2015 Vol. 40, No. 11
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2015, 40(11): 1781-1795.
doi: 10.3799/dqkx.2015.159
Abstract:
It is generally accepted that the Jiangnan orogenic belt led to the amalgamation of the Yangtze with Cathaysia blocks during the Neoproterozoic period. However, its tectonic evolution and amalgamation timing are still in debate. This paper presents a set of new geochronological and geochemical data for the newly-identified Neoproterozoic high-Mg volcanics from Cihua (Jiangxi). LA-ICP-MS zircon U-Pb dating of the representative sample yields a weighted mean age of 832±12 Ma (n=16, MSWD=0.12), representing the eruption age of the andesite. Geochemical results indicate that they can be classified as high-Mg andesites with SiO2 ranging from 57.67% to 61.33%, MgO from 3.51% to 4.29% and Mg-number from 52 to 57. Their chondrite-normalized REE patterns exhibit a left-sloping pattern with enriched LREEs relative to HREEs. On the primitive mantle-normalized multi-element patterns, these samples have strong enrichment in LILE and depletion in HFSE with marked negative Nb-Ta, Ti and positive Th anomalies, similar to those of the typical arc volcanics. The generation of the volcanic rocks might have been attributed to an interaction of the subducted melt/fluid or sediment with the overlying refractory mantle, suggesting the central Jiangnan orogen was still on the subduction till ~832 Ma. It is concluded that the Jiangnan orogen consists of several branches with distinct amalgamation evolution.
It is generally accepted that the Jiangnan orogenic belt led to the amalgamation of the Yangtze with Cathaysia blocks during the Neoproterozoic period. However, its tectonic evolution and amalgamation timing are still in debate. This paper presents a set of new geochronological and geochemical data for the newly-identified Neoproterozoic high-Mg volcanics from Cihua (Jiangxi). LA-ICP-MS zircon U-Pb dating of the representative sample yields a weighted mean age of 832±12 Ma (n=16, MSWD=0.12), representing the eruption age of the andesite. Geochemical results indicate that they can be classified as high-Mg andesites with SiO2 ranging from 57.67% to 61.33%, MgO from 3.51% to 4.29% and Mg-number from 52 to 57. Their chondrite-normalized REE patterns exhibit a left-sloping pattern with enriched LREEs relative to HREEs. On the primitive mantle-normalized multi-element patterns, these samples have strong enrichment in LILE and depletion in HFSE with marked negative Nb-Ta, Ti and positive Th anomalies, similar to those of the typical arc volcanics. The generation of the volcanic rocks might have been attributed to an interaction of the subducted melt/fluid or sediment with the overlying refractory mantle, suggesting the central Jiangnan orogen was still on the subduction till ~832 Ma. It is concluded that the Jiangnan orogen consists of several branches with distinct amalgamation evolution.
2015, 40(11): 1796-1801.
doi: 10.3799/dqkx.2015.160
Abstract:
As a typical ore grade estimation method, inverse distance weighting (IDW) has a long-time standing deficiency in reliability evaluation for its estimates, which has seriously limited its practicability. A statistical solution is presented in this paper to address the issue. A key character of IDW, that weight of each participation sample is the probability that the current un-sampled value is equal to the corresponding sample value, is proposed and proved by considering the participation samples as cutoff values during an indicating process. Based on this character, the conditional cumulative distribution function (CCDF) models related to the points to be estimated are constructed to fully characterize the uncertainty of IDW estimates. At last, a case study is carried out using cross validation and a test dataset from exploration engineering of a real ore-body. It is found that the real character of test dataset has been successfully revealed by the medium, expected and variance drawing from the constructed CCDFs, showing that the theoretical analysis and practical application can prove the validity and practicability of the proposed method to some extent.
As a typical ore grade estimation method, inverse distance weighting (IDW) has a long-time standing deficiency in reliability evaluation for its estimates, which has seriously limited its practicability. A statistical solution is presented in this paper to address the issue. A key character of IDW, that weight of each participation sample is the probability that the current un-sampled value is equal to the corresponding sample value, is proposed and proved by considering the participation samples as cutoff values during an indicating process. Based on this character, the conditional cumulative distribution function (CCDF) models related to the points to be estimated are constructed to fully characterize the uncertainty of IDW estimates. At last, a case study is carried out using cross validation and a test dataset from exploration engineering of a real ore-body. It is found that the real character of test dataset has been successfully revealed by the medium, expected and variance drawing from the constructed CCDFs, showing that the theoretical analysis and practical application can prove the validity and practicability of the proposed method to some extent.
2015, 40(11): 1802-1809.
doi: 10.3799/dqkx.2015.161
Abstract:
Every porphyry copper deposit has different geological structure, metallogenic epoch and ore controlling factors. Therefore, it is necessary to carry out geological investigation to obtain the information of the iconic alteration mineral assemblage to extract the alteration information by using remote sensing technology and determine prospective areas. A comprehensive analysis of geological characteristics and ore controlling factors of porphyry copper deposit in southern Peru is carried out in this study. The combined information of argillic- and phyllic-alteration and propylitic alteration is established as the ore prospecting indicator and the technology of alteration information extraction is explored with ASTER data. Combined with existing mining geological data, hyperspectral image and field survey results, alteration extraction results are confirmed as reliable and effective and the other two prospective areas are delineated. The multi-spectral remote sensing prospecting model is constructed and its application proves successful in other porphyry copper districts such as Chile, Argentina.
