Fischer图解及其在塔里木盆地巴楚地区早奥陶世海平面变化中的响应  

Fischer Plot and Its Response to the Changes of the Early Ordovician Sea in the Bachu Area,Tarim Basin

作　　者：胡晓贤[1,2,3] 樊太亮[2,3] 高志前 吴鹏[1,2,3] Hu Xiaoxian;Fan Tailiang;Gao Zhiqian;Wu Peng(China United Coalbed Methane Corporation Ltd. , Beijing 100011, China;School of Energy Resources;The Key Laboratory of Marine Reservoir Evolution and Hydrocarbon Accumulation Mechanism of the Ministry of Education, China University of Geosciences（Beijing）, Beijing 100083, China)

机构地区：[1]中联煤层气有限责任公司,北京100011 [2]中国地质大学(北京)能源学院,北京100083 [3]中国地质大学(北京)海相储层演化与富集机理教育部重点实验室,北京100083

出　　处：《地质科技情报》2018年第1期88-95,共8页Geological Science and Technology Information

基　　金：国家自然科学基金项目(51574208);中科院A类先导项目(XDZ14010201-02);中央高校基本业务费项目(2-9-2015-141)

摘　　要：基于典型露头、钻测井及地震资料,利用自然伽马测井曲线做出Fischer图解,可识别出具有米兰科维奇旋回特征的高频旋回,旨在分析塔里木盆地巴楚地区早奥陶世的相对海平面变化。对和田1井下奥陶统蓬莱坝组的自然伽马测井曲线进行了预处理和计算,共识别出103个米兰科维奇旋回,并做出Fischer图解。结果表明,下奥陶统蓬莱坝组发育1个Ⅲ级层序,7个Ⅳ级层序和28个Ⅴ级层序,反映塔里木盆地巴楚地区的海平面在早奥陶世呈现出无明显变化-快速上升-迅速下降的相对变化趋势,其结果与柯坪地区野外露头碳、氧同位素曲线指示的相对海平面变化有很好的一致性,说明Fischer图解有很强的适用性,对今后塔里木盆地相对海平面变化的研究有一定指导意义。Based on the typical outcrops,and drilling,logging and seismic data,this paper uses gamma ray log data for Fischer plot to identify the high frequency cycles with the Milankovitch cycle characteristics in order to analyze the Early Ordovician relative sea-level change of Tarim Basin.The Bachu Uplift,located in the western border of Tazhong area in Tarim Basin,contains a large number of borehole data.High-frequency sedimentary cycles are well developed in the Lower Ordovician Penglaiba Formation in these boreholes.Well Hetian1 is selected for pretreating and calculating its gamma ray log data of Penglaiba Formation.The calculated results show that there are 103 Milankovitch cycles developed from the bottom to the top of the Lower Ordovician Penglaiba Formation in Well Hetian1.The cycle thickness varies from 2.7 to9.4 m,with an average 5.2 m.In the Early Ordovician,a stable carbonate platform sedimentary developed in the Bachu Uplift,whose tectonic subsidence rate could be assumed as linear variation.Based on these data above,a Fischer plot is made with the number of the cycles as abscissa and average cumulative thickness as ordinate.The result suggests that there are 1 third-order sequence,7 fourth-order sequences and28 fifth-order sequences in the Lower Ordovician Penglaiba Formation.This shows that,the relative sea level in Bachu area of Tarim Basin had no significant change at first,then rose rapidly and finally declined quickly during the Early Ordovician.The maximum flooding surface occurred in the middle of the fifth four-order cycle.These results are insistent with those reflected by the C-O isotope of Penglaiba Formation,suggesting that Fischer plot is very applicable for studying the relative sea-level change in Tarim Basin in future.

关 键 词：米兰科维奇旋回 巴楚地区 早奥陶世 Fischer图解 海平面变化 

分 类 号：P736[天文地球—海洋地质]