data, it proposes that each basement on the northern Yangtze Block maybe coexisted in different parts of the Sclavia supercraton at the end of the Neoarchean, and the periphery of the Dabie orogen represented by the Wengmen complex maybe was located closer to the margin of the supercraton.
The Wengmen complex, a newly identified Early Precambrian metamorphic basement with shallow metamorphism, opens a fresh avenue for future research on the formation and evolution of the early continental crust of the Dabie orogen on the northern Yangtze Block. In this paper, it presents a comprehensive study of in situ zircon U-Pb geochronology and Hf isotopes of representative meta-granitic rocks from the Wengmen complex. The results show that two meta-tonalite gneisses were formed at 2 914±24.5 Ma and 2 874±6.6 Ma respectively, two monzonitic granitic gneisses were formed at 2 669±10.7 Ma and 2 644±7.1 Ma respectively, and one mylonitized monzonitic granite was formed at 2 454±6.5 Ma, which confirms the existence of Archean to Early Paleoproterozoic continental crust basement in the southern Dabie orogen. The dating results also show that the formation ages of the two eyeball-like granitic gneisses are 2 011±6.3 Ma and 2 010±5.4 Ma, respectively. Moreover, ca. 2.0 Ga metamorphic zircon age has been obtained from the Wengmen Archean rocks, indicating that the complex may have been involved in the Paleoproterozoic orogenic event. The available data indicate that the newly discovered Wengmen complex in the southern Dabie orogen and the Kongling complex in the Yangtze continental core have synchronous tectono-magmatic thermal events and crustal accretion history during the Archean to Early Paleoproterozoic. However, the periphery of the Dabie orogen shows uniqueness due to its well-developed ~2.5 Ga tectono-magmatic thermal event, which is consistent with those of the ancient continental blocks in the world and may be the record of the final maturation and stabilization during the end of the Archean. Integrating the new and published data, it proposes that each basement on the northern Yangtze Block maybe coexisted in different parts of the Sclavia supercraton at the end of the Neoarchean, and the periphery of the Dabie orogen represented by the Wengmen complex maybe was located closer to the margin of the supercraton.
2023, 48(11): 4088-4102.
doi: 10.3799/dqkx.2022.122
Abstract:
Due to the lack of stable radioisotopic chronoscope in sedimentary strata for a long time, determination of their absolute ages has become the bottleneck both in stratigraphic and petroleum geological investigations. In this paper it uses quantitative cyclostratigraphy theory and method, combining with the constraint by U-Pb dating of bedding-parallel fibrous calcite, to re-determine the absolute age of the main statigraphic interfaces of the Gaoyou sag in Subei basin, and obtains the different duration of Sanduo movement and the coupling relationship in time between the structural transforming surface of dual rifting stages and the Pacific plate subduction bending (50 Ma±).The top and base of Sanduo Formation in Gaoyou sag are 34.0 Ma and 43.3 Ma respectively. The base of Dainan Formation is 50.5 Ma and that of Fu 1 and Fu 2 Members are 66.0 Ma and 56.5 Ma individually. The duration of residual strata of Sanduo Formation from Yong'an 38, which is in the sub-sag area, is 8.28 Ma, and its starting age of uplift denudation is 34.06 Ma, while the end is 23.03 Ma, which means the denudation time is 11.03 Ma. The time of denudation of uplift and slope was earlier than 34.06 Ma, and the time of denudation was longer. The U-Pb dating of Fu 4 member is 53.1±3.7 Ma. The results show follows: (1) The 50 Ma± and 23.03 Ma± interfaces in Gaoyou sag of the Subei basin are tectonic responses of the Pacific plate subduction bending and the collision between the Indian plate and the Eurasian plate. The depocenter of Gaoyou sag early uplifted comparatively since the Late Eocene (34.06 Ma) and underwent the denudation span of 11.03 Ma. The main reason is perhaps related to the remote effect of the overall performance of Indo-Eurasian plate collision with compression regime in the South China block, and lack of NE-trending deep mantle uplift. (2) The U-Pb dating result of bedding-parallel fibrous calcite veins developed in the source rock system can be used as the sedimentary age of the strata, providing an excellent anchor point constraint for quantitative cyclostratigraphic analysis of sedimentary basins.
Due to the lack of stable radioisotopic chronoscope in sedimentary strata for a long time, determination of their absolute ages has become the bottleneck both in stratigraphic and petroleum geological investigations. In this paper it uses quantitative cyclostratigraphy theory and method, combining with the constraint by U-Pb dating of bedding-parallel fibrous calcite, to re-determine the absolute age of the main statigraphic interfaces of the Gaoyou sag in Subei basin, and obtains the different duration of Sanduo movement and the coupling relationship in time between the structural transforming surface of dual rifting stages and the Pacific plate subduction bending (50 Ma±).The top and base of Sanduo Formation in Gaoyou sag are 34.0 Ma and 43.3 Ma respectively. The base of Dainan Formation is 50.5 Ma and that of Fu 1 and Fu 2 Members are 66.0 Ma and 56.5 Ma individually. The duration of residual strata of Sanduo Formation from Yong'an 38, which is in the sub-sag area, is 8.28 Ma, and its starting age of uplift denudation is 34.06 Ma, while the end is 23.03 Ma, which means the denudation time is 11.03 Ma. The time of denudation of uplift and slope was earlier than 34.06 Ma, and the time of denudation was longer. The U-Pb dating of Fu 4 member is 53.1±3.7 Ma. The results show follows: (1) The 50 Ma± and 23.03 Ma± interfaces in Gaoyou sag of the Subei basin are tectonic responses of the Pacific plate subduction bending and the collision between the Indian plate and the Eurasian plate. The depocenter of Gaoyou sag early uplifted comparatively since the Late Eocene (34.06 Ma) and underwent the denudation span of 11.03 Ma. The main reason is perhaps related to the remote effect of the overall performance of Indo-Eurasian plate collision with compression regime in the South China block, and lack of NE-trending deep mantle uplift. (2) The U-Pb dating result of bedding-parallel fibrous calcite veins developed in the source rock system can be used as the sedimentary age of the strata, providing an excellent anchor point constraint for quantitative cyclostratigraphic analysis of sedimentary basins.
