Significant Dinoflagellate Cyst Biohorizons in the Upper Cretaceous- Palaeocene Succession of the Khasi Hills, Meghalaya

Abstract

The Upper Cretaceous Palaeocene rocks of the Khasi Hills, Meghalaya have yielded rich dinoflagellate cysts assemblages recovered from the Mahadeo Formation, the Langpar Formation, lower part of the Therisa Formation and lower part of the Sylhet Limestone Formation Occurrence of several globally recognized marker dinoflagellate cyst taxa having Well-Established First appearance Datum (FAD) and Last Appearance Datum (LAD), is noted in these assemblages. A succession of cosmopolitan dinoflagellate cyst biohorizons (based on comparisons with global records) are summarized highlighting their potential in precise age determination and demarcation of time boundaries within Late Campanian-Late Thanetian interval. The dinoflagellate cyst evidence demonstrates that the succession is not older than Late Campanian in age.