Letters to Nature
Nature 213, 1219-1220 (25 March 1967) | doi:10.1038/2131219a0; Received 28 November 1966
1. Department of Geology, University
of Kerala , Trivandrum , India
Abstract
ALTHOUGH microscopic pyrite
from marine and non-marine argillaceous sediments of most geological ages has
been extensively studied, its mode of origin has not been clearly understood.
Berner1 and Kalliokoski2 attributed the origin to the reaction of
hydrogen sulphide formed by sulphite reduction, with iron-bearing minerals in
sediments; but these minerals were not discovered. I have recorded framboidal
and other types of diagenetic pyrite in the thin bed of marine, fossiliferous,
Quilon limestone3 of Burdigalian age4. Recent examination of the heavy
minerals from limestone samples at Padappakara the type area has brought
forward some new evidence, which clearly establishes that the fine-grained
pyrite was produced by an alteration of detrital, iron-bearing mica, optically
identified as biotite.
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