Cretaceous calcareous nannofossils from Tanot #1, Jaisalmer Basin, Rajasthan, Western India: morphotaxonomy and biostratigraphy

Abstract

The present paper deals with the record of rich and highly diversified calcareous nannofossil assemblage of Late Albian to Early Maastrichtian age from the subsurface sediments of Jaisalmer Basin, western India. The nannofossil assemblage include, 222 species belonging to 86 genera and 22 families including 6 nannolith families which are Braarudosphaeraceae, Ceratolithaceae, Lapideacassaceae, Microrhabdulaceae, Nannoconaceae, Polycyclolithaceae and one holococcolith family Calyptrosphaeraceae. An alpha–numeric zonal scheme has been proposed in the present study which will be useful for shallow shelf areas of low latitude. 17 Zones are assigned on the presence of last occurrence (LO) of zonal markers and 5 subzones of basal most zone (TA1) are demarcated on the basis of first occurrence (FO) of subzonal markers with due nomenclature procedures.