Deformed soft-sediment deformation structures(SSDS)can indicate polyphase deformation events and provide valuable insights into the inversion process of a basin.Herein,we present the Miocene–Quaternary deformation in...Deformed soft-sediment deformation structures(SSDS)can indicate polyphase deformation events and provide valuable insights into the inversion process of a basin.Herein,we present the Miocene–Quaternary deformation inversion history of the Bomun sub-basin in the Gyeongju area of SE Korea.The inferred ENE compression direction(σHmax)based on paleostress analysis of the fault system,displacing Miocene sediments and SSDS,corresponds to the current stress field.The widespread occurrence of clear liquefaction structures and the vertical repetition of SSDS indicate substantial seismic activity during the basin opening stage.Brittle deformation features observed at both outcrop-and microstructural-scale along the faults suggest a reactivation as reverse faulting associated with a tilting process.The tectonic history of the study area is distinguished by SSDS associated with seismic activity,and reverse faulting associated with inversion process under ENE orientedσHmax.The Environmental Seismic Intensity Scale(ESI-07)based on the SSDS indicates seismic intensity of IX-X,which might be related with the opening of the Bomun sub-basin.Therefore,detailed analyses of SSDS could provide valuable insights on the dynamics of local geology and contribute to further extensive research on seismic hazards and basin inversion.展开更多
Modelling the diagenetic history of a tectonically active basin is crucial for understanding the depositional and post-depositional processes including the evolution and development of porosity and permeability.This s...Modelling the diagenetic history of a tectonically active basin is crucial for understanding the depositional and post-depositional processes including the evolution and development of porosity and permeability.This study describes the diagenetic imprints of the inverted Lower Cretaceous Weald Basin and examines the depositional and tectonic controls on the diagenetic,porosity and permeability evolution of its sandstones.Seventy-two representative sandstone samples from the Weald Basin were subjected to detailed microscopic(optical and scanning electron)analyses.The dominant early diagenetic fabrics include grain-coating detrital clays,degraded and dissolved detrital grains,and vermiform kaolinite pore-filling cement while uplift-related or telogenetic characteristics are mainly post-compactional pore-filling goethite and hematite cement.This work is significant because it presents the first diagenetic model of the Lower Cretaceous Wealden sandstones which can be very useful for understanding basins with similar depositional and tectonic settings.展开更多
Late Miocene shortening rate, uplift rate, and inversion rate in the central inversion zone of the Xihu （西湖） depression, East China Sea basin, were independently determined from a large number of 2D reflection sei...Late Miocene shortening rate, uplift rate, and inversion rate in the central inversion zone of the Xihu （西湖） depression, East China Sea basin, were independently determined from a large number of 2D reflection seismic data and methods. Shortening rate was estimated from the 2DMOVE balanced cross-section technology, uplift rate was calculated after absolute erosions were determined from seismic data during the uplifting time, and inversion rate was measured using the improved calculation method by Song （1997）. The cross correlations among shortening rate, uplift rate, and inversion rate show a good positive relationship, with some differences existing in local areas. This article analyzes the cross correlation between these structural rates and discusses the dynamics of mechanisms for basin inversion and their influence on hydrocarbon accumulation.展开更多
The third member of Shahejie Formation （Sha-3 member; 42–38Ma of Eocene） in the Bozhong Depression, offshore Bohai Bay Basin was subject to multiple post-depositional modifications. The present structural framework...The third member of Shahejie Formation （Sha-3 member; 42–38Ma of Eocene） in the Bozhong Depression, offshore Bohai Bay Basin was subject to multiple post-depositional modifications. The present structural framework of the Bozhong Depression, which is characterized by sags alternating with uplifts, does not reflect its original sedimentary pattern. Previous studies have not discussed the post-depositional modification of this succession, including the sedimentary pattern variations and the depositional geodynamic setting. This work determined the characteristics of the post-depositional modification and original sedimentary pattern of the Bozhong Depression through analysis of seismic data, well-log data and fission-track ages. The results demonstrate that the Shijiutuo rise, a major structural feature of the current basin, did not exist during the major depositional stage of the Sha-3 member, when the Qinnan sag was largely connected to the Bozhong sag to form a single contiguous deposition area within the basin. By contrast, the Shaleitian and Chengbei rises, located in the western part of the Bozhong Depression, have existed before the depositional period of the Eocene Sha-3 member; these features were manifested as syn-depositional tilted fault blocks, the uplifted footwall blocks of which provided sediments for the neighboring Shanan and Chengbei sags. The western part of the Bonan low rise, located in the southern part of the Bozhong Depression, did not experience uplifting during the depositional phase of the Eocene Sha-3 member. The Huanghekou sag was connected with the Bozhong sag in