Site 646 ( ODP).

S. P. Srivastava, Michael Allan Arthur

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

More than 100 m of double APC cores provides a nearly complete, high-resolution record from 1.2 Ma to present. Fluctuations in carbonate content (0%-40%), vague color variations, magnetic-susceptibility changes, microfossil abundance and diversity, and dropstone abundances record continuous glacial-interglacial cycles. A continuous record through isotope stage 21 is probably contained in APC cores. The onset of major ice rafting at about 2.5 Ma (236 mbsf) coincides with a major change in seismic character. A significant biotic change occurred at the early Pliocene/late Pliocene boundary (3.4 Ma; 314 mbsf). Biosiliceous material is common to abundant above, whereas calcareous nannofossils and planktonic foraminifers are more abundant below. This event probably represents significant cooling of surface water masses over the site accompanied by higher productivity of siliceous plankton. The changes in surface waters also closely correspond to a period of apparent intensification of deep circulation, beginning at about 4.0 Ma, as suggested by erosional modification of the drift sequence and construction of a pronounced ridge observed in the regional seismic lines. A generally warm early Pliocene is indicated by relatively high and constant carbonate contents and abundant calcareous nannofossils and dinocysts.-from Author

Original languageEnglish (US)
Pages (from-to)419-674
Number of pages256
JournalUnknown Journal
StatePublished - Jan 1 1987

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Ocean Drilling Program
Pliocene
nanofossil
ice rafting
surface water
carbonate
glacial-interglacial cycle
planktonic foraminifera
microfossil
magnetic susceptibility
water mass
plankton
isotope
cooling
productivity

All Science Journal Classification (ASJC) codes

  • Environmental Science(all)
  • Earth and Planetary Sciences(all)

Cite this

Srivastava, S. P., & Arthur, M. A. (1987). Site 646 ( ODP). Unknown Journal, 419-674.
Srivastava, S. P. ; Arthur, Michael Allan. / Site 646 ( ODP). In: Unknown Journal. 1987 ; pp. 419-674.
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Srivastava, SP & Arthur, MA 1987, 'Site 646 ( ODP).', Unknown Journal, pp. 419-674.

Site 646 ( ODP). / Srivastava, S. P.; Arthur, Michael Allan.

In: Unknown Journal, 01.01.1987, p. 419-674.

Research output: Contribution to journalArticle

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Srivastava SP, Arthur MA. Site 646 ( ODP). Unknown Journal. 1987 Jan 1;419-674.