M. Mohanti et S. Das, MICROBIAL SIGNATURES IN LACUSTRINE AND FLUVIAL CARBONATES - GONDWANA (PERMIAN) AND HOLOCENE EXAMPLES, INDIA, Facies, 36, 1997, pp. 234-238
Laminated microbial carbonates occur in the siliciclastic sequence of
the Talchir Formation (Lower Permian) of Gondwana basin, Orissa State,
India. The microbial mat largely thrived in a lake-deltaic setting in
near-shore, very shallow part of the lake and in peri-lacustrine swam
ps and marginal fluvial regime, Petrographic and stable isotope studie
s suggest periodic saline (marine?) groundwater input and evaporation
under semi-arid condition. A nearby marine setting seems probable. Lat
e Holocene microbial travertines-tufas (dominantly of stromatolitic cr
usts) occur in parts of Orissa State and appear to be constructed of p
ossible Phormidium, Scytonema, Schizothrix and diatoms. Stable isotope
s suggest dominantly an inorganic precipitation from freshwater in flu
vial regime of streams and small river.