【摘要】 通过对地震剖面观察和沉积构造分析,根据反转褶皱隆起及其伴生的断层发育程度,将东海陆架盆地西湖凹陷的反转构造划分为宽缓隆褶、陡窄隆褶、宽缓隆断褶和陡窄隆断褶4种类型。西湖凹陷的构造反转强度及特征具有东西分带、南北分区的特点。在东西排列的三带中,中央突起带反转最强,东部断阶带次之,西部斜坡带反转最弱。在南北分布的三区里,北区发育较强陡窄隆褶,中区总体反转强、局部反转弱,南区总体反转弱、局部反转强。西湖凹陷的反转构造以褶皱为主,并不同程度地伴生断裂。据此,选取反转逆断距、反转褶皱波幅和缩短率3个参数,对中央突起带反转构造的分布规律进行定量研究。研究和统计结果表明,中央突起带的北部反转强烈,中部构造反转最强和较弱地区相邻并存,南部总体反转较弱、局部较强。反转构造主要由中新世中晚期龙井运动形成,反转逆断层由先存断层逆向再活动发展而来,逆断距一般自下向上逐渐减小;而反转褶皱主要发生在上部沉积层,其发育程度自下而上逐渐增强。西湖凹陷构造反转的形成,主要是中新世菲律宾板块向亚洲板块俯冲,导致冲绳海槽弧后扩张,进而产生向西推挤的作用所致。更多还原

【Abstract】 Through seismic section study and sedimentary-tectonic analyzing,based on the volume of uplift and associated fault,the inversion structures in the Xihu Depression of East China Sea shelf basin are divided into four types:wide fold,narrow fold,wide fold with reverse fault,and narrow fold with reverse fault.The inversion structures in the Xihu Depression are characterized by the zonation from east to west and the partition from south to north.The Central Uplift Belt has the strongest inversion structure,the East Marginal Belt is relatively gentle and the inversion in the West Marginal Belt is the weakest.The North Block comprises a lot narrow folds,while the Middle Block comprises strong inversion generally but weak in some places,The South Block have the opposite regulation to Middle Block.The inversion structures in the study area are mostly folds and supplemented with different degree of faults,so three parameters that are reverse displacement of inversion fault,amplitude of inversion fold and compression ratio in the Central Uplift Belt are chosen to quantitatively study the inversion characteristics in the Central Uplift Belt.The result shows that the inversion structure in the North Central Uplift Belt is strong,but limited;while the inversion structure in the Middle Central Uplift Belt is very strong or weak;the South Central Uplift Belt comprises strong inversion in some places,but weak mostly.The inversion structures in the Xihu Depression were caused by Longjing tectonic movement in the middle-late Miocene.The inversion faults were evolved by the reversal reactivation of pre-existing normal fault;the reverse displacement generally reduced from bottom to the top.Inversion folds are more likely to develop on the top strata;it generally enhanced from bottom to the top.The subduction of Philippine Sea Plate to Asian Plate,caused Okinawa Trough to open,which caused the west boundary of Okinawa Trough to be pushed toward west.This push made the inversion structures in the Xihu Depression formed.更多还原