THE PALAEOBIOLOGICAL REMAINS OF THE OWK SHALE, KURNOOL BASIN: A DISCUSSION ON THE AGE OF THE BASIN

摘要

Proterozoic microfossils emerge as a powerful tool of Precambrian biostratigraphy in determining age of encompassing rocks and correlation of the distant sedimentary successions. In the absence of any direct radiometric dating, the age of Kurnool Group is poorly constrained. In the Owk Shale assemblage, four species of Obruchevella, viz. O. delicata, O. minor, O. parva and O. valdaica were recorded as an organic walled microfossil. In addition, sphaeromorphic acritrach Leiosphaeridia and probable Vaucherian algae Jacutianema also make their appearance in the present assemblage. Documented species of Obruchevella are reported mostly from close to the Precambrian-Cambrian boundary successions thereby implying the younger age of the Kurnool basin. The present study discounts the possibility of recently assigned Mesoproterozoic age of the basin and supports the Neoproterozoic age for the Kurnool basin.