Iraqi National Journal of Earth Sciences

Abstract

Monotypic shell beds of molluscan skeletal sand are contained in the non-marine, fluvial sequence of Injana Formation of Upper Miocene age-Kand Anticline, as yet undescribed previously. These carbonate beds are characterised only by abundant pelecypod, oyster with scarce and opportunists gastropods and smooth-shelled ostracods. This faunal assemblage is consignable with non-marine low salinity euryhaline fresh, brackish water. The sudden change in their composition and distribution has been influence by salinity variation. The exclusion of normal marine-stenohaline fauna point to their deposition in non-marine setting including interchannel lake initiated on distal floodplain and/or river dominated bay esturay, or fan delta lake-lagoon.