Environmental distribution of scleractinian corals in the Jurassic of Kachchh, western India

Scleractinian corals commonly occur at specific horizons and localities, in carbonate and in siliciclastic sediments, throughout the Jurassic (Bajocia n to Oxfordian) of Kachchh as meadows, biostromes, boulder beds and as scat tered specimens. In many cases they are part of the autochthonous benthic f auna and in others they suffered short intra-basinal transport. Cerioid for ms of low diversity (Amphiastraea, Isastraea, etc.) abound in high-energy s iliciclastic sediments. High diversity coral faunas, which include thamnast erioid (Microsolena, Dimorpharaea and Kobya) and solitary (Trocharaea and T rochoplegma) taxa with fenestrate septa and plocoid forms (Stylina), domina te in carbonate sediments deposited in low energy, deeper-water environment s. The solitary Montlivaltia exhibits a great physiological tolerance of en vironmental stress. In all, eight coral assemblages have been recognized wi thin the ?Early Bajocian to Late Callovian sediments of the Kachchh basin. The distribution of scleractinian coral assemblages has been governed mainl y by the rate of sedimentation and particularly by the influx of coarse sil iciclastic material. As a consequence the distribution pattern reflects ons hore-offshore gradients and the general deepening of the Kachchh basin towa rds the Oxfordian.