2023, 48(11): 4103-4116.
doi: 10.3799/dqkx.2023.004
Abstract:
In recent years, industrial oil and gas has been found in Keping area of the Tarim basin. However, the tectonic evolution in this region is complex and the research on the process of hydrocarbon accumulation is weak. In this research, taking the Silurian Kepingtage Formation in Well XSD 1 as an example, the diagenesis and hydrocarbon accumulation process were analyzed based on combined experiments of thin section observation, cathodic luminescence, inclusion petrography, fluorescence spectrum and microthermometry. The results show that the Silurian sandstone reservoir in Keping area develops two stages of oil and gas inclusions. The first stage is yellow fluorescent petroleum inclusions, which is earlier than the formation of quartz secondary enlargement. The second stage is blue fluorescent petroleum inclusions, accompanied by bitumen inclusions and gas-oil-bitumen inclusions, reflecting gas and oil mix to form condensate gas and bitumen precipitation.The hydrocarbon accumulation process of the Keping Silurian has been divided into three stages. The first stage is described as low maturity oil from Ordovician charging in Late Hercynian. The second stage occurred in the Late Indosinian to Early Yanshanian, when the condensate reservoir and bitumen have been formed by high mature dry gas from Cambrian mixed with normal oil from Ordovician. The third stage is in the Late Yanshanian-Himalayan stage, in which the early formed oil and gas reservoirs experienced adjustment and transformation. The hydrocarbon reservoirs near Shajingzi fault with strong activity were destroyed, whereas the reservoirs in slope zones far from active faults were preserved.
In recent years, industrial oil and gas has been found in Keping area of the Tarim basin. However, the tectonic evolution in this region is complex and the research on the process of hydrocarbon accumulation is weak. In this research, taking the Silurian Kepingtage Formation in Well XSD 1 as an example, the diagenesis and hydrocarbon accumulation process were analyzed based on combined experiments of thin section observation, cathodic luminescence, inclusion petrography, fluorescence spectrum and microthermometry. The results show that the Silurian sandstone reservoir in Keping area develops two stages of oil and gas inclusions. The first stage is yellow fluorescent petroleum inclusions, which is earlier than the formation of quartz secondary enlargement. The second stage is blue fluorescent petroleum inclusions, accompanied by bitumen inclusions and gas-oil-bitumen inclusions, reflecting gas and oil mix to form condensate gas and bitumen precipitation.The hydrocarbon accumulation process of the Keping Silurian has been divided into three stages. The first stage is described as low maturity oil from Ordovician charging in Late Hercynian. The second stage occurred in the Late Indosinian to Early Yanshanian, when the condensate reservoir and bitumen have been formed by high mature dry gas from Cambrian mixed with normal oil from Ordovician. The third stage is in the Late Yanshanian-Himalayan stage, in which the early formed oil and gas reservoirs experienced adjustment and transformation. The hydrocarbon reservoirs near Shajingzi fault with strong activity were destroyed, whereas the reservoirs in slope zones far from active faults were preserved.
2023, 48(11): 4117-4134.
doi: 10.3799/dqkx.2022.091
Abstract:
The main fault zone in Shunbei area is favorable for hydrocarbon accumulation. In order to clarify the control effect of the strike-slip fault on oil and gas reservoirs in this area, through the fine interpretation of the 3D seismic data of the mid-north part of Shunbei No. 5 strike-slip fault zone, and combined with the previous research results and oil and gas exploration practices, in this paper it discusses the differential activity characteristics and reservoir control effect of the mid-north part of Shunbei No. 5 strike-slip fault. The study shows follows. (1) The Paleozoic of the Shunbei No. 5 strike-slip fault zone is dominated by linear and en echelon normal faults, and the plane distribution of Mesozoic-Cenozoic faults has almost no spatial relationship with Paleozoic faults; the deeper part of the profile is characterized by steep strike slip fault, and the middle to shallow part are flower structure. (2) Shunbei No.5 strike-slip fault zone is characterized by distinct activity and can be subdivided into 16 segments, including strike-slip extrusion, strike-slip extension and pure strike-slip. (3) Shunbei No.5 strike-slip fault zone has experienced multi-stage structural movement superimposition transformation, among which the main active periods are Middle Caledonian Ⅰ, Middle Caledonian Ⅲ, Late Caledonian-Early Hercynian and Middle-Late Hercynian. (4) The differences in the plane segmental pattern, vertical structural pattern and activity of the strike-slip fault zone cause the differences in the scale of reservoirs and reservoirs in different parts of the same fault zone.
The main fault zone in Shunbei area is favorable for hydrocarbon accumulation. In order to clarify the control effect of the strike-slip fault on oil and gas reservoirs in this area, through the fine interpretation of the 3D seismic data of the mid-north part of Shunbei No. 5 strike-slip fault zone, and combined with the previous research results and oil and gas exploration practices, in this paper it discusses the differential activity characteristics and reservoir control effect of the mid-north part of Shunbei No. 5 strike-slip fault. The study shows follows. (1) The Paleozoic of the Shunbei No. 5 strike-slip fault zone is dominated by linear and en echelon normal faults, and the plane distribution of Mesozoic-Cenozoic faults has almost no spatial relationship with Paleozoic faults; the deeper part of the profile is characterized by steep strike slip fault, and the middle to shallow part are flower structure. (2) Shunbei No.5 strike-slip fault zone is characterized by distinct activity and can be subdivided into 16 segments, including strike-slip extrusion, strike-slip extension and pure strike-slip. (3) Shunbei No.5 strike-slip fault zone has experienced multi-stage structural movement superimposition transformation, among which the main active periods are Middle Caledonian Ⅰ, Middle Caledonian Ⅲ, Late Caledonian-Early Hercynian and Middle-Late Hercynian. (4) The differences in the plane segmental pattern, vertical structural pattern and activity of the strike-slip fault zone cause the differences in the scale of reservoirs and reservoirs in different parts of the same fault zone.
2023, 48(11): 4135-4152.
doi: 10.3799/dqkx.2022.470
Abstract:
To study the genetic relationship between oil and source rock in Wushi sag, geochemical analyses of crude oil and source rock samples were carried out in this paper. The results show that crude oils in Wushi sag can be classified into three groups: group Ⅰ crude oil is distributed in the Weizhou Formation and 1-member of Liushagang Formation reservoir in the deep sag belt. The maturity of this crude oil is relatively high, and the abundances of C19 tricyclic terpenes, C24 tetracyclic terpenes, and oleanane are relatively high, while the abundances of C23 tricyclic terpenes and C30 4-methylsteranes are relatively low, which reflects the characteristics of double input of lower aquatic organisms and terrigenous higher plants. Group Ⅱ and group Ⅲ crude oil is mainly distributed in the 2-member and 3-member of the Liushagang Formation reservoir in the reversal tectonic belt and gentle slope belt, and their maturity is overall lower than that of group Ⅰ crude oil. The abundances of C19 tricyclic terpanes, C24 tetracyclic terpanes, and oleanane of these oils are relatively low, and the abundances of C23 tricyclic terpanes and 4-methylsteranes are relatively high, indicating their parent material is mainly from lower aquatic organisms. The difference between the two groups of crude oils mainly lies in the Pr/Ph value and the stable carbon isotope characteristics of whole oil. Compared with group Ⅱ crude oil, group Ⅲ crude oil has a lower Pr/Ph value and lighter stable carbon isotope. The oil-source rock correlation shows that the group Ⅰ crude oil mainly comes from the upper sub-member of 2-member of Liushagang Formation source rock. Both group Ⅱ and group Ⅲ oils are derived from the lower sub-member of the 2-member of Liushagang Formation source rock.
