Microfauna and age of the Sangcha Malla Formation of Garhwal Tethys Himalaya, India

摘要

Biostratigraphic investigations of the Sangcha Malla Formation in the type area of the Garhwal Tethys Himalaya were carried out during an expedition. Systematic investigations of samples from this unit led to the recovery of several well-p reserved species of Archaeoglobigerina, Rosita, Globotruncana, Globotruncanita, Heterohelix and Pseudotextularia. The faunal assemblage is indicative of deposition under a deep marine condition. The foraminiferal taxa are recorded from the upper part of the Sangelia Malla Formation, which is the youngest marine litho-unit deposited in the Garhwal Tethys Himalaya. Stratigraphic distribution of the taxa indicates that this part of the Sangcha Malla Formation was deposited during the Campanian times. The fauna recovered herein from the Garhwal Tethys Himalaya shows a close affinity with that of the Zanskar region of Ladakh Himalaya and the Spiti region of Himachal Pradesh, suggesting thereby that during the Late Cretaceous times there were marine connections in these regions and the Upper Cretaceous sediments were deposited under similar (deep marine) palaeoenvironment.