Barremian and Albian Foraminifera, Site 549, Leg 80

Abstract

The Early Cretaceous series of Site 549 have been analyzed from both an ecological and a chronostratigraphical viewpoint. Lithology and microfaunal assemblages allow the division of these deposits into two parts. The lower part extends from the lower Barremian to the basal upper Barremian and possibly down into the upper Hauterivian. Three foraminiferal associations suggest an orderly evolution from a low-energy, littoral environment, in which continental influences dominated, to progressively more open marine conditions. A dolosparite bed (which has not yet been dated) separates these synrift deposits from lower to basal middle Albian postrift sediments that developed in a pelagic bathyal environment on the middle to nearby lower continental slope.

Aptian-Albian Foraminifers from Site 766, Cuvier Abyssal Plain, and Comparison with Coeval Faunas from the Australian Region

“…The species classed as Serovαinα and included in the Bagginidae are similar to mid-Cretaceous types referred elsewhere to Vαlvulineriα or Gyroidinoides (e.g., Ludbrook, 1966;Dailey, 1973;Scheibnerová, , 1978aScheibnerová, , 1978bSliter, 1977Sliter, , 1986Gradstein, 1978;Basov et al, 1979;Dupeuble, 1979;Basov and Krasheninnikov, 1983;Moullade, 1984;Magniez and Sigal, 1985). However, the species lack an open umbilicus and well-developed umbilical flaps, features typical of the optically radial Vαlvulineriα and the optically granular Gyroidinoides.…”