To study the genetic relationship between oil and source rock in Wushi sag, geochemical analyses of crude oil and source rock samples were carried out in this paper. The results show that crude oils in Wushi sag can be classified into three groups: group Ⅰ crude oil is distributed in the Weizhou Formation and 1-member of Liushagang Formation reservoir in the deep sag belt. The maturity of this crude oil is relatively high, and the abundances of C19 tricyclic terpenes, C24 tetracyclic terpenes, and oleanane are relatively high, while the abundances of C23 tricyclic terpenes and C30 4-methylsteranes are relatively low, which reflects the characteristics of double input of lower aquatic organisms and terrigenous higher plants. Group Ⅱ and group Ⅲ crude oil is mainly distributed in the 2-member and 3-member of the Liushagang Formation reservoir in the reversal tectonic belt and gentle slope belt, and their maturity is overall lower than that of group Ⅰ crude oil. The abundances of C19 tricyclic terpanes, C24 tetracyclic terpanes, and oleanane of these oils are relatively low, and the abundances of C23 tricyclic terpanes and 4-methylsteranes are relatively high, indicating their parent material is mainly from lower aquatic organisms. The difference between the two groups of crude oils mainly lies in the Pr/Ph value and the stable carbon isotope characteristics of whole oil. Compared with group Ⅱ crude oil, group Ⅲ crude oil has a lower Pr/Ph value and lighter stable carbon isotope. The oil-source rock correlation shows that the group Ⅰ crude oil mainly comes from the upper sub-member of 2-member of Liushagang Formation source rock. Both group Ⅱ and group Ⅲ oils are derived from the lower sub-member of the 2-member of Liushagang Formation source rock.
2023, 48(11): 4153-4174.
doi: 10.3799/dqkx.2022.080
Abstract:
In recent years, a large amount of oil and gas was discovered for the first time above the Archean large metamorphic granite buried hill condensate gas reservoir in the Bozhong 19-6 structure in the deep (buried depth greater than 3 500 m) Kongdian Formation glutenite reservoir. But it is characterized with larger reservoir difference.In order to identify the causes of deep conglomerate reservoir quality, using analyses of thin section casting and test data, particle size, conventional physical properties, such as inclusion, combined with burial history analysis, quantitative analysis of the physical properties of deep glutenite reservoirs in Bozhong 19-6 and its surroundings of the Bohai Sea was carried out, and the main controlling factors for the development of high-quality glutenite reservoirs in the Kongdian Formation were clarified. It is found that: (1) The deep Kongdian Formation in the study area has developed fan delta glutenite reservoirs with a buried depth greater than 3 500-4 200 m. It is a deep glutenite reservoir with poor physical properties, mainly low porosity and low permeability, and the diagenesis stage is in the middle diagenesis from A2 to B stage, and dissolution pores are developed. (2) Potassium-rich feldspar framework particles, atmospheric fresh water leaching, organic acid dissolution, overpressure and crack are the main controlling factors for the development of high-quality glutenite reservoirs in the Kongdian Formation in the study area. (3) The Kongdian Formation glutenite reservoirs have mainly experienced atmospheric freshwater enhancement-early diagenesis long-term, rapid burial, rapid compaction-reduction-medium diagenesis A1 mid-to-long-term, rapid burial, slow compaction-reduction, organic acid and ultra pressure massive dissolution to increase pores, first filling of oil and gas-mid-diagenetic A2 or B period, short-term, rapid burial, slow cementation, pore reduction, (or formation of corrosion cracks) and large-scale oil and gas filling. (4) However, the diagenetic evolution stages and pore evolution strength experienced by different structures are obviously different. The Kongdian Formation glutenite reservoir in Bozhong 19-6 structure has experienced early diagenesis → middle diagenesis A1 → middle diagenesis A2 to B, corresponding The porosity of Bozhong has undergone an evolution process of 32.6%→17.3%→12.6%→10.6%, the reduction in porosity due to compaction and cementation is 22.0%, and the total reduction in porosity is 67.6%, respectively; while Bozhong 25-1 tectonic glutenite reservoirs mainly experienced early diagenesis → middle diagenesis A1 → middle diagenetic A2, and the corresponding porosity experienced an evolution process of 32.8%→19.9%→14.2%→13.2%, which suffered compaction and cementation. The porosity reduction is 19.6%, and the total porosity reduction rate is 59.7%. (5) Compared with the BZ 19-6 structure, the Kongdian Formation glutenite reservoir compaction in the BZ 25-1 structure is relatively weak, the overpressure is stronger, and the dissolution is stronger, which are the main factors for the relatively good porosity of the structure. And the coarse-grained and intragranular dissolution pores-fractures formed by the late strong compaction are the main factors for the relatively high permeability of the BZ 19-6 structural glutenite reservoir.
In recent years, a large amount of oil and gas was discovered for the first time above the Archean large metamorphic granite buried hill condensate gas reservoir in the Bozhong 19-6 structure in the deep (buried depth greater than 3 500 m) Kongdian Formation glutenite reservoir. But it is characterized with larger reservoir difference.In order to identify the causes of deep conglomerate reservoir quality, using analyses of thin section casting and test data, particle size, conventional physical properties, such as inclusion, combined with burial history analysis, quantitative analysis of the physical properties of deep glutenite reservoirs in Bozhong 19-6 and its surroundings of the Bohai Sea was carried out, and the main controlling factors for the development of high-quality glutenite reservoirs in the Kongdian Formation were clarified. It is found that: (1) The deep Kongdian Formation in the study area has developed fan delta glutenite reservoirs with a buried depth greater than 3 500-4 200 m. It is a deep glutenite reservoir with poor physical properties, mainly low porosity and low permeability, and the diagenesis stage is in the middle diagenesis from A2 to B stage, and dissolution pores are developed. (2) Potassium-rich feldspar framework particles, atmospheric fresh water leaching, organic acid dissolution, overpressure and crack are the main controlling factors for the development of high-quality glutenite reservoirs in the Kongdian Formation in the study area. (3) The Kongdian Formation glutenite reservoirs have mainly experienced atmospheric freshwater enhancement-early diagenesis long-term, rapid burial, rapid compaction-reduction-medium diagenesis A1 mid-to-long-term, rapid burial, slow compaction-reduction, organic acid and ultra pressure massive dissolution to increase pores, first filling of oil and gas-mid-diagenetic A2 or B period, short-term, rapid burial, slow cementation, pore reduction, (or formation of corrosion cracks) and large-scale oil and gas filling. (4) However, the diagenetic evolution stages and pore evolution strength experienced by different structures are obviously different. The Kongdian Formation glutenite reservoir in Bozhong 19-6 structure has experienced early diagenesis → middle diagenesis A1 → middle diagenesis A2 to B, corresponding The porosity of Bozhong has undergone an evolution process of 32.6%→17.3%→12.6%→10.6%, the reduction in porosity due to compaction and cementation is 22.0%, and the total reduction in porosity is 67.6%, respectively; while Bozhong 25-1 tectonic glutenite reservoirs mainly experienced early diagenesis → middle diagenesis A1 → middle diagenetic A2, and the corresponding porosity experienced an evolution process of 32.8%→19.9%→14.2%→13.2%, which suffered compaction and cementation. The porosity reduction is 19.6%, and the total porosity reduction rate is 59.7%. (5) Compared with the BZ 19-6 structure, the Kongdian Formation glutenite reservoir compaction in the BZ 25-1 structure is relatively weak, the overpressure is stronger, and the dissolution is stronger, which are the main factors for the relatively good porosity of the structure. And the coarse-grained and intragranular dissolution pores-fractures formed by the late strong compaction are the main factors for the relatively high permeability of the BZ 19-6 structural glutenite reservoir.