Every porphyry copper deposit has different geological structure, metallogenic epoch and ore controlling factors. Therefore, it is necessary to carry out geological investigation to obtain the information of the iconic alteration mineral assemblage to extract the alteration information by using remote sensing technology and determine prospective areas. A comprehensive analysis of geological characteristics and ore controlling factors of porphyry copper deposit in southern Peru is carried out in this study. The combined information of argillic- and phyllic-alteration and propylitic alteration is established as the ore prospecting indicator and the technology of alteration information extraction is explored with ASTER data. Combined with existing mining geological data, hyperspectral image and field survey results, alteration extraction results are confirmed as reliable and effective and the other two prospective areas are delineated. The multi-spectral remote sensing prospecting model is constructed and its application proves successful in other porphyry copper districts such as Chile, Argentina.
2015, 40(11): 1810-1823.
doi: 10.3799/dqkx.2015.162
Abstract:
The successful exploration and development of shale gas have triggered an upsurge of research in global marine shale. However, more reservoir quality research of non-marine shale in oil window is still needed. Reservoir quality potential of Upper Triassic Chang 7 shale in Ordos basin was analyzed based on the data from thin section, FE-SEM, environmental SEM, nano-CT, GRI, and gas adsorption. Chang 7 shale is deposited in semi-deep to deep lake, covering an area of 10×104 km2. Geochemical data suggests that Chang 7 shale has potential of great hydrocarbon (HC) generation, with TOC > 2%, Ro=0.8%-1.0% and HI=124-480 mg/g. The brittle mineral content is 45%-59%. The total porosity and permeability are 0.6%-3.8%, 0.000 72×10-3-0.002 30×10-3 μm2 respectively. Three types of pores including interparticle pores, intra-particle pores and intra-organic matter (OM) pores are discovered, and intra-illite/smectite mix-layers pores dominate in the storage space, with small number of OM pores. The diameter of pores is 30-200 nm and the connectivity of pore system is medium to good, indicating that Chang 7 shale is of the potential to become reservoir for shale oil. The pore volume is more related to illite/smectite mix-layers content than to that of maturity and hydrocarbon index, which may suggest that the porosity in Chang 7 shale is controlled by diagenesis rather than HC generation. The residual HC is absorbed and distributed as free hydrocarbons in intra-pyrite pores, intra-illite/smectite mix-layer pores, intra-illite pores and inter-feldspar pores.
The successful exploration and development of shale gas have triggered an upsurge of research in global marine shale. However, more reservoir quality research of non-marine shale in oil window is still needed. Reservoir quality potential of Upper Triassic Chang 7 shale in Ordos basin was analyzed based on the data from thin section, FE-SEM, environmental SEM, nano-CT, GRI, and gas adsorption. Chang 7 shale is deposited in semi-deep to deep lake, covering an area of 10×104 km2. Geochemical data suggests that Chang 7 shale has potential of great hydrocarbon (HC) generation, with TOC > 2%, Ro=0.8%-1.0% and HI=124-480 mg/g. The brittle mineral content is 45%-59%. The total porosity and permeability are 0.6%-3.8%, 0.000 72×10-3-0.002 30×10-3 μm2 respectively. Three types of pores including interparticle pores, intra-particle pores and intra-organic matter (OM) pores are discovered, and intra-illite/smectite mix-layers pores dominate in the storage space, with small number of OM pores. The diameter of pores is 30-200 nm and the connectivity of pore system is medium to good, indicating that Chang 7 shale is of the potential to become reservoir for shale oil. The pore volume is more related to illite/smectite mix-layers content than to that of maturity and hydrocarbon index, which may suggest that the porosity in Chang 7 shale is controlled by diagenesis rather than HC generation. The residual HC is absorbed and distributed as free hydrocarbons in intra-pyrite pores, intra-illite/smectite mix-layer pores, intra-illite pores and inter-feldspar pores.
2015, 40(11): 1824-1833.
doi: 10.3799/dqkx.2015.163
Abstract:
Organic reservoir is one of the important reservoir types in shale. The development of organic reservoir space in lacustrine shales within oil window is lack of research work. In view of this, lacustrine shale samples with different maturities in oil window were selected and prepared by argon ion-milling techniques. Joint Quanta200 scanning electron microscope and EDAX energy spectrometer, and JSM-6700f field emission scanning electron microscope were employed to observe the microstructure and analyze the composition of lacustrine shales. Both back scattered images and secondary electronic images show that abundant mixtures of dark banded organic matter (OM)-clay-carbonate and OM-clay-sulfate were developed in shales. Pores were easily developed in the mixtures. From 2 500 m to 4 000 m, the pores continuously exist. At the depths less than 3 600 m, the pore size generally occurs on micron scale. With the continued evolution, nano pores increase and are densely distributed. The intra-pores in the mixtures are synchronous with the rapid increasing of oil saturation and the rising of free organic acids in shales, respectively. The development of the pores not only depends on the hydrocarbon generation, but also on the interaction of hydrocarbon conversion and the organic acid dissolution. The results indicate that in lacustrine shales within oil window, organic matter and inorganic minerals undergo evolution as a whole and interact with each other. The combination of hydrocarbon generation and dissolution form abundant reservoir space in the hybrid of organic matter and minerals, which has important significance to the occurrence of oil and gas in continental shales.
