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2024, 49(10): 3445-3458.
doi: 10.3799/dqkx.2023.150
Abstract:
The basement architecture and evolution is of important role in dechipering sedimentary basin dynamitics.Based on the compiled geochronological and geochemical data, it has a review on the hot debates on the basement architecture, tectonic environment and evolution of the Neoproterozoic Tarim Basin.The results show that the southern and northern Tarim terranes are assemblied during 1.9-1.8 Ga, and the Early Neoproterozoic sedimentary succession and Paleoproterozoic igneous succession are composed to form a unified metamorphic basement during 780-750 Ma, and to form a complex metamorphic basement structure with differences between northern and southern terranes by multi-stage tectonic-thermal events. The Neoproterozoic was characterized by multi-stage of advancing subduction at ca. 950-900 Ma, 860-840 Ma, 830-800 Ma, 780-760 Ma, and multi-stages of retreating subduction at ca. 760-720 Ma, 670-610 Ma, which resulting in a Neoproterozoic advancing-retreating subduction cycle with the switch at ca. 760 Ma. The Neoproterozoic advancing subduction controlled the origin and evolution of the metamorphic basement, and the subsequent retreating subduction controlled the initiation and evolution of continental rift basin, which suggests a different basin dynamic mechanism and evolutionary process from the classical Wilson cycle.
The basement architecture and evolution is of important role in dechipering sedimentary basin dynamitics.Based on the compiled geochronological and geochemical data, it has a review on the hot debates on the basement architecture, tectonic environment and evolution of the Neoproterozoic Tarim Basin.The results show that the southern and northern Tarim terranes are assemblied during 1.9-1.8 Ga, and the Early Neoproterozoic sedimentary succession and Paleoproterozoic igneous succession are composed to form a unified metamorphic basement during 780-750 Ma, and to form a complex metamorphic basement structure with differences between northern and southern terranes by multi-stage tectonic-thermal events. The Neoproterozoic was characterized by multi-stage of advancing subduction at ca. 950-900 Ma, 860-840 Ma, 830-800 Ma, 780-760 Ma, and multi-stages of retreating subduction at ca. 760-720 Ma, 670-610 Ma, which resulting in a Neoproterozoic advancing-retreating subduction cycle with the switch at ca. 760 Ma. The Neoproterozoic advancing subduction controlled the origin and evolution of the metamorphic basement, and the subsequent retreating subduction controlled the initiation and evolution of continental rift basin, which suggests a different basin dynamic mechanism and evolutionary process from the classical Wilson cycle.
2024, 49(10): 3459-3470.
doi: 10.3799/dqkx.2023.125
Abstract:
Genetic mechanism of the high-quality reservoirs developed by the Paleogene Shahejie Formation mixed rock in the Laizhouwan Sag, Bohai Bay Basin is still unclear. Based on fluid inclusion, vitrinite reflectance and petrological observation, combined with measured physical properties, it studies the effects of thermal fluid activities on reservoir under the complex mixing background of lacustrine carbonate rocks, terrigenous clastic rocks and volcanic rocks in the Shahejie Formation. The high homogenization temperatures of fluid inclusions, vitrinite reflectance, and paleo-salinity of fluid inclusions indicate the activity of deep hot brines. Acid dissolution exists widely in the reservoir: There are a large number of secondary dissolution pores in tuff, micrite dolomite interstitials and feldspar grains, and the common grain margin fractures, which may be caused by the intrusion of high pressure acid hydrothermal solution driven by magmatic activity. As the fluid temperature pressure drops, hydrothermal mineral precipitation also resulted in a strong and dense reservoir. In general, hydrothermal can produce both constructive and destructive effects on the reservoir, which strengthens the spatial differentiation of reservoir physical properties to a certain extent.
Genetic mechanism of the high-quality reservoirs developed by the Paleogene Shahejie Formation mixed rock in the Laizhouwan Sag, Bohai Bay Basin is still unclear. Based on fluid inclusion, vitrinite reflectance and petrological observation, combined with measured physical properties, it studies the effects of thermal fluid activities on reservoir under the complex mixing background of lacustrine carbonate rocks, terrigenous clastic rocks and volcanic rocks in the Shahejie Formation. The high homogenization temperatures of fluid inclusions, vitrinite reflectance, and paleo-salinity of fluid inclusions indicate the activity of deep hot brines. Acid dissolution exists widely in the reservoir: There are a large number of secondary dissolution pores in tuff, micrite dolomite interstitials and feldspar grains, and the common grain margin fractures, which may be caused by the intrusion of high pressure acid hydrothermal solution driven by magmatic activity. As the fluid temperature pressure drops, hydrothermal mineral precipitation also resulted in a strong and dense reservoir. In general, hydrothermal can produce both constructive and destructive effects on the reservoir, which strengthens the spatial differentiation of reservoir physical properties to a certain extent.
2024, 49(10): 3471-3487.
doi: 10.3799/dqkx.2023.146
Abstract:
Whether a strike-slip fault zone of S-N trend developed in the centre South China Sea (SCS) has been focused by geologists who study tectonic evolution, but no any conclusion due to lack of data.The difficult issue has been resolved in this paper by studying the distribution of residual Mesozoic strata and interpreting new geological and geophysics data in the SCS. Zhongnan-Liyue (ZL) fault zone, a strike-slip fault zone with S-N trend, developed at both southern and northern continental margins and the initial time of its activity was at least in Mesozoic.Before sea-floor spreading of the SCS, this strike-slip fault zone attains about 700 km at southern and northern continental margins. In different geological times this fault zone was of different characteristics of tectonic movement, that was strike slip of left-rotation in Mesozoic, strike slip and extension in Early-Middle Paleogene, in order to strike slip in Late Paleogene and Early Neogene, last one strike slip accompanying pressure function in Middle-Late Neogene.
Whether a strike-slip fault zone of S-N trend developed in the centre South China Sea (SCS) has been focused by geologists who study tectonic evolution, but no any conclusion due to lack of data.The difficult issue has been resolved in this paper by studying the distribution of residual Mesozoic strata and interpreting new geological and geophysics data in the SCS. Zhongnan-Liyue (ZL) fault zone, a strike-slip fault zone with S-N trend, developed at both southern and northern continental margins and the initial time of its activity was at least in Mesozoic.Before sea-floor spreading of the SCS, this strike-slip fault zone attains about 700 km at southern and northern continental margins. In different geological times this fault zone was of different characteristics of tectonic movement, that was strike slip of left-rotation in Mesozoic, strike slip and extension in Early-Middle Paleogene, in order to strike slip in Late Paleogene and Early Neogene, last one strike slip accompanying pressure function in Middle-Late Neogene.
2024, 49(10): 3488-3498.
doi: 10.3799/dqkx.2023.133
Abstract:
The discovery of Palogue oilfield in Melut Basin has opened a new exploration direction of the Central African Rift Paleogene and confirmed that the northern sag of Melut Basin is rich in oil and gas resources. The Lower Cretaceous source rock is the major source rock of Melut basin, the Palaeogene is its main seal⁃reservoir assemblage. The formation mechanism and model of oil and gas accumulated were proposed based on the specific tectonic-stratigraphic assemblages and evolution history of the Melut Basin. Oil and gas accumulations were influenced of mantle CO2. Relationship between CO2 and hydrocarbon accumulation was investigated using a suite of hydrocarbon generation and expulsion history, tectonic evolution history, fluid inclusions, CO2 and crude by taking Palogue oil reservoir as an example. The results show that the Late Paleogene-Neogene, the occurrence of the mantle source CO2 migration tectonic thermal event have an important influence on oil and gas accumulation in Palogue oilfield. Under the action of tectonic-thermal events, the thermal evolution of source rocks rapidly enters the mature stage, and intense hydrocarbon generation and expulsion occurs, CO2 in supercritical state quickly blends into crude oil. The crude oil saturated with supercritical CO2 quickly migrated through the reservoir and developed a large number of high-temperature mixed hydrocarbon inclusions, which showed the rapid accumulation event under the abnormal high heat event. After the crude oil full of supercritical CO2 entered the Palogue trap, CO2 gas began to separate out from the crude oil layer by layer due to the change of formation temperature and pressure conditions, CO2 gas carries light components into the upper reservoir for mixing. This results in a series of changes in vertical physical properties.
The discovery of Palogue oilfield in Melut Basin has opened a new exploration direction of the Central African Rift Paleogene and confirmed that the northern sag of Melut Basin is rich in oil and gas resources. The Lower Cretaceous source rock is the major source rock of Melut basin, the Palaeogene is its main seal⁃reservoir assemblage. The formation mechanism and model of oil and gas accumulated were proposed based on the specific tectonic-stratigraphic assemblages and evolution history of the Melut Basin. Oil and gas accumulations were influenced of mantle CO2. Relationship between CO2 and hydrocarbon accumulation was investigated using a suite of hydrocarbon generation and expulsion history, tectonic evolution history, fluid inclusions, CO2 and crude by taking Palogue oil reservoir as an example. The results show that the Late Paleogene-Neogene, the occurrence of the mantle source CO2 migration tectonic thermal event have an important influence on oil and gas accumulation in Palogue oilfield. Under the action of tectonic-thermal events, the thermal evolution of source rocks rapidly enters the mature stage, and intense hydrocarbon generation and expulsion occurs, CO2 in supercritical state quickly blends into crude oil. The crude oil saturated with supercritical CO2 quickly migrated through the reservoir and developed a large number of high-temperature mixed hydrocarbon inclusions, which showed the rapid accumulation event under the abnormal high heat event. After the crude oil full of supercritical CO2 entered the Palogue trap, CO2 gas began to separate out from the crude oil layer by layer due to the change of formation temperature and pressure conditions, CO2 gas carries light components into the upper reservoir for mixing. This results in a series of changes in vertical physical properties.
