DISTRIBUTION OF HOLOCENE BENTHIC FORAMINIFERA FROM THE TROPICAL SOUTHWEST PACIFIC-OCEAN

A suite of 62 surface and near surface samples has been examined for i ts benthic foraminiferal faunas, The cores sampled ranged from 110 to 8900 m water depth, and are distributed across the tropical southwest pacific Ocean, north and east of Australia, A total of 606 species wer e identified, Census data was obtained for each sample, and species fo und in statistically significant fractional abundances (88 in all) wer e analyzed using a new Q-mode clustering algorithm (Error Weighted Max imum Likelihood [EWML]), Both the fun data set, and an edited data set comprising 44 samples and 39 species, were analyzed. With the aid of these analyses, ten benthic foraminiferal assemblages were identified, Three manually constrained assemblages, each represented by a single sample, were recognized, namely tbe Bolivina dilatata-Siphouvigerina i nterrupda Assemblage, the Cymbaloporetta squammosa-Brizalina abbreviat a Assemblage, and the Brizalina beyrichi-Melonis barleeanum Assemblage , Five statistically constrained assemblages were recognized, each hav ing a water depth range coincident with the range for known wafer mass es of the region, The Astrononion echolsi-Cassidulina teretis Assembla ge and the Nuttallides bradyanus Assemblage were developed in samples from depths bathed by waters of the Deep Oxygen Minimum, the Epistomin ella exigua-Globocassidulina rarilocula Assemblage was developed in sa mples from depths bathed by Deep Water, a derivative of Antarctic Bott om Water, and both the Globocassidulina subglobosa-Pseudoparrella parc a Assemblage and the Nuttallides umboniferus Assemblage were developed in samples from depths bathed by Antarctic Bottom Water proper, From depths very near the calcite compensation depth (CCD), a Mixed Calcare ous/ Agglutinated Abyssal Assemblage was developed in a pair of sample s, whereas below the CCD, the tenth assemblage, the Abyssal Agglutinat ed Assemblage, was developed, with only a few corroded calcareous spec imens accompanying the agglutinated benthic faunas, These latter two a ssemblages were also manually constrained,