Organic reservoir is one of the important reservoir types in shale. The development of organic reservoir space in lacustrine shales within oil window is lack of research work. In view of this, lacustrine shale samples with different maturities in oil window were selected and prepared by argon ion-milling techniques. Joint Quanta200 scanning electron microscope and EDAX energy spectrometer, and JSM-6700f field emission scanning electron microscope were employed to observe the microstructure and analyze the composition of lacustrine shales. Both back scattered images and secondary electronic images show that abundant mixtures of dark banded organic matter (OM)-clay-carbonate and OM-clay-sulfate were developed in shales. Pores were easily developed in the mixtures. From 2 500 m to 4 000 m, the pores continuously exist. At the depths less than 3 600 m, the pore size generally occurs on micron scale. With the continued evolution, nano pores increase and are densely distributed. The intra-pores in the mixtures are synchronous with the rapid increasing of oil saturation and the rising of free organic acids in shales, respectively. The development of the pores not only depends on the hydrocarbon generation, but also on the interaction of hydrocarbon conversion and the organic acid dissolution. The results indicate that in lacustrine shales within oil window, organic matter and inorganic minerals undergo evolution as a whole and interact with each other. The combination of hydrocarbon generation and dissolution form abundant reservoir space in the hybrid of organic matter and minerals, which has important significance to the occurrence of oil and gas in continental shales.
2015, 40(11): 1834-1845.
doi: 10.3799/dqkx.2015.164
Abstract:
Nanpu depression is abundant in deep oil and gas resources, but the origin of the hydrocarbon is still unclear. High resolution mass spectrometry (negative-ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS)) is utilized to carry out the composition and distribution of heteroatom compounds of crude oils from the Nanpu depression and its geochemical significance for the first time. The heteroatoms, N1, N1O1, N1O2, N1O3, N2, O1, O2, O3 and O4 class species, were identified by negative-ion ESI FT-ICR MS. And N1, O1, O2 class species are universal in all samples with higher relative abundance. It is found that thermal maturity obviously controls the distribution of carbon numbers and the degree of condensation of N1 and O1 class species. It is observed that parameters like C16—20/C21—50-DBE12-N1, C20—24/C25—50-DBE15-N1, DBE12/DBE9-N1 and DBE8—9/DBE4-O1 have a good correlation with Ts/Tm and TMNr. They could be used as indicators of thermal maturity of crude oils in the depression, reflecting the kinetics of thermal evolution of hydrocarbons. Significant difference was found among different layers of oils detected by negative-ion ESI FT-ICR MS, indicating that it can be applied to characterize source rocks. After a comprehensive investigation, we believe that FT-ICR MS technique is applicable in multiple geochemical aspects, such as maturity level estimation and source rock and relevant hydrocarbons determination. FT-ICR MS is significant in both the compositional characterization of the NSO compounds and the application in petroleum exploration.
Nanpu depression is abundant in deep oil and gas resources, but the origin of the hydrocarbon is still unclear. High resolution mass spectrometry (negative-ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS)) is utilized to carry out the composition and distribution of heteroatom compounds of crude oils from the Nanpu depression and its geochemical significance for the first time. The heteroatoms, N1, N1O1, N1O2, N1O3, N2, O1, O2, O3 and O4 class species, were identified by negative-ion ESI FT-ICR MS. And N1, O1, O2 class species are universal in all samples with higher relative abundance. It is found that thermal maturity obviously controls the distribution of carbon numbers and the degree of condensation of N1 and O1 class species. It is observed that parameters like C16—20/C21—50-DBE12-N1, C20—24/C25—50-DBE15-N1, DBE12/DBE9-N1 and DBE8—9/DBE4-O1 have a good correlation with Ts/Tm and TMNr. They could be used as indicators of thermal maturity of crude oils in the depression, reflecting the kinetics of thermal evolution of hydrocarbons. Significant difference was found among different layers of oils detected by negative-ion ESI FT-ICR MS, indicating that it can be applied to characterize source rocks. After a comprehensive investigation, we believe that FT-ICR MS technique is applicable in multiple geochemical aspects, such as maturity level estimation and source rock and relevant hydrocarbons determination. FT-ICR MS is significant in both the compositional characterization of the NSO compounds and the application in petroleum exploration.
2015, 40(11): 1846-1857.
doi: 10.3799/dqkx.2015.165
Abstract:
The research of the controls on the degrees of petroleum biodegradation within heavy oil reservoirs will benefit heavy oil reservoirs developing optimization and enhancing recovery efficiency.The characteristics of biodegradation of the saturated hydrocarbon for core extracts from the Liuhua11-1 reef reservoir are analyzed in this study, and the results show that bottom water and intercalation within the oil reservoir can significantly control the degree of petroleum biodegradation and affect the prediction of oil physical property. Liuhua11-1 reservoir has the one oil-water contact (OWC), with the hydrocarbon generated from the same source rock at similar high maturity and suffered from biodegradation less than level 6. Although the intercalations may lead to the occurrence of inversion of biodegradation level of oil columns, biodegradation level is mainly controlled by the vertical distance from its in situ place to OWC, which is characterized by the biodegradation degree increasing from the top of oil columns to the bottom with excellent gradient variations. Laterally, the biodegradation level varies significantly within the reservoir. It is mainly dominated by the extent of oil-water-contact area controlled by intercalations. And intercalations also lead to the insufficient supply of nutrients and poor metabolism exchange because the fluid flow can hardly pass in the area where intercalations develop, which results in lower biodegradation. A model of control effects of petroleum biodegradation degree by bottom water and reservoir heterogeneity within the oil reservoir is established, and its application in heavy oil reservoir development is discussed in this paper.
