Abstract

Quaternary sediments of this inner trench slope are chiefly foraminiferal-pteropod-nanno oozes that have been reworked and/or emplaced by gravity currents. These oozes are mixed with volcanogenic sediments and minor amounts of material derived from the insular shelf. Reworking occurs on topographic highs where fines are winnowed out and mass wasting and gravity currents are initiated; these processes utimately result in the leveling of irregular floors of deeper, intervening slope basins. Petrographic analyses of graded intervals from the basin floors and slopes reveal the sands to be mixtures of plankic foraminifers (35%), pteropods (10%), and fresh, angular volcanic detritus (10-90%). On the east flank of the Barbados Ridge, graded sands of insular-shelf origin are locally important; these sands consist of molluscan, algal, and barnacle fragments (0-25%), quartz (0-30%), and minor metaquartz, K-feldspar, and gneissic fragments. The prescence of these terrigenous constituents suggests reworking of sediment from Tertiary land or subsea outcrops; additional evidence in favor of reworking is the occurrence of recrystallized radiolarians (Oceanic Group) and biomicrite gravels. Volcanogenic sediments are areally widespread and dispersed throughout the upper 6 m of the cores. We believe these sediments have experienced reworking and resedimentation by bottom currents, with the initial deposition related to volcanic activity on nearby St. Vincent.--Modified journal abstract.

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