【摘要】：被譽(yù)為“世界屋脊”的青藏高原地處亞洲大陸的南部,由于其獨(dú)特的自然環(huán)境和復(fù)雜的地殼結(jié)構(gòu),長期以來一直為廣大地學(xué)工作者所關(guān)注。它是印度板塊向歐亞板塊俯沖碰撞的結(jié)果,而碰撞過程是連續(xù)的,無法留下明顯可見的地質(zhì)記錄,因此需要利用碰撞事件發(fā)生前后產(chǎn)生的地質(zhì)記錄來確定事件發(fā)生的上限時間和下限時間,后逐漸縮小上限和下限的間隔,從而預(yù)測碰撞事件的時代。本文主要是運(yùn)用微體古生物地層學(xué)的研究方法來確定西藏特提斯最終閉合的時間,從而為印度—亞歐板塊碰撞拼合的時間上限提供約束條件。本次研究的剖面—古魯浦剖面位于西藏南部亞東堆納地區(qū),在沉積—構(gòu)造分區(qū)上位于特提斯喜馬拉雅帶的南亞帶。該區(qū)域海相古近系發(fā)育較好,且古生物化石種類多,含豐富的浮游有孔蟲、底棲有孔蟲、介形蟲、藻類等。本文主要對該剖面的介形蟲生物群進(jìn)行研究。通過對西藏亞東堆納古魯浦剖面遮普惹組砂頁巖段的介形蟲化石進(jìn)行鑒定及分析,共鑒定出介形蟲化石18屬36種,劃分出3個介形蟲化石組合,自老至新分別是:Alocopocythere curvata-Cytherella compressa組合,Bairdia fabaeformis-Monsmirabilia subovata組合,Bairdia dignata-Bairdia lauta組合。通過對劃分出來的這3個介形蟲化石組合特征的分析,并結(jié)合與其共同產(chǎn)出的有孔蟲化石組合的時代特征,確定亞東堆納古魯浦剖面遮普惹組砂頁巖段的時代為Priabonian早期以后。
[Abstract]:The Qinghai-Xizang Plateau, known as the "roof of the world", is located in the southern part of the Asian continent. Due to its unique natural environment and complex crustal structure, it has long been the focus of geoscientists. It is the result of a subduction of the Indian plate to the Eurasian plate, and the collision process is continuous and cannot leave a visible geological record. Therefore, it is necessary to use the geological records before and after the collision event to determine the upper and lower limit time of the event, then gradually reduce the interval between the upper and lower bound, so as to predict the time of collision event. In this paper, the method of micropaleostratigraphy is used to determine the time of final closure in Tethys, Tibet, thus providing a constraint for the upper limit of the time limit for the collision of the Indo-Eurasian plate. The profile-Gulupu section in this study is located in the Yadong Dina area in southern Tibet and in the south Asia belt of the Tethys Himalayan belt on the sedimental-tectonic zoning. The marine Paleogene is well developed, and there are a lot of paleontological fossils, including planktonic foraminifera, benthic foraminifera, ostracoda, algae and so on. In this paper, the ostracod biota of this section is studied. Based on the identification and analysis of ostracoda fossils in the sand shale section of the Zapuja formation in the Nagurupu section of Yadong, Tibet, a total of 18 genera and 36 species of ostracoda fossils were identified and divided into 3 assemblages of ostracoda fossils. From old to new are: Alocopocythere curvata-Cytherella compressa combination, Bairdia fabaeformis-Monsmirabilia subovata combination, Bairdia dignata-Bairdia lauta combination. Based on the analysis of the characteristics of the three ostracod fossil assemblages and the age characteristics of the foraminiferal assemblages, it is concluded that the age of the sand shale of the Zapuja formation in the Nagurupu section of the Yadong DUI is after the early Priabonian.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：Q915;P534.6

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相關(guān)期刊論文 前1條

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本文編號：2385480