【作者】 韩洪斗；

【导师】 万晓樵； 李国彪；

【作者基本信息】 中国地质大学（北京） ， 古生物学与地层学， 2008， 硕士

【摘要】 我国的海相白垩系在西藏南部沿特提斯-喜马拉雅带广泛分布。该地区由于大化石相对稀少,微体化石的研究就显得尤为重要。特提斯-喜马拉雅南亚带白垩系已经建立了较为系统的生物地层序列,与之相比,北亚带白垩系生物地层学的研究相对零散而薄弱,而康马田巴白垩系的生物地层学研究则处于空白,所以有必要开展对该地区的生物地层学研究。鉴于田巴与江孜地区的白垩系处于同一个沉积盆地,两个地区的白垩系在岩性组合方面极其相似,因此,本文对康马地区的白垩系岩石地层的划分沿用前人在江孜地区白垩系所采用的岩石地层划分方案,即自下而上分别划分为:甲不拉组,床得组,宗卓组。本文对康马田巴地区白垩系的微体古生物(主要是有孔虫及放射虫等)进行了较为详细的研究。根据标准化石的始/末现面,确定了各化石带在剖面上的位置。在田巴(a、b)剖面自下而上识别出Lagena apiculata,Globotruncana elevata带,Dorothia stephensoni带, Trochammina globigeriniformis带, Dentalina catenula带,Haplophragmoides trifolium带等6个有孔虫化石带及Xitus sp,Cyrtocapsa campi,Orbiculiforma renillaeformis,Stichomitra compsa等四个放射虫化石组合;在达巴剖面自下而上识别出Trochammina wetteri带,Lenticulina carlsbadensis带,Haplophragmoides trifolium带,Haplophragmoides calcula带,Globotruncana lapparenti带,Gavelinella pertusa带等6个有孔虫化石带和Paronaella solanoensis,Amphipyndax stocki,Orbiculiforma renillaeformis等3个放射虫化石组合。初步厘定该区上白垩统的生物地层格架。更多还原

【Abstract】 The marine upper Cretaceous strata are widespred in the Tethys-Himalays belt, southern Tibet. Macrofossils being relatively scarce, the microfossiles are quite important for us to study the biostratigraphy of Cretacous in this area. A detailed biostratigraphic study has been made and a systematic systematic Cretaceous biostratigraphic framework have been established in the South Tethys-Himalayas subbelt, which is located south of the Tingri-Gamba fault. In contrast, a shallow and fragmentary biostratigraphic study has been made about the Cretaceous in the North Tethys-Himalayas subbelt, which is located north of the Tingri-Gamba fault. Especially, there is no any biostratigraphic work has been made about the Cretaceous in the Tianba area of Kangma. Therefore, it is relatively necessary for us to make a further biostratigraphic study on the Cretaceus of Tianba area in Kangma.This thesis based on the detailed fieldwork at the Cretacous strata in Tianba, Kangma. Three new sections were measures in this area. Based on its being in the same depositional basin and similar lithologic association with the Cretaceous strata of Gyangtze area, the Cretaceous of Tianba area can aslo be ascendingly indiveded into Jiabula, Chungde and Zongzhuo formations.No macrofossils have been discovered from the Cretacous Zongzhuo Formation of Tianba area. However, a boundant microfossils (mainly foraminiferas and radiolarian) are present this formation. From the Zongzhuo Formation the Tianba sections of a and b, six foraminiferal assemblages have been ascendinly recognized as (1) Lagena apiculata Zone, (2) Globotruncana elevata Zone,(3)Dorothia stephensoni Zone,(4) Trochamminave globigeriniformis Zone,(5) Dentalina catenula Zone and (6) Haplophragmoides trifolium Zone; And four radiolarian assemblages have been ascendinly recognized as (1) Xitus sp , (2) Cyrtocapsa campi , (3) Orbiculiforma renillaeformis and (4) Stichomitra compsa.In the Daba section, six foraminiferal assemblages have been ascendinly recognized as (1) Trochammina wetteri Zone, (2) Lenticulina carlsbadensis Zone, (3) Haplophragmoides trifolium Zone, (4) Haplophragmoides calcula Zone, (5) Globotruncana lapparenti Zone, and (6) Gavelinella pertusa Zone; And three radiolarian assemblages have been ascendinly recognized as (1) Paronaella solanoensis,(2) Amphipyndax stocki,and (3) Orbiculiforma renillaeformis. The microfossil assemblages indicate a Campanian-Maastrichtian age for the Zongzhuo Formation of Tianba area..更多还原