Age-diagnostic dinoflagellate cysts from the lignite-bearing sediments of the Vastan lignite mine, Surat district, Gujarat, western India

Abstract

The lignite-bearing succession (corresponding to Cambay Shale) of the Vastan lignite mine, Gujarat has been extensively studied in the past few years for its rich vertebrate fauna. However, no age-diagnostic fossils with chronological significance are reported. In the present study, several dinoflagellate cysts from different levels in the lignite-bearing sediments (Succession A) of the Vastan lignite mine arc identified which are age diagnostic. Occurrence of Muratodinium Jimbriatum, Heteraulacacysta granulata and Operculodinium severind in the lower part indicates an age not older than late Thanetian/Sparnacian (-55 Ma). Presence of rich Kenleyia complex including LAD of Kenleyiu lophophora in the upper half of the succession indicates basal Ypresian age (-54 Ma). Occurrence of Lanternosphaeridium lanosum in the upper part suggests an age not younger than middle Ypresian (-52 Ma) for the topmost part of the Vastan succession. Thus, in terms of traditional European stages, the succession ranges from Ilerdian to basal Cuisian (-55-52 Ma) corresponding to upper SBZ7 to basal SBZI 0 larger foraminifera zones. Age of the mammal fossil horizons in the lower part of the succession appears to be Sparnacian (-55-54 Ma).