UNDAMAGED SEDIMENTED COCCOLITHOPHORIDS IN A DEEP ENVIRONMENT (CONTINENTAL-SLOPE OF THE GULF OF LIONS)

At different periods of the year, undisturbed sediment samples from th e continental slope of the Gulf of Lions were collected with a multipl e gravity corer. The overlying water (0-20 cm above the sediment) and the surface water masses were also collected. The following stations w ere sampled: R(4), an interfluve (a platform between two canyons), 760 m deep; R(5), at the junction of two canyon floors, 1540 m and R(6), at the top of the wall, 1280 m. At all stations, the top sediment laye r and the overlying water were enriched with coccoliths. During a late spring cruise (March 22-April 5, 1991) a thin microphyte-enriched lay er at the water-sediment interface of station R, contained encysted di atoms, dinophytes and coccolithophorids. Several of the coccolithophor id species were in good preservation, among which Emiliania: huxleyi w as dominant and showed a considerable range of morphological variation s in coccolith length and degree of calcification. The presence of tin tinnids that use coccoliths to build their loricae reflects the specie s composition in the water masses from which this biodeposit originate d. Homogeneous hydrological conditions favoured the accumulation of th is deep biodeposit.