拉分盆地.pptx

,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,#,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,#,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,#,Pull-Apart Basins,Major:Marine geology,2013.01.02,General,description,Main characters,Unique key points,Examples,General description,concept,A,pull-apart,basin,(strike-slip basin,rhombochasm)is,type of,structural basin,which is developed between two offset segments or at a flexure in a,strike-slip fault,or a,transform fault,.,A pull-apart basin,develops where the sense of offset leads to extension,either at a right-stepping offset on a dextral sense fault or a left-stepping offset on a sinistral fault.This geometry means that fault displacement will literally pull a section of crust apart and cause the,extension.,General description,settings,The Dead Sea and the Salton Sea depressions are pull apart,basins(Kearey,Philip,and Frederick J.Vine,1996).,The,Cayman Trough in the northern Caribbean is an example of an,elongated pull apart basin,which has developed a spreading ridge in the,center(,Einsele,Gerhard,2000).,Along strike-slip boundary zones(transform faults)between rigid,continental plates.,In zones of oblique subduction along volcanic arcs.,In zones of“continental escape”in response to collision.,T.h.Nilson;R.J.McLaughlin,1985,Nilson,和,McLaughlin(1985),根据,Little Sulphur Creek,盆地、,Ridge,盆地和,Hornelen,盆地的研究成果，系统总结了拉分盆地,地层和沉积充填特征,。,Main characters,Main characters,Originate from,strike-slip motions,.,Occur on both,continental and oceanic,crust,.,Typically,narrow,(50 km wide)and of variable length.,The floor of long basins tends to,subside,deeper than that of short basins.Long basins may develop,oceanic spreading troughs,with the intrusion of,basaltic,magama.,Rapid strike-slip causes extremely,fast subsidence,and thus often an early,short phase of basin deepening.Later subsidence is driven mainly by the increasing sediment load.,Gerhard Einsele,2000,Unique key points and differences from other basins,Sedimentary facies change rapidly.,Strike-slip fault,developed,within,the basin.,Li Xiaoqing,Wang Zecheng,2003,Example Gulf of California,加利福尼亚及其邻近地区的断层系统和盆地（,Lachenbruch,和,Sass,1980),After an initial shallow-marine“proto-gulf”rift stage,the present Gulf of California formed,along the transform boundary between the North American and the Pacific plates,.The dextral,somewhat transtensional plate motions operated at an average rate of several cm/a.As a result,a series of pull-apart basins was generated which now lie 2000-3000 m below sea level,seperated by the growing pull-apart basins,new oceanic crust was accreted,(stage of early drifting).In contrast to mid-oceanic spreading ridges of mature oceans,the spreading centers of these pull-apart basins are located in the,morphological basin deeps,thus forming spreading troughs.Although these troughs collect large amounts of hemipelagic sediments,turbidites,and mass flows from nearby slopes and marine deltas,they remain open due to the continuing rapid growth of the basins.,Example Gulf of California,加利福尼亚边界区走滑构造格架图（据,Moore,1969;Junger,1976),Example Gulf of California,图片据,T.h.Nilson;R.J.McLaughlin,1985,里奇盆地。,该盆地在圣安德烈斯弯曲处形成，故认为是,断弯盆地,的典型代表。它是位于圣安德烈斯断裂和圣加布里尔断层间的豆英断块。块体北部处于释压弯曲处，属张扭性环境，形成拉分盆地，而在其西南部处于处于压扭环境，形成隆起，向盆地供应沉积物。,References,1.Kearey,Philip and Frederick J.Vine,Global,Tectonics,Blackwell,Science,2,nd,ed,.,1996,pp.131-133,2.,Einsele,Gerhard,Sedimentary Basins:Evolution,Facies,and Sediment Budget,Springer,2nd ed.,2000,p.630,3.,H.Nilsen and Robert J.,McLaughlin,，,Comparison of tectonic framework and,depositional,patterns of Hornelen strike-slip basin in Norway and Ridge and Little,Sulphur,Creek strike-slip basins of,California,，,AAPG Bulletin(April 1984),68(4):513,4.,AH Lachenbruch,JH,Sass,Heat,flow and energetics of t he,San Andreas Fault zone,J,.Geophys.Res.,85,6185 6222,1980,.,5.,李晓清,汪泽成,程有义等,.,拉分盆地分析与含油气性,.,石油大学出版社,.2003:p18-28.,6.,刘,庆,.,走滑断裂系中的重要构造,拉分盆地,.,地质科技情报,.1986,5(2):p7-14.,谢谢，请批评指正！,谢谢大家,