The research of the controls on the degrees of petroleum biodegradation within heavy oil reservoirs will benefit heavy oil reservoirs developing optimization and enhancing recovery efficiency.The characteristics of biodegradation of the saturated hydrocarbon for core extracts from the Liuhua11-1 reef reservoir are analyzed in this study, and the results show that bottom water and intercalation within the oil reservoir can significantly control the degree of petroleum biodegradation and affect the prediction of oil physical property. Liuhua11-1 reservoir has the one oil-water contact (OWC), with the hydrocarbon generated from the same source rock at similar high maturity and suffered from biodegradation less than level 6. Although the intercalations may lead to the occurrence of inversion of biodegradation level of oil columns, biodegradation level is mainly controlled by the vertical distance from its in situ place to OWC, which is characterized by the biodegradation degree increasing from the top of oil columns to the bottom with excellent gradient variations. Laterally, the biodegradation level varies significantly within the reservoir. It is mainly dominated by the extent of oil-water-contact area controlled by intercalations. And intercalations also lead to the insufficient supply of nutrients and poor metabolism exchange because the fluid flow can hardly pass in the area where intercalations develop, which results in lower biodegradation. A model of control effects of petroleum biodegradation degree by bottom water and reservoir heterogeneity within the oil reservoir is established, and its application in heavy oil reservoir development is discussed in this paper.
2015, 40(11): 1858-1869.
doi: 10.3799/dqkx.2015.166
Abstract:
Development of hot dry rock geothermal energy under the guidance of continental dynamics and earth system dynamics plays a key role in the ongoing energy revolution and industrial revolution. However, theoretical study on the hot dry rock geology is still very weak. In this paper, we discuss the definition of hot dry rock from the perspectives of geology and economics, propose a comprehensive classification of geothermal energy based on basin-orogen thermal tectonic system, and analyze the tectonic and petrological system of hot dry rocks in the solid and semi-solid rheological behavior according to rock rheology and tectonophysics. Under the guidance of four-dimensional non-uniform rheological property of active basin-orogen tectonic system, the spatial distribution and mechanism of hot dry rocks are discussed. It is suggested that the theories of earth system dynamics should be integrated in theoretical and applied studies of hot dry rock within the framework of related earth resources, geohazards, geoenvironments and engineering geology. In addition, an integrated exploration, assessment and development of hot dry rock geothermal energy should be carried out in the North China, the Tibetan plateau and its adjacent areas, the coast regions of Southeast China and Taiwan, which respectively belong to four different types of tectonically active geothermal units.
Development of hot dry rock geothermal energy under the guidance of continental dynamics and earth system dynamics plays a key role in the ongoing energy revolution and industrial revolution. However, theoretical study on the hot dry rock geology is still very weak. In this paper, we discuss the definition of hot dry rock from the perspectives of geology and economics, propose a comprehensive classification of geothermal energy based on basin-orogen thermal tectonic system, and analyze the tectonic and petrological system of hot dry rocks in the solid and semi-solid rheological behavior according to rock rheology and tectonophysics. Under the guidance of four-dimensional non-uniform rheological property of active basin-orogen tectonic system, the spatial distribution and mechanism of hot dry rocks are discussed. It is suggested that the theories of earth system dynamics should be integrated in theoretical and applied studies of hot dry rock within the framework of related earth resources, geohazards, geoenvironments and engineering geology. In addition, an integrated exploration, assessment and development of hot dry rock geothermal energy should be carried out in the North China, the Tibetan plateau and its adjacent areas, the coast regions of Southeast China and Taiwan, which respectively belong to four different types of tectonically active geothermal units.
2015, 40(11): 1870-1875.
doi: 10.3799/dqkx.2015.167
Abstract:
The characteristics of formation water are important factors to study the basin evolution and heavy oil distribution. Geochemical studies can facilitate the exploration of heavy oil which dominates the oil reserves in Liaohe basin. Based on the test of formation water and isotope analyses of western depression, the geochemistry and origin of formation water are discussed in this paper. The total dissolved solid (TDS) and chemical compositions are controlled by the buried depth. The formations water shows vertical flow. The differences of chemical compositions of formation water and characters are related to intensity of surface water injection in different areas and local formation water flowing characters which are main reasons of crude oil bio-degradation. The isotope analyses also show that surface water injection is much stronger in Jinzhou, Huanxiling and Lenji areas. The different cycle characters of formation water lead to chemical conditions and crude oil bio-degradation. Surface water leaching is the necessary condition of degradation heavy oil development.
The characteristics of formation water are important factors to study the basin evolution and heavy oil distribution. Geochemical studies can facilitate the exploration of heavy oil which dominates the oil reserves in Liaohe basin. Based on the test of formation water and isotope analyses of western depression, the geochemistry and origin of formation water are discussed in this paper. The total dissolved solid (TDS) and chemical compositions are controlled by the buried depth. The formations water shows vertical flow. The differences of chemical compositions of formation water and characters are related to intensity of surface water injection in different areas and local formation water flowing characters which are main reasons of crude oil bio-degradation. The isotope analyses also show that surface water injection is much stronger in Jinzhou, Huanxiling and Lenji areas. The different cycle characters of formation water lead to chemical conditions and crude oil bio-degradation. Surface water leaching is the necessary condition of degradation heavy oil development.