the western part of the Bozhong Depression. The original sedimentary boundary of the southern Miaoxi sag possibly extended eastward about 10 km and connected with the Bozhong sag at its northern part. The present-day Bodong low rise, which is bounded by the Tan–Lu fault zone, also formed after the depositional period of Eocene Sha-3 member. It is thus concluded that the Bozhong Depression formed a connected large-scale sub-basin during the depositional stage of the Eocene Sha-3 member. Several neighboring sags that are now separated by rises, including the Qinnan, Shanan, Chengbei, Huanghekou, Miaoxi and Bodong sags, formed a single contiguous depositional area during the Eocene. The significant differences between the present and original basin patter and framework provide valuable information for better understanding the history of basin inversion and its impact on related hydrocarbon-system evolution.展开更多
Qasab basin is one of the most promising areas for the sustainable development in the Eastern Desert fringes of the Nile Valley, Egypt. The integration between statistical analysis, stable isotopes as well as geochemi...Qasab basin is one of the most promising areas for the sustainable development in the Eastern Desert fringes of the Nile Valley, Egypt. The integration between statistical analysis, stable isotopes as well as geochemical modeling tools delineated the geochemical possesses affecting groundwater quality and detected the main recharge source in Qasab basin. The most of groundwater samples are brackish (88%), while the minority (12%) of the samples are fresh. The electrical conductivity of groundwater ranged from 1135 to 10,030 μS/cm. The statistical analysis and hydrochemical diagrams suggest that the groundwater quality is mainly controlled by several intermixed processes (rock weathering and agricultural activities). The mineralization of the Pleistocene groundwater is regulated by the rock weathering source, evaporation processes and reverse cation exchange. The isotopic signatures (δ<sup>2</sup>H and δ<sup>18</sup>O) represent two groundwater groups. The first group, is enriched with the isotopic signature of δ<sup>18</sup>O, which ranges from 0.9‰ to 5.5‰. This group is mostly affected by the recent meteoric recharge from the surface water leakage. The second group, is relatively depleted with the isotopic signature of δ<sup>18</sup>O, reflecting a palaeo recharge source of colder climate. The δ<sup>18</sup>O‰ varies from <span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">-</span>10.1‰ to <span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">-</span>6.4‰, indicating upward leakage of the Nubian sandstone aquifer through deep seated faults. The inverse geochemical model reflects that the salinity source of the groundwater samples is due to the leaching and dissolution processes of carbonate, sulphate and chloride minerals from the aquifer matrix. This study can demonstrate the hydrochemistry assessment guide to support sustainable development in Qasab basin to ensure that adequate groundwater management can play to reduce poverty and support socioeconomic development.展开更多
基金supported by a grant(2022-MOIS62-001(RS-2022-ND640011))from the National Disaster Risk AnalysisManagement Technology in Earthquake funded by the Ministry of Interior and Safety(MOIS,Korea).
文摘Deformed soft-sediment deformation structures(SSDS)can indicate polyphase deformation events and provide valuable insights into the inversion process of a basin.Herein,we present the Miocene–Quaternary deformation inversion history of the Bomun sub-basin in the Gyeongju area of SE Korea.The inferred ENE compression direction(σHmax)based on paleostress analysis of the fault system,displacing Miocene sediments and SSDS,corresponds to the current stress field.The widespread occurrence of clear liquefaction structures and the vertical repetition of SSDS indicate substantial seismic activity during the basin opening stage.Brittle deformation features observed at both outcrop-and microstructural-scale along the faults suggest a reactivation as reverse faulting associated with a tilting process.The tectonic history of the study area is distinguished by SSDS associated with seismic activity,and reverse faulting associated with inversion process under ENE orientedσHmax.The Environmental Seismic Intensity Scale(ESI-07)based on the SSDS indicates seismic intensity of IX-X,which might be related with the opening of the Bomun sub-basin.Therefore,detailed analyses of SSDS could provide valuable insights on the dynamics of local geology and contribute to further extensive research on seismic hazards and basin inversion.
文摘Modelling the diagenetic history of a tectonically active basin is crucial for understanding the depositional and post-depositional processes including the evolution and development of porosity and permeability.This study describes the diagenetic imprints of the inverted Lower Cretaceous Weald Basin and examines the depositional and tectonic controls on the diagenetic,porosity and permeability evolution of its sandstones.Seventy-two representative sandstone samples from the Weald Basin were subjected to detailed microscopic(optical and scanning electron)analyses.The dominant early diagenetic fabrics include grain-coating detrital clays,degraded and dissolved detrital grains,and vermiform kaolinite pore-filling cement while uplift-related or telogenetic characteristics are mainly post-compactional pore-filling goethite and hematite cement.This work is significant because it presents the first diagenetic model of the Lower Cretaceous Wealden sandstones which can be very useful for understanding basins with similar depositional and tectonic settings.
