Browsing by Author "Narendra Kumar Swami"

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Evolution of Dras arc in the backdrop of the India-Eurasia collision: evidence from the discovery of ammonite from Indus Suture Zone, Ladakh Himalaya, India
(Springer Nature, 2025) Prasenjit Barman; Shruti Ranjan Mishra; Narendra Kumar Swami; Arindam Roy; Alok C. Pande
We report Late Jurassic ammonite Aulacosphinctes sp. from the volcano-sedimentary sequences of the Dras Formation in the Ladakh Himalaya, India, for the first time. The Cretaceous Dras Formation, characterized by its thick layers of volcano-sedimentary deposits, preserves mainly foraminifera and radiolarians. In this paper, we try to bring about a perception change regarding the age of the Dras Formation. The discovery of Aulacosphinctes sp. from the Dras Formation—undoubtedly speaks for the Tithonian age. The interspersed nature of the volcano-sedimentary sequences of Dras Formation with the basalt of Dras volcanics further indicates episodic volcanism along the southern margin of Neotethyan ocean between India and Eurasia. This discovery prompts a reassessment of the palaeogeographic position and evolution of the Dras arc during the Late Jurassic. © Indian National Science Academy 2025.
First report of Acanthochaetetes (Porifera: Demospongiae) from the Cretaceous Khalsi Formation, Ladakh Himalaya, India
(Cambridge University Press, 2021) Prasenjit Barman; Francisco Sánchez-Beristain; Shruti Ranjan Mishra; Mohd Ibrahim; Narendra Kumar Swami; Mukesh Bamniya; Shailendra Singh
The Cretaceous chaetetid sponge Acanthochaetetes huauclillensis Sánchez-Beristain and García-Barrera is reported for the first time from the Aptian-Cenomanian Khalsi Formation, Ladakh Himalaya, India. Its low-To high-domical growth form could suggest an adaptation to either an environment with constant sedimentation rates, or to an irregular substrate. However, these growth forms also may indicate an absence of important environmental/sedimentological changes during the lifespan of the sponges. In addition, the growth form of this species suggests a calm, non-Turbulent, reef-like microenvironment. Along with the other faunal assemblages, such as the rudists, corals, and the gastropod Nerinea, A. huauclillensis indicates a tropical to subtropical shallow marine carbonate platform setting. This new finding extends its stratigraphic range from the upper Hauterivian to the Aptian-Cenomanian interval in the eastern Tethyan realm. Copyright © The Author(s), 2021. Published by Cambridge University Press on behalf of The Paleontological Society.