江南—雪峰隆起北缘海相油气富集主控因素和破坏机制

Major Factors of Accumulation and Destruction Mechanisms of Marine Strata-Related Hydrocarbon in the Northern Margin of the Jiangnan-Xuefeng Uplift

全球油气巨量富集带主要发育于被动大陆边缘、活动大陆边缘及大陆裂谷系中,而江南—雪峰隆起北缘具有区别于这3类的陆内坳陷斜坡带和古隆起边缘斜坡带的大地构造背景。通过对江南—雪峰隆起北缘(扬子南缘)海相油气陆内巨量富集的主控因素和破坏机制的研究,对比全球油气聚集带(区)发育的主要原因,试图建立海相油气富集和破坏的相关模式。类似于江南—雪峰隆起北缘的陆内坳陷斜坡带与古隆起边缘斜坡带的叠合斜坡带,是大陆块体内一种新的油气富集单元。通过研究,认为下寒武统和下志留统两套优质烃源岩、加里东旋回中—晚期和晚印支期—早燕山旋回早期两期良好的成藏时空匹配关系是海相油气富集的主控因素,而加里东旋回末期和晚印支期—早燕山旋回晚期两个关键破坏期,通过隆升剥蚀、断裂开启和岩浆活动等方式导致了海相油气的破坏。时空匹配的叠合斜坡带既是油气聚集的有利场所,又是油气改造的活跃区域。

The regions of huge amount of hydrocarbon mainly develop in passive continental margin,active continental margin and continental rifts in the global,while the northern margin of the JiangnanXuefeng uplif has the different tectonic settings of the slopes about intracontinental depression and paleouplift margin.We explore the major factors and destruction mechanisms of marine hydrocarbon enrichment of the study area,and compare to the main reasons about the development of hydrocarbon enrichment zones（regions）all over the world,and try to build the related patterns of marine hydrocarbon enrichment and destruction.We attempt to explain a new marine enrichment unit in intercontinent block,which is a superimposed slope zone of intracontinental depression and paleo-uplift margin and similar to the northern margin of the Jiangnan-Xuefeng uplift.We suggest two main controlling factors for the massive accumulation.One is two sets of high-quality hydrocarbon source rocks of the Lower Cambrian and Lower Silurian.The other is two stages of favorable space-time matching relation for accumulation on the middle-late Caledonian cycle and the early of Late IndosinianEarly Yanshannian cyle.During the two key destruction stages of the late Caledonian cycle and the late of the Late Indosinian-Early Yanshannian cycle,marine accumulation were destroyed by uplifting and denudation,fault opening and magmatic activity.Our results suggests the spactial-temperal matching superimposed slope zone is a favorable accumulation area,but also an active transformation area for hydrocarbon.