Extensive mass transport deposits（MTDs）, which form a significant component of the stratigraphic record in ancient and modern deep water systems, mostly distributed in the continental margin of ocean basins worldwid...Extensive mass transport deposits（MTDs）, which form a significant component of the stratigraphic record in ancient and modern deep water systems, mostly distributed in the continental margin of ocean basins worldwide. To date, no large-scale MTDs have been found in Chinese terrestrial basins. Based on integrated analysis of the seismic, drilling, core and logging data, this article report MTDs have been found in Songliao terrestrial basin（SLTB）, Northeast China. During the depositional period of the Upper Cretaceous Qingshankou Formation, slope break of lacustrine basins was an ideal discharge place for gravity depositions. Regional sedimentary study of MTDs reveals that Cretaceous-age MTDs in SLTB were deposited in slope-break environments by slide, slump and debris flow, and MTDs were mixed with little turbidite simultaneously. Besides the massive aspect, key features of MTDs are the common presence of deformational structures or softsedimentary deformation, floating shale clasts, boudins, microfaults, distortion beddings, rotated sand debris. Detailed mapping of two three-dimensional（3-D） seismic surveys acquired in Yingtai（YT） and Haituozi（HTZ） areas reveals that MTDs are characterized by chaotic, mounded, and transparent seismic reflection. Growth fault, slope gully and geomorphology of the slope break greatly influenced the sedimentary process and external geometry of MTDs, and as a consequence, MTDs in SLTB exhibit classic fan-like geometry and some special（non-fan-like） external geometry. Furthermore, fanlike MTDs can be divided into three subcategories, including isolated fan, mother-son fan and stacked fan. Non-fan-like MTDs can be divided into two subcategories, strip-like MTDs and faulted-pit MTDs. A new sedimentary model has been built for MTDs in SLTB. MTDs have become a new exploration and development target in the SLTB.展开更多
针对鄂尔多斯盆地西南缘奥陶系平凉组重力流沉积类型及特征进行了研究。通过露头、薄片及粒度分析等资料分析可知:1)研究区岩石类型丰富,发育砾屑灰岩、泥晶灰岩、砂屑灰岩、砾岩、砂岩及泥岩等。沉积构造丰富,块状层理、粒序层理、交...针对鄂尔多斯盆地西南缘奥陶系平凉组重力流沉积类型及特征进行了研究。通过露头、薄片及粒度分析等资料分析可知:1)研究区岩石类型丰富,发育砾屑灰岩、泥晶灰岩、砂屑灰岩、砾岩、砂岩及泥岩等。沉积构造丰富,块状层理、粒序层理、交错层理、平行层理及槽模等发育。2)东部为碳酸盐岩沉积区,中部为碎屑岩沉积区,西部为碳酸盐沉积区。3)重力流沉积可分为块状搬运复合体(mass transport deposits,MTD)、碎屑流沉积及浊流沉积。MTD以砾屑灰岩及泥晶灰岩为主,变形构造发育,规模大小不一。碎屑流沉积以砾屑灰岩、砾岩为主,块状层理发育,少见粒序层理,呈层状及透镜状,为海底扇内扇-中扇及水道沉积。浊流沉积以砂岩及砂屑灰岩为主,交错层理、平行层理及槽模等极为发育,构成不完整的鲍玛序列,多呈层状及透镜状。4)东部以MTD及深水水道沉积体系为主,中部发育海底扇,包括大型水道及朵叶,西部朵叶沉积较为发育,沉积物分选及磨圆较好。展开更多
High-resolution bathymetric and partial seismic data were utilized to determine the characteristics and distribution of mass-transport deposits(MTDs)in the Xisha area,North of the South China Sea.Many isolated carbona...High-resolution bathymetric and partial seismic data were utilized to determine the characteristics and distribution of mass-transport deposits(MTDs)in the Xisha area,North of the South China Sea.Many isolated carbonate platforms are found in this area,providing mass-wasting materials as a sediment source for MTDs.The MTDs in the study area were divided into three types(slide,slump,and debris flow)based on their rheological properties.The MTDs were mostly distributed at the toe of the carbonate platform slope,where a large amount of carbonate debris accumulated.A total of 32 MTDs were identified on the carbonate platform slopes.A systematic assessment of the MTD morphometric parameters showed that their total area covered 2225.2 km2,with the largest MTD covering 354.1 km2.These MTDs differ largely from the MTDs of other areas,especially in terms of sediment compositions and deposit processes.Gullies and channels on the slope and reefs on the top of the platform act as sediment conduits and carbonate-producing sources,respectively,playing vital roles in the distribution and generation of gravity flow deposits.The development model proposed in this work states that reefs disintegrate into carbonate debris and mix with seawater to form gravity flows,which scour the seafloor and accumulate at the downslope,eventually resulting in failure.Sediments from these failures turn into gravity flows,flowing into submarine canyons and channels.The results of this research further our understanding of the development pattern of MTDs in a carbonate setting.展开更多
