Benthic foraminifera of mass-transport deposits (MTDs) in the Amazon Fan

Author(s): Vilela, Claudia Gutterres
Author Affiliation(s): Primary:
Universidade Federal do Rio de Janeiro, Departamento de Geologia, Rio de Janeiro, Brazil
Volume Title: Proceedings of the LOICZ symposium (Land-ocean interactions in the coastal zone) during the XXXIX Brazilian geological congress
Volume Author(s): Suguio, Kenitiro; Dominguez, Jose Maria Landim; Lessa, Guilherme Camargo; Souza, Celia Regina de Gouveia; Tomazelli, Luiz Jose; Villwock, Jorge Alberto
Source: Anais da Academia Brasileira de Ciencias, 70(2), p.173-185; XXXIX Brazilian geological congress, Salvador, Brazil, Sept. 1-6, 1996, Kenitiro Suguio, Jose Maria Landim Dominguez, Guilherme Camargo Lessa, Celia Regina de Gouveia Souza, Luiz Jose Tomazelli and Jorge Alberto Villwock. Publisher: Academia Brasileira de Ciencias, Rio de Janeiro, Brazil. ISSN: 0001-3765 CODEN: AABCAD
Note: In English. 19 refs.; illus., incl. sects., 2 plates, 2 tables, sketch map
Summary: Samples from the Amazon Fan deep mass-transport deposits (MTDs) were analyzed to investigate the benthic foraminiferal assemblages. The data were compared with a detailed study of recent benthic foraminiferal contents of the Amazon shelf and slope, and with benthic foraminiferal contents of Holocene and Last Glacial Maximum (LGM) hemipelagic sediments collected in the Amazon Fan. The analyzed sediments were recovered during the Ocean Drilling Program, Leg 155. Low values for abundance and diversity were encountered in the benthic foraminiferal contents. Microfaunal differences between holes are mainly observed in rare and sparse species. Buliminids and uvigerinids, which are common on the Amazon continental slope, were found in the MTDs. Globocassidulina subglobosa and Cassidulina laevigata are common on the upper slope and were also found in the MTDs. Species like Quinqueloculina lamarckiana, Quinqueloculina cf. stalkeri, and Pseudononion atlanticum, which are present on the Amazon shelf, were also present in the MTDs. The different assemblages found in both abyssal and MTDs demonstrate their distinct origin. Dominance of buliminids suggests that the MTDs originated mostly from bathyal environments. Sparse occurrences of characteristic species indicate the continental shelf as another sediment source.
Year of Publication: 1998
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Amazon Fan; Assemblages; Atlantic Ocean; Benthic taxa; Cenozoic; Depositional environment; Equatorial Atlantic; Foraminifera; Holocene; Invertebrata; Last glacial maximum; Leg 155; Marine environment; Marine sedimentation; North Atlantic; Ocean Drilling Program; Pleistocene; Protista; Quaternary; Sedimentation; Shelf environment; Slope environment; Species diversity; Submarine fans; Transport
Coordinates: N040000 N070000 W0460000 W0490000
Record ID: 1999006428
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