鄂尔多斯盆地南缘奥陶系浅水台地与深水斜坡砾屑灰岩识别特征  

Identification characteristics of calcirudite limestone of shallow water platform or deep water slope origin in middle-late Ordovician in southern Ordos Basin

作　　者：庞军刚 国吉安 李文厚[3] 吴少波 王桂成 马治国 王起琮 PANG Jungang;GUO Ji′an;LI Wenhou;WU Shaobo;WANG Guicheng;MA Zhiguo;WANG Qicong(School of Earth Science and Engineering,Xi′an Shiyou University,Xi′an 710065,China;No.2 Comprehensive Geophysical Prospecting Brigade Shaanxi Geological Mining Co.,Ltd.,Xi′an 710016,China;Geological Department/State Key Laboratory of Continental Dynamics,Northwest University,Xi′an 710069,China)

机构地区：[1]西安石油大学地球科学与工程学院,陕西西安710065 [2]陕西地矿第二综合物探大队有限公司,陕西西安710016 [3]西北大学地质学系/大陆动力学国家重点实验室,陕西西安710069

出　　处：《西北大学学报（自然科学版）》2019年第6期961-969,共9页Journal of Northwest University（Natural Science Edition）

基　　金：中国地质调查局矿产资源调查评价基金资助项目(121201011000150014);地质矿产调查评价基金资助项目(21201011000150014);“十三五”国家科技重大专项(2016ZX05050006);国家科技重大专项(2017ZX05005-002-04);西安石油大学科研创新团队基金资助(2013KYCXTD03)

摘　　要：根据典型露头剖面的沉积学研究,采用野外观察与室内研究相结合的方法。分析不同成因砾屑灰岩的识别特征,查明鄂尔多斯南缘奥陶系的沉积体系、岩相古地理特征及沉积模式。研究可知,研究区奥陶系平凉组、背锅山组主要发育开阔海台地、台地边缘礁滩相、台地前缘斜坡相、以及深水斜坡-海槽相;不同成因砾屑灰岩在构造背景、砾屑特征、背景岩石类型等方面具有明显的差异,从而准确地识别和划分了浅水台地与深水斜坡;在此基础上,恢复了平凉期及背锅山期的沉积体系展布,明确了奥陶系岩相古地理的演化,构筑了发育浅水台地、深水斜坡和深水盆地沉积体系的塌积边缘型沉积模式。研究后认为,在继续重视马家沟组古岩溶及白云石化有关储层的同时,也要加强浅水台地礁滩相和深水斜坡区重力流颗粒灰岩储层的勘探。Ascertain depositional systems,paleogeographic characteristics and evolution,and sedimentary model of the middle-late Ordovician in Ordos Basin.Based on large quantities of outcrop,combined research methods of field exploration and indoor analysis are adopted.Open platform,platform margin reef-shoal facies,platform margin slope and deep water slope-sea trough mainly developed in Pingliang and Beiguoshan Formation.These calcirudite with different origins shows significant differences in such aspects as tectonic setting,characteristics of calcirudite,differences of the background rock,resulting to shallow water platform and deep water slope are accurately distinguished and identified in study area,forthermore,the distributions of sedimentary systemduring Pingliang and Beiguoshan were restored,and the evolution of lithofacies paleogeography of ordovician is clearly constructed.Furthermore,the sedimentary model with colluvial marginal is constructed,which develops the sedimentary systems of shallow water platform,deep water slope and deep water basin.The reservoirs intimately related with origins of paleokarst and dolomitization of Majiagou Formation are still the target of exploration and exploitation in the near future,meanwhile the exploration of the reservoirs intimately related with origins of reef-shoal facies in shallow water platform and gravity-flow grain limestone in deep-water slope areas should be increased.

关 键 词：砾屑灰岩 浅水台地 深水斜坡 沉积特征 鄂尔多斯 下古生界 

分 类 号：P618.13[天文地球—矿床学]