The synonymous use of the general term ＂landslide＂, with a built-in reference to a sliding motion, for all varieties of mass-transport deposits （MTD）, which include slides, slumps, debrites, topples, creeps, debri...The synonymous use of the general term ＂landslide＂, with a built-in reference to a sliding motion, for all varieties of mass-transport deposits （MTD）, which include slides, slumps, debrites, topples, creeps, debris avalanches etc. in subaerial, sublacustrine, sub- marine, and extraterrestrial environments has created a multitude of conceptual and nomen- clatural problems. In addition, concepts of triggers and Iong-runout mechanisms of mass movements are loosely applied without rigor. These problems have enormous implications for studies in process sedimentology, sequence stratigraphy, palaeogeography, petroleum geol- ogy, and engineering geology. Therefore, the objective of this critical review is to identify key problems and to provide conceptual clarity and possible solutions. Specific issues are the fol- lowing： （1） According to ＂limit equilibrium analyses＂ in soil mechanics, sediment failure with a sliding motion is initiated over a shear surface when the factor of safety for slope stability （F） is less than 1. However, the term landslide is not meaningful for debris flows with a flowing mo- tion. （2） Sliding motion can be measured in oriented core and outcrop, but such measurement is not practical on seismic profiles or radar images. （3） Although 79 MTD types exist in the geological and engineering literature, only slides, slumps, and debrites are viable depositional facies for interpreting ancient stratigraphic records. （4） The use of the term landslide for high- velocity debris avalanches is inappropriate because velocities of mass-transport processes cannot be determined in the rock record. （5） Of the 21 potential triggering mechanisms of sediment failures, frequent short-term events that last for only a few minutes to several hours or days （e.g., earthquakes, meteorite impacts, tsunamis, tropical cyclones, etc.） are more relevant in controlling deposition of deep-water sands than sporadic long-term events that last for thousands to millions of years （e.g., sea-level Iowstands）. （6） The comparison of HIL （fall height/runout distance） ratios of MTD in subaerial environments with H/L ratios of MTD in submarine and extraterrestrial environments is incongruous because of differences in data sources （e.g., outcrop vs. seismic or radar images）. （7） Slides represent the pre-transport dis- position of strata and their reservoir quality （i.e., porosity and permeability） of the provenance region, whereas debrites reflect post-transport depositional texture and reservoir quality. How- ever, both sandy slides and sandy debrites could generate blocky wireline （gamma-ray） log motifs. Therefore, reservoir characterization of deep-water strata must be based on direct examination of the rocks and related process-specific facies interpretations, not on wireline logs or on seismic profiles and related process-vague facies interpretations. A solution to these problems is to apply the term ＂landslide＂ solely to cases in which a sliding motion can be em- pirically determined. Otherwise, a general term MTD is appropriate. This decree is not just a quibble over semantics; it is a matter of portraying the physics of mass movements accurately. A precise interpretation of a depositional facies （e.g., sandy slide vs. sandy debrite） is vital notonly for maintaining conceptual clarity but also for characterizing petroleum reservoirs.展开更多
