钓鱼岛隆褶带物质构成及东海西湖凹陷原型盆地东边界再认识

古近系原型盆地的恢复是关乎西湖凹陷主要勘探层系花港组和平湖组沉积体系和成藏地质研究的关键问题，对西湖凹陷东缘钓鱼岛隆褶带构造演化的合理认识是解决古近纪原型盆地难题的钥匙.受限于研究区薄弱的资料基础，创新性地通过重、磁、震资料综合分析以获取地质认识上的突破.研究表明钓鱼岛隆褶带早期为"东海陆架外缘隆起"的一部分，后期经历了强烈的岩浆增生改造.在结构上，隆褶带内T20界面之下主要由古老变质基底、岩浆岩体和残余洼陷充填层构成.隆褶带内的残余洼陷及地层具有北东向、雁列式分布的特征，这些地层主要为渐新世岩浆增生改造前沉积的始新统平湖组，局部为渐新统花港组，是古近系西湖凹陷原型盆地东缘残留的一部分.西湖凹陷古近系原型盆地东边界位于现今的钓鱼岛隆褶带范围内，为北东向雁列式分布的断裂，断裂之间存在不同类型的变换过渡.在钓鱼岛隆褶带岩浆增生过程中，岩体顺边界断裂上涌，"淹没"了原型盆地边界，原型盆地东缘地层经受了大规模隆升剥蚀，原有的构造面貌和形态发生了极大的变化. 

Material Composition of Diaoyu Islands Folded Zone and Reanalysis of Eastern Boundary of Prototype Basin of Xihu Sag in East China Sea

The restoration of Paleogene prototype basin is a key problem related to the study of sedimentary system and hydrocarbon accumulation of Huagang Formation and Pinghu Formation in the main exploration strata in Xihu Sag, whereas a reasonable understanding of the structural evolution of Diaoyu Islands folded zone in the east margin of Xihu Sag is the key to the problem.However, relevant studies are often limited by the weak data base of the research area.In this paper a breakthrough in the geological understanding through the comprehensive analysis of gravity, magnetic and seismic data innovatively is obtained.It is believed that in the early stage the Diaoyu Islands folded zone was part of the "East China Sea shelf outer margin uplift" and underwent intense magmatic hyperplasia in the later stage.Structurally, the part under the T20 interface in the folded zone is mainly composed of ancient metamorphic basement, magmatic rock mass and residual sag filling layer.The residual sag and strata in the folded zone are characterized by NE-trending and enechel on distribution.These strata are mainly Eocene Pinghu Formation deposited before Oligocene magmatic hyperplasia and transformation, and are the residual part of the eastern margin of the Paleogene prototype basin of Xihu Sag.The eastern boundary of the Paleogene prototype basin of Xihu Sag is located in the current Diaoyu Islands folded zone, and is a series of NE-trending faults in enechel on distribution, and there are different types of transition between faults.In the process of magmatic proliferation in the Diaoyu Islands folded zone, the rock mass upwelling along the boundary fault "submerged" the boundary of the prototype basin.The strata in the eastern margin of the prototype basin underwent large-scale uplift and denudation, and the original structural appearance and morphology were greatly changed.