2023, 48(11): 4175-4189.
doi: 10.3799/dqkx.2022.051
Abstract:
The intermittency and low controllability of renewable energy power generation often lead to a mismatch between power supply and demand, which in turn leads to wind abandonment. Power-to-gas (PtG) is a technology that firstly makes full use of excess electrical energy to produce hydrogen (H2) by electrolyzing water, then synthesizes methane (CH4), by combining with carbon dioxide (CO2). Combined with geological storage technology, PtG based subsurface energy storage is expected to become the one of future effective energy storage technology options. However, it is difficult to avoid the mixing of CO2 and CH4 when they are stored in the same reservoir. If stored in different reservoirs, a large amount of CH4 has to be used as cushion gas to maintain the necessary pressure of the reservoir, which causes a large amount of energy loss. Therefore, in this paper it innovatively proposes a new geological energy storage system by using hydraulically connected reservoirs. A three-dimensional multiphase flow model including the wellbore-reservoir injection-production system is established by using reservoir software MUFITS. The process of using hydraulically connected reservoirs for geological energy storage and fluid migration is studied. The advantages of the energy storage model through the production of CO2 and CH4 production wells are quantitatively analyzed. It is found that during the injection stage of cushion gas, the injected fluids move up rapidly and migrates laterally along the overlying layer, the spatial distribution range of CO2 saturation is in a controllable range. In addition, according to the established injection and production rate, the pressure response of the CO2 target reservoir is more moderate than that of the CH4 target reservoir. The overall pressure surge of the reservoir can be weakened due to easy compressibility of CO2. In the process of geological energy storage in hydraulically connecting reservoirs, interaction of pressure between connecting reservoirs has a significant effect on increasing the production of CO2 and CH4.
The intermittency and low controllability of renewable energy power generation often lead to a mismatch between power supply and demand, which in turn leads to wind abandonment. Power-to-gas (PtG) is a technology that firstly makes full use of excess electrical energy to produce hydrogen (H2) by electrolyzing water, then synthesizes methane (CH4), by combining with carbon dioxide (CO2). Combined with geological storage technology, PtG based subsurface energy storage is expected to become the one of future effective energy storage technology options. However, it is difficult to avoid the mixing of CO2 and CH4 when they are stored in the same reservoir. If stored in different reservoirs, a large amount of CH4 has to be used as cushion gas to maintain the necessary pressure of the reservoir, which causes a large amount of energy loss. Therefore, in this paper it innovatively proposes a new geological energy storage system by using hydraulically connected reservoirs. A three-dimensional multiphase flow model including the wellbore-reservoir injection-production system is established by using reservoir software MUFITS. The process of using hydraulically connected reservoirs for geological energy storage and fluid migration is studied. The advantages of the energy storage model through the production of CO2 and CH4 production wells are quantitatively analyzed. It is found that during the injection stage of cushion gas, the injected fluids move up rapidly and migrates laterally along the overlying layer, the spatial distribution range of CO2 saturation is in a controllable range. In addition, according to the established injection and production rate, the pressure response of the CO2 target reservoir is more moderate than that of the CH4 target reservoir. The overall pressure surge of the reservoir can be weakened due to easy compressibility of CO2. In the process of geological energy storage in hydraulically connecting reservoirs, interaction of pressure between connecting reservoirs has a significant effect on increasing the production of CO2 and CH4.
2023, 48(11): 4190-4201.
doi: 10.3799/dqkx.2021.255
Abstract:
Rearranged hopanes have gradually been reported in sediments deposited in various sedimentary environments and related crude oils, but their biological origins and formation mechanisms are still controversial. In this paper it systematically identified four types of rearranged hopanes in the Mesoproterozoic Xiamaling black shales and Jurassic lacustrine crude oils. Based on the relationship between the relative abundance of rearranged hopanes and their biosynthetic reaction schemes, it is proposed that their relative abundance and generation rate are mainly controlled by the biological origins and times of methyl rearrangement reaction. The formation process of early eluting rearranged hopane and 28-nor-spergulanes is more complicated than that of 17α(H)-diahopane, which makes their distribution in sediments and crude oil more limited. In addition, 18α(H)-neohopane can not only be derived from the bacteriohopanetetrol of prokaryotic organisms, but also from diplopterol and/or diploptene, so it is widely distributed in geological samples. Importantly, although sediments and crude oils rich in rearranged hopanes are frequently reported, they may not originate from ubiquitous prokaryotic bacteria, but may only exist in a small number of bacterial communities living in a specific environment.
Rearranged hopanes have gradually been reported in sediments deposited in various sedimentary environments and related crude oils, but their biological origins and formation mechanisms are still controversial. In this paper it systematically identified four types of rearranged hopanes in the Mesoproterozoic Xiamaling black shales and Jurassic lacustrine crude oils. Based on the relationship between the relative abundance of rearranged hopanes and their biosynthetic reaction schemes, it is proposed that their relative abundance and generation rate are mainly controlled by the biological origins and times of methyl rearrangement reaction. The formation process of early eluting rearranged hopane and 28-nor-spergulanes is more complicated than that of 17α(H)-diahopane, which makes their distribution in sediments and crude oil more limited. In addition, 18α(H)-neohopane can not only be derived from the bacteriohopanetetrol of prokaryotic organisms, but also from diplopterol and/or diploptene, so it is widely distributed in geological samples. Importantly, although sediments and crude oils rich in rearranged hopanes are frequently reported, they may not originate from ubiquitous prokaryotic bacteria, but may only exist in a small number of bacterial communities living in a specific environment.
