Facies characteristics and depositional environments of the Paleocene–Eocene strata of the Jaisalmer basin, western India

Abstract

The Paleocene-Eocene succession of the Jaisalmer area has hydrocarbon potential. This succession is dominantly represented by calcareous and argillaceous rocks with a subordinate proportion of arenites in the basal part. This succession is subjected for facies analysis using field characteristics coupled with petrography and we attempt to establish depositional environments based on facies analysis. A total of eight lithofacies are identified; those are cross-bedded sandstone, thinly bedded sandstone, laminated sandstone, yellow calcareous shale, chalky limestone, fossiliferous shale, fossiliferous limestone and nodular limestone. The upper Paleocene sandstones were deposited in shoreface to foreshore zones on barrier margins of a ramp/platform. The overlying lower Eocene to middle Eocene sequences containing limestone-shale alternation suggests their deposition in lagoons and tidal flats. The occurrence of ooids and peloids and diverse genera of larger foraminifera demonstrates that the deposition of carbonates took place in a tropical climatic condition. The facies associations suggest a complete 2nd order cycle of transgression-regression of the sea from shoreface to tidal flat in the Jaisalmer pericartonic basin.

Depositional environments and sources for the middle Eocene Fulra Limestone Formation, Kachchh Basin, western India: Evidences from facies analysis, mineralogy, and geochemistry

“…The Eocene epoch in the Indian Subcontinent and Arabian Peninsula is largely known for the massive development of carbonate build‐ups, large turnover of marine biota including larger foraminifers and, presence of coal, oil, and gas resources. In recent years, facies analysis approach was applied in India and abroad for both siliciclastic and carbonate sequences to reconstruct depositional set‐ups (e.g., Patra & Singh, ; Srivastava & Singh, ; Srivastava & Singh, ). Furthermore, the geochemistry is being utilized as an additional tool for interpreting depositional environments and the nature of the seawater precipitating the carbonates.…”

Palaeoenvironmental interpretation based on lithofacies derived from Keera Dome, Kachchh, western India

“…The intercalations of limestones with shales suggest sediments were deposited below the normal wave base in the transition zone (Solanki et al, 2016). The limestones containing the bioclasts (bivalves, brachiopods, Belemnites, and ammonites) were deposited on the platform margin (Patra and Singh, 2015). Thus, the FLF suggests the offshore-transition depositional environment.…”

The Rare Earth Element Distribution in Marine Carbonates as a Potential Proxy for Seawater pH on Early Earth

“…Hence, phase-specific sampling of marine carbonate cement may be a safer way to circumvent detrital influence. Here, Gd, Dy, and Er anomalies may increase the uncertainty of the pH estimation, but because most of the records still show seawater signatures and consistency, the measurements and pH estimates should still be a rough estimate for Eocene seawater (Patra & Singh, 2015Srivastava & Singh, 2019).…”