Verard et el. （2015, Journal of Palaeogeography, 4（1 ）： 64-84） claim that their global geodynamic model allows one to reconstruct the surface features of topography on rand and in adjacent oceans （i.e., pateobat...Verard et el. （2015, Journal of Palaeogeography, 4（1 ）： 64-84） claim that their global geodynamic model allows one to reconstruct the surface features of topography on rand and in adjacent oceans （i.e., pateobathymetry） anywhere on the gtobe and at any geological time during the past 600 miltion years （Ma）. Such a grand model requires a rigorous scrutiny. The purpose of this discussion is to illustrate that the modet suffers from （1） the selective omission of real-world datasets that do not fit the model, （2） the inclusion of datasets without revealing their original sources or without citing relevant peer-reviewed publications, （3） the emphasis on ＇unpublished＇ internal company datasets that disallow open access to the international scientific community, and （4） the use of poorly understood concepts without providing the basic conceptual clarity. These deficiencies undermine the credibility of the heuristic modet.展开更多
基金supported by the National Basic Research Program of China (Grant No.2007CB209604)
文摘Extensive mass transport deposits（MTDs）, which form a significant component of the stratigraphic record in ancient and modern deep water systems, mostly distributed in the continental margin of ocean basins worldwide. To date, no large-scale MTDs have been found in Chinese terrestrial basins. Based on integrated analysis of the seismic, drilling, core and logging data, this article report MTDs have been found in Songliao terrestrial basin（SLTB）, Northeast China. During the depositional period of the Upper Cretaceous Qingshankou Formation, slope break of lacustrine basins was an ideal discharge place for gravity depositions. Regional sedimentary study of MTDs reveals that Cretaceous-age MTDs in SLTB were deposited in slope-break environments by slide, slump and debris flow, and MTDs were mixed with little turbidite simultaneously. Besides the massive aspect, key features of MTDs are the common presence of deformational structures or softsedimentary deformation, floating shale clasts, boudins, microfaults, distortion beddings, rotated sand debris. Detailed mapping of two three-dimensional（3-D） seismic surveys acquired in Yingtai（YT） and Haituozi（HTZ） areas reveals that MTDs are characterized by chaotic, mounded, and transparent seismic reflection. Growth fault, slope gully and geomorphology of the slope break greatly influenced the sedimentary process and external geometry of MTDs, and as a consequence, MTDs in SLTB exhibit classic fan-like geometry and some special（non-fan-like） external geometry. Furthermore, fanlike MTDs can be divided into three subcategories, including isolated fan, mother-son fan and stacked fan. Non-fan-like MTDs can be divided into two subcategories, strip-like MTDs and faulted-pit MTDs. A new sedimentary model has been built for MTDs in SLTB. MTDs have become a new exploration and development target in the SLTB.
文摘针对鄂尔多斯盆地西南缘奥陶系平凉组重力流沉积类型及特征进行了研究。通过露头、薄片及粒度分析等资料分析可知:1)研究区岩石类型丰富,发育砾屑灰岩、泥晶灰岩、砂屑灰岩、砾岩、砂岩及泥岩等。沉积构造丰富,块状层理、粒序层理、交错层理、平行层理及槽模等发育。2)东部为碳酸盐岩沉积区,中部为碎屑岩沉积区,西部为碳酸盐沉积区。3)重力流沉积可分为块状搬运复合体(mass transport deposits,MTD)、碎屑流沉积及浊流沉积。MTD以砾屑灰岩及泥晶灰岩为主,变形构造发育,规模大小不一。碎屑流沉积以砾屑灰岩、砾岩为主,块状层理发育,少见粒序层理,呈层状及透镜状,为海底扇内扇-中扇及水道沉积。浊流沉积以砂岩及砂屑灰岩为主,交错层理、平行层理及槽模等极为发育,构成不完整的鲍玛序列,多呈层状及透镜状。4)东部以MTD及深水水道沉积体系为主,中部发育海底扇,包括大型水道及朵叶,西部朵叶沉积较为发育,沉积物分选及磨圆较好。
基金This work was supported by the Key Research and Development Program of Hainan Province(No.ZDYF2020209)the National Natural Science Foundation of China(No.42176083)the Key-Area Research and Deve-lopment Program of Guangdong Province(No.2020B1111020002).
