Early Cretaceous Foraminiferal Biostratigraphy In Gamba, Southern Tibet

During the Cretaceous period, a series of geological events occurred on Earth, such as geological structure, biological evolution, and ancient marine events. During that time, the earth made numerous great revolutions. Since the 150Ma, the environmental and biological changes in the Earth's 21st century identified as priority fields of study by international geologists. So if we carry out research on Cretaceous biostratigraphy, it will be beneficial for scientific theory of geological research, global environmental change research, wxploration of mineral resources, geological hazards research and so on. Studing biological events occurred in marine cretaceous strata is the most important among cretaceous research.In china, in addition to a larger area of marine Cretaceous strata exposed in southern Tibet, poorly exposed elsewhere. Our study area is located south of Gamba, Tibet.It is belong to the southern of Tethyan Himalayan zone. At that area, the macrofossil is scarce, but the microfossil is abundant, especially foraminifera. Therefore, research on microfossils is particularly important. Predecessors have been established a systematic biostratigraphic sequence in southern of Tethyan Himalayan Zone, but the complete sequence is only limited to the Late Cretaceous, Early Cretaceous biostratigrphic sequence is far from complete.It is necessary to improve bio-stratigraphic sequence which was established by predecessors in southern of Tethyan Himalayan Zone.In this study, the Qiangdong profile is a new profile which we measured in the Gamba region. Qiangdong profile, dongshan profile, zongshan profile, and Gongzha profile which is in Tingri region, are in the same sedimentary basin. Cretaceous strata in these two regions are similar in terms of lithologic. Therefore, i use the previous program to divide Cretaceous strata of Qiangdong profile. Qiangdong profile can divide into Gucuo, Dongshan, Chaqiela, Lengqingre, and formations.Foraminifera in Qiangdong profile were studied in detail, combined with previous research data, we determine 11 fossil zones, at the Early Cretaceous strata in southern of Tethyan Himalayan Zone. They are as follow: Hedbergella sigali, Globigerinelloides blowi, Schakoina cabri, Globigerinelloides algeriana,Hedbergella gorbachikae, Ticinella bejaouensis, Ticinella primula, Biticinella breggiensis, Rotalipora subticinensis, Rotalipora ticinensis, Rotalipora appenninica. We further improve the bio-stratigraphic sequence Early Cretaceous which is in the southern of Tethyan Himalayas Zone.