The bathyal benthic foraminiferal palaeoecology east of Trinidad is currently unknown. The area is oceanographically complex, comprising a pro-delta deep-sea fan building across a transpressional plate boundary. Outflow from the Orinoco River forms a high-productivity surface plume that abuts low-productivity water of the tropical western Atlantic Ocean across a laterally extensive but sharp front. The plume's areal extent differs between the rainy and dry seasons, which are governed by the position of the inter-tropical convergence zone (ITCZ). Upper Quaternary benthic foraminifera are examined in two ~ 4 m-long piston cores, taken near the eastern edge of the plume. CHIRP profiles show that core BGT086 (water depth 626 m) comprised in situ material throughout, while the lower part of core BGT096 (water depth 700 m) consisted of slumped material. Benthic foraminiferal assemblages in BGT086 were examined quantitatively, while those in BGT096 were examined qualitatively only for comparison. Core BGT086 shows a transition from a low-diversity, Cibicidoides pachyderma-dominated community with subdominant Cassidulina curvata to a later high-diversity, low-dominance Bulimina alazanensis–Osangularielloides rugosa–Epistominella exigua community. The former is indicative of low-productivity, and the latter of high-productivity, surface water. The restriction of E. exigua to the core's upper part may reflect a change from an aseasonal to a seasonal organic flux. The faunal change was detected by both SHE and cluster analyses and an assemblage turnover index (ATI). It may be related to either (a) expansion of the Orinoco plume due to northward migration of the ITCZ approximately 600 yr after the end of the Younger Dryas, (b) eastward progradation of the Orinoco Delta, which would in turn push the front of the Orinoco plume eastward, or (c) both. No other boundary detected was common to all three procedures. A boundary between 124 and 130 cm below the seafloor detected by SHE analysis might equate to the 8000–7500 yr BP meltwater pulse 1C. While some specialist species were restricted to the C. pachyderma or the B. alazanensis–O. rugosa–E. exigua communities, the percentage abundance of some others, concluded to be relative generalists (e.g., Bulimina aculeata and Sphaeroidina bulloides), varied little through the core. The undisturbed section of core BGT096 showed the same general faunal succession as core BGT086. The slumped material in this core was rich in Eponides regularis, which was rare elsewhere. This species shows that the allochthonous sediment was derived from the outer shelf and upper slope (100–400 m water depth) during Late Pleistocene time.