2023, 48(11): 4202-4213.
doi: 10.3799/dqkx.2022.003
Abstract:
The solute exchange between karst conduit and matrix is a common phenomenon during solute transport in karst groundwater, which has a key control effect on pollutant transport in karst water system. The solute exchange between conduit and matrix becomes very complicated under the concentrated recharge condition, which is a challenge to characterize the physical process and simulation.Based on literature in related fields, in this paper it summarizes the observation, test methods, mechanism, control factors, as well as current simulation methods of solute exchange between karst conduit and matrix, and points out the existing problems in the researches. The solute exchange control experiments under the conditions of unsteady flow should be conducted by indoor conduit-matrix physical models for further researches, which will help analyze its influencing control factors and reveal the physical mechanism of solute exchange between the conduit and matrix. The mathematical model of solute transport coupled solute exchange process should be established by describing solute exchange boundary conditions, which needs to be verified by field tracer tests.
The solute exchange between karst conduit and matrix is a common phenomenon during solute transport in karst groundwater, which has a key control effect on pollutant transport in karst water system. The solute exchange between conduit and matrix becomes very complicated under the concentrated recharge condition, which is a challenge to characterize the physical process and simulation.Based on literature in related fields, in this paper it summarizes the observation, test methods, mechanism, control factors, as well as current simulation methods of solute exchange between karst conduit and matrix, and points out the existing problems in the researches. The solute exchange control experiments under the conditions of unsteady flow should be conducted by indoor conduit-matrix physical models for further researches, which will help analyze its influencing control factors and reveal the physical mechanism of solute exchange between the conduit and matrix. The mathematical model of solute transport coupled solute exchange process should be established by describing solute exchange boundary conditions, which needs to be verified by field tracer tests.
2023, 48(11): 4214-4228.
doi: 10.3799/dqkx.2022.018
Abstract:
It remains controversial whether the Yichang and Yangluo gravel beds in the west and east of the Jianghan basin are related to the evolution and development of the Yangtze River. To address the problem, it carried out the detrital zircon U-Pb age analysis from the Yichang and Yangluo gravel layers. The U-Pb age analysis was also conducted on the Juzhang and Qingjiang rivers close to the Yichang gravel layers. It also analyzes detrital zircon U-Pb ages in Huanshui, Daoshui and Jushui rivers surrounding the Yangluo gravel bed. A total of 654 new zircon U-Pb ages have been reported. It collected the published detrital zircon U-Pb ages from the upper reach of the Yangtze River in the region, combined with the sedimentary age of the gravel beds, and systematically identified the material sources of the Yichang and Yangluo gravel beds. The results show that the Yangtze River becomes the sand material supply river of Yichang and Yangluo gravel beds in 1.2-0.7 Ma and 1.3 Ma, respectively. The comparison with the gravel beds in the upper and lower reaches of the Yangtze River and the provenance tracing results indicate that the Yangtze River appeared in the Early Pleistocene in response to the uplift of the Tibetan plateau and the intensification of the East Asian summer monsoon. Therefore, the combination of continuous tectonic processes and environmental changes in East Asia during the Early Pleistocene was crucial to the stable emergence of the Yangtze River with a continent-scale length of more than 6 000 km.
It remains controversial whether the Yichang and Yangluo gravel beds in the west and east of the Jianghan basin are related to the evolution and development of the Yangtze River. To address the problem, it carried out the detrital zircon U-Pb age analysis from the Yichang and Yangluo gravel layers. The U-Pb age analysis was also conducted on the Juzhang and Qingjiang rivers close to the Yichang gravel layers. It also analyzes detrital zircon U-Pb ages in Huanshui, Daoshui and Jushui rivers surrounding the Yangluo gravel bed. A total of 654 new zircon U-Pb ages have been reported. It collected the published detrital zircon U-Pb ages from the upper reach of the Yangtze River in the region, combined with the sedimentary age of the gravel beds, and systematically identified the material sources of the Yichang and Yangluo gravel beds. The results show that the Yangtze River becomes the sand material supply river of Yichang and Yangluo gravel beds in 1.2-0.7 Ma and 1.3 Ma, respectively. The comparison with the gravel beds in the upper and lower reaches of the Yangtze River and the provenance tracing results indicate that the Yangtze River appeared in the Early Pleistocene in response to the uplift of the Tibetan plateau and the intensification of the East Asian summer monsoon. Therefore, the combination of continuous tectonic processes and environmental changes in East Asia during the Early Pleistocene was crucial to the stable emergence of the Yangtze River with a continent-scale length of more than 6 000 km.
2023, 48(11): 4229-4242.
doi: 10.3799/dqkx.2022.084
Abstract:
To find out the characteristics of Sb content in groundwater of Quaternary basin on the Zi River estuary area, in this paper it studies the distribution characteristics of Sb concentration and sources of Sb in groundwater by collecting surface water and groundwater samples from the main stream and estuary area, combined the correlation analysis of\begin{document}$ {\rm{ \mathsf{ δ} }}^{2}\mathrm{H},{\rm{ \mathsf{ δ} }}^{18}\mathrm{O} $\end{document}
To find out the characteristics of Sb content in groundwater of Quaternary basin on the Zi River estuary area, in this paper it studies the distribution characteristics of Sb concentration and sources of Sb in groundwater by collecting surface water and groundwater samples from the main stream and estuary area, combined the correlation analysis of
2023, 48(11): 4243-4255.
doi: 10.3799/dqkx.2022.112
Abstract:
In order to find out the spatial distribution characteristics of the underground aquifer in Xiong'an New Area, it carried out the areal transient electromagnetic survey in Xiong'an New Area.The results show that TEM can be used to quickly delineate the planar distribution of alluvial-diluvial fans and ancient channels, which has advantages of quick delineation of near surface water sources and favorable water-rich areas.According to 3D geoelectric model analysis, alluvial-diluvial fan and Minghuazhen Formation aquifers are characterized by high resistivity, the thickness of alluvial-diluvial fan is less than 100 m and gradually disappears from west to east, the alluvial-diluvial fan is irregularly distributed from north Gaoyang-An'xin-Xiongxian and North Bazhou, alluvial-diluvial fan is the main aquifer in Xiong'an New Area, the Minghuazhen Formation aquifer is horizontally layered below 400 m, and its water content is weaker than the surface alluvial diluvial fan. In this paper, it analyzes the spatial distribution characteristics of different water bodies from 3D space, providing a reliable geophysical basis for rational utilization and protection of groundwater resources in the Xiong'an New Area.