2024, 49(10): 3499-3515.
doi: 10.3799/dqkx.2023.141
Abstract:
The Changning-Menglian suture zone is the main ocean of the Paleo-Tethys which is considered to be opened in the Devonian according to previous studies. Recently, some scholars put forward that it was formed in the Early Paleozoic. It is a controversial topic that when and how it opened. In this paper, samples were collected from the oldest strata Wenquan Formation within the suture zone, detrital zircon chronology of them obtain similar characteristics, showing two distinctive age peaks at ~440 Ma and ~980 Ma with other age population around 600 Ma, 780 Ma, 1 100 Ma, 2 500 Ma, respectively. Zircons with ~440 Ma have better crystalline morphology and more prominent magmatic oscillation zones, as well as a wide range of Lu-Hf isotopic compositions with in-situ εHf(t) values from -11.9 to +7.2. Zircons comprising the major age peak at ~440 Ma are from the andesite dominant volcanic arc in the Lincang block and western Simao block, while is supported by the andesitic fragment in thin sections. Zircons forming the secondary age peak at ~960 Ma come from the Gondwana. Zircons whose age larger than 500 Ma have rounded shape come from long distance transportation or resediments from Pre-Devonian sandstone. To sum up, the Lincang and Simao blocks located to the east of the suture zone are the main provenance of Wenquan Formation, while the Gondwana and Baoshan block contributes a small number of debris, based on sedimentology, petrology and detrital zircon chronology. The Wenquan Formation deposited on the west side of the Paleo-Tethyan ophiolites, but it received detrital materials from the opposite continental margin. Thus, the main Paleo-Tethyan Ocean basin was not broad enough to cut off the transport of detrital materials. It was a narrow basin in the Devonian during the rifting stage, rather than a mature, broad pelagic oceanic basin.
The Changning-Menglian suture zone is the main ocean of the Paleo-Tethys which is considered to be opened in the Devonian according to previous studies. Recently, some scholars put forward that it was formed in the Early Paleozoic. It is a controversial topic that when and how it opened. In this paper, samples were collected from the oldest strata Wenquan Formation within the suture zone, detrital zircon chronology of them obtain similar characteristics, showing two distinctive age peaks at ~440 Ma and ~980 Ma with other age population around 600 Ma, 780 Ma, 1 100 Ma, 2 500 Ma, respectively. Zircons with ~440 Ma have better crystalline morphology and more prominent magmatic oscillation zones, as well as a wide range of Lu-Hf isotopic compositions with in-situ εHf(t) values from -11.9 to +7.2. Zircons comprising the major age peak at ~440 Ma are from the andesite dominant volcanic arc in the Lincang block and western Simao block, while is supported by the andesitic fragment in thin sections. Zircons forming the secondary age peak at ~960 Ma come from the Gondwana. Zircons whose age larger than 500 Ma have rounded shape come from long distance transportation or resediments from Pre-Devonian sandstone. To sum up, the Lincang and Simao blocks located to the east of the suture zone are the main provenance of Wenquan Formation, while the Gondwana and Baoshan block contributes a small number of debris, based on sedimentology, petrology and detrital zircon chronology. The Wenquan Formation deposited on the west side of the Paleo-Tethyan ophiolites, but it received detrital materials from the opposite continental margin. Thus, the main Paleo-Tethyan Ocean basin was not broad enough to cut off the transport of detrital materials. It was a narrow basin in the Devonian during the rifting stage, rather than a mature, broad pelagic oceanic basin.
2024, 49(10): 3516-3528.
doi: 10.3799/dqkx.2023.143
Abstract:
The discharge variability controls the formation and evolution of braid bars and influences the internal structure and superimposition of braid bars. However, the control of discharge variability on the developments and evolution of braid bars are unclear. Google Earth software was used to selected 13 river reaches with braided river deposits worldwide, and the discharge data of the selected river reaches are collected from the Global Runoff Data Center (GRDC). Then, the coefficient of annual peak discharge variation (CVQp) was used to study the process and evolution of the braid bars. The results are as follow. (1) In terms of the degree of discharge variability, the braid bar evolution of braided river with lower discharge variability (CVQp < 0.4) mainly develops bar tail deposition and downstream migration. In braided rivers with higher discharge variability (CVQp > 0.4), the braid bar evolves relatively fast. Before and after flood event, the original braid bar is easy to be destroyed and transformed into a new braid bar, and the braid bar burst is common. (2) In a single river, the braid bar distribution of length to width ratio of the braided river with lower discharge variability is relatively concentrated, and the morphology is relatively stable, which is easy to form a relatively-stable braided river. While braided river with higher discharge variability is easy to form classical braided river because of the scattered braid bar distribution of length to width ratio, different morphology and great changes in development position.(3) Downstream accumulation is more common in the evolution of braid bar with lower discharge variability, so it is easy to form compound bars after long time evolution. The flood events of braided rivers with higher discharge variability have a strong influence on the evolution process of the bars, and the braid bar evolution is relatively complex and has poor regularity in the time scale. Clarifying the evolution of braid bars under different discharge conditions can provide guidance for the prediction of sandstone distribution of braided river reservoirs and may provide a basis for the paleo-environment reconstruction and paleo-discharge restoration.
The discharge variability controls the formation and evolution of braid bars and influences the internal structure and superimposition of braid bars. However, the control of discharge variability on the developments and evolution of braid bars are unclear. Google Earth software was used to selected 13 river reaches with braided river deposits worldwide, and the discharge data of the selected river reaches are collected from the Global Runoff Data Center (GRDC). Then, the coefficient of annual peak discharge variation (CVQp) was used to study the process and evolution of the braid bars. The results are as follow. (1) In terms of the degree of discharge variability, the braid bar evolution of braided river with lower discharge variability (CVQp < 0.4) mainly develops bar tail deposition and downstream migration. In braided rivers with higher discharge variability (CVQp > 0.4), the braid bar evolves relatively fast. Before and after flood event, the original braid bar is easy to be destroyed and transformed into a new braid bar, and the braid bar burst is common. (2) In a single river, the braid bar distribution of length to width ratio of the braided river with lower discharge variability is relatively concentrated, and the morphology is relatively stable, which is easy to form a relatively-stable braided river. While braided river with higher discharge variability is easy to form classical braided river because of the scattered braid bar distribution of length to width ratio, different morphology and great changes in development position.(3) Downstream accumulation is more common in the evolution of braid bar with lower discharge variability, so it is easy to form compound bars after long time evolution. The flood events of braided rivers with higher discharge variability have a strong influence on the evolution process of the bars, and the braid bar evolution is relatively complex and has poor regularity in the time scale. Clarifying the evolution of braid bars under different discharge conditions can provide guidance for the prediction of sandstone distribution of braided river reservoirs and may provide a basis for the paleo-environment reconstruction and paleo-discharge restoration.
2024, 49(10): 3529-3546.
doi: 10.3799/dqkx.2023.119
Abstract:
Petroleum resources are abundant in deep formation of the foreland thrust belt, the large-scale oil and gas reservoir exploration field. However, due to the large buried depth, low exploration degree and complex reservoir forming mechanism, it also faces great challenges. It is of great scientific and guiding significance to reveal the reservoir control factors and enrichment rules under complex reservoir forming conditions. Taking the southern margin of Junggar Basin as an example, basing on core observation, thin section identification, logging and single well facies analysis, the sand body sedimentary microfacies and reservoirs type and key factors of Qingshuihe Formation in Gaoquan area were clarified. The comprehensive analysis shows follows: (1) The Cretaceous Qingshuihe Formation sand bodies in Gaoquan structure were superposed by multi-stage underwater distributary channel sand bodies in the fan delta front, with fast lateral changes in sand body reservoir performance and strong heterogeneity. (2) The oil and gas reservoir preservation conditions of the Qingshuihe Formation vary greatly. The Gaoquan anticline structure had been an inherited structure since the Yanshanian Period. Affected by multiple tectonic movements, the anticline structure was severely cut and transformed by faults. In the anticline wing with strong compression deformation, deep and shallow faults were vertically connected, causing the oil and gas in the anticline wing to disperse along the fault adjustment, and only enriched and formed reservoirs at the structural highs. (3) The physical properties of the sand bodies at the bottom of the Qingshuihe Formation were controlled by the paleogeomorphology of the sedimentary period. The sand bodies deposited in areas with relatively high ancient landforms have low shale content, good sorting and excellent reservoir physical properties. The gravels deposited in areas with relatively low ancient landforms are poorly sorted and rounded, with high shale content and poor reservoir physical properties. (4) The oil and gas accumulation of Qingshuihe Formation in Gaoquan structure area are controlled by two key factors: high-quality reservoir and preservation conditions. Focusing on the two major reservoir control factors and based on 3D seismic data, ancient landform restoration and sensitive attribute analysis are carried out to predict the high-quality reservoir development area of Qingshuihe Formation in Gaoquan structure, which is mainly distributed in the southwest of the 3D work area, in NW-SE strip distribution, with a favorable area of about 110 square kilometers, it provides effective support and reference for deep oil and gas exploration in this area.
