Upper Cenomanian Foraminifers from the Southern Part of the San Juan Basin, NewMexico (Chapter N)

摘要

Foraminifers recovered from six outcrops of the Whitewater Arroyo Tongue and fromone outcrop of the basal part of the lower member of the Mancos Shale show that the Whitewater Arroyo represents a shallower, nearshore, better oxygenated bottom environment than does the lower member. The greatest abundance and diversity of foraminifers in the Whitewater Arroyo assemblage at the Laguna section indicate a northerly flow of southern ocean waters and an increase in vertical circulation of the sea that produced an oxygenated sea floor. In contrast, the dominance of planktonic foraminifers in the lower member of the Mancos at Laguna indicates a deeper water, open-marine environment and oxygen-reduced sea floor.