THE IMPORTANCE OF INDEX FOSSILS IN THE DETERMINATION OF THE GEOLOGIC AGE OF STRATA: A CASE OF BAND-E-AMIR OF BAMIYAN PROVINCE, CENTRAL AFGHANISTAN
Determining the geologic age of sedimentary rock layers has been one of the major and basic parts of geological sciences. Carrying out any geological projects from the prospection to exploitation without knowing the geologic age may be considered incomplete. This work aims to define the geological age of the sedimentary layers within the Band-e-Amir region of Bamiyan province over central Afghanistan using the index fossils. In this study, more than 12 fossil specimens were collected and identified over the sedimentary layers of the study area. Different genus and species of Bivalves, Brachiopods, Echinodermata, Corals, and Gastropods were recorded and presented from Band-e-Amir sedimentary layers. Among them, three index fossils determined the relative age of strata, namely: Terebratulina Chrysalis, Cataceramus Balticus, and Carneithyris Subcardinalis. According to the guide fossils and using the assembly fossils aging method, the second sedimentary layer is aged Maastrichtian, and the third layer is aged Campanian. The specifications and living features of the recorded fossils derive a warm oceanic environment in the Late Cretaceous.