Cambrian biostratigraphy in the Tethyan sequences of the Spiti Valley, Himachal Himalaya, India
Parcha, S. K.
Newsletters on Stratigraphy Volume 37 Number 3 (1999), p. 177 - 190
published: Dec 16, 1999
ArtNo. ESP026003703004, Price: 29.00 €
The Spiti basin together with the Zanskar basin is the largest basin among the Himalayan Tethyan basins. Of all the known fossiliferous Cambrian rocks of Himalaya, the Cambrian sequences of the Spiti Himalaya are among the best exposed sections. The Cambrian rocks of the Spiti Valley are exposed in the Pin and Parahio Valleys and in the Kunzam La and Takche sections. The fossiliferous horizons of these areas are comparatively restricted geographically as compared to the Younger Palaeozoic sequences in Himalaya. The biostratigraphy of the Cambrian sequence of the Spiti Valley, based on trace fossils and on polymerid and agnostid trilobite assemblage, establishes Diplichnites-Rusophycus and Redlichia noetlingi Zones in Early Cambrian; Peronopsis, Pagetia-Oryctocephalus, Anomocaraspis- Hundwarella and Ptychoparia Zones in the Middle Cambrian and Olenus Zone in the early Late Cambrian. In total seven assemblage zones have been identified in the Cambrian succession of the Spiti Valley. Faunal gaps occur in the lower part of Early Cambrian, early Middle Cambrian and in the upper part of Middle and Late Cambrian. The range of the individual taxa has been compared with those of related forms. The Cambrian fauna of the Himalaya when compared with the fauna of the other parts of the world reveals that the bulk of the fauna is of cosmopolitan nature.