中国科学院南京地质古生物研究所机构知识库

Part of the lowermost deposits of the Triassic to Early-mid Jurassic (up to Bajocian) sedimentary succession spread across the Rajasthan shelf on the western part of the Indian craton is found in the Jaisalmer Basin east of Jaisalmer with the best exposed sections along the Jodhpur-Jaisalmer Highway. Based on lithostratigraphic characteristics, the succession is divided into four: Odania and Thaiat members, Lathi Formation; and Hamira and Joyan members, Jaisalmer Formation. Six facies are defined from microfacies, sedimentary structures, biotic components and depositional environments: (1) ferruginous, pebbly, cross-bedded sandstone-high-energy, fluvial; (2) cross-bedded, poorly sorted, fossil wood-bearing sandstone-high-energy, terrestrial, with high influx of sediment and warm and humid climate; (3) cross-bedded to rarely bioturbated, alternating silt to fine-grained sandstone-fluctuating sedimentation rates and energy-nearshore, mesohaline embayment to lagoonal; (4) partly bioturbated, storm-dominated, mixed siliciclastic-carbonate facies-fully marine; (5) low angle cross-laminated, silt to fine-grained sandstone-nearshore shallow water, above fair weather wave base; and (6) thick rudstones with mega-ripples and reworked coral heads-storm deposits representing the peak of first major marine transgression across the basin.