2015, 40(11): 1876-1886.
doi: 10.3799/dqkx.2015.168
Abstract:
Understanding the seasonal variation of arsenic occurrence in shallow groundwater system is one of the challenges and hot spots concerning the research on high arsenic groundwater, which plays an important role in evaluation of safe groundwater availability and remediation of arsenic-affected aquifer. To investigate the seasonal variation of arsenic speciation in the shallow aquifer from the endemic arsenicosis area in the Jianghan plain, groundwater from shallow phreatic aquifer and unconfined aquifer were monitored for arsenic speciation (As(Ⅲ), As(Ⅴ) and acid-leacheable particulate As) and water level during pre-monsoon (May), monsoon (July-August) and post-monsoon (November-December) seasons. Arsenic concentration and speciation in groundwater varied temporally: the concentration of As(Ⅴ) and particulate As were higher, together with higher particulate Fe in most samples during the pre-monsoon seasons; As(Ⅴ) and particulate As decreased significantly during monsoon seasons, while dissovled As and Fe increased dramatically. Higher As concentrations were associated with an increasing percentage of As(Ⅲ) in rainy season and a decrease towards the end of dry season, indicating a reductive moblization responding to groundwater level fluctuation.
Understanding the seasonal variation of arsenic occurrence in shallow groundwater system is one of the challenges and hot spots concerning the research on high arsenic groundwater, which plays an important role in evaluation of safe groundwater availability and remediation of arsenic-affected aquifer. To investigate the seasonal variation of arsenic speciation in the shallow aquifer from the endemic arsenicosis area in the Jianghan plain, groundwater from shallow phreatic aquifer and unconfined aquifer were monitored for arsenic speciation (As(Ⅲ), As(Ⅴ) and acid-leacheable particulate As) and water level during pre-monsoon (May), monsoon (July-August) and post-monsoon (November-December) seasons. Arsenic concentration and speciation in groundwater varied temporally: the concentration of As(Ⅴ) and particulate As were higher, together with higher particulate Fe in most samples during the pre-monsoon seasons; As(Ⅴ) and particulate As decreased significantly during monsoon seasons, while dissovled As and Fe increased dramatically. Higher As concentrations were associated with an increasing percentage of As(Ⅲ) in rainy season and a decrease towards the end of dry season, indicating a reductive moblization responding to groundwater level fluctuation.
2015, 40(11): 1887-1895.
doi: 10.3799/dqkx.2015.169
Abstract:
Brackish water distributes widely in arid area of Northwest China and the NaCl and trace element contents in brackish water are higher than those in fresh water. Cotton (Gossypium hirsutum L.) is likely to be affected by simultaneous NaCl and manganese toxicity stress when irrigated with brackish water. The crop yields including cotton (Gossypium hirsutum L.) are usually reduced by poor quality of irrigation water or the low contents of nutrient elements in soil. Many experiments indicate that some salinities in irrigation water or soil will affect the cotton growth and yield, and the predominant salt damage to cotton plant is from sodium (Na+). Meanwhile proper nutrient supply for cotton plant, especially trace elements for cotton, is important. Cotton diseases and abnormal growth are caused by lack or excess of trace elements. However, it remains beyond our full understanding as to the combined effect of salinity and trace elements on cotton growth and its uptake of nutrient elements. Thus we selected the trace element zinc which is sensitive to cotton growth, and conducted a pot experiment including 24 different treatments in irrigation with 6 NaCl levels (0 mmol/L, 5 mmol/L, 15 mmol/L, 25 mmol/L, 35 mmol/L and 45 mmol/L) and 4 Zn levels (0.192 0 μmol/L, 0.767 6 μmol/L, 3.068 0 μmol/L and 12.272 0 μmol/L) in three replicates randomly in a greenhouse at Wuhan Botanical Garden, Chinese Academy of Sciences. During the experiment, cotton growth of different treatments was measured every ten days after germination and cotton plants were harvested 197 days after sowing. The cotton bolls were harvested and air dried and weighted the wool without seeds to calculate the lint yields. Cotton samples of roots, stems, leaves and fruits were brushed to remove the sand and dusts, rinsed with deionized water; oven dried at 70 ℃ for two days and weighed dry weight. The dry matters of cotton for each treatment were triturated and sampled 0.5 g for acid digestion. Twenty-seven elements were measured in triplicate by ICP-OES (ICAP6300, Thermo Scientific, England). Nine of the 27 elements i.e. K, Ca, Mg, Na, B, Cu, Fe, Mn and Zn (cotton nutrient elements) are chosen for analysis in this paper. The results show that salinity promoted cotton root, steam growth and cotton lint yields when electrical conductivities (EC) of irrigation water fell in the range of 2.90 to 3.95 dS/m in the zinc deficiency environment. While in the zinc-rich environment, salinity inhibited cotton lint yields when EC was greater than 5.04 dS/m. Cotton plant vegetative growth become faster when Zn concentration of irrigation water in the range of 0.192 to 3.068 μmol/L, while when Zn concentration was greater than 0.767 μmol/L would cause cotton plant lint yields decline. Analysis of variance among cotton growth, root and stem dry weight parameters revealed significant influence by salinity effect but not by Zn. Cotton lint yield parameters revealed that the effect of Zn was more obvious than salinity. Interactive effect on cotton growth and yield between NaCl and Zn in the irrigation water was not observed but antagonistic effect was observed. Contents of nutrient elements Ca, K, Mg, B and Fe, in cotton leaves were higher than those in other organizations. Nutrient elements Cu and Zn in cotton bolls were higher than other organizations. Nutrient elements Na and Mn were not so movable that they are easily accumulated in roots. Zn concentration levels in irrigation water under salinity stress affected the nutrient elements uptake of cotton, caused different contents of nutrient elements in cotton, and then influenced cotton growth and yields.
