塔里木盆地沙雅隆起北部震旦纪地层特征与锆石U-Pb年龄约束

发布时间：2018-02-07 14:15

本文关键词： 岩石地层地层特征锆石测年震旦纪沙雅隆起塔里木盆地新疆　出处：《地层学杂志》2017年04期 　论文类型：期刊论文

【摘要】：综合钻井岩芯、岩石薄片、测井、地震资料和野外露头资料,对塔里木盆地沙雅隆起北部的震旦纪地层进行划分对比和时代研究。该区震旦系分别以角度不整合位于变质岩基底之上、寒武系玉尔吐斯组泥岩或中生代地层之下,由下部的陆相碎屑岩和上部的台地相碳酸盐岩组成,厚度约在220~260m。其中碳酸盐岩厚度约在200m左右,自上而下分为藻云岩段、泥质云岩段、白云岩和灰岩夹白云岩段4个岩性段,相当于塔里木盆地西北缘的奇格布拉克组;震旦系下部的碎屑岩厚度20m左右,以褐色泥岩为主,相当于塔里木盆西北缘的苏盖特布拉克组。利用锆石测年对震旦系底部碎屑岩及其下伏变质岩时代进行限定,其基底年龄不早于776 Ma,相当于青白口系阿克苏群。研究区震旦系与塔里木盆地西北缘露头地层的对比表明,在震旦系苏盖特布拉克组沉积期,沙雅隆起北部可能处于隆起区,具有较长时间的沉积间断,至奇格布拉克组沉积期整个塔北才开始沉降并重新接受海相沉积。
[Abstract]:Integrated drilling core, rock sheet, logging, seismic data and field outcrop data, The Sinian strata in the northern part of the Shaya uplift in the Tarim Basin are divided and compared. The Sinian system in this area is located on the metamorphic basement at an angle, and under the mudstone or Mesozoic strata of the Cambrian Yultux formation. The carbonate rocks are composed of continental clastic rocks in the lower part and carbonate rocks in the platform facies in the upper part, the thickness of which is about 220 ~ 260 m. The carbonate rocks are about 200 m thick, which can be divided into four lithologic segments from the top to bottom: the algal dolomite segment, the argillaceous dolomite section, the dolomite segment and the limestone intercalated dolomite segment. The detrital rocks in the lower part of the Sinian are about 20m thick and mainly brown mudstone, which is equivalent to the Chigebrak formation in the northwestern margin of the Tarim Basin. The Sugait Burak formation, which corresponds to the northwestern margin of the Tarim Basin, defines the age of the bottom clastic rocks and their underlying metamorphic rocks of the Sinian by using zircon dating. The basement age is no earlier than 776 Ma, corresponding to the Qingbaikou Aksu group. The correlation between the Sinian system and outcrop strata in the northwest margin of the Tarim Basin shows that the northern part of the Shaya uplift may be located in the uplift area during the sedimentary period of the Sugaitbrak formation of the Sinian system. The sedimentary discontinuity occurred for a long time, and it was not until the deposition period of Chigebrak formation that the whole Tarim Basin began to subsidence and re-accept marine deposits.
【作者单位】：中国石化西北油田分公司勘探开发研究院;西北大学地质学系;
【基金】：国家重大专项课题“海相碳酸盐岩层系大中型油气分布规律及勘探评价”(2011ZX05005-002)资助
【分类号】：P534.31;P597

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