Neogene oceanographic variations recorded in manganese nodules from the Somali Basin

Author(s): Banakar, V. K.; Nair, R. R.; Tarkian, M.; Haake, B.
Author Affiliation(s): Primary:
National Institute of Oceanography, Geological Oceanography Division, Dona Paula, Goa, India
Other:
Universität Hamburg, Hamburg 13, Federal Republic of Germany
Volume Title: Marine Geology
Source: Marine Geology, 110(3-4), p.393-402. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0025-3227 CODEN: MAGEA6
Note: In English. 38 refs.; illus. incl. 1 table, sketch map
Summary: A detailed study of a nodule from the Somali Basin dated by 230Thexcess was correlated with the paleoceanographic events recorded in Site 236 (Leg 24) Deep Sea Drilling Project (DSDP) cores. Tentative indications are that the phase of nodule accretion starting with the development of pillar structure at a depth of 20mm in the nodule around 13 Ma coincides with increased Antarctic Bottom Water (AABW) flow and an elevated calciumcarbonate compensation depth (CCD). The Late Miocene lowering of the CCD is represented by the mottled zones between 8 and 18mm in the nodule is characterised by an abundant silicate component (>20%) of aeolian origin. The Miocene/Pliocene boundary (5 Ma) occurs at a depth of about 8mm and is represented by the development of pillar structure and a minimum of aeolian dust (10.3%). The increased biological productivity of the Somali surface water since the Middle Miocene is demonstrated by the increasing Corg content of the nodule (from 0.11 to 0.19%) towards its surface.
Year of Publication: 1993
Research Program: DSDP Deep Sea Drilling Project
Key Words: 07 Marine Geology and Oceanography; 12 Stratigraphy, Historical Geology and Paleoecology; Absolute age; Antarctic Ocean; Antarctic bottom water; Carbonate compensation depth; Cenozoic; Indian Ocean; Lower Pliocene; Manganese composition; Miocene; Neogene; Nodules; Paleo-oceanography; Paleocirculation; Pliocene; Somali Basin; Stratigraphic boundary; Tertiary; Th/Th; Upper Miocene; X-ray diffraction data
Coordinates: S060000 S060000 E0520000 E0520000
Record ID: 1993013650
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands