西藏亚东堆纳地区古近纪浮游有孔虫生物地层

发布时间：2018-02-13 08:20

本文关键词： 古近纪特提斯洋浮游有孔虫生物地层亚东　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】：青藏高原是在中生代以来印度板块与亚洲板块碰撞作用下形成的,并成为全球地学界普遍关注的课题。但迄今为止学者们仍不能准确确定它们碰撞的起始时间,特别是这一过程中特提斯洋的闭合时间。其原因是多方面的,本文认为碰撞符合通行的陆陆碰撞模式,研究特提斯洋闭合时间,可为印度板块与亚洲板块的碰撞演化过程提供一个重要的时间约束,因此就可以通过对浮游有孔虫生物地层学的研究来寻找研究区的海相地层消失的时间,进而为特提斯洋的封闭和碰撞的起始时间提供时间约束。在我国古近纪沉积类型主要是陆相的,只有在西藏、新疆以及台湾的部分地区才发育有海相古近纪地层(万晓樵,1987)。藏南地区保存有连续的海相古新世到始新世地层,这些地层中保存着在特提斯海具有广泛分布特性的化石,它们不仅种类多、而且数量丰富,其生物演化序列能够与欧洲阿尔卑斯经典特提斯研究区相对比。藏南亚东地区曾是特提斯演化晚期残留海的居留地,具有很高的研究意义。本文选择位于特提斯喜马拉雅南亚带、古近纪海相地层发育连续、微体化石丰富的亚东堆纳古鲁浦地区进行极为详细的浮游有孔虫生物地层学的研究,共鉴定出浮游有孔虫25属121种,划分出7个化石带:Morozovella formosa formosa带、Morozovella aragonensis带、Acarinina pentacamerata带、Morozovella spinulosa Acarinina bullbrooki带、Globigerina officinalis Turborotalia cerroazulensis cerroazulensis带、Truncorotaloides rohri带、Globigerinatheka semiinvoluta带。根据对古鲁浦剖面中浮游有孔虫的研究,认为研究区内遮普惹组砂岩页段顶部沉积时代可达Priabonian中期。
[Abstract]:The Qinghai-Xizang Plateau was formed by the collision of the Indian plate and the Asian plate since Mesozoic, and has become a subject of general concern in the global geosciences. But so far, scholars have not been able to determine exactly when the collision began. In particular, the closing time of the Tethys ocean in this process is due to many reasons. In this paper, it is considered that the collision accords with the prevailing continental collision model, and the closing time of the Tethys ocean is studied. It can provide an important time constraint for the collision and evolution of the Indian plate and the Asian plate, so we can find the time of the marine strata disappearing in the study area through the study of planktonic foraminiferal biostratigraphy. Thus providing time constraints for the start time of the closure and collision of the Tethys Ocean. In China, the Paleogene sedimentary types are mainly continental, only in Tibet, It was only in Xinjiang and parts of Taiwan that marine Paleogene strata were developed (Wan Xiaoqiao and 19870.The southern Tibetan area has a series of marine Paleocene to Eocene strata, in which fossils with widespread distribution in the Tethys Sea are preserved. They are not only abundant in species, but also abundant in quantity, and their biological evolution sequences can be compared with those of the European Alps classic Tethys study area. The southern and eastern regions of Tibet were once the residence sites of the residual seas in the late Tethys evolution. In this paper, a detailed study of planktonic foraminiferal biostratigraphy in the southern Asian belt of the Tethys Himalayas with continuous development of Paleogene marine strata and abundant microfossils in the Nagurupu area of Yadongdui has been carried out. A total of 121 species belonging to 25 genera of planktonic foraminifera were identified, and 7 fossilized zones, Morozovella formosa formosa, Morozovella aragonensis, Acarinina pentacamerata, Morozovella spinulosa spinulosa Acarinina bullbrooki, Globigerina officinalis Turborotalia cerroazulensis cerroazulensis, Truncorotaloides rohri, Globigerinatheka semiinvoluta, were identified. It is considered that the top depositional age of sandstone in the Zapuyakarta formation in the study area can reach the middle of Priabonian.
【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】：Q915

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