In order to find out the spatial distribution characteristics of the underground aquifer in Xiong'an New Area, it carried out the areal transient electromagnetic survey in Xiong'an New Area.The results show that TEM can be used to quickly delineate the planar distribution of alluvial-diluvial fans and ancient channels, which has advantages of quick delineation of near surface water sources and favorable water-rich areas.According to 3D geoelectric model analysis, alluvial-diluvial fan and Minghuazhen Formation aquifers are characterized by high resistivity, the thickness of alluvial-diluvial fan is less than 100 m and gradually disappears from west to east, the alluvial-diluvial fan is irregularly distributed from north Gaoyang-An'xin-Xiongxian and North Bazhou, alluvial-diluvial fan is the main aquifer in Xiong'an New Area, the Minghuazhen Formation aquifer is horizontally layered below 400 m, and its water content is weaker than the surface alluvial diluvial fan. In this paper, it analyzes the spatial distribution characteristics of different water bodies from 3D space, providing a reliable geophysical basis for rational utilization and protection of groundwater resources in the Xiong'an New Area.
2023, 48(11): 4256-4269.
doi: 10.3799/dqkx.2022.367
Abstract:
The contradiction between supply and demand of water resources in Dongting basin has become increasingly prominent. In order to evaluate the age, circulation and renewal of groundwater, 12 groups water samples of tritium (3H) and CFCs were collected from shallow groundwater in Zijiang basin of Dongting basin in 2021. The piston flow (PFM) model was used to calculate the 3H and CFCs ages of groundwater. The results show that the groundwater age in the study area gradually ages from the piedmont hilly area to the plain area. In the piedmont hilly area, the groundwater age is generally less than 40 years, the recharge ratio of fresh water was 96.36%-86.41%, the actual flow rate of groundwater is 2.18 m/d, and the groundwater circulation renewal was fast. The age of groundwater in plain area is above 50 years, the proportion of new water recharge is 37.09%, the actual groundwater flow rate is 1.2-1.59 m/d, and the infiltration flow rate is 0.000 8-0.001 2 m/d. The groundwater cycle renewal is slow. Combined with the regional hydrogeological conditions, the piedmont hilly area mainly developed local water flow system, and groundwater in the plain area belongs to the intermediate water flow system. The groundwater age in the central plain is more than 80 years, which may overlap with the regional circulation system.
The contradiction between supply and demand of water resources in Dongting basin has become increasingly prominent. In order to evaluate the age, circulation and renewal of groundwater, 12 groups water samples of tritium (3H) and CFCs were collected from shallow groundwater in Zijiang basin of Dongting basin in 2021. The piston flow (PFM) model was used to calculate the 3H and CFCs ages of groundwater. The results show that the groundwater age in the study area gradually ages from the piedmont hilly area to the plain area. In the piedmont hilly area, the groundwater age is generally less than 40 years, the recharge ratio of fresh water was 96.36%-86.41%, the actual flow rate of groundwater is 2.18 m/d, and the groundwater circulation renewal was fast. The age of groundwater in plain area is above 50 years, the proportion of new water recharge is 37.09%, the actual groundwater flow rate is 1.2-1.59 m/d, and the infiltration flow rate is 0.000 8-0.001 2 m/d. The groundwater cycle renewal is slow. Combined with the regional hydrogeological conditions, the piedmont hilly area mainly developed local water flow system, and groundwater in the plain area belongs to the intermediate water flow system. The groundwater age in the central plain is more than 80 years, which may overlap with the regional circulation system.
2023, 48(11): 4270-4278.
doi: 10.3799/dqkx.2022.454
Abstract:
Soil salinization has become a worldwide environmental problem. In order to explore the new biological technology for salinized soil improvement, laboratory simulation experiments were carried out in this study, in which an indigenous microalgae isolated from the biological soil crust of salinized soil in Xinjiang was used to explore the salt tolerance of the algae and its effect on saline-alkali soil. The results show that the microalgae had high salt tolerance to grow in 1 mol/L NaCl solution. The synthesis of algal photosynthetic pigments was inhibited by salt stress with obvious gradient effect. After 18 d incubation, the contents of the soluble salts in 0.5 mol/L, 1.0 mol/L, 1.5 mol/L NaCl treatment groups decreased by 16.99%, 9.23%, and 3.27%, respectively. The soil microalgae were inoculated and cultivated on the surface of high saline-alkali soil. The experimental groups with initial chlorophyll a of 3 μg/cm2, 5 μg/cm2 and 8 μg/cm2 soil, the soil moisture content increased by 29.41%, 38.29% and 39.54%, and extracellular polymers (EPS) increased by 82.84%, 86.04%, and 116.06%, respectively. These results indicate that soil microalgae can reduce soluble salt, control soil salt transport, and maintain soil moisture. This study provides an important theoretical basis for saline soil improvement by soil microalgae.
Soil salinization has become a worldwide environmental problem. In order to explore the new biological technology for salinized soil improvement, laboratory simulation experiments were carried out in this study, in which an indigenous microalgae isolated from the biological soil crust of salinized soil in Xinjiang was used to explore the salt tolerance of the algae and its effect on saline-alkali soil. The results show that the microalgae had high salt tolerance to grow in 1 mol/L NaCl solution. The synthesis of algal photosynthetic pigments was inhibited by salt stress with obvious gradient effect. After 18 d incubation, the contents of the soluble salts in 0.5 mol/L, 1.0 mol/L, 1.5 mol/L NaCl treatment groups decreased by 16.99%, 9.23%, and 3.27%, respectively. The soil microalgae were inoculated and cultivated on the surface of high saline-alkali soil. The experimental groups with initial chlorophyll a of 3 μg/cm2, 5 μg/cm2 and 8 μg/cm2 soil, the soil moisture content increased by 29.41%, 38.29% and 39.54%, and extracellular polymers (EPS) increased by 82.84%, 86.04%, and 116.06%, respectively. These results indicate that soil microalgae can reduce soluble salt, control soil salt transport, and maintain soil moisture. This study provides an important theoretical basis for saline soil improvement by soil microalgae.
2023, 48(11): 4279-4294.
doi: 10.3799/dqkx.2021.251
Abstract:
Abundant terrestrial ichnofossils were recovered from the middle and lower members of the Middle Triassic Ermaying Formation in Jiyuan area, West Henan Province. A total of 7 ichnogenera and 9 ichnospecies have been found and identified, including Skolithos linearis, Palaeophycus tubularis, Palaeophycus alternatus, Scoyenia gracilis, Planolites beverleyensis, Planolites montanus, Taenidium barretti, Didymaulichnus roualti and rhizoliths. According to the pattern, composition and distribution of ichnofossils, five kinds of ichnofabrics have been discriminated: (1) Skolithos ichnofabric represents the fluvial or shore lacustrine sedimentary environment with mud, fine sand deposits; (2) Palaeophycus-Planolites ichnofabric appears in the sedimentary environment of low-medium hydropower fluvial embankment or lacustrine mudflat deposits; (3) Scoyenia ichnofabric forms in the periodically submerged flood plain sedimentary environment; (4) Taenidium ichnofabric emerges from the flood plain environment under semi-arid climate; (5) rhizoliths ichnofabric preserves from embank oroverbank environment under semi-arid climate conditions. Based on the ichnofabrics and sedimentary characteristics, fluvio-lacustrine strata are dominant in the middle and lower members of the Ermaying Formation. From bottom to top, braided stream-meandering river-lacustrine deposits were formed successively. It can be divided into six sedimentary subfacies: meandering channel subfacies, embankment subfacies, overbank subfacies, braided channel subfacies, floodplain subfacies and shore lacuetrine subfacies. The whole sedimentary period is characterized by alternation of humid and semi-arid, with the transformation from reduction environment to oxidation environment.
