Facies associations and chemostratigraphy of the Lower Cretaceous Kurnub Group and their boundaries, King Talal Dam section, northwestern Jordan

Abstract

Integrated petrographic and chemostratigraphic studies have enabled the identification of sequence boundaries, sequence stratigraphy, and their system tracts for the Lower Cretaceous strata of the Kurnub Group (Jordan); the latter is underlain by the Jurassic (Callovian) strata and overlain by the Cretaceous (Cenomanian). Based on physical characteristics (sharp vertical facies changes) and geochemical parameters (SiO2/Al2O3, K2O/Al2O3, TiO2/Al2O3, Sr/Ca millimoles per mole, Mn parts per million, and the minor elements), 4 sequence boundaries are identified, associated with 11 facies types (from alluvial plain to the intertidal environment) and 9 system tracts, thus enabling the identification of record Lower Cretaceous sea-level fluctuations. The identified sequences mirror the Arabian plate sequences and suggest a eustatic origin. The siliciclastic Kurnub Group was derived mainly from felsic granite–gneiss and metasedimentary rocks (Arabian shield) and was deposited in a passive continental margin setting under semiarid-to-humid climatic conditions.