Brackish water distributes widely in arid area of Northwest China and the NaCl and trace element contents in brackish water are higher than those in fresh water. Cotton (Gossypium hirsutum L.) is likely to be affected by simultaneous NaCl and manganese toxicity stress when irrigated with brackish water. The crop yields including cotton (Gossypium hirsutum L.) are usually reduced by poor quality of irrigation water or the low contents of nutrient elements in soil. Many experiments indicate that some salinities in irrigation water or soil will affect the cotton growth and yield, and the predominant salt damage to cotton plant is from sodium (Na+). Meanwhile proper nutrient supply for cotton plant, especially trace elements for cotton, is important. Cotton diseases and abnormal growth are caused by lack or excess of trace elements. However, it remains beyond our full understanding as to the combined effect of salinity and trace elements on cotton growth and its uptake of nutrient elements. Thus we selected the trace element zinc which is sensitive to cotton growth, and conducted a pot experiment including 24 different treatments in irrigation with 6 NaCl levels (0 mmol/L, 5 mmol/L, 15 mmol/L, 25 mmol/L, 35 mmol/L and 45 mmol/L) and 4 Zn levels (0.192 0 μmol/L, 0.767 6 μmol/L, 3.068 0 μmol/L and 12.272 0 μmol/L) in three replicates randomly in a greenhouse at Wuhan Botanical Garden, Chinese Academy of Sciences. During the experiment, cotton growth of different treatments was measured every ten days after germination and cotton plants were harvested 197 days after sowing. The cotton bolls were harvested and air dried and weighted the wool without seeds to calculate the lint yields. Cotton samples of roots, stems, leaves and fruits were brushed to remove the sand and dusts, rinsed with deionized water; oven dried at 70 ℃ for two days and weighed dry weight. The dry matters of cotton for each treatment were triturated and sampled 0.5 g for acid digestion. Twenty-seven elements were measured in triplicate by ICP-OES (ICAP6300, Thermo Scientific, England). Nine of the 27 elements i.e. K, Ca, Mg, Na, B, Cu, Fe, Mn and Zn (cotton nutrient elements) are chosen for analysis in this paper. The results show that salinity promoted cotton root, steam growth and cotton lint yields when electrical conductivities (EC) of irrigation water fell in the range of 2.90 to 3.95 dS/m in the zinc deficiency environment. While in the zinc-rich environment, salinity inhibited cotton lint yields when EC was greater than 5.04 dS/m. Cotton plant vegetative growth become faster when Zn concentration of irrigation water in the range of 0.192 to 3.068 μmol/L, while when Zn concentration was greater than 0.767 μmol/L would cause cotton plant lint yields decline. Analysis of variance among cotton growth, root and stem dry weight parameters revealed significant influence by salinity effect but not by Zn. Cotton lint yield parameters revealed that the effect of Zn was more obvious than salinity. Interactive effect on cotton growth and yield between NaCl and Zn in the irrigation water was not observed but antagonistic effect was observed. Contents of nutrient elements Ca, K, Mg, B and Fe, in cotton leaves were higher than those in other organizations. Nutrient elements Cu and Zn in cotton bolls were higher than other organizations. Nutrient elements Na and Mn were not so movable that they are easily accumulated in roots. Zn concentration levels in irrigation water under salinity stress affected the nutrient elements uptake of cotton, caused different contents of nutrient elements in cotton, and then influenced cotton growth and yields.
2015, 40(11): 1896-1903.
doi: 10.3799/dqkx.2015.170
Abstract:
The suspension solids, salts and organic nutrients in sewage efflunts can significantly affect soil porosity condition. Based on the laboratory simulation and computed tomography, the numbers of soil pores, porosity and shape were quantitatively studied under the condition of irrigation with sewage. The results show that the soils irrigated with sewage effluents exhibited higher total pore numbers and macropore numbers(≥1.00 mm in diameter) in the upper layer but lower total pore numbers, macropore numbers, coarse pore numbers (0.26-1.00 mm in diameter), total porosity, macroporosity and coarse porosity in the subsoil layer when compared with the soils irrigated with groundwater (p < 0.05). Under the condition of irrigation with suspension or with salt solution, total pore numbers, coarse pore numbers and coarse porosity increased, while macropore numbers, total porosity, macroporosity and cycle rate decreased. Under the condition of irrigation with nutrient solution, total pore numbers, macropore numbers, coarse pore numbers and coarse porosity increased, while macroporosity and cycle rate decreased. For the soil in the study fields, the effect of irrigation with suspension on the soil pores was stronger than that with salt solution. For the same irrigation with suspension or with salt solution, the effect of sewage irrigation on pores in groundwater irrigated soils was stronger than that in sewage irrigated soils.
The suspension solids, salts and organic nutrients in sewage efflunts can significantly affect soil porosity condition. Based on the laboratory simulation and computed tomography, the numbers of soil pores, porosity and shape were quantitatively studied under the condition of irrigation with sewage. The results show that the soils irrigated with sewage effluents exhibited higher total pore numbers and macropore numbers(≥1.00 mm in diameter) in the upper layer but lower total pore numbers, macropore numbers, coarse pore numbers (0.26-1.00 mm in diameter), total porosity, macroporosity and coarse porosity in the subsoil layer when compared with the soils irrigated with groundwater (p < 0.05). Under the condition of irrigation with suspension or with salt solution, total pore numbers, coarse pore numbers and coarse porosity increased, while macropore numbers, total porosity, macroporosity and cycle rate decreased. Under the condition of irrigation with nutrient solution, total pore numbers, macropore numbers, coarse pore numbers and coarse porosity increased, while macroporosity and cycle rate decreased. For the soil in the study fields, the effect of irrigation with suspension on the soil pores was stronger than that with salt solution. For the same irrigation with suspension or with salt solution, the effect of sewage irrigation on pores in groundwater irrigated soils was stronger than that in sewage irrigated soils.
