Thermal history of the Sichuan Basin,SW China:Evidence from deep boreholes  

作　　者：ZHU Chuan Qing HU ShengBiao QIU NanSheng RAO Song YUAN YuSong 

机构地区：[1]State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing 102249,China [2]College of Geosciences,China University of Petroleum,Beijing 102249,China [3]State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China [4]College of Geosciences,Yangtze University,Jinzhou 434023,China [5]Exploration and Productton Research Institute,SINOPEC,Beijing 100083,China

出　　处：《Science China Earth Sciences》2016年第1期70-82,共13页中国科学（地球科学英文版）

基　　金：the National Natural Science Foundation of China(Grant No.41102152);the PetroChina Innovation Foundation(Grant No.2013D-5006-0102);the National Basic Research Program of China(Grant No.2012CB214703);the Science Foundation of China University of Petroleum,Beijing(Grant No.YJRC2013-002)

摘　　要：The Sichuan Basin is a superimposition basin composed of terrestrial and marine sediments that is well known for its abundant petroleum resources. Thermal history reconstruction using paleogeothermal indicators, including vitrinite reflectahoe and thermochronological data, shows that different structural subsections of the Sichuan Basin have experienced various paleogeothermal episodes since the Paleozoic. The lower structural subsection comprising the Lower Paleozoic to Middle Permian （Pz-P2） successions experienced a high paleogeothermal gradient （23.0-42.6℃/km） at the end of the Middle Permian （P2）, whereas the upper structural subsection comprising Late Permian to Mesozoic strata underwent a relatively lower paleogeothermal gradient （13.2-26.9℃/km） at the beginning of the denudation （Late Cretaceous or Paleocene in the different regions）. During the denudation period, the Sichuan Basin experienced a successive cooling episode. The high paleogeothermal gradient resulted from an intensive thermal event correlated to the Emeishan mantle plume. The heat flow value reached 124.0 mW/m2 in the southwestern basin near the center of the Emeishan large igneous province. The low geothermal gradient episode with heat flow ranging from 31.2 to 70.0 mW/m2 may be related to the foreland basin evolution. The cooling event is a result of the continuous uplift and denudation of the basin.The Sichuan Basin is a superimposition basin composed of terrestrial and marine sediments that is well known for its abundant petroleum resources. Thermal history reconstruction using paleogeothermal indicators, including vitrinite reflectance and thermochronological data, shows that different structural subsections of the Sichuan Basin have experienced various paleogeothermal episodes since the Paleozoic. The lower structural subsection comprising the Lower Paleozoic to Middle Permian(Pz–P_2) successions experienced a high paleogeothermal gradient(23.0–42.6°C/km) at the end of the Middle Permian(P_2), whereas the upper structural subsection comprising Late Permian to Mesozoic strata underwent a relatively lower paleogeothermal gradient(13.2–26.9°C/km) at the beginning of the denudation(Late Cretaceous or Paleocene in the different regions). During the denudation period, the Sichuan Basin experienced a successive cooling episode. The high paleogeothermal gradient resulted from an intensive thermal event correlated to the Emeishan mantle plume. The heat flow value reached 124.0 m W/m^2 in the southwestern basin near the center of the Emeishan large igneous province. The low geothermal gradient episode with heat flow ranging from 31.2 to 70.0 m W/m^2 may be related to the foreland basin evolution. The cooling event is a result of the continuous uplift and denudation of the basin.

关 键 词：Paleotemperature gradient Paleo-heat flow Vitrinite reflectance Emeishan mantle plume Sichuan Basin 

分 类 号：P618.13[天文地球—矿床学]