Browsing by Author "Indra Bir Singh"

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Faunal response to transgressive-regressive cycles: example from the Jurassic of western India
(1991) Franz T. Fürsich; Wolfgang Oschmann; Anand K. Jaitly; Indra Bir Singh
Upper Callovian to Oxfordian shelf sediments at Ler in the Kachchh Basin, western India, are interpreted in terms of transgressive-regressive cycles. The transgressive phases are represented by thin layers of reworked and bored concretions, sometimes in association with skeletal concentrations, the regressive phases are documented by much thicker units of largely fine-grained sediments. The benthic fauna of transgressive and regressive phases differes markedly and thus mirrors the sedimentary cycles: During transgressive phases non-sedimentation produced hard substrates colonized mainly by byssate, cemented, or pedicle-attached suspension-feeding epifaunal species, whilst sediment input during regressive phases lead to soft substrate conditions characterized by infaunal deposit- and suspension-feeders as well as by epifaunal opportunists. Whereas the composition of the "regressive fauna" remains fairly constant through time, that of successive "transgressive faunas" often differs drastically. This is possibly due to a greater environmental sensitivity of epifaunal taxa as compared to infaunal taxa. © 1991.
Implications of new data on Mesozoic rocks of Kachchh, western India
(1983) Jai Krishna; Indra Bir Singh; James D. Howard; Syed Abbas Jafar
A lack of detailed facies studies has resulted in a false impression of the Mesozoic depositional setting in Kachchh, western India (previously, Kachchh has been termed 'Kutch' or 'Cutch'). In addition, designation of part of this sequence as Gondawana implies, by tradition, a predominantly non-marine origin. Recently, we examined these Jurassic-Cretaceous units and found numerous wave-built sedimentary structures that have been previously overlooked or unreported, abundant marine trace fossils, and highly bioturbated and glauconite-rich beds. Thus, we now propose a marine origin for the entire Kachchh succession. This interpretation has important implications regarding similar sequences around the Indian plate margin. © 1983 Nature Publishing Group.