2015, 40(11): 1904-1912.
doi: 10.3799/dqkx.2015.171
Abstract:
Deformation modulus is an important parameter for rock engineering design. However, the relation between longitudinal wave velocity and deformation modulus is often used to estimate the deformation modulus of large-scale and deep rock mass in the hydroelectric projects because it is difficult to conduct many in-situ and laboratory deformation modulus tests due to the limited funds, time and test size during the engineering survey and the test results have no general representativeness. In this paper, the intrinsic relation between longitudinal wave velocity and rock deformation modulus is theoretically explained based on the wave differential equation. Meanwhile, 132 in-situ test data derived from 4 hydropowers are used to set up an experience formula between longitudinal wave velocity and deformation modulus for basalt in the Jinsha River area. The results show that there is close relation between the basalt longitudinal wave velocity and its deformation modulus. The deformation modulus difference of different basalt rock masses by calculating of longitudinal wave velocity is small when Vp < 4 500 m/s. While it becomes larger when Vp > 4 500 m/s. The optimal equation is helpful to evaluate the deformation modulus of basalt rock mass, and it offers a quick and scientific method for selecting basic parameters of dam foundation in the hydropower projects.
Deformation modulus is an important parameter for rock engineering design. However, the relation between longitudinal wave velocity and deformation modulus is often used to estimate the deformation modulus of large-scale and deep rock mass in the hydroelectric projects because it is difficult to conduct many in-situ and laboratory deformation modulus tests due to the limited funds, time and test size during the engineering survey and the test results have no general representativeness. In this paper, the intrinsic relation between longitudinal wave velocity and rock deformation modulus is theoretically explained based on the wave differential equation. Meanwhile, 132 in-situ test data derived from 4 hydropowers are used to set up an experience formula between longitudinal wave velocity and deformation modulus for basalt in the Jinsha River area. The results show that there is close relation between the basalt longitudinal wave velocity and its deformation modulus. The deformation modulus difference of different basalt rock masses by calculating of longitudinal wave velocity is small when Vp < 4 500 m/s. While it becomes larger when Vp > 4 500 m/s. The optimal equation is helpful to evaluate the deformation modulus of basalt rock mass, and it offers a quick and scientific method for selecting basic parameters of dam foundation in the hydropower projects.
2015, 40(11): 1913-1921.
doi: 10.3799/dqkx.2015.172
Abstract:
With increasing global concern of nature gas hydrate exploration and development, more and more attention has been paid to drilling technology in gas hydrate bearing sediment (GHBS). However, the dissociation and reformation of gas hydrates in borehole will affect the stability of wellbore during drilling. Based on the drilling characteristics in hydrate formation, existing nano-materials, and a large number of experiments, a kind of new nano-SiO2 drilling fluid for drilling in GHBS is introduced: seawater+2% nano-SiO2+3% bentonite+1%Na-CMC+3%SMP-2+1%PVP(K90)+2%KCl, subsequently low-temperature traditional performance and hydrate formation inhibition of the drilling fluid were evaluated. Experimental results show that the drilling fluid is featured with optimum density, good low-temperature rheology and shale hydration inhibition, and it can effectively inhibit free gas from hydrate dissociation near borehole reformat hydrate in drilling fluid circulation system for a long time. Therefore, the drilling fluid is beneficial to keep borehole safety and to ensure successful drilling operation while drilling in GHBS.
With increasing global concern of nature gas hydrate exploration and development, more and more attention has been paid to drilling technology in gas hydrate bearing sediment (GHBS). However, the dissociation and reformation of gas hydrates in borehole will affect the stability of wellbore during drilling. Based on the drilling characteristics in hydrate formation, existing nano-materials, and a large number of experiments, a kind of new nano-SiO2 drilling fluid for drilling in GHBS is introduced: seawater+2% nano-SiO2+3% bentonite+1%Na-CMC+3%SMP-2+1%PVP(K90)+2%KCl, subsequently low-temperature traditional performance and hydrate formation inhibition of the drilling fluid were evaluated. Experimental results show that the drilling fluid is featured with optimum density, good low-temperature rheology and shale hydration inhibition, and it can effectively inhibit free gas from hydrate dissociation near borehole reformat hydrate in drilling fluid circulation system for a long time. Therefore, the drilling fluid is beneficial to keep borehole safety and to ensure successful drilling operation while drilling in GHBS.