Abundant terrestrial ichnofossils were recovered from the middle and lower members of the Middle Triassic Ermaying Formation in Jiyuan area, West Henan Province. A total of 7 ichnogenera and 9 ichnospecies have been found and identified, including Skolithos linearis, Palaeophycus tubularis, Palaeophycus alternatus, Scoyenia gracilis, Planolites beverleyensis, Planolites montanus, Taenidium barretti, Didymaulichnus roualti and rhizoliths. According to the pattern, composition and distribution of ichnofossils, five kinds of ichnofabrics have been discriminated: (1) Skolithos ichnofabric represents the fluvial or shore lacustrine sedimentary environment with mud, fine sand deposits; (2) Palaeophycus-Planolites ichnofabric appears in the sedimentary environment of low-medium hydropower fluvial embankment or lacustrine mudflat deposits; (3) Scoyenia ichnofabric forms in the periodically submerged flood plain sedimentary environment; (4) Taenidium ichnofabric emerges from the flood plain environment under semi-arid climate; (5) rhizoliths ichnofabric preserves from embank oroverbank environment under semi-arid climate conditions. Based on the ichnofabrics and sedimentary characteristics, fluvio-lacustrine strata are dominant in the middle and lower members of the Ermaying Formation. From bottom to top, braided stream-meandering river-lacustrine deposits were formed successively. It can be divided into six sedimentary subfacies: meandering channel subfacies, embankment subfacies, overbank subfacies, braided channel subfacies, floodplain subfacies and shore lacuetrine subfacies. The whole sedimentary period is characterized by alternation of humid and semi-arid, with the transformation from reduction environment to oxidation environment.
2023, 48(11): 4295-4310.
doi: 10.3799/dqkx.2022.308
Abstract:
InSAR technology is widely used in the identification of hidden dangers of geological disasters. Different InSAR methods have certain application conditions and limiting factors. However, the disaster-causing mechanism of geological disasters in alpine and canyon areas is complex and the disaster patterns are diverse, which is often difficult to effectively identify using one technical method. In this paper, differential interferometry (D-InSAR), permanent scatterer measurement (PS-InSAR), small baseline set measurement (SBAS-InSAR), distributed target measurement (DS-InSAR) and offset tracking (Offset-tracking) a total of 5 InSAR technologies, taking the Xichang area along the Yalong River as the research area to identify potential geological hazards, and to carry out comparison and analysis of different InSAR technology methods. The results show that a total of 28 deformation points were identified, of which 16 were identified by D-InSAR, 27 by SBAS-InSAR, 3 by PS-InSAR, 21 by DS-InSAR, and 21 by Offset-tracking 0.In the alpine and canyon areas, SBAS-InSAR technology has the widest application range and the largest number of hidden danger points. Taking into account the accuracy and efficiency, it can effectively identify the hidden dangers of geological disasters in the alpine and canyon areas. Based on the analysis of the particularity of using InSAR technology to identify hidden dangers of geological disasters in high mountains and valleys, a technical route of using InSAR technology to identify hidden dangers of geological disasters in high mountains and valleys is proposed according to the characteristics of different methods and technologies, so as to identify hidden dangers of geological disasters more efficiently and accurately.
InSAR technology is widely used in the identification of hidden dangers of geological disasters. Different InSAR methods have certain application conditions and limiting factors. However, the disaster-causing mechanism of geological disasters in alpine and canyon areas is complex and the disaster patterns are diverse, which is often difficult to effectively identify using one technical method. In this paper, differential interferometry (D-InSAR), permanent scatterer measurement (PS-InSAR), small baseline set measurement (SBAS-InSAR), distributed target measurement (DS-InSAR) and offset tracking (Offset-tracking) a total of 5 InSAR technologies, taking the Xichang area along the Yalong River as the research area to identify potential geological hazards, and to carry out comparison and analysis of different InSAR technology methods. The results show that a total of 28 deformation points were identified, of which 16 were identified by D-InSAR, 27 by SBAS-InSAR, 3 by PS-InSAR, 21 by DS-InSAR, and 21 by Offset-tracking 0.In the alpine and canyon areas, SBAS-InSAR technology has the widest application range and the largest number of hidden danger points. Taking into account the accuracy and efficiency, it can effectively identify the hidden dangers of geological disasters in the alpine and canyon areas. Based on the analysis of the particularity of using InSAR technology to identify hidden dangers of geological disasters in high mountains and valleys, a technical route of using InSAR technology to identify hidden dangers of geological disasters in high mountains and valleys is proposed according to the characteristics of different methods and technologies, so as to identify hidden dangers of geological disasters more efficiently and accurately.
2023, 48(11): 4311-4320.
doi: 10.3799/dqkx.2022.287
Abstract:
To better understand microbial dissolution and oxidation of stibnite at the community level, microbial communities were enriched from the tailings in the Xikuangshan tailings pond, Hunan Province, which were further used to study microbial interaction with stibnite. pH, total Sb, Sb(Ⅴ), Sb(Ⅲ) and SO42- were measured periodically. 16S rRNA high-throughput sequencing and X-ray powder diffractometer (XRD) were exploited to detect compositions of microbial communities and mineral phases, respectively. The results show that microbial communities can grow with sodium lactate and increase the pH of the solution under aerobic condition, which facilitated the dissolution of stibnite. The concentration of Sb(Ⅴ) accumulated in the solution due to the oxidation of the released Sb(Ⅲ), with an decrease after the 12th day. The Sb(Ⅲ) concentration in the solution increased after the 9th day and was a little bit higher than that of Sb(Ⅴ) at the end of the experiments. The incomplete oxidation of Sb(Ⅲ) may result from the low relative abundances of antimony-oxidizing bacteria such as Paracoccus and Bosea in the enriched culture. The variation of solution chemistry, particularly the Sb concentration, exerted strong selection on microbial communities. Microbial communities were dominated by Herbaspirillum sp., with strong resistance to metals, such as and Sb. However their relative abundances decreased after 11 days' interaction potentially due to the accumulation of Sb in the system. Secondary Sb(Ⅴ)-bearing mineral, sodium antimonite, was detected at the end of the experiments in the biotic systems, which matched well with the decrease of the concentration of Sb(Ⅴ) in the solution. Our results further confirm the mechanism of microbial dissolution of stibnite followed by oxidation and transformation of minerals at the community level, which provides new insights of understanding the impact of microbial communities on the dissolution of Sb-bearing secondary minerals, oxidation, migration and formation of antimony in natural environments.