Petroleum resources are abundant in deep formation of the foreland thrust belt, the large-scale oil and gas reservoir exploration field. However, due to the large buried depth, low exploration degree and complex reservoir forming mechanism, it also faces great challenges. It is of great scientific and guiding significance to reveal the reservoir control factors and enrichment rules under complex reservoir forming conditions. Taking the southern margin of Junggar Basin as an example, basing on core observation, thin section identification, logging and single well facies analysis, the sand body sedimentary microfacies and reservoirs type and key factors of Qingshuihe Formation in Gaoquan area were clarified. The comprehensive analysis shows follows: (1) The Cretaceous Qingshuihe Formation sand bodies in Gaoquan structure were superposed by multi-stage underwater distributary channel sand bodies in the fan delta front, with fast lateral changes in sand body reservoir performance and strong heterogeneity. (2) The oil and gas reservoir preservation conditions of the Qingshuihe Formation vary greatly. The Gaoquan anticline structure had been an inherited structure since the Yanshanian Period. Affected by multiple tectonic movements, the anticline structure was severely cut and transformed by faults. In the anticline wing with strong compression deformation, deep and shallow faults were vertically connected, causing the oil and gas in the anticline wing to disperse along the fault adjustment, and only enriched and formed reservoirs at the structural highs. (3) The physical properties of the sand bodies at the bottom of the Qingshuihe Formation were controlled by the paleogeomorphology of the sedimentary period. The sand bodies deposited in areas with relatively high ancient landforms have low shale content, good sorting and excellent reservoir physical properties. The gravels deposited in areas with relatively low ancient landforms are poorly sorted and rounded, with high shale content and poor reservoir physical properties. (4) The oil and gas accumulation of Qingshuihe Formation in Gaoquan structure area are controlled by two key factors: high-quality reservoir and preservation conditions. Focusing on the two major reservoir control factors and based on 3D seismic data, ancient landform restoration and sensitive attribute analysis are carried out to predict the high-quality reservoir development area of Qingshuihe Formation in Gaoquan structure, which is mainly distributed in the southwest of the 3D work area, in NW-SE strip distribution, with a favorable area of about 110 square kilometers, it provides effective support and reference for deep oil and gas exploration in this area.
2024, 49(10): 3547-3558.
doi: 10.3799/dqkx.2022.045
Abstract:
Overpressure is widely developed of Yinggehai Formation in Ledong area of the central diapir zone. The overpressure mudstone is characterized by abnormally higher acoustic travel time, lower resistivity and density than that of the normal pressured mudstones.In this paper, the contribution rate of overpressure caused by different mechanisms is quantitatively evaluated based on the comprehensive analysis of the overpressure mechanisms of Yinggehai Formation in the central diapir zone of Yinggehai basin.The results indicate that the main causes of overpressure in Yinggehai Formation in Ledong area of the central diapir zone include undercompaction, hydrocarbon generation of organic matter and overpressure transfer. The contribution of clay mineral transformation to the overpressure is not obvious. The quantitative study of overpressure contribution rate reveals the contribution of fluid pressure transfer and hydrocarbon generation to mudstone overpressure in the diapir area of Yinggehai Basin. The contribution rate of overpressure caused by undercompaction in the Ledong Area of the Central Diapir Zone of Yinggehai Basin ranges from 38% to 100%. As the burial depth increases, the contribution rate of undercompaction-induced overpressure gradually decreases. The main overpressure mechanisms in the first member of Yinggehai Formation is undercompaction with the shallow buried depth and weak hydrocarbon generation capacity. While the hydrocarbon generation capacity of mudstone in the second member of Yinggehai Formation is significantly enhanced, the contribution caused by hydrocarbon generation is up to 51.53%. Microfractures and faults are developed in the diapir area, which make the deep fluid migrate to the shallow layer and produces pressure transfer. The maximum contribution rate of pressure transfer is more than 50% in Yinggehai Formation.
Overpressure is widely developed of Yinggehai Formation in Ledong area of the central diapir zone. The overpressure mudstone is characterized by abnormally higher acoustic travel time, lower resistivity and density than that of the normal pressured mudstones.In this paper, the contribution rate of overpressure caused by different mechanisms is quantitatively evaluated based on the comprehensive analysis of the overpressure mechanisms of Yinggehai Formation in the central diapir zone of Yinggehai basin.The results indicate that the main causes of overpressure in Yinggehai Formation in Ledong area of the central diapir zone include undercompaction, hydrocarbon generation of organic matter and overpressure transfer. The contribution of clay mineral transformation to the overpressure is not obvious. The quantitative study of overpressure contribution rate reveals the contribution of fluid pressure transfer and hydrocarbon generation to mudstone overpressure in the diapir area of Yinggehai Basin. The contribution rate of overpressure caused by undercompaction in the Ledong Area of the Central Diapir Zone of Yinggehai Basin ranges from 38% to 100%. As the burial depth increases, the contribution rate of undercompaction-induced overpressure gradually decreases. The main overpressure mechanisms in the first member of Yinggehai Formation is undercompaction with the shallow buried depth and weak hydrocarbon generation capacity. While the hydrocarbon generation capacity of mudstone in the second member of Yinggehai Formation is significantly enhanced, the contribution caused by hydrocarbon generation is up to 51.53%. Microfractures and faults are developed in the diapir area, which make the deep fluid migrate to the shallow layer and produces pressure transfer. The maximum contribution rate of pressure transfer is more than 50% in Yinggehai Formation.
2024, 49(10): 3559-3575.
doi: 10.3799/dqkx.2023.136
Abstract:
In order to explore the structural difference and control mechanism of Yangjiang east sag in Zhusan depression, the development characteristics of main faults in the sag are finely explained and their activity is analyzed by using three-dimensional seismic data, the distribution characteristics of magmatic diapir are identified and summarized, and the structural differences of different depressions in Yangjiang east sag in Early Cenozoic are systematically studied. The study shows that the special structural position of Yangjiang east sag influences the formation of the sag, and the structural transformation zone controls the differential development of each sag in the study area. Yangjiang No.24 depression in the west is a simple half graben structure with north fault and south overlap, while Enping No.19, No.20 and No.21 depressions in the middle and east is a compound half graben structure with north-south double faults. The deformation of lithospheric crust in the initial stage of rifting is different due to the different extension modes of subsag under the regional stress field. During the same rifting stage, the magma migrated to the lower pressure transition zone and accumulated to form magma chamber. The deep faults in the basement communicated with the deep crust and controlled the magma upwelling and emplacement. The thermal action of magma makes the crustal brittle deformation change into ductile deformation, so the sag near the Yangjiang-Yitong'ansha blind fault zone develops oblique slip fault and presents a compound half graben structure. The above analysis provides a theoretical basis for the prediction and exploration of source rocks in the study area.
In order to explore the structural difference and control mechanism of Yangjiang east sag in Zhusan depression, the development characteristics of main faults in the sag are finely explained and their activity is analyzed by using three-dimensional seismic data, the distribution characteristics of magmatic diapir are identified and summarized, and the structural differences of different depressions in Yangjiang east sag in Early Cenozoic are systematically studied. The study shows that the special structural position of Yangjiang east sag influences the formation of the sag, and the structural transformation zone controls the differential development of each sag in the study area. Yangjiang No.24 depression in the west is a simple half graben structure with north fault and south overlap, while Enping No.19, No.20 and No.21 depressions in the middle and east is a compound half graben structure with north-south double faults. The deformation of lithospheric crust in the initial stage of rifting is different due to the different extension modes of subsag under the regional stress field. During the same rifting stage, the magma migrated to the lower pressure transition zone and accumulated to form magma chamber. The deep faults in the basement communicated with the deep crust and controlled the magma upwelling and emplacement. The thermal action of magma makes the crustal brittle deformation change into ductile deformation, so the sag near the Yangjiang-Yitong'ansha blind fault zone develops oblique slip fault and presents a compound half graben structure. The above analysis provides a theoretical basis for the prediction and exploration of source rocks in the study area.
2024, 49(10): 3576-3588.
doi: 10.3799/dqkx.2023.122
Abstract:
High-production oil flow was obtained from Lower Cretaceous Qingshuihe Formation in Well Gaotan-1, which is located in the southern margin of Junggar Basin. The result proves that high-quality conglomerate reservoirs are developed in Qingshuihe Formation. In this paper it analyzes the rock minerals, physical properties, pore structure and diagenesis of the conglomerate of Qingshuihe Formation in Gaoquan structure zone, Sikeshu sag, by using cores and thin section data, porosity-permeability analysis and X-ray diffraction whole rock mineral analysis. The main controlling factors of high-quality conglomerate reseroirs were analyzed based on the result. The studies show that the tuffaceous gravels are the major content of the reservoir. The content of sandy grains is typically less than 50%. Based on the contact relationship of the gravels and the content of sandy grains, the conglomerate can be divided into grain supported conglomerate and matrix supported conglomerate. The reservoir space is strong in heterogeneity, which is dominated by primary pores. The development of reservoir space is affected by a variety of diagenesis, among which physical compaction is the major contributor to the porosity loss. The conglomerate reservoir has undergone the burial process of early long-term shallow burial and late rapid deep burial, and is currently in the mesogenesis stage A. The forming of high-quality conglomerate reservoir derives from the following controlling factors. Conglomerate from underwater distributary channels in fan-delta front is the foundation to form high-quality reservoir. Low geothermal gradient and the the burial process of early long-term shallow burial and late rapid deep burial are key contributors to the formation of the reservoir. The alkaline diagenetic environment in the early stage of diagenesis and later acid diagenetic environment, as well as the overpressure are also important to the formation of the reservoir.
