从冷科1井下部地层的归属探讨柴达木盆地成盆时间  

Inquiry of Initiation Age of the Qaidam Basin Based on Stratigraphic Study of the Lower Part of the Well Lengke-1

作　　者：刘桂侠[1] 杨永泰[2] 管全俊[3] 

机构地区：[1]西南石油学院,四川南充637100 [2]中国石油勘探开发科学研究院,北京100083 [3]青海油田分公司勘探开发研究院,甘肃敦煌736202

出　　处：《地球学报》2003年第2期133-136,共4页Acta Geoscientica Sinica

基　　金：中国石油天然气股份有限公司项目"新盆地;新层系;新领域研究和科学探井的选择与实践"(95 81 1C)的成果

摘　　要：冷科 1井是近年来柴达木盆地北缘最重要的一口科学探索井。因该井首次发现了巨厚的新地层 ,所以对该井的4 666～ 5 2 0 0m地层划分存在较大争议。前人主要依据孢粉资料把冷科 1井 4 666～ 5 2 0 0m层段归属为下侏罗统 ,也有人依据从该段发现的海相化石碎片认为该段为石炭系。本文从岩性组合、古生物特征、地震剖面、测井电性及水介质特征等多方面对该层段进行了分析 ,否定了该段为下侏罗统和石炭系的可能 ,认为该段为上三叠统。该研究改变了过去柴达木盆地始于早侏罗世的观点 。Lengke 1,a well for the scientific research drilling project, is the most important exploration well in the northern Qaidam basin. As great thickness of strata was for the first time discovered in the well, there is much controversy over stratigraphic division of the interval from 4 666 to 5 200 m. Based on the sporopollen assemblage, most geologists hold that the interval is of Lower Jurassic, while some others consider it to be Carboniferous according to some detritus of marine fossils found in this interval. Based on analyzing such characteristics of this interval as its lithological associations,palaeontology,seismic sections,well logging data and water medium quality,this paper rules out the possibility of being Lower Jurassic or Carboniferous,and points out that the strata in this interval are Upper Triassic. This research changes the former idea that Qaidam basin originated in Early Jurassic,and reveals that the basin originated from Late Triassic sporadic rifts.

关 键 词：成盆时间 柴达木盆地 上三叠统 孢粉资料 海相化石 岩性组合 古生物 

分 类 号：P544.4[天文地球—构造地质学]