文摘High-resolution bathymetric and partial seismic data were utilized to determine the characteristics and distribution of mass-transport deposits(MTDs)in the Xisha area,North of the South China Sea.Many isolated carbonate platforms are found in this area,providing mass-wasting materials as a sediment source for MTDs.The MTDs in the study area were divided into three types(slide,slump,and debris flow)based on their rheological properties.The MTDs were mostly distributed at the toe of the carbonate platform slope,where a large amount of carbonate debris accumulated.A total of 32 MTDs were identified on the carbonate platform slopes.A systematic assessment of the MTD morphometric parameters showed that their total area covered 2225.2 km2,with the largest MTD covering 354.1 km2.These MTDs differ largely from the MTDs of other areas,especially in terms of sediment compositions and deposit processes.Gullies and channels on the slope and reefs on the top of the platform act as sediment conduits and carbonate-producing sources,respectively,playing vital roles in the distribution and generation of gravity flow deposits.The development model proposed in this work states that reefs disintegrate into carbonate debris and mix with seawater to form gravity flows,which scour the seafloor and accumulate at the downslope,eventually resulting in failure.Sediments from these failures turn into gravity flows,flowing into submarine canyons and channels.The results of this research further our understanding of the development pattern of MTDs in a carbonate setting.
文摘The synonymous use of the general term ＂landslide＂, with a built-in reference to a sliding motion, for all varieties of mass-transport deposits （MTD）, which include slides, slumps, debrites, topples, creeps, debris avalanches etc. in subaerial, sublacustrine, sub- marine, and extraterrestrial environments has created a multitude of conceptual and nomen- clatural problems. In addition, concepts of triggers and Iong-runout mechanisms of mass movements are loosely applied without rigor. These problems have enormous implications for studies in process sedimentology, sequence stratigraphy, palaeogeography, petroleum geol- ogy, and engineering geology. Therefore, the objective of this critical review is to identify key problems and to provide conceptual clarity and possible solutions. Specific issues are the fol- lowing： （1） According to ＂limit equilibrium analyses＂ in soil mechanics, sediment failure with a sliding motion is initiated over a shear surface when the factor of safety for slope stability （F） is less than 1. However, the term landslide is not meaningful for debris flows with a flowing mo- tion. （2） Sliding motion can be measured in oriented core and outcrop, but such measurement is not practical on seismic profiles or radar images. （3） Although 79 MTD types exist in the geological and engineering literature, only slides, slumps, and debrites are viable depositional facies for interpreting ancient stratigraphic records. （4） The use of the term landslide for high- velocity debris avalanches is inappropriate because velocities of mass-transport processes cannot be determined in the rock record. （5） Of the 21 potential triggering mechanisms of sediment failures, frequent short-term events that last for only a few minutes to several hours or days （e.g., earthquakes, meteorite impacts, tsunamis, tropical cyclones, etc.） are more relevant in controlling deposition of deep-water sands than sporadic long-term events that last for thousands to millions of years （e.g., sea-level Iowstands）. （6） The comparison of HIL （fall height/runout distance） ratios of MTD in subaerial environments with H/L ratios of MTD in submarine and extraterrestrial environments is incongruous because of differences in data sources （e.g., outcrop vs. seismic or radar images）. （7） Slides represent the pre-transport dis- position of strata and their reservoir quality （i.e., porosity and permeability） of the provenance region, whereas debrites reflect post-transport depositional texture and reservoir quality. How- ever, both sandy slides and sandy debrites could generate blocky wireline （gamma-ray） log motifs. Therefore, reservoir characterization of deep-water strata must be based on direct examination of the rocks and related process-specific facies interpretations, not on wireline logs or on seismic profiles and related process-vague facies interpretations. A solution to these problems is to apply the term ＂landslide＂ solely to cases in which a sliding motion can be em- pirically determined. Otherwise, a general term MTD is appropriate. This decree is not just a quibble over semantics; it is a matter of portraying the physics of mass movements accurately. A precise interpretation of a depositional facies （e.g., sandy slide vs. sandy debrite） is vital notonly for maintaining conceptual clarity but also for characterizing petroleum reservoirs.
文摘Verard et el. （2015, Journal of Palaeogeography, 4（1 ）： 64-84） claim that their global geodynamic model allows one to reconstruct the surface features of topography on rand and in adjacent oceans （i.e., pateobathymetry） anywhere on the gtobe and at any geological time during the past 600 miltion years （Ma）. Such a grand model requires a rigorous scrutiny. The purpose of this discussion is to illustrate that the modet suffers from （1） the selective omission of real-world datasets that do not fit the model, （2） the inclusion of datasets without revealing their original sources or without citing relevant peer-reviewed publications, （3） the emphasis on ＇unpublished＇ internal company datasets that disallow open access to the international scientific community, and （4） the use of poorly understood concepts without providing the basic conceptual clarity. These deficiencies undermine the credibility of the heuristic modet.
