东海陆架盆地新生代扩张率的估算
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摘要
东海陆架盆地是位于中国大陆东部边缘大陆地壳之上的边缘海盆地。盆地新生代构造演化经历了断陷（初始沉降）和坳陷（热控沉降）两个阶段。本文利用钻井及地震反射剖面资料，通过钻井古地层剥蚀量和剥蚀时间的恢复，应用Ｍｃｋｅｎｚｉｅ（１９７８）的均一拉伸模式和Ｓｃｌａｔｅｒ（１９８５）的双层拉伸模式对陆架盆地，主要是浙东坳陷的西湖凹陷进行了基底沉降和地壳岩石圈扩张率的定量估算。计算结果表明东海陆架盆地沉降速率早期较快，后期变慢。西湖凹陷新生代以来地壳岩石圈扩张率，在凹陷北部（Ｄ８００测线）为４０％—５０％，中部（Ｄ６８８测线）为１００％—１４０％，南部（Ｇ４５５测线）为６０％—１２０％
The East China Sea Shelf Basin is a marginal sea basin located on Continental crust of China eastern margin. The formation and evolution of the basin have been controlled by the interaction of the Eurasian,Indian, and Pacific plates. The Cenozoic evolution of the basin underwent two stages of fault controlled subsidence and thermal subsidence. Their geological framework is tectonically characterized by zonation from west to east and blocks from south to north. From west to east tectonics, faults, and depositional faces become younger. The transition from fault controlled subsidence stage to thermal subsidence stage took place at the early Eocene in the western part of East China Sea Shelf Basin, and at the late Eocene in the eastern part. By using the drilling data and seismic reflection profile data, this paper analyzes Cenozoic tectonic evolution of East China Sea Shelf Basin (mainly for Xihu sag of Zhedong depression) by using uniform lithosphere extension model and two layer extension model. The effect of eroding amount and ages of late tectonic event have been considered in the processes of calculation. The result of calculation show that the rate of subsidence was relatively large at the early stage and relatively small at the late stage. Since Tertiary the rate of crustal stretching at Xihu sag of Zhedong depression was 40—50% in the northern part (D800 measurement line), and 100—140% in the middle part (D688 measurement line), and 60%—120% in the southern part (G455 measurement line).
The East China Sea Shelf Basin is a marginal sea basin located on Continental crust of China eastern margin. The formation and evolution of the basin have been controlled by the interaction of the Eurasian,Indian, and Pacific plates. The Cenozoic evolution of the basin underwent two stages of fault controlled subsidence and thermal subsidence. Their geological framework is tectonically characterized by zonation from west to east and blocks from south to north. From west to east tectonics, faults, and depositional faces become younger. The transition from fault controlled subsidence stage to thermal subsidence stage took place at the early Eocene in the western part of East China Sea Shelf Basin, and at the late Eocene in the eastern part. By using the drilling data and seismic reflection profile data, this paper analyzes Cenozoic tectonic evolution of East China Sea Shelf Basin (mainly for Xihu sag of Zhedong depression) by using uniform lithosphere extension model and two layer extension model. The effect of eroding amount and ages of late tectonic event have been considered in the processes of calculation. The result of calculation show that the rate of subsidence was relatively large at the early stage and relatively small at the late stage. Since Tertiary the rate of crustal stretching at Xihu sag of Zhedong depression was 40—50% in the northern part (D800 measurement line), and 100—140% in the middle part (D688 measurement line), and 60%—120% in the southern part (G455 measurement line).
引文
郭振轩．1988．东海地质构造特征及油气远景．海洋地质与第四纪地质．8（3）∶35—41．郝重涛，叶洪．1997．沉积盆地中地层剥蚀量与基底沉降幅度的计算．中国数学地质8．北京：地质出版社．182—191．刘光鼎．1990．中国海大地构造演化．石油与天然气地质，11（1）：23—37．刘光鼎．1988．东海的地质与油气勘探．地球物理学报，31（2）：184—197．秦蕴珊，赵一阳，陈丽蓉，等主编．1987．东海地质．北京：科学出版社．264—286．许薇龄，乐俊英．1988．东海的构造运动及演化．海洋地质与第四纪地质，8（1）：9—21．杨兆宇．1992．东海新生代沉积盆地的类型和成盆期．海洋地质与第四纪地质，11（1）：8—12．周志武，赵金海，殷培龄．1990．东海地质构造特征及含油气性．中国新生代沉积盆地．北京：石油工业出版社．226—242．朱夏．1987．关于中国大陆边缘构造演化．海洋地质与第四纪地质，7（3）：115—120．GuidishTM，KendalCGSTC，LercheIetal．1985．Basinevolutionusingburialhistorycalculations：anOverview，AAPGBuletin，69（1）：92—105．HelingerSJ，SclaterJG．1983．Somecommentsontwolayerextensionalmodelsfortheevolutionofsedimentarybasin，JournalofGeophysicalResearch．，88：8251—8269．JarvisGT，MckenzieD．1980．Sedimentarybasinformationwithfiniteextensionrates，EarthPlanet．Sci．let．，48：42—52．MckenzieD．1978．Someremarksonthedevelopmentofsedimentarybasins，EarthandPlanetarySci．Let．，40：25—32．ScalaterJG，ChristiePAF．1980．Continentalstretching：anexplanationofpost－mid－cretaceoussubsidenceofthecentralNorthseabasin．JournalofGeophysicalResearch，85：3711—3739．ScalaterJG，HelingerSJ，ShedlockKMetal．1985．TheCenozoicevolutionoftheNorthChinaBasin，Tectonics，4：343—358．StecklerMS，WatsAB．1978．SubsidenceoftheAtlantic－typecontinentalmarginofNewYork．EarthPlanet．Sci．Let．，41：1—13
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