本文選題：西藏南部　切入點(diǎn)：江孜　出處：《中國(guó)地質(zhì)大學(xué)(北京)》2015年碩士論文

【摘要】：白堊紀(jì)海相地層在我國(guó)出露較少,僅見于西藏、新疆及臺(tái)灣等地區(qū),其中在西藏南部地區(qū)保存完整并有良好露頭可供研究,因而該地區(qū)成為眾多地質(zhì)學(xué)家們探究白堊紀(jì)海相地層的理想場(chǎng)所。白堊紀(jì)大洋紅層(Cretaceous oceanic red beds)通常被認(rèn)為是深水環(huán)境中的沉積物被氧化后在原地堆積的產(chǎn)物。大洋紅層沉積的出現(xiàn)代表當(dāng)時(shí)的海洋具有氧化能力,使海洋中的有機(jī)碳發(fā)生氧化反應(yīng),產(chǎn)生大量CO2,從而影響全球的碳循環(huán)以及氣候環(huán)境。對(duì)大洋紅層進(jìn)行研究可進(jìn)一步探討紅層沉積時(shí)期古海洋和古地理的環(huán)境變化,探究環(huán)境變化機(jī)制,對(duì)未來氣候和環(huán)境的變化具有指示意義。江孜地區(qū)的大洋紅層沉積指示該地區(qū)在白堊紀(jì)時(shí)期總體上處于一種水體相對(duì)較深的大陸斜坡-大洋盆地沉積環(huán)境。大洋紅層中常見的微體化石主要包含有孔蟲、放射蟲以及少量的介形蟲,通過研究這些微體化石,可以厘定地層時(shí)代,為重建古地理、古環(huán)境以及探究古氣候提供重要的科學(xué)依據(jù)。本文針對(duì)大洋紅層保存良好的江孜床得西剖面,對(duì)其開展浮游有孔蟲生物地層學(xué)的研究,通過鑒定浮游有孔蟲屬種,進(jìn)行化石帶的劃分,從而推斷大洋紅層地層的時(shí)代。論文針對(duì)江孜床得西白堊紀(jì)地層(主要是床得組)剖面中所含的浮游有孔蟲化石進(jìn)行系統(tǒng)的研究和鑒定,最終結(jié)果為10屬37種,根據(jù)有孔蟲的組合特征劃分出3個(gè)浮游有孔蟲化石帶:①Globotruncana ventricosa帶,②Radotruncana calcarata帶,③Globotruncanella havanensis帶。鑒于床得西剖面中浮游有孔蟲組合的特征,將該剖面的時(shí)代厘定為坎潘期-馬斯特里赫特期。其中,紅層沉積為剖面一段,時(shí)間被定為早坎潘晚期-早馬斯特里赫特期,總體上屬于坎潘期。
[Abstract]:The Cretaceous marine strata in China outcrops, found only in Tibet, Xinjiang and Taiwan and other regions, including in the southern region of Tibet to preserve the integrity and good outcrop for study, so this area is an ideal place for many geologists study the Cretaceous marine strata of Cretaceous oceanic red beds. Ji (Cretaceous oceanic red beds) is usually that is a product of sediment in deep water is oxidized in situ accumulation. CORBs deposition time on behalf of ocean with oxidation, the organic carbon in the ocean oxidation reaction occurs to produce large quantity of CO2, thus affecting the global carbon cycle and climate. The oceanic red beds were studied for further research changes of paleo ocean and paleogeographic environment during the deposition of the red layer, to explore the mechanisms of environmental changes, is the indication of future climate and environmental changes in Jiangzi ocean red. The indicator layer deposition area in the Cretaceous period, generally in a relatively deep water continental slope - ocean basin sedimentary environment. Fossils of common oceanic red beds mainly contains foraminifera, radiolaria and a small amount of ostracods, by studying these microfossils, to determine stratigraphic age, for the reconstruction of ancient geography, ancient environment and to explore the ancient climate provide an important scientific basis. This paper Jiangzi bed oceanic red beds is well preserved in the west section, the planktonic foraminiferal biostratigraphy research, through the identification of planktonic foraminiferal species, divide the fossil zone, thus infer oceanic red layer. According to the Jiangzi times to the west of the Cretaceous strata (bed the bed is mainly to study group) and identification system contained in the profile of planktonic foraminiferal fossils, the final result is 10 genera and 37 species, according to the foraminiferal assemblages Divided into 3 planktonic foraminiferal zones: Globotruncana ventricosa belt, the Radotruncana calcarata band, Globotruncanella havanensis band. In view of the characteristics of planktonic foraminifera in the West combined bed profile, the profile of the age for the Campanian Maastricht period. Among them, for a red layer deposition profile, time is late Early Campanian early Maastricht period, generally belong to the Campanian.

【學(xué)位授予單位】：中國(guó)地質(zhì)大學(xué)(北京)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：Q915

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本文編號(hào)：1695002