Biostratigraphical dating conundrums in the Cambrian and earlier stratigraphy of the Indian subcontinent

Abstract

Dating rocks by using fossils remains one of the most important stratigraphic tools both for Phanerozoic sedimentary rocks and, increasingly, for older rocks too. Inevitably situations arise in which different types of data offer seemingly contradictory indications of age, of which several examples from Cambrian and earlier rocks of Indian subcontinent are discussed herein. These examples highlight the main kinds of biostratigraphical conundrums and their resolution, their role in moving stratigraphic geology forward, and also surprising ways in which they are misused. The growth of geological knowledge regionally and globally, along with the introduction of additional techniques for dating rock strata, means that the temporal range of the alternative explanations related to particular conundrums has tended to decline with time, although a controversy with alternatives over 1.0 Ga apart is currently active concerning Vindhyan geology. Although important in their own right, the solutions to this and other conundrums must integrate with other types of geological data if age determination is to be satisfactorily concluded and the wider geological and evolutionary implications of biostratigraphical dating are to be realised.