2015, 40(11): 1922-1932.
doi: 10.3799/dqkx.2015.173
Abstract:
The self-boring in-situ shear pressure-meter test can obtain the strength and deformation parameters directly through its unique multi-level loading mode; however, the deformation mechanism of the soil surrounding the probe has seldom been studied. To reveal the deformation mechanism of the sand sample surrounding the probe of the self-boring in-situ shear pressure-meter (SBISP) during the loading process, the SBISP model test is simulated by PFC3D (particle flow code in three dimensions) program in this study. The development of the displacement and stress field of the soil surrounding the probe, as well as the deformation modulus of each grade of the numerical sample and the motion trails of the soil particles, are studied under multi-level loading process. The results of numerical experiments show that the displacement of particles in central area increases with the shear stress imposed stepwise, and the direction of displacement vector shows a clearly preferred direction. Several radial stress cores of approximately symmetrical distribution have formed near both sides of the probe. At the same time, the vertical stress has formed flat stress zones, and it has produced some stress concentration areas in the shoulder of the probe. The motion trails of the particles are step-like lines in the central area which can be divided into three characteristic zones as the distance to the probe increases. The vertical and horizontal displacements of particles descend in a negative exponential form, but the vertical displacement has a faster attenuation rate.
The self-boring in-situ shear pressure-meter test can obtain the strength and deformation parameters directly through its unique multi-level loading mode; however, the deformation mechanism of the soil surrounding the probe has seldom been studied. To reveal the deformation mechanism of the sand sample surrounding the probe of the self-boring in-situ shear pressure-meter (SBISP) during the loading process, the SBISP model test is simulated by PFC3D (particle flow code in three dimensions) program in this study. The development of the displacement and stress field of the soil surrounding the probe, as well as the deformation modulus of each grade of the numerical sample and the motion trails of the soil particles, are studied under multi-level loading process. The results of numerical experiments show that the displacement of particles in central area increases with the shear stress imposed stepwise, and the direction of displacement vector shows a clearly preferred direction. Several radial stress cores of approximately symmetrical distribution have formed near both sides of the probe. At the same time, the vertical stress has formed flat stress zones, and it has produced some stress concentration areas in the shoulder of the probe. The motion trails of the particles are step-like lines in the central area which can be divided into three characteristic zones as the distance to the probe increases. The vertical and horizontal displacements of particles descend in a negative exponential form, but the vertical displacement has a faster attenuation rate.
2015, 40(11): 1933-1944.
doi: 10.3799/dqkx.2015.174
Abstract:
Milankovitch cycle is the manifestation of sedimentary stratigraphy recorded, its time implication is an effective means of high resolution stratigraphic division and correlation, from the reservation information of Milankovitch cycles, which enrich stratigraphic theory, especially cyclostratigraphic theory. Characteristics of Milankovitch cycle in the eastern depression of the North Yellow Sea basin are explored in this study. Major parameters of Milankovitch cycle are worked out by J. Laskar solution in the Eocene formation: the eccentricity cycle is 125 ka and 99 ka; the obliquity cycle is 51 ka and 39 ka; and the precession cycle is 23 ka and 19 ka. It is found by frequency spectrum analysis of the GR and SP well logging of three wells that the spectrum peak cycle corresponds well to its astronomy cycle, indicating well-preserved Milankoitch cycle in the formation. Stratigraphic cycle thickness is of 13.03 to 15.89 m long-cycle, 3.70 to 5.21 m mid-cycle and 2.17 to 2.94 m short-cycle, by which the formation sedimentation rate is calculated as between 121.20 to 127.12 m/Ma. The sedimentary duration is increasingly longer and the deposition thickness is increasingly thicker from uplift along the slope toward the center of the lake basin. However, the sedimentation rate is relatively stable.As to sublayer division of Encene with the continuous wavelet transform, it can be divided into six sedimentary bodies, with each body as a separate window for spectrum analysis to calculate the duration and rate of sedimentation. From the perspective of the impact of climate change on the sedimentary environment, it is concluded that, E6 period was low water system tract, E5 and E4 were lake expand system tract, E3 was highstand systerm tract, E2 and E1 were lakes contraction system tract from the bottom to top sequence stratigraphy. It is confirmed that Milankovitch cycle is an effective approach for depositional cycle analysis.
Milankovitch cycle is the manifestation of sedimentary stratigraphy recorded, its time implication is an effective means of high resolution stratigraphic division and correlation, from the reservation information of Milankovitch cycles, which enrich stratigraphic theory, especially cyclostratigraphic theory. Characteristics of Milankovitch cycle in the eastern depression of the North Yellow Sea basin are explored in this study. Major parameters of Milankovitch cycle are worked out by J. Laskar solution in the Eocene formation: the eccentricity cycle is 125 ka and 99 ka; the obliquity cycle is 51 ka and 39 ka; and the precession cycle is 23 ka and 19 ka. It is found by frequency spectrum analysis of the GR and SP well logging of three wells that the spectrum peak cycle corresponds well to its astronomy cycle, indicating well-preserved Milankoitch cycle in the formation. Stratigraphic cycle thickness is of 13.03 to 15.89 m long-cycle, 3.70 to 5.21 m mid-cycle and 2.17 to 2.94 m short-cycle, by which the formation sedimentation rate is calculated as between 121.20 to 127.12 m/Ma. The sedimentary duration is increasingly longer and the deposition thickness is increasingly thicker from uplift along the slope toward the center of the lake basin. However, the sedimentation rate is relatively stable.As to sublayer division of Encene with the continuous wavelet transform, it can be divided into six sedimentary bodies, with each body as a separate window for spectrum analysis to calculate the duration and rate of sedimentation. From the perspective of the impact of climate change on the sedimentary environment, it is concluded that, E6 period was low water system tract, E5 and E4 were lake expand system tract, E3 was highstand systerm tract, E2 and E1 were lakes contraction system tract from the bottom to top sequence stratigraphy. It is confirmed that Milankovitch cycle is an effective approach for depositional cycle analysis.
