本文選題：上白堊統(tǒng) + 介形蟲�。� 參考：《中國地質(zhì)大學(xué)(北京)》2015年碩士論文

【摘要】：青藏高原南緣地處特提斯—喜馬拉雅構(gòu)造域的東段,是印度板塊與歐亞板塊碰撞的前鋒地帶,地質(zhì)構(gòu)造極其復(fù)雜。西藏南部地區(qū)發(fā)育有良好的海相白堊紀(jì)地層,地層中含有的微體古生物化石(有孔蟲、放射蟲及介形蟲等)較為豐富。白堊紀(jì)是新特提斯演化的一個關(guān)鍵時期,藏南白堊紀(jì)微體古生物地層的研究,可為探討新特提斯洋演化及白堊紀(jì)時期古地理、古環(huán)境提供重要依據(jù)。本文的研究重點為藏南江孜床得地區(qū)介形蟲生物地層。藏南地區(qū)白堊紀(jì)特提斯-喜馬拉雅沉積分帶明顯,以定日—定結(jié)—崗巴大斷裂為界,分為特提斯喜馬拉雅北亞帶和特提斯喜馬拉雅南亞帶。北帶(康馬—江孜一帶)整體上為大陸斜坡—大洋盆地的沉積環(huán)境,沉積水體相對較深,浮游類生物化石(浮游有孔蟲、放射蟲及箭石等)豐富,大洋紅層(CORBs)分布廣泛;南帶(崗巴—定日—札達(dá)一帶)為印度板塊北緣被動陸緣盆地,整體上屬于大陸架沉積環(huán)境,沉積水體相對較淺,化石門類相對減少,尤其以放射蟲極為罕見為特征。本文主要對位于特提斯喜馬拉雅北亞帶的江孜地區(qū)床得西剖面進行了詳細(xì)的介形蟲生物地層研究,其中床得組紫紅色頁巖(紅層)中化石含量較為豐富。通過對床得西剖面所含介形蟲化石的系統(tǒng)研究及鑒定,共鑒定出24屬41種,劃分出5個生物組合:①Xestoleberis eximia—Talicypridea ventricosa組合,②Schuleridea shalayiensis—Candona longireniformis組合,③Uroleberis inflata—Candoniella subcurvata—Argilloecia組合,④Talicypridea occultaca—Bairdia acrocaudalis—Xestoleberis組合,⑤Cypridopsis zhungaerensis—Cyclocypris cf.calculaformis組合。根據(jù)介形蟲化石生物屬種及所在層位浮游有孔蟲的代表屬種,將江孜床得西剖面地層的時代厘定為三冬晚期—馬斯特里赫特早期。其中,床得組紅層的時代推測為坎潘期至馬斯特里赫特早期。論文同時還對床得西剖面的巖石特征及沉積環(huán)境進行了初步探討,由分析推斷該地區(qū)在白堊紀(jì)時期的沉積環(huán)境為大陸斜坡至深水洋盆。
[Abstract]:The southern margin of the Qinghai-Xizang Plateau is located in the eastern part of the Tethys Himalayan tectonic domain and is the front zone of the collision between the Indian plate and the Eurasian plate. The geological structure is extremely complex. There are good marine Cretaceous strata in southern Tibet, which contain abundant micropaleontological fossils (foraminifera, radiolaria, ostracoda, etc.). The Cretaceous is a key period of the Neo-Tethys evolution. The study of the Cretaceous micro-paleostratigraphy in southern Tibet can provide an important basis for the study of the evolution of the Neo-Tethys Ocean and the paleogeography and paleoenvironment of the Cretaceous period. This paper focuses on the ostracod biostratigraphy in Jiangzi bed area, southern Tibet. The Cretaceous Tethys Himalayan Sedimentary zonation is obvious in the south of Tibet and is divided into the Tethys Himalayan North Asia Zone and the Tethys Himalayan South Asia Zone. The northern belt (Kangma-Jiangzi area) is the sedimentary environment of continental slope and oceanic basin, the sedimentary water is relatively deep, the planktonic fossils (planktonic foraminifera, radiolaria and quiver) are abundant, and the oceanic red beds (CORBs) are widely distributed. The southern belt (Gangba Dingri Zanda area) is a passive continental margin basin in the northern margin of the Indian plate. It belongs to the sedimentary environment of the continental shelf on the whole, with relatively shallow sedimentary water bodies and relatively reduced fossils, especially characterized by the extremely rare radiolaria. In this paper, a detailed study on the western section of the bed in Jiangzi area, located in the northern subzone of Tethys Himalayas, has been carried out, in which there are abundant fossils in the purple red shale (red bed) of the bed formation. A total of 24 genera and 41 species were identified by systematic study and identification of ostracia fossils in the Dexi section of the bed. The species were divided into 5 assemblages: 1 Xestoleberis eximia-Talicypridea ventricosa (2Schuleridea shalayiensis-Candona longireniformis) and 3Uroleberis inflata-Candoniella subcurvata-Argilloecia assemblage. 4Talicypridea occultaca-Bairdia acrocaudalis-Xestoleberis assemblage. According to the species of fossil ostracia and the representative genera of planktonic foraminifera in the strata, the stratigraphic age of the west section of Jiangzi bed is determined to be the late three-winter to the early Maastricht. Among them, the age of the bed formation red layer is supposed to be from the Kampan period to the early Maastricht period. At the same time, the rock characteristics and sedimentary environment of the western section of the bed are discussed. The sedimentary environment of the area during the Cretaceous period is from continental slope to deep water ocean basin.
【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】：Q913;P534.53

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