Formation and evolution of Weiyuan-Anyue tensional corrosion trough in Sinian system, Sichuan Basin

Abstract

Based on comprehensive analysis of deposition and structure, the horizontal and vertical characteristics of the Weiyuan-Anyue erosion-extension groove have been studied by outcrop, drilling, well logging and seismic data. According to the strata, lithology, structure and regional evolution, Sinian system before the erosion has been reconstructed to show the development and transformation of the erosion-extension groove in the Tongwan movement. The Weiyuan-Anyue tensional corrosion trough is distributed along the Penglai-Anyue-Rongchang in NW direction, with the west area steeper than the east in groove. According to the study of the Weiyuan-Longnüsi seismic profile across the middle area of erosion-extension groove, the formation of the Weiyuan-Anyue tensional corrosion trough is the synthetic result of different geological processes from differential uplift, differential erosion and dissolution in the Dengying Formation caused by the multiple-phase episode grabon or horst movement of the basement fault in Sinian. The formation of the Weiyuan-Anyue erosion-extension groove can be divided into three stages, and the erosion and dissolution can be calculated quantitatively by denudation recovery profile, its maximum can reach 600 m. Key words: Sichuan Basin, Sinian, Weiyuan-Anyue, tensional corrosion trough, formation and evolution