High-production oil flow was obtained from Lower Cretaceous Qingshuihe Formation in Well Gaotan-1, which is located in the southern margin of Junggar Basin. The result proves that high-quality conglomerate reservoirs are developed in Qingshuihe Formation. In this paper it analyzes the rock minerals, physical properties, pore structure and diagenesis of the conglomerate of Qingshuihe Formation in Gaoquan structure zone, Sikeshu sag, by using cores and thin section data, porosity-permeability analysis and X-ray diffraction whole rock mineral analysis. The main controlling factors of high-quality conglomerate reseroirs were analyzed based on the result. The studies show that the tuffaceous gravels are the major content of the reservoir. The content of sandy grains is typically less than 50%. Based on the contact relationship of the gravels and the content of sandy grains, the conglomerate can be divided into grain supported conglomerate and matrix supported conglomerate. The reservoir space is strong in heterogeneity, which is dominated by primary pores. The development of reservoir space is affected by a variety of diagenesis, among which physical compaction is the major contributor to the porosity loss. The conglomerate reservoir has undergone the burial process of early long-term shallow burial and late rapid deep burial, and is currently in the mesogenesis stage A. The forming of high-quality conglomerate reservoir derives from the following controlling factors. Conglomerate from underwater distributary channels in fan-delta front is the foundation to form high-quality reservoir. Low geothermal gradient and the the burial process of early long-term shallow burial and late rapid deep burial are key contributors to the formation of the reservoir. The alkaline diagenetic environment in the early stage of diagenesis and later acid diagenetic environment, as well as the overpressure are also important to the formation of the reservoir.
2024, 49(10): 3589-3609.
doi: 10.3799/dqkx.2023.080
Abstract:
The Luhai and Zhundalai uranium deposits in southwestern margin of the Manite Depression in Erlian Basin are large sandstone-type uranium deposits newly discovered in recent years. The ore-bearing strata are mainly the upper Saihan Formation of the Lower Cretaceous. Provenance analysis of the upper Saihan Formation is of great significance to enrich the sandstone-type uranium metallogenic theory and guide the prospecting work in this area. In this paper, petrology, heavy minerals, and detrital zircon U-Pb geochronology were carried out on the ore-hosting sand bodies. The ore-hosting sandstone type is dominated by lithic feldspar sandstone, followed by feldspar lithic sandstone, indicating that the clastic material is mainly derived from the re-rotational collisional orogenic zone, followed by the island arc magmatic zone, with mixed characteristics. The characteristics of heavy minerals reflect the paleogeographical pattern that two main channels, NE-SW and SE-NW, converged in the Zhundalai area during the depositional period of the upper Saihan Formation. The age composition of detrital zircon can be divided into four age ranges of 120-140 Ma、200-240 Ma、260-360 Ma、390-510 Ma. The Early Paleozoic and Mesozoic zircon ages have a higher proportion in Luhai area, while the Late Paleozoic zircon ages in Zhundalai area have increased significantly. After comparing with the age spectrum of the surrounding rock mass and combined with the analysis results of heavy minerals, it believes that the provenance of the upper Saihan Formation in Luhai area may come from the Bayinbaolige rise in the north of the study area and the northern part of the Sunite rise in the south. The clastic material in Zhundalai area is mainly from the southern part of the Sunite rise. In general, the study area presents a north-south two-way supply model. On the basis of understanding the provenance conditions, it has analyzed the uranium supply capacity of the erosion source area. The uplift of Sunite rise since Early Cretaceous and the denudation of high uranium-bearing plutons have more significant effect on the sandstone-type uranium mineralization in the study area. This indicates that the southwestern margin of the Manite Depression has good sandstone-type uranium mineralization prospects.
The Luhai and Zhundalai uranium deposits in southwestern margin of the Manite Depression in Erlian Basin are large sandstone-type uranium deposits newly discovered in recent years. The ore-bearing strata are mainly the upper Saihan Formation of the Lower Cretaceous. Provenance analysis of the upper Saihan Formation is of great significance to enrich the sandstone-type uranium metallogenic theory and guide the prospecting work in this area. In this paper, petrology, heavy minerals, and detrital zircon U-Pb geochronology were carried out on the ore-hosting sand bodies. The ore-hosting sandstone type is dominated by lithic feldspar sandstone, followed by feldspar lithic sandstone, indicating that the clastic material is mainly derived from the re-rotational collisional orogenic zone, followed by the island arc magmatic zone, with mixed characteristics. The characteristics of heavy minerals reflect the paleogeographical pattern that two main channels, NE-SW and SE-NW, converged in the Zhundalai area during the depositional period of the upper Saihan Formation. The age composition of detrital zircon can be divided into four age ranges of 120-140 Ma、200-240 Ma、260-360 Ma、390-510 Ma. The Early Paleozoic and Mesozoic zircon ages have a higher proportion in Luhai area, while the Late Paleozoic zircon ages in Zhundalai area have increased significantly. After comparing with the age spectrum of the surrounding rock mass and combined with the analysis results of heavy minerals, it believes that the provenance of the upper Saihan Formation in Luhai area may come from the Bayinbaolige rise in the north of the study area and the northern part of the Sunite rise in the south. The clastic material in Zhundalai area is mainly from the southern part of the Sunite rise. In general, the study area presents a north-south two-way supply model. On the basis of understanding the provenance conditions, it has analyzed the uranium supply capacity of the erosion source area. The uplift of Sunite rise since Early Cretaceous and the denudation of high uranium-bearing plutons have more significant effect on the sandstone-type uranium mineralization in the study area. This indicates that the southwestern margin of the Manite Depression has good sandstone-type uranium mineralization prospects.
2024, 49(10): 3610-3628.
doi: 10.3799/dqkx.2023.139
Abstract:
The Ramba leucogranite, located in the eastern part of the Northern Himalaya, is mainly composed of two-mica granite. The amphibolite in contact with it is commonly skarnized and accompanied by scheelite mineralization. To qualify the diagenetic and metallogenic ages and the ore-forming fluid characters, an integrated approach involving zircon U-Pb and mica Ar-Ar dating, and mineral geochemistry was carried out. The Ar-Ar age (6.3 Ma) of muscovite from the scheelite-bearing quartz vein yielded is comparable to the zircon U-Pb age (7.3 Ma) of two-mica granite, indicating that the granite emplacement and associated tungsten mineralization both occurred in the Late Miocene, which is the youngest known rare-metal mineralization event in the region. The iron ratios of garnet and pyroxene mineral pairs within the scheelite-bearing skarn (3.12 to 3.74), and the relatively low Mo content (12.0×10-6-56.8×10-6) of scheelite, collectively indicate that the ore-forming fluid is reduced, which is consistent with the magmatic zircon oxygen fugacity calculated results (ΔFMQ=-5.78 to -2.08). The rare-earth element characteristics of scheelite are inherited from the leucogranite granite, further indicating that the W-rich ore-forming fluid was dissolved from the evolved granitic melt and subsequently reacted with the Ca-rich wall rocks to induce the precipitation of scheelite. This study reveals that the contact metamorphic zone between Himalayan leucogranite and surrounding wall rock is a favorable site for rare-metals, and deserves attention in future prospecting.
The Ramba leucogranite, located in the eastern part of the Northern Himalaya, is mainly composed of two-mica granite. The amphibolite in contact with it is commonly skarnized and accompanied by scheelite mineralization. To qualify the diagenetic and metallogenic ages and the ore-forming fluid characters, an integrated approach involving zircon U-Pb and mica Ar-Ar dating, and mineral geochemistry was carried out. The Ar-Ar age (6.3 Ma) of muscovite from the scheelite-bearing quartz vein yielded is comparable to the zircon U-Pb age (7.3 Ma) of two-mica granite, indicating that the granite emplacement and associated tungsten mineralization both occurred in the Late Miocene, which is the youngest known rare-metal mineralization event in the region. The iron ratios of garnet and pyroxene mineral pairs within the scheelite-bearing skarn (3.12 to 3.74), and the relatively low Mo content (12.0×10-6-56.8×10-6) of scheelite, collectively indicate that the ore-forming fluid is reduced, which is consistent with the magmatic zircon oxygen fugacity calculated results (ΔFMQ=-5.78 to -2.08). The rare-earth element characteristics of scheelite are inherited from the leucogranite granite, further indicating that the W-rich ore-forming fluid was dissolved from the evolved granitic melt and subsequently reacted with the Ca-rich wall rocks to induce the precipitation of scheelite. This study reveals that the contact metamorphic zone between Himalayan leucogranite and surrounding wall rock is a favorable site for rare-metals, and deserves attention in future prospecting.
2024, 49(10): 3629-3646.
doi: 10.3799/dqkx.2023.147
Abstract:
In order to understand the evolution history of Quaternary vegetation and climate in Yangtze delta, the study of Core LZK1 from Hengshan Island, Shanghai on sediment lithology and high resolution spore-pollen data suggests that the changes in pollen assemblage in Quaternary have resulted from the joint effect of topography, transgression and, which show a regular pattern of variation, including coniferous and broad-leaved mixed forest-shrub meadow, coniferous and deciduous broad-leaved mixed forest-shrub meadow, coniferous forest-shrub meadow, evergreen and deciduous broad-leaved mixed forest, coniferous and deciduous broad-leaved mixed forest, deciduous broad-leaved forest, coniferous forest, broad-leaved and coniferous mixed forest, coniferous and deciduous broad-leaved mixed forest-shrub meadow, evergreen and deciduous broad-leaved mixed forest-shrub meadow, evergreen and deciduous broad-leaved mixed forest, deciduous broad-leaved and coniferous mixed forest. The climate changes reflected by the sedimentary environment and palynological assemblages of Core LZK1 can be responded to the climatic events such as the Kunlun glaciation, the great interglaciation, the Guxiang glaciation and the last interglaciation. The climate of the last deglaciation period was cool and slightly dry. At the end of the Late Pleistocene, the study area was sensitive to the cold events such as Oldest Dryas, IACP events, and Younger Dryas. When entering the Holocene, the climate warmed up, the humidity increased, and the sea level continued to rise. During this period, there were cold events of -8.2 ka and -4.2 ka, and a brief process of cooling and drought occurred. Influenced by the Little Ice Age in the Late Holocene, the temperature and humidity decreased and the sea water retreated eastward.
