CRETACEOUS BRACKISH WATER CONCHOSTRACA FROM POTIGUAR BASIN, NORTHEASTERN BRAZIL

Resumen

Although conchostracofaunas are common in ephemeral freshwater ponds of hot, alkaline waters, they can occur even in brackish waters of nearshore lagoons and tidally-influenced zones. This is presumed to be the life environments of Late Cretaceous conchostracans in the Potiguar Basin. The Estheriina astartoides Jones fauna occurs in the lower section of the Jandaíra Formation. This rock unit ranges from Lower Turonian to Middle Campanian age and consists mainly of carbonate marine facies. The monospecific conchostracofauna was found in exposures of marls within the Jandaíra Formation (Dix-Sept Rosado Gypsum quarry, Rio Grande do Norte State). The paleoenvironmental context, taphonomic features and associated palynofacies suggest that Estheriina astartoides could withstand saline conditions, such as those recorded in the evaporitic supratidal enviranment of the Dix-Sept Rosado Gypsum quarry.

KEY WORDS. Conchostraca. Halotolerant. Palynoforaminifera. Late Cretaceous. Potiguar Basin.