论文部分内容阅读
四川盆地位于上扬子克拉通西北部,川中地块是位于四川盆地中部蒲江-巴中、华蓥山深大断裂之间的坚硬块体,这一块体一直被认为是扬子克拉通最古老、最稳定的核心,基底均一、硬化程度高.本文应用覆盖范围达5万余平方公里高分辨率地震并结合大比例尺航磁资料,通过对川中地块深层构造的精细解释,发现川中地块新元古代发育近东西向、北东东向、北西向展布规模不等的8支伸展构造,这改变了川中地块为统一块体的传统认识.这些伸展构造纵向剖面发育一期或两期伸展作用,其内充填厚达3000~5000 m的弱磁性物质.四川盆地威远地区基底A型花岗岩与川西苏雄组双峰式火山岩的发育均证实川中地块新元古代处于伸展构造背景.初步讨论了新元古代伸展构造对川中地块烃源岩、有利沉积相带展布,储层发育及天然气成藏的作用.
The Sichuan Basin is located in the northwestern part of the Upper Yangtze Craton. The Central Sichuan Block is a hard block located between Pujiang-Bazhong and Huayingshan deep faults in the central Sichuan Basin. This block has been considered as the oldest, Stable core, uniform base and high degree of hardening.Through the high resolution seismic coverage of more than 50000 square kilometers combined with the large-scale aeromagnetic data, through the fine interpretation of the deep structure of the central Sichuan block, we found that the central Sichuan block The ancient development of nearly east-west, north east-east, north-west distribution of the scale of 8 extended structure, which changed the Central Sichuan block as a unified block of traditional understanding of these extensional structure of the longitudinal profile of one or two stages of development Which is filled with 3000 ~ 5000 m thick weak magnetic materials.The development of basal A-type granites in Weiyuan area of Sichuan Basin and the bimodal volcanic rocks of Suxu formation in western Sichuan Basin confirm that the Neoproterozoic of the Central Sichuan Block is in an extensional tectonic setting. Discussed the effect of the Neoproterozoic extensional structures on the source rocks of the central Sichuan block, favorable sedimentary facies distribution, reservoir development and natural gas accumulation.