In order to understand the evolution history of Quaternary vegetation and climate in Yangtze delta, the study of Core LZK1 from Hengshan Island, Shanghai on sediment lithology and high resolution spore-pollen data suggests that the changes in pollen assemblage in Quaternary have resulted from the joint effect of topography, transgression and, which show a regular pattern of variation, including coniferous and broad-leaved mixed forest-shrub meadow, coniferous and deciduous broad-leaved mixed forest-shrub meadow, coniferous forest-shrub meadow, evergreen and deciduous broad-leaved mixed forest, coniferous and deciduous broad-leaved mixed forest, deciduous broad-leaved forest, coniferous forest, broad-leaved and coniferous mixed forest, coniferous and deciduous broad-leaved mixed forest-shrub meadow, evergreen and deciduous broad-leaved mixed forest-shrub meadow, evergreen and deciduous broad-leaved mixed forest, deciduous broad-leaved and coniferous mixed forest. The climate changes reflected by the sedimentary environment and palynological assemblages of Core LZK1 can be responded to the climatic events such as the Kunlun glaciation, the great interglaciation, the Guxiang glaciation and the last interglaciation. The climate of the last deglaciation period was cool and slightly dry. At the end of the Late Pleistocene, the study area was sensitive to the cold events such as Oldest Dryas, IACP events, and Younger Dryas. When entering the Holocene, the climate warmed up, the humidity increased, and the sea level continued to rise. During this period, there were cold events of -8.2 ka and -4.2 ka, and a brief process of cooling and drought occurred. Influenced by the Little Ice Age in the Late Holocene, the temperature and humidity decreased and the sea water retreated eastward.
2024, 49(10): 3647-3673.
doi: 10.3799/dqkx.2023.117
Abstract:
The Moroccan Devonian is renowned in the fields of geology, especially in paleontology, for its abundant and well-preserved fossils, which have yielded trilobites, cephalopods, corals, brachiopods, conodonts, fishes, and plants. These fossils provide valuable evidence for clarifying stratigraphic sequences, ascertaining fossil communities, paleoenvironments and geological events. Moreover, due to Morocco's unique paleogeographic location in the Devonian, the identification of rock associations, biotic provinces and their spatiotemporal distribution contributes to the reconstruction of the ocean systems between Gondwana and Laurussia. In this article it reviews the history of Morocco geological surveys and discusses the three main stages of Morocco Devonian research. In recent years, interdisciplinary study and cross-regional cooperation have emerged as the main development trends. Significant new discoveries and insights have been made in the fields of paleontology, paleogeography, and paleoclimatology by leveraging the abundant fossil resources in Morocco. Making full use of this treasure trove of fossils will help to better understand the evolutionary history of the earth and deal with today's biodiversity crisis and environmental problems.
The Moroccan Devonian is renowned in the fields of geology, especially in paleontology, for its abundant and well-preserved fossils, which have yielded trilobites, cephalopods, corals, brachiopods, conodonts, fishes, and plants. These fossils provide valuable evidence for clarifying stratigraphic sequences, ascertaining fossil communities, paleoenvironments and geological events. Moreover, due to Morocco's unique paleogeographic location in the Devonian, the identification of rock associations, biotic provinces and their spatiotemporal distribution contributes to the reconstruction of the ocean systems between Gondwana and Laurussia. In this article it reviews the history of Morocco geological surveys and discusses the three main stages of Morocco Devonian research. In recent years, interdisciplinary study and cross-regional cooperation have emerged as the main development trends. Significant new discoveries and insights have been made in the fields of paleontology, paleogeography, and paleoclimatology by leveraging the abundant fossil resources in Morocco. Making full use of this treasure trove of fossils will help to better understand the evolutionary history of the earth and deal with today's biodiversity crisis and environmental problems.
2024, 49(10): 3674-3684.
doi: 10.3799/dqkx.2023.142
Abstract:
Marine redox variations have been frequently used to explain the radiation and extinction of early animals during the Early Cambrian. However, this hypothesis remains unclear. Here, it conducted total organic carbon, iron speciation, major elements, and trace elements in the basinal Zhalagou Section. The new redox results were compared with published redox environments from the coeval other sections in South China and Siberian. The results suggest that oxic waters were intensively expanded during Cambrian Age 2-3, whereas the degree of oceanic anoxia was enhanced during Cambrian Age 4. Comparison of ocean redox states and fossils suggests that enhanced ocean oxygenation might play key roles in the radiation of early animals during Cambrian Age 2-3, but expanded ocean anoxia might have significant effects on the decreased diversification of early animals and extinction of archaeocyaths during Cambrian Age 4.
Marine redox variations have been frequently used to explain the radiation and extinction of early animals during the Early Cambrian. However, this hypothesis remains unclear. Here, it conducted total organic carbon, iron speciation, major elements, and trace elements in the basinal Zhalagou Section. The new redox results were compared with published redox environments from the coeval other sections in South China and Siberian. The results suggest that oxic waters were intensively expanded during Cambrian Age 2-3, whereas the degree of oceanic anoxia was enhanced during Cambrian Age 4. Comparison of ocean redox states and fossils suggests that enhanced ocean oxygenation might play key roles in the radiation of early animals during Cambrian Age 2-3, but expanded ocean anoxia might have significant effects on the decreased diversification of early animals and extinction of archaeocyaths during Cambrian Age 4.
2024, 49(10): 3685-3696.
doi: 10.3799/dqkx.2023.132
Abstract:
Soil samples, at the depth of 0 cm, 10 cm, 30 cm, and 50 cm, were collected from the Dajiuhu peatland for four quarters in 2019 to investigate the distribution patterns of methanogens and methanotrophs in vertical profile and their response to the abiotic environment. High-through put sequencing was implemented to analyze the community structure of methanogens and methanotrophs, then construct molecular ecological networks. Methanoregula and Methylocapsa were found as the largest dominant genus of methanogens and methanotrophs in the Dajiuhu peatland. The ecological networks of methanogens and methanotrophs and their synergism varied with depth, and the opposite situation was observed in methanogens and methanogens. Moreover, Methanoregula, Methanocella, Methanobacterium were identified as key species in the methanogenic community, and 4 key species of methanotrophs were Methylocapsa, Candidatus Methyloumidiphilus, Methylocystis, Candidatus Methylospira. The results demonstrated that total carbon, total nitrogen, ammonium, and nitrite could affect the structure of methanogens and methanogens, thereby controlling CH4 emissions in the Dajiuhu peatland.
Soil samples, at the depth of 0 cm, 10 cm, 30 cm, and 50 cm, were collected from the Dajiuhu peatland for four quarters in 2019 to investigate the distribution patterns of methanogens and methanotrophs in vertical profile and their response to the abiotic environment. High-through put sequencing was implemented to analyze the community structure of methanogens and methanotrophs, then construct molecular ecological networks. Methanoregula and Methylocapsa were found as the largest dominant genus of methanogens and methanotrophs in the Dajiuhu peatland. The ecological networks of methanogens and methanotrophs and their synergism varied with depth, and the opposite situation was observed in methanogens and methanogens. Moreover, Methanoregula, Methanocella, Methanobacterium were identified as key species in the methanogenic community, and 4 key species of methanotrophs were Methylocapsa, Candidatus Methyloumidiphilus, Methylocystis, Candidatus Methylospira. The results demonstrated that total carbon, total nitrogen, ammonium, and nitrite could affect the structure of methanogens and methanogens, thereby controlling CH4 emissions in the Dajiuhu peatland.
2024, 49(10): 3697-3711.
doi: 10.3799/dqkx.2023.127
Abstract:
The compositional variations and rhythmicity of the positive anomalous natural gamma (GR) layers developed in the Upper Permian of West Guizhou are not clear. In this paper, it analyzed the lithological characteristics, geochemical characteristics and periodicity of positive anomalous GR layers. Al2O3/TiO2, REE patterns, REE-La/Yb, La/Sc-Co/Th, Zr/TiO2-Al2O3/TiO2 and Nb/Ta-Zr/Hf diagrams indicate that the sources of highly radioactive layers include Emeishan basalt, volcanic ash originates from the Emeishan large igneous province during its waning phase and South China volcanic ash. The positive anomalous GR layers were formed during a period of relatively hot and low sea level, with long and short eccentricity cycles. The hot climate change caused rapid sea level rise and ice volume drop, and the rapid change of stress state on the region triggered volcanic activity to form periodic positive anomalous GR formations. Precise identification of positive anomalous GR layers can be used to compare and delineate the regional stratigraphic framework, and to analyze the magmatic evolution and critical element enrichment of the late Emeishan large igneous province.
