The discovery of Neoproterozoic extensional struct

Authors: ZhiDong Gu ZeCheng Wang

Publish Date: 2014/09/30

Volume: 57, Issue: 11, Pages: 2758-2768

PDF Link

Abstract

The Central Sichuan Block CSB is the hardest block between the deep faults of PujiangBazhong and Huaying Mountain in the central part of Sichuan Basin which lies in the northwestern part of the upper Yangtze Craton The CSB has long been considered as the oldest and most stable core area of Yangtze Craton with the uniform basement and high level of hardening Here we present a detailed interpretation of deep structures in the CSB by integrating highresolution seismic data approx 50000 km2 with largescale aeromagnetic data Results show that eight Neoproterozoic extensional structures of different scales are nearly EW NEE and NWtrending in the CSB Discovery of these extensional structures changes previous understanding of the CSB as a unified block The extensional structures experienced one or two stages of extension in the longitudinal section and filled with 3000–5000mthick weakly magnetic materials Development of basal Atype granite in Weiyuan Sichuan Basin and bimodal volcanic rocks of the Suxiong Formation Western Sichuan confirms the CSB’s Neoproterozoic extensional tectonic setting The newly discovered Neoproterozoic extensional structures are of great significance for source rock and favorable sedimentary facies distribution reservoir development and gas accumulation

Keywords: