A photomicrograph dataset of Cretaceous siliciclastic rocks from Xigaze Forearc basin, southern Tibet

Abstract

Developed along the south margin of the Lhasa terrane, the Cretaceous Xigaze forearc basin consists of mainly siliciclastic rocks interbedded with minor marls and limestone, recording the north subduction of the Neotethys to the Lhasa terrane. The Xigaze forearc basin includes the Chongdui, Sangzugang, Ngamring, Padana and Qubeiya formations, with overlying Quxia and Jialazi formations deposited during the initial India-Asia collision. The forearc basin has been well-studied during decades due to completed preservation and well-exposure. However, basic petrological data published is still limited, and petrological work has to be carried out repeatedly. Therefore, a total of 191 pieces of Cretaceous clastic rocks collected from the Chongdui, Ngamring and Padana formations were selected and taken photos by polarized light microscopes in Nanjing University, so as to better share and use these basic geological data. The selected rock samples include 5 shales, 2 siltstones, 158 sandstones, 11 conglomerates, 7 gravels, 7 siliceous rocks and 1 pyroclastic rock. In addition, the dataset also contains the detailed information of 10 stratigraphic sections where these rock samples are located. Besides providing materials for basic geological research, this dataset of Cretaceous rocks can also be applied to interdisciplinary cooperative research, like artificial intelligence recognition.