The compositional variations and rhythmicity of the positive anomalous natural gamma (GR) layers developed in the Upper Permian of West Guizhou are not clear. In this paper, it analyzed the lithological characteristics, geochemical characteristics and periodicity of positive anomalous GR layers. Al2O3/TiO2, REE patterns, REE-La/Yb, La/Sc-Co/Th, Zr/TiO2-Al2O3/TiO2 and Nb/Ta-Zr/Hf diagrams indicate that the sources of highly radioactive layers include Emeishan basalt, volcanic ash originates from the Emeishan large igneous province during its waning phase and South China volcanic ash. The positive anomalous GR layers were formed during a period of relatively hot and low sea level, with long and short eccentricity cycles. The hot climate change caused rapid sea level rise and ice volume drop, and the rapid change of stress state on the region triggered volcanic activity to form periodic positive anomalous GR formations. Precise identification of positive anomalous GR layers can be used to compare and delineate the regional stratigraphic framework, and to analyze the magmatic evolution and critical element enrichment of the late Emeishan large igneous province.
2024, 49(10): 3712-3722.
doi: 10.3799/dqkx.2023.121
Abstract:
The most significant feature of the river hyporheic zone is the dynamic change of water chemical composition caused by the periodical alternation of river water and groundwater, and the interval between periods is different. The hyporheic zone is a denitrification hot zone, and the response law of nitrification and denitrifying microorganisms to this periodical change determines the nitrogen removal efficiency of the hyporheic zone. According to this, different nitrogen, DO, etc. were supplied multiple times at different intervals to study the kinetics of nitrification and denitrification in multiple cycles. The nitrification and denitrification rates in the first cycle were slow, and there was an obvious hysteresis period. In the subsequent second and third cycles, regardless of the length of substrate dosing interval, no significant hysteresis period was observed for nitrification and denitrification, the reaction rate was accelerated, and the number of functional bacteria increased, but the number of functional bacteria was inversely proportional to the interval time. The initial concentration of nitrate nitrogen significantly affects the nitrous nitrogen kinetic process. The increase in the number of nitrifying and denitrifying bacteria and the maintenance of high reactivity for a long time are one of the efficient nitrogen removal mechanisms in the hyporheic zone.
The most significant feature of the river hyporheic zone is the dynamic change of water chemical composition caused by the periodical alternation of river water and groundwater, and the interval between periods is different. The hyporheic zone is a denitrification hot zone, and the response law of nitrification and denitrifying microorganisms to this periodical change determines the nitrogen removal efficiency of the hyporheic zone. According to this, different nitrogen, DO, etc. were supplied multiple times at different intervals to study the kinetics of nitrification and denitrification in multiple cycles. The nitrification and denitrification rates in the first cycle were slow, and there was an obvious hysteresis period. In the subsequent second and third cycles, regardless of the length of substrate dosing interval, no significant hysteresis period was observed for nitrification and denitrification, the reaction rate was accelerated, and the number of functional bacteria increased, but the number of functional bacteria was inversely proportional to the interval time. The initial concentration of nitrate nitrogen significantly affects the nitrous nitrogen kinetic process. The increase in the number of nitrifying and denitrifying bacteria and the maintenance of high reactivity for a long time are one of the efficient nitrogen removal mechanisms in the hyporheic zone.
2024, 49(10): 3723-3735.
doi: 10.3799/dqkx.2023.148
Abstract:
Generating a series of stochastic models (realizations) by applying stochastic inverse modeling method is sometimes an efficient way to improve hydrogeological cognition accuracy of a site, such as obtaining a more clarity aquifer structure or a probabilistic capture zone of a spring. However, the borehole data size often cannot meet the requirements of stochastic modeling in a general project. Considering geological analysis result and borehole data, it may be a rational and effective method to translate geophysical prospecting (TEM) points into virtual boreholes to solve the data shortage problem. Using the PEST program, stochastic models established through practical boreholes and virtual boreholes can be screened with groundwater level data as the reference. The stratigraphic structure of the filtered models is then checked artificially to guarantee model geological rationality. In this paper, a total of 503 realizations are generated by using a transition probability Markov chain (T-PORGS) based on 74 data points (including virtual boreholes). With data from 9 groundwater observation points within the site as a benchmark, 67 models that effectively describe the hydrogeological characteristics of the site are selected through PEST. Finally, the probabilistic capture zones of the target spring in a fracture aquifer are calculated from these selected models. This modeling process enables stochastic modeling at a site scale even in the absence of sufficient borehole data, providing valuable hydrogeological information for the site.
Generating a series of stochastic models (realizations) by applying stochastic inverse modeling method is sometimes an efficient way to improve hydrogeological cognition accuracy of a site, such as obtaining a more clarity aquifer structure or a probabilistic capture zone of a spring. However, the borehole data size often cannot meet the requirements of stochastic modeling in a general project. Considering geological analysis result and borehole data, it may be a rational and effective method to translate geophysical prospecting (TEM) points into virtual boreholes to solve the data shortage problem. Using the PEST program, stochastic models established through practical boreholes and virtual boreholes can be screened with groundwater level data as the reference. The stratigraphic structure of the filtered models is then checked artificially to guarantee model geological rationality. In this paper, a total of 503 realizations are generated by using a transition probability Markov chain (T-PORGS) based on 74 data points (including virtual boreholes). With data from 9 groundwater observation points within the site as a benchmark, 67 models that effectively describe the hydrogeological characteristics of the site are selected through PEST. Finally, the probabilistic capture zones of the target spring in a fracture aquifer are calculated from these selected models. This modeling process enables stochastic modeling at a site scale even in the absence of sufficient borehole data, providing valuable hydrogeological information for the site.
2024, 49(10): 3736-3748.
doi: 10.3799/dqkx.2023.081
Abstract:
The northeast margin of Pamir tectonic junction is enriched with medium-high temperature geothermal resources. Most previous studies are limited to a single geothermal field and lack of regional systematic research. Here, it applies geothermal hydro-geochemistry as an effective method to study geothermal resources. Based on the geothermal geological characteristics of the northeast margin of the Pamirs Plateau, the hydrochemical genesis, characteristics and isotope analysis of 8 hot spring water, 1 cold spring water, 11 hot well water and 6 surface water in the study area were analyzed and revealed the evolution characteristics of regional geothermal fluid thermal reservoir and cooling mechanism in the northeast of Pamir. It provides a certain geochemical basis for the exploration of geothermal resources in the northeast of Pamir. The results show that the major ions in geothermal water are mainly originated from sodium/potassium feldspar, cation exchange and magmatic water. The high correlation of ratio in B/Cl、B/Li、B/Cs、Li/Cs、Na/Cl、K/Cl shows that hot water probably has a common parent geothermal fluid. The characteristics of hydrogen and oxygen isotopes indicate that geothermal water is recharged by atmospheric precipitation, snowmelt water and deep magmatic water. A variety of solute thermometers, silicon-enthalpy model and chlorine-enthalpy model were used to reconstruct the geothermal reservoir temperature, cooling process and evolution mode of geothermal groundwater. It inferred that there may be multiple thermal reservoirs under the study area, which the temperature of the deepest parent geothermal fluid storage is about 358-418 ℃ with the Cl- concentrations about 300-400 mg/L. Combined with regional geology and geothermal geological conditions analysis, it believes the geothermal anomaly in the northeast margin of the Pamir Plateau is a result of uncooling magma in the crust and high radioactive granite.
The northeast margin of Pamir tectonic junction is enriched with medium-high temperature geothermal resources. Most previous studies are limited to a single geothermal field and lack of regional systematic research. Here, it applies geothermal hydro-geochemistry as an effective method to study geothermal resources. Based on the geothermal geological characteristics of the northeast margin of the Pamirs Plateau, the hydrochemical genesis, characteristics and isotope analysis of 8 hot spring water, 1 cold spring water, 11 hot well water and 6 surface water in the study area were analyzed and revealed the evolution characteristics of regional geothermal fluid thermal reservoir and cooling mechanism in the northeast of Pamir. It provides a certain geochemical basis for the exploration of geothermal resources in the northeast of Pamir. The results show that the major ions in geothermal water are mainly originated from sodium/potassium feldspar, cation exchange and magmatic water. The high correlation of ratio in B/Cl、B/Li、B/Cs、Li/Cs、Na/Cl、K/Cl shows that hot water probably has a common parent geothermal fluid. The characteristics of hydrogen and oxygen isotopes indicate that geothermal water is recharged by atmospheric precipitation, snowmelt water and deep magmatic water. A variety of solute thermometers, silicon-enthalpy model and chlorine-enthalpy model were used to reconstruct the geothermal reservoir temperature, cooling process and evolution mode of geothermal groundwater. It inferred that there may be multiple thermal reservoirs under the study area, which the temperature of the deepest parent geothermal fluid storage is about 358-418 ℃ with the Cl- concentrations about 300-400 mg/L. Combined with regional geology and geothermal geological conditions analysis, it believes the geothermal anomaly in the northeast margin of the Pamir Plateau is a result of uncooling magma in the crust and high radioactive granite.
2024, 49(10): 3749-3760.
doi: 10.3799/dqkx.2023.076
Abstract:
The presence of geogenic high iodine groundwater in alluvial aquifers in the middle reach of the Yangtze River poses a serious threat to regional water supply security. Iron minerals and organic matter in aquifer sediments are the main carriers of iodine, and revealing the control mechanism of climate change on iodine enrichment in aquifers since the Late Pleistocene from the perspective of regional-geological background and sedimentary evolution is a prerequisite for scientific understanding of the causes of high iodine groundwater and ensuring water supply security. In this study, Quaternary sediments in the distribution area of high iodine groundwater in the middle reach of the Yangtze River were collected, and sediment geochemistry was systematically characterized to identify the main carriers of iodine enrichment in aquifer sediments and to reveal the controlling mechanisms of iodine enrichment in aquifers by weathering and deposition pocesses driven by paleoclimatic changes. The results show that the main iodine speciation in sediments are iron oxide-bounded (IFe-ox) and organic matter bounded (Iorg), and the chemical weathering index CIA and K/Na ratio of sediments are significantly positively correlated with IFe-ox and Iorg. Amorphous iron oxides (Feox1), clay minerals and organic matter are the main carriers of iodine. Climate changed from cold and arid to warm and humid since the Late Pleistocene and Holocene, enhanced chemical weathering, which contributed to the formation of more amorphous iron oxides, and the expansion of lakes after the Holocene led to the co-burial of iodine, organic matter and iron oxides in the lacustrine sediments. Paleoclimatic changes play an important role in controlling iodine enrichment in the middle Yangtze River aquifer.
