柴达木盆地北缘全吉群年代格架与全吉地块前寒武纪构造属性

发布时间：2018-03-13 12:20

本文选题：全吉群　切入点：全吉地块　出处：《中国地质大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：柴达木盆地北缘前寒武纪沉积盖层全吉群角度不整合覆盖在由德令哈杂岩和达肯大坂岩群组成的全吉地块变质基底之上。前人主要认为全吉群时代为南华纪-震旦纪,底界年龄在760 Ma左右,是新元古代Rodinia超大陆裂解的产物;全吉地块是从塔里木陆块裂离出来的一个克拉通碎块(片),新太古代至古元古代构造热事件及其性质与华北陆块相同或相似,共同响应全球Columbia超大陆汇聚事件,其构造属性可能亲缘于华北陆块,但是自新元古代以来,全吉地块和其塔里木母陆块与扬子陆块地质演化历史极其相似。本文选择全吉地块之上全吉山、石灰沟南和欧龙布鲁克山三处剖面的前寒武纪沉积盖层全吉群进行研究,确认了全吉群内部存在两个平行不整合面。通过放射性同位素测年、古生物化石和沉积特征的区域对比等的分析,将全吉群解体,厘定后的全吉群包含麻黄沟组、枯柏木组、石英梁组与红藻山组等四个组,时代归属长城纪。将全吉群底界年龄限定在1.78 Ga左右。认为全吉地块是华北板块西南缘的一部分,全吉群为Columbia超大陆初始裂解阶段的一套裂陷槽沉积序列。
[Abstract]:The angle unconformity of Quanji Group of Precambrian sedimentary caprock in the northern margin of Qaidam Basin is overlaid by the metamorphic basement of the Quan Ji block composed of Delingha complex and Dacken Osaka rock group. The bottom boundary age is about 760Ma, which is the product of Rodinia supercontinent cracking in Neoproterozoic. The whole Kyrgyzstan block is a craton fragment (NeoArchaeo-#china_person0#) tectonic heat event separated from the Tarim continent block, and its characteristics are the same or similar to those of the North China block, and respond jointly to the global Columbia supercontinental convergence event. The tectonic attributes may be related to the North China block, but since the Neoproterozoic, the geological evolution history of the Quan Ji block and its Tarim block is very similar to that of the Yangtze block. In this paper, the Precambrian Sedimentary caprock Quanji Group in three sections of south Liogou and Oulong Brook Mountain is studied, and it is confirmed that there are two parallel unconformities in Quanji Group. Based on the analysis of the regional correlation of paleontological fossils and sedimentary characteristics, the Quanji group was disintegrated. The determined group consists of four groups: mahuanggou formation, Kubamu formation, quartz-liang formation and Hongzaoshan formation. The age belongs to the Great Wall. The age of the bottom boundary of Quanji Group is about 1.78 Ga. It is considered that the Quanji block is a part of the southwestern margin of the North China plate, and the Quanji Group is a set of rift trough sedimentary sequence in the initial pyrolysis stage of Columbia supercontinent.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P534.41

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