Albian roveacrinids from the southern Congo Basin off Angola

Microfacies study of the Albian of the Pinda Formation in Well BAGRE 1 (Blo ck 2, Angola offshore) revealed several echinoderm-rich layers. Contrary to other fossil remains, the echinoderms have not been dolomitized and are th erefore potentially useful for stratigraphic purposes. The remains are comp ared to those found in the Sergipe Basin in Brasil and assigned to the Rove acrinidae, a group of stemless microcrinoids. The following species were id entified: Roveacrinus communis Douglas, 1908; Roveacrinus cf. communis Doug las, 1908; Roveacrinus aff. geinitzi Schneider, 1989; Roveacrinus pyramidal is Peck, 1943; Roveacrinus sp. The assemblage provides a relatively precise stratigraphic framework in comparison to previous age determinations. Alth ough some species have a wide stratigraphic range, the occurrence of the ge nus Roveacrinus and the species R. pyramidalis Peck, 1943 suggests a late A lbian age, which makes the Angolan assemblages among the oldest known. The main area of distribution of roveacrinids is the Tethyan realm, so these ex tremely southern occurrences in Angola appear to support the theory of a se away through the Gulf of Guinea in the late Albian. (C) 2001 Published by E lsevier Science Ltd.