The presence of geogenic high iodine groundwater in alluvial aquifers in the middle reach of the Yangtze River poses a serious threat to regional water supply security. Iron minerals and organic matter in aquifer sediments are the main carriers of iodine, and revealing the control mechanism of climate change on iodine enrichment in aquifers since the Late Pleistocene from the perspective of regional-geological background and sedimentary evolution is a prerequisite for scientific understanding of the causes of high iodine groundwater and ensuring water supply security. In this study, Quaternary sediments in the distribution area of high iodine groundwater in the middle reach of the Yangtze River were collected, and sediment geochemistry was systematically characterized to identify the main carriers of iodine enrichment in aquifer sediments and to reveal the controlling mechanisms of iodine enrichment in aquifers by weathering and deposition pocesses driven by paleoclimatic changes. The results show that the main iodine speciation in sediments are iron oxide-bounded (IFe-ox) and organic matter bounded (Iorg), and the chemical weathering index CIA and K/Na ratio of sediments are significantly positively correlated with IFe-ox and Iorg. Amorphous iron oxides (Feox1), clay minerals and organic matter are the main carriers of iodine. Climate changed from cold and arid to warm and humid since the Late Pleistocene and Holocene, enhanced chemical weathering, which contributed to the formation of more amorphous iron oxides, and the expansion of lakes after the Holocene led to the co-burial of iodine, organic matter and iron oxides in the lacustrine sediments. Paleoclimatic changes play an important role in controlling iodine enrichment in the middle Yangtze River aquifer.
2024, 49(10): 3761-3772.
doi: 10.3799/dqkx.2023.188
Abstract:
The migration and transformation of NH4-N are influenced by the interactions between surface water and groundwater. However, the mechanisms remain poorly understood. Continuous monitoring of the water level and its hydrochemical composition was conducted in the Shahu site. Column experiments and reactive transport modeling were applied to identify the migration and transformation of NH4-N under conditions of both surface water recharge and groundwater discharge. In this study it indicates that most injected NH4-N is adsorbed on shallow sediment. Infiltration of surface water enhances desorption of NH4-N from sediment particle and subsequent nitrification reactions. In contrast, adsorption of NH4-N on sediment is favored during discharge of NH4-N containing groundwater. Simulating results emphasize the crucial role of cation exchange in NH4-N mobility. Alterations in the hydrogeochemical environment during surface water-groundwater interactions impact the NH4-N adsorption/desorption behaviors and associated biogeochemical reactions.
The migration and transformation of NH4-N are influenced by the interactions between surface water and groundwater. However, the mechanisms remain poorly understood. Continuous monitoring of the water level and its hydrochemical composition was conducted in the Shahu site. Column experiments and reactive transport modeling were applied to identify the migration and transformation of NH4-N under conditions of both surface water recharge and groundwater discharge. In this study it indicates that most injected NH4-N is adsorbed on shallow sediment. Infiltration of surface water enhances desorption of NH4-N from sediment particle and subsequent nitrification reactions. In contrast, adsorption of NH4-N on sediment is favored during discharge of NH4-N containing groundwater. Simulating results emphasize the crucial role of cation exchange in NH4-N mobility. Alterations in the hydrogeochemical environment during surface water-groundwater interactions impact the NH4-N adsorption/desorption behaviors and associated biogeochemical reactions.
Changes of Temperature and Driving Force during Phase Change in High Temperature Hydrothermal System
2024, 49(10): 3773-3783.
doi: 10.3799/dqkx.2023.126
Abstract:
The theory of groundwater flow system based on gravity is the main tool to describe the seepage characteristics of groundwater system. The gravity potential generated by water head difference is the main driving force of groundwater migration. However, in the hydrothermal system, there is a deep heat source other than geothermal gradient, which will provide additional energy to the groundwater system and generate new driving force. In the convective hydrothermal system, the temperature of groundwater is lower in the recharge section and higher in the discharge section. The high temperature groundwater in the discharge section will produce changes in density, salinity and viscosity, which will lead to changes in the pressure head of geothermal water and form geothermal driving force. In the high temperature hydrothermal system, the temperature of groundwater in the discharge section is higher, and there may be a phase transition process from liquid water to gaseous water, which causes the groundwater temperature to change abruptly, thus causing the change of geothermal driving force. In this paper, the Yangbajing geothermal field in Tibet is taken as an example. Using SiO2 geothermometer, it is found that there is a large difference in water temperature at the same depth between the geothermal reservoir and the geothermal well. By comparing the saturated evaporation line, it is determined that the phase change process causing the temperature drop occurred at 43.9 m from the wellhead. Combined with the first law of thermodynamics, the temperature difference before and after the phase transition is calculated to be about 23.6 ℃, and the resulting change in geothermal driving force is -1.02 m. The results show that the geothermal driving force in the hydrothermal system only exists in the discharge section, and the phase change of geothermal water in the discharge section will cause the change of geothermal driving force.
The theory of groundwater flow system based on gravity is the main tool to describe the seepage characteristics of groundwater system. The gravity potential generated by water head difference is the main driving force of groundwater migration. However, in the hydrothermal system, there is a deep heat source other than geothermal gradient, which will provide additional energy to the groundwater system and generate new driving force. In the convective hydrothermal system, the temperature of groundwater is lower in the recharge section and higher in the discharge section. The high temperature groundwater in the discharge section will produce changes in density, salinity and viscosity, which will lead to changes in the pressure head of geothermal water and form geothermal driving force. In the high temperature hydrothermal system, the temperature of groundwater in the discharge section is higher, and there may be a phase transition process from liquid water to gaseous water, which causes the groundwater temperature to change abruptly, thus causing the change of geothermal driving force. In this paper, the Yangbajing geothermal field in Tibet is taken as an example. Using SiO2 geothermometer, it is found that there is a large difference in water temperature at the same depth between the geothermal reservoir and the geothermal well. By comparing the saturated evaporation line, it is determined that the phase change process causing the temperature drop occurred at 43.9 m from the wellhead. Combined with the first law of thermodynamics, the temperature difference before and after the phase transition is calculated to be about 23.6 ℃, and the resulting change in geothermal driving force is -1.02 m. The results show that the geothermal driving force in the hydrothermal system only exists in the discharge section, and the phase change of geothermal water in the discharge section will cause the change of geothermal driving force.
2024, 49(10): 3784-3798.
doi: 10.3799/dqkx.2023.140
Abstract:
The glacier and snow-related geohazard chain pose a significant threat to the economic activities in the Southeast Tibetan Plateau. Analyzing the evolution law of disaster can provide support for the risk prevention and mitigation, and also for the early identification of disaster. Based on field survey, remote sensing interpretation, and hazard monitoring, in this paper it aims to analyze the evolution of disaster formation conditions and the activity characteristics of six geohazard chain events since the 1950. The results show that the geohazard chain in Zhibai Gully was driven by glacier activity and rock collapse. The evolution models of geohazard chain are summarized into two types: physical property change chain induced by ice water phase transformation, and geological cascade chain induced by coupling of multi factors. It is found that the disaster activity is significantly controlled by the earthquake, and the disaster characteristics is correlated with the temporal-spatial evolution of the formation conditions. Under the influence of the earthquake and deglacialtion, the initiation of disaster chain is transformed from glacier active to rock collapse. The increasing of soil material sources and the effect of ice water phase transformation both enhance the evolution length and scale of disaster. For the present, the Zelongnong glacier is retreating seriously, decreasing the possibility of a geohazard triggered by a glacier. Corresponding the ice/rock avalanche becomes the key to the geohazard chain.
The glacier and snow-related geohazard chain pose a significant threat to the economic activities in the Southeast Tibetan Plateau. Analyzing the evolution law of disaster can provide support for the risk prevention and mitigation, and also for the early identification of disaster. Based on field survey, remote sensing interpretation, and hazard monitoring, in this paper it aims to analyze the evolution of disaster formation conditions and the activity characteristics of six geohazard chain events since the 1950. The results show that the geohazard chain in Zhibai Gully was driven by glacier activity and rock collapse. The evolution models of geohazard chain are summarized into two types: physical property change chain induced by ice water phase transformation, and geological cascade chain induced by coupling of multi factors. It is found that the disaster activity is significantly controlled by the earthquake, and the disaster characteristics is correlated with the temporal-spatial evolution of the formation conditions. Under the influence of the earthquake and deglacialtion, the initiation of disaster chain is transformed from glacier active to rock collapse. The increasing of soil material sources and the effect of ice water phase transformation both enhance the evolution length and scale of disaster. For the present, the Zelongnong glacier is retreating seriously, decreasing the possibility of a geohazard triggered by a glacier. Corresponding the ice/rock avalanche becomes the key to the geohazard chain.
