Effects of Intracratonic Strike-slip Fault on the Differentiation of Carbonate Microfacies: A Case Study of a Permian Platform Margin in the Sichuan Basin(SW China)  

作　　者：LIU Jiawei WU Guanghui TANG Qingsong WU Yonghong ZHANG Wenjin ZHAO Zhongyu 

机构地区：[1]School of Geoscience and Technology,Southwest Petroleum University,Chengdu 610500,China [2]Qiangtang Basin Research Institute,Southwest Petroleum University,Chengdu 610500,China [3]Southwest Petroleum University,Division of Key Laboratory of Carbonate Reservoirs of CNPC,Chengdu 610500,China [4]PetroChina Southwest Oil&Gasfield Company,Chengdu 610051,China

出　　处：《Acta Geologica Sinica(English Edition)》2024年第4期936-954,共19页地质学报（英文版）

基　　金：partly supported by the National Natural Science Foundation of China (Grant No. 4224100017);Science and Technology Cooperation Project of the CNPC-SWPU Innovation Alliance (Grant No.2020CX010300)。

摘　　要：In intracratnoic basins, the effect of strike-slip faults on sedimentary microfacies is generally underestimated due to their small scale. Based on the integration of core, well logs, and three-dimensional seismic data, this study presents a comprehensive analysis of the Permian carbonate platform and strike-slip faults in the southwestern Kaijiang-Liangping trough of the Sichuan Basin. The relationship between strike-slip faults and Permian carbonate microfacies is investigated. The results reveals the existence of a NW-trending strike-slip fault zone along the platform margin, exhibiting clear segmentation. The western side of the study area exhibits a rimmed platform margin characterized by type I reefs, which corresponds to the presence of a large-scale strike-slip fault zone. In contrast, the eastern side is characterized by a norimmed and weak rimmed platform margin, accompanied by type II reefs, which align with smaller strike-slip fault zones. It was found that the strike-slip fault had some effects on the platform and reef-shoal complex of the Permain Changxing Formation. First, the platform was divided by strike-slip fault into three segments to show rimmed, week rimmed and norimmed platform. Second, reef-shoal complex devolped along the faulted high position in the strike-slip fault zone, and separated by faulted depression. Third, strike-slip faults can offset or migrated the reef-shoal complex and platform margin. Additionally, the thickness of the platform margin varies across strike-slip fault zone, which is related to the activity of strike-slip faults. The strike-slip faults affect the microfacies by controlling the pre-depositional paleotopography. This case suggests that the strike-slip faults play a crucial role in the diversity and distribution of carbonate microfacies in the intracratonic basin.

关 键 词：strike-slip faults segmentation carbonate platform sediment dispersal pattern Changxing Formation Kaijiang–Liangping trough Sichuan Basin 

分 类 号：P618.13[天文地球—矿床学]