Fossil diatoms and their significance

Abstract

A brief introduction to diatoms, an important group of siliceous organisms, is presented. This includes the history of diatom study, their classification and morphology, cell structure, ecology, nutrition and reproduction, palaeogeography and evolutionary history. Association of diatoms with volcanism and silica dissolution and overgrowth of fossil diatoms are also provided. The significance of fossil diatoms in palaeoecology and biostratigraphy including palaeoceanography is highlighted. Fossil diatoms known from India and a few DSDP sites of the Indian Ocean are listed along with their geological horizon. In India, reports of marine and freshwater diatoms were made from the Miocene rocks of Nancowry Island (Ehrenberg, 1851) and from the Karewa Formation of Kashmir (Lundquist, 1936), respectively.