2024, 49(10): 3799-3814.
doi: 10.3799/dqkx.2023.129
Abstract:
Slope instability is very common in the process of building hydropower projects in alpine canyon areas, which has an important impact on engineering construction. In this paper, the slope of the inlet/outlet of the lower reservoir of the Warang pumped storage power station in the upper reach of the Yellow River is taken as the research object. Based on the methods of adit logging and borehole TV, the rock mass structural plane is counted: Through borehole wave velocity test, unloading zoning of slope rock mass is carried out. Accordingly, the potential failure mode of the slope is qualitatively analyzed. Through UDEC software, a discrete element model of slope based on DFN discrete fracture network is established. Considering three working conditions of natural, rainstorm and earthquake, the numerical simulation of natural slope, unsupported excavation process and supported excavation process are carried out respectively to reveal the main controlling factors of potential deformation of slope. The results show that the deformation and failure of the slope are mainly controlled by two groups of structural planes: unloading fissures and gently inclined fissures along the slope. The potential deformation mode is step-like slip-crack failure. The stability study shows that the anti-sliding stability of the natural slope does not meet the specification requirements under three working conditions. In order to ensure the safety of inlet and outlet, combined with slope deformation mode and engineering experience, the corresponding excavation support scheme is proposed. The research shows that the supporting scheme is effective and feasible, which can effectively improve the slope stability and make the stability coefficient meet the specification requirements under different working conditions.
Slope instability is very common in the process of building hydropower projects in alpine canyon areas, which has an important impact on engineering construction. In this paper, the slope of the inlet/outlet of the lower reservoir of the Warang pumped storage power station in the upper reach of the Yellow River is taken as the research object. Based on the methods of adit logging and borehole TV, the rock mass structural plane is counted: Through borehole wave velocity test, unloading zoning of slope rock mass is carried out. Accordingly, the potential failure mode of the slope is qualitatively analyzed. Through UDEC software, a discrete element model of slope based on DFN discrete fracture network is established. Considering three working conditions of natural, rainstorm and earthquake, the numerical simulation of natural slope, unsupported excavation process and supported excavation process are carried out respectively to reveal the main controlling factors of potential deformation of slope. The results show that the deformation and failure of the slope are mainly controlled by two groups of structural planes: unloading fissures and gently inclined fissures along the slope. The potential deformation mode is step-like slip-crack failure. The stability study shows that the anti-sliding stability of the natural slope does not meet the specification requirements under three working conditions. In order to ensure the safety of inlet and outlet, combined with slope deformation mode and engineering experience, the corresponding excavation support scheme is proposed. The research shows that the supporting scheme is effective and feasible, which can effectively improve the slope stability and make the stability coefficient meet the specification requirements under different working conditions.
2024, 49(10): 3815-3825.
doi: 10.3799/dqkx.2023.134
Abstract:
The development of geological disasters is often affected by the surface erosion environment. Landform processes such as collapse, landslide, and debris flow are the most intuitive embodiment of surface erosion. The geological and geomorphological conditions are complex and the surface hydrodynamics are highly developed in alpine canyon areas. In this paper it takes Songpan County, a typical alpine canyon in West Sichuan Province, as the research area. The alpine canyon's surface erosion capacity evaluation system was established based on the MPSIAC model after a detailed investigation of regional erosion status. The surface erosion capacity evaluation of Songpan County was carried out, and the InSAR technology was used to test this result. The result shows that the high-intensity surface erosion of Songpan County is distributed in Minjiang Town and Zhenjiangguan Town in the southeast. In contrast, the low-intensity surface erosion of Songpan County is mainly distributed in Maoergai Town and Chuanzhusi Town in the north.The MPSIAC model can be modified to accurately evaluate surface erosion capacity in alpine canyon areas.
The development of geological disasters is often affected by the surface erosion environment. Landform processes such as collapse, landslide, and debris flow are the most intuitive embodiment of surface erosion. The geological and geomorphological conditions are complex and the surface hydrodynamics are highly developed in alpine canyon areas. In this paper it takes Songpan County, a typical alpine canyon in West Sichuan Province, as the research area. The alpine canyon's surface erosion capacity evaluation system was established based on the MPSIAC model after a detailed investigation of regional erosion status. The surface erosion capacity evaluation of Songpan County was carried out, and the InSAR technology was used to test this result. The result shows that the high-intensity surface erosion of Songpan County is distributed in Minjiang Town and Zhenjiangguan Town in the southeast. In contrast, the low-intensity surface erosion of Songpan County is mainly distributed in Maoergai Town and Chuanzhusi Town in the north.The MPSIAC model can be modified to accurately evaluate surface erosion capacity in alpine canyon areas.
2024, 49(10): 3826-3840.
doi: 10.3799/dqkx.2023.145
Abstract:
Postfire debris flows are hazards that can easily occur and are highly destructive, making them an important target for hazard prevention and mitigation in mountainous areas. Postfire debris flow prediction models developed by researchers outside China offer good prediction results only for regions corresponding to the databases used but poor prediction results for other regions. A forest fire can significantly increase the water repellency of the soil under the forest, and when rainfall occurs, flash floods with high flows form very easily and trigger debris flows. In the first rainy season after a wildfire, the rainfall threshold for debris flow occurrence is very low and the probability of debris flow occurrence is very high. Using wildfires in Liangshan Prefecture, Sichuan Province, China, a concept of equivalent antecedent rainfall (EAR) was introduced, and an EAR calculation model was established through artificial rainfall experiments. An early warning model for the first postfire gully-type debris flow was established using the general quation. The reliability of the method was verified using initial postfire debris flow events in Sichuan, China, and in the United States. The early warning model for first postfire debris flow in this study is a new method for hazard mitigation and the prevention of postfire debris flows.
Postfire debris flows are hazards that can easily occur and are highly destructive, making them an important target for hazard prevention and mitigation in mountainous areas. Postfire debris flow prediction models developed by researchers outside China offer good prediction results only for regions corresponding to the databases used but poor prediction results for other regions. A forest fire can significantly increase the water repellency of the soil under the forest, and when rainfall occurs, flash floods with high flows form very easily and trigger debris flows. In the first rainy season after a wildfire, the rainfall threshold for debris flow occurrence is very low and the probability of debris flow occurrence is very high. Using wildfires in Liangshan Prefecture, Sichuan Province, China, a concept of equivalent antecedent rainfall (EAR) was introduced, and an EAR calculation model was established through artificial rainfall experiments. An early warning model for the first postfire gully-type debris flow was established using the general quation. The reliability of the method was verified using initial postfire debris flow events in Sichuan, China, and in the United States. The early warning model for first postfire debris flow in this study is a new method for hazard mitigation and the prevention of postfire debris flows.
2024, 49(10): 3841-3854.
doi: 10.3799/dqkx.2022.451
Abstract:
A single machine learning model is often difficult to meet the needs of landslide vulnerability mapping, in order to improve the accuracy of landslide vulnerability assessment. In this paper, a method of machine learning model combination optimization based on integrated strategy is proposed, twelve townships in the west of Yunyang County, Chongqing were taken as an example. First, based on 366 landslide data and 9 index factors such as elevation and slope, the susceptibility evaluation index system was constructed. Then used the three algorithms of ensemble learning, bagging, boosting and stacking, to build combined models based on Decision Tree Mode (DT), Logic Regression (LR) and Bayesian Network (BN).The combined models used Particle Swarm Optimization (PSO), Bayesian Optimization (BO) for super parameter optimization and K-Nearest Neighbor (KNN) was used for model recombination. Finally, ROC curve and statistical analysis were used to calculate the accuracy of each integrated learning model. The research results show that compared with the basic classifier models, the accuracy of the three types of integrated learning models was improved. the DT-LR-BN model increased by 3.5%-12.8%, the RF model increased by 8%; the BO-XGBoost model increased by 13.1%; the KNN-stacking model increased by 7.4%-17%, and the AUC value of BO-XGBoost model was the highest at 0.811. Integrated learning can effectively improve the performance of machine learning models, improve the accuracy of landslide susceptibility mapping, and provide a new idea and method for the combination optimization between machine learning models.
A single machine learning model is often difficult to meet the needs of landslide vulnerability mapping, in order to improve the accuracy of landslide vulnerability assessment. In this paper, a method of machine learning model combination optimization based on integrated strategy is proposed, twelve townships in the west of Yunyang County, Chongqing were taken as an example. First, based on 366 landslide data and 9 index factors such as elevation and slope, the susceptibility evaluation index system was constructed. Then used the three algorithms of ensemble learning, bagging, boosting and stacking, to build combined models based on Decision Tree Mode (DT), Logic Regression (LR) and Bayesian Network (BN).The combined models used Particle Swarm Optimization (PSO), Bayesian Optimization (BO) for super parameter optimization and K-Nearest Neighbor (KNN) was used for model recombination. Finally, ROC curve and statistical analysis were used to calculate the accuracy of each integrated learning model. The research results show that compared with the basic classifier models, the accuracy of the three types of integrated learning models was improved. the DT-LR-BN model increased by 3.5%-12.8%, the RF model increased by 8%; the BO-XGBoost model increased by 13.1%; the KNN-stacking model increased by 7.4%-17%, and the AUC value of BO-XGBoost model was the highest at 0.811. Integrated learning can effectively improve the performance of machine learning models, improve the accuracy of landslide susceptibility mapping, and provide a new idea and method for the combination optimization between machine learning models.
2013, 38(3): 454-460.
doi: 10.3799/dqkx.2013.045
2021, 46(12): 4452-4469.
doi: 10.3799/dqkx.2021.117
2014, 39(3): 261-270.
doi: 10.3799/dqkx.2014.025
2014, 39(3): 283-292.
doi: 10.3799/dqkx.2014.027
2013, 38(6): 1327-1330.
doi: 10.3799/dqkx.2013.000