To better understand microbial dissolution and oxidation of stibnite at the community level, microbial communities were enriched from the tailings in the Xikuangshan tailings pond, Hunan Province, which were further used to study microbial interaction with stibnite. pH, total Sb, Sb(Ⅴ), Sb(Ⅲ) and SO42- were measured periodically. 16S rRNA high-throughput sequencing and X-ray powder diffractometer (XRD) were exploited to detect compositions of microbial communities and mineral phases, respectively. The results show that microbial communities can grow with sodium lactate and increase the pH of the solution under aerobic condition, which facilitated the dissolution of stibnite. The concentration of Sb(Ⅴ) accumulated in the solution due to the oxidation of the released Sb(Ⅲ), with an decrease after the 12th day. The Sb(Ⅲ) concentration in the solution increased after the 9th day and was a little bit higher than that of Sb(Ⅴ) at the end of the experiments. The incomplete oxidation of Sb(Ⅲ) may result from the low relative abundances of antimony-oxidizing bacteria such as Paracoccus and Bosea in the enriched culture. The variation of solution chemistry, particularly the Sb concentration, exerted strong selection on microbial communities. Microbial communities were dominated by Herbaspirillum sp., with strong resistance to metals, such as and Sb. However their relative abundances decreased after 11 days' interaction potentially due to the accumulation of Sb in the system. Secondary Sb(Ⅴ)-bearing mineral, sodium antimonite, was detected at the end of the experiments in the biotic systems, which matched well with the decrease of the concentration of Sb(Ⅴ) in the solution. Our results further confirm the mechanism of microbial dissolution of stibnite followed by oxidation and transformation of minerals at the community level, which provides new insights of understanding the impact of microbial communities on the dissolution of Sb-bearing secondary minerals, oxidation, migration and formation of antimony in natural environments.
2023, 48(11): 4321-4334.
doi: 10.3799/dqkx.2023.106
Abstract:
As a complex marine ecosystem, reefs underwent a significant change in the composition of major builders during the Precambrian-Cambrian transition. The wide distribution of reef-building metazoans was likely a response to the co-evolution of life and oceans in the Early Cambrian. In this study, it performed a systematic sedimentological analysis on the archaeocyath-bearing reefs of the Xiannüdong Formation in the northern margin of the Upper Yangtze block. Petrological evidence indicates that the archaeocyaths may have contributed to the formation of the reefs individually or in combination with calcimicrobes. In some situations, archaeocyaths acted only as inhabitants of large thrombolitic reefs. The archaeocyath-dominated reefs are characterized by low-relief morphological units and partially cemented internal structures, and are thought to have formed in mid-ramp and inter-shoal environments with relatively low hydrodynamic conditions. Archaeocyath-calcimicrobial reefs and archaeocyath-bearing microbial reefs can form separately or develop as multiple stacked complexes in depositional successions thought to have formed in subtidal environments. Within the reef complexes, some archaeocyaths are coated or crusted by calcified microbes and few reefal cements are visible. The lack of archaeocyath-dominated reefs in shallow, high-energy conditions may be related to their small body size and thin skeletal structures, which cannot withstand the washing and destruction of waves and storms during this period. In addition, the relatively high nutrient levels in coastal environments, possibly caused by increased terrigenous input, may be more conducive to the development of calcimicrobe-dominated reef systems than archaeocyath-dominated reefs due to the greater nutrient competitiveness of the microbes.
As a complex marine ecosystem, reefs underwent a significant change in the composition of major builders during the Precambrian-Cambrian transition. The wide distribution of reef-building metazoans was likely a response to the co-evolution of life and oceans in the Early Cambrian. In this study, it performed a systematic sedimentological analysis on the archaeocyath-bearing reefs of the Xiannüdong Formation in the northern margin of the Upper Yangtze block. Petrological evidence indicates that the archaeocyaths may have contributed to the formation of the reefs individually or in combination with calcimicrobes. In some situations, archaeocyaths acted only as inhabitants of large thrombolitic reefs. The archaeocyath-dominated reefs are characterized by low-relief morphological units and partially cemented internal structures, and are thought to have formed in mid-ramp and inter-shoal environments with relatively low hydrodynamic conditions. Archaeocyath-calcimicrobial reefs and archaeocyath-bearing microbial reefs can form separately or develop as multiple stacked complexes in depositional successions thought to have formed in subtidal environments. Within the reef complexes, some archaeocyaths are coated or crusted by calcified microbes and few reefal cements are visible. The lack of archaeocyath-dominated reefs in shallow, high-energy conditions may be related to their small body size and thin skeletal structures, which cannot withstand the washing and destruction of waves and storms during this period. In addition, the relatively high nutrient levels in coastal environments, possibly caused by increased terrigenous input, may be more conducive to the development of calcimicrobe-dominated reef systems than archaeocyath-dominated reefs due to the greater nutrient competitiveness of the microbes.
2023, 48(11): 4335-4348.
doi: 10.3799/dqkx.2022.104
Abstract:
In this study, it aims to examine the fractional abundance of GDGTs and GDGT-based proxies in 28 lakes in the middle and lower reaches of Yangtze River. It compares the GDGT distributions of these lakes with the published Chinese soil data to determine the lacustrine GDGT sources. The results indicate that there are different distributions of isoGDGTs between lake sediments and soils, however, the brGDGT distributions show no significant difference between lake sediments and soils, indicating that brGDGTs from lacustrine sediments may come from soils surrounding the lakes. It further measured the relationship between chemical parameters and GDGT distributions of these lakes affected by varying degrees of eutrophication. Our results show that only the water depth displays significant correlation with crenarchaeol, which implies that water depth may influence the production of Thaumarchaeota in these lake environments.
In this study, it aims to examine the fractional abundance of GDGTs and GDGT-based proxies in 28 lakes in the middle and lower reaches of Yangtze River. It compares the GDGT distributions of these lakes with the published Chinese soil data to determine the lacustrine GDGT sources. The results indicate that there are different distributions of isoGDGTs between lake sediments and soils, however, the brGDGT distributions show no significant difference between lake sediments and soils, indicating that brGDGTs from lacustrine sediments may come from soils surrounding the lakes. It further measured the relationship between chemical parameters and GDGT distributions of these lakes affected by varying degrees of eutrophication. Our results show that only the water depth displays significant correlation with crenarchaeol, which implies that water depth may influence the production of Thaumarchaeota in these lake environments.