基金supported by 863 National High-tech Research and Development Major Projects of China (No. 2006AA09A101 ), and CNOOC China Limited
文摘Late Miocene shortening rate, uplift rate, and inversion rate in the central inversion zone of the Xihu （西湖） depression, East China Sea basin, were independently determined from a large number of 2D reflection seismic data and methods. Shortening rate was estimated from the 2DMOVE balanced cross-section technology, uplift rate was calculated after absolute erosions were determined from seismic data during the uplifting time, and inversion rate was measured using the improved calculation method by Song （1997）. The cross correlations among shortening rate, uplift rate, and inversion rate show a good positive relationship, with some differences existing in local areas. This article analyzes the cross correlation between these structural rates and discusses the dynamics of mechanisms for basin inversion and their influence on hydrocarbon accumulation.
基金supported by the National Natural Science Foundation of China(grant No.41330315)National Science and Technology Major Project(grant No.2011ZX05023001-002)MOST Special Funds from the State Key Laboratory of Continental Dynamics(grant No.BJ081334)
文摘The third member of Shahejie Formation （Sha-3 member; 42–38Ma of Eocene） in the Bozhong Depression, offshore Bohai Bay Basin was subject to multiple post-depositional modifications. The present structural framework of the Bozhong Depression, which is characterized by sags alternating with uplifts, does not reflect its original sedimentary pattern. Previous studies have not discussed the post-depositional modification of this succession, including the sedimentary pattern variations and the depositional geodynamic setting. This work determined the characteristics of the post-depositional modification and original sedimentary pattern of the Bozhong Depression through analysis of seismic data, well-log data and fission-track ages. The results demonstrate that the Shijiutuo rise, a major structural feature of the current basin, did not exist during the major depositional stage of the Sha-3 member, when the Qinnan sag was largely connected to the Bozhong sag to form a single contiguous deposition area within the basin. By contrast, the Shaleitian and Chengbei rises, located in the western part of the Bozhong Depression, have existed before the depositional period of the Eocene Sha-3 member; these features were manifested as syn-depositional tilted fault blocks, the uplifted footwall blocks of which provided sediments for the neighboring Shanan and Chengbei sags. The western part of the Bonan low rise, located in the southern part of the Bozhong Depression, did not experience uplifting during the depositional phase of the Eocene Sha-3 member. The Huanghekou sag was connected with the Bozhong sag in the western part of the Bozhong Depression. The original sedimentary boundary of the southern Miaoxi sag possibly extended eastward about 10 km and connected with the Bozhong sag at its northern part. The present-day Bodong low rise, which is bounded by the Tan–Lu fault zone, also formed after the depositional period of Eocene Sha-3 member. It is thus concluded that the Bozhong Depression formed a connected large-scale sub-basin during the depositional stage of the Eocene Sha-3 member. Several neighboring sags that are now separated by rises, including the Qinnan, Shanan, Chengbei, Huanghekou, Miaoxi and Bodong sags, formed a single contiguous depositional area during the Eocene. The significant differences between the present and original basin patter and framework provide valuable information for better understanding the history of basin inversion and its impact on related hydrocarbon-system evolution.
文摘Qasab basin is one of the most promising areas for the sustainable development in the Eastern Desert fringes of the Nile Valley, Egypt. The integration between statistical analysis, stable isotopes as well as geochemical modeling tools delineated the geochemical possesses affecting groundwater quality and detected the main recharge source in Qasab basin. The most of groundwater samples are brackish (88%), while the minority (12%) of the samples are fresh. The electrical conductivity of groundwater ranged from 1135 to 10,030 μS/cm. The statistical analysis and hydrochemical diagrams suggest that the groundwater quality is mainly controlled by several intermixed processes (rock weathering and agricultural activities). The mineralization of the Pleistocene groundwater is regulated by the rock weathering source, evaporation processes and reverse cation exchange. The isotopic signatures (δ<sup>2</sup>H and δ<sup>18</sup>O) represent two groundwater groups. The first group, is enriched with the isotopic signature of δ<sup>18</sup>O, which ranges from 0.9‰ to 5.5‰. This group is mostly affected by the recent meteoric recharge from the surface water leakage. The second group, is relatively depleted with the isotopic signature of δ<sup>18</sup>O, reflecting a palaeo recharge source of colder climate. The δ<sup>18</sup>O‰ varies from <span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">-</span>10.1‰ to <span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">-</span>6.4‰, indicating upward leakage of the Nubian sandstone aquifer through deep seated faults. The inverse geochemical model reflects that the salinity source of the groundwater samples is due to the leaching and dissolution processes of carbonate, sulphate and chloride minerals from the aquifer matrix. This study can demonstrate the hydrochemistry assessment guide to support sustainable development in Qasab basin to ensure that adequate groundwater management can play to reduce poverty and support socioeconomic development.
