A DEEPER WATER BRACHIOPOD - CRINOID ASSOCIATION IN THE LATE OLIGOCENE OF ANTIGUA, WEST INDIES

Extant brachiopods and stalked crinoids flourish together in the deeper waters of the Caribbean Sea. Analogous brachiopod/crinoid associations have been reported from diverse paleoenvironments in the Neogene of the region. Studied examples include the Pleistocene of Jamaica (deeper-water forereef), and the Miocene of Jamaica (island slope chalks), Barbados (accretionary prism) and Carriacou (turbiditic siliciclastic shelf). Comparison with analogous modern environments indicates deposition in 150 + m water depth.

This association has now been extended back into the Late Oligocene. Weiss (1994, Caribbean Journal of Science, vol. 30, p. 22) noted that crinoids and brachiopods both occur in the Antigua Formation of Antigua; the latter occur high in the formation, implying deeper water in this retrograde succession. Cooper (Smithsonian Contributions to Paleobiology, no. 37) recorded Argyrotheca dubia (Cooper) and Tichosina foresti Cooper from the Antigua Formation. At Half Moon Bay in southeast Antigua, high in the Antigua Formation, we have found columnals of isocrinid crinoids (cf. Isocrinus sp.) associated with rare brachiopods (Terebratulina sp.). These taxa provide independent evidence for the deeper water aspect of this part of the Antigua Formation, in beds which also yield large, thin-walled fossil sponges.

We gratefully acknowledge the support provided by National Geographic Society grant #GEFNE55-12.