Biostratigraphy, mineralogy and paleoenvironmental analysis of the Miocene Gaj Formation from the Dwarka Basin, western India

Article Type

Research Article

Publication Title

Geological Magazine

Abstract

The Dwarka Basin in the Kathiawar Peninsula, western margin of the Indian subcontinent, offers crucial insights into marine sedimentation processes and faunal evolution during the Miocene epoch. This research employs a combination of biostratigraphy, microfacies analysis and geochemical data to examine the Gaj Formation, a major stratigraphic unit of the Dwarka Basin, with the aim of reconstructing the paleoclimatic and depositional conditions. Foraminiferal biostratigraphy suggests that the Gaj Formation ranges from the Aquitanian to the Langhian stage, with the intermediate Burdigalian stage comprising most of the succession. Microfacies analysis reveals that the formation was primarily deposited in shelf environments, influenced by regional tectonic and climatic factors. The fossil assemblages and morphological adaptations observed in foraminiferal shells provide clear evidence of the Middle Miocene Climatic Optimum (MMCO). Climate-driven global warming during this climatic phase caused morphological evolution (e.g., dwarfism) and decreased faunal diversity in response to environmental stress. This study also aims to reconcile discrepancies in stratigraphic classification in the basin through lithostratigraphic data and high-resolution faunal analyses. Results highlight the dynamic nature of marine depositional environments as impacted by global sea-level changes, regional tectonics and climatic fluctuations. The study foregrounds the importance of multi-proxy analyses in reconstructing complex depositional histories and Miocene climatic transitions and their effects on regional marine ecosystems.

DOI

10.1017/S0016756825100356

Publication Date

11-25-2025

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