Local and regional geochemical signatures of surface sediments from the Cariaco Basin and Orinoco Delta, Venezuela

N. C. Martinez, R. W. Murray, R. C. Thunell, Larry C Peterson, F. Muller-Karger, L. Lorenzoni, Y. Astor, R. Varela

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

We have analyzed the chemical compositions of 87 samples from the Cariaco Basin and 20 samples from the Orinoco Delta, Venezuela, in order to better characterize the fluvial sources of material to the Cariaco Basin. We observe distinctive regional patterns in composition; shelf sediments found near the Tuy River, Manzanares River, the Araya-Margarita region, and in the northern portion of the Unare platform record reproducible compositional differences. However, linear mixing models using only the composition from these rivers do not satisfy the variability observed in modern sediment trap samples collected from the basin. Average trap values are best approximated by mixing upper crust (30%-50%) with local river sources (50%-70% of either the Tuy, Unare, or Neverí Rivers) and eolian dust (<2%). The chemical data suggest a glacial-interglacial switching of sources, with the Tuy-Tacarigua, Unare, and Neverí being more important during glacials, and the larger Tuy and Manzanares being more important during interglacials. The K/Al in shelf sediments (0.14-0.27) spans the range of previously documented glacial to interglacial values (0.16-0.26), and the high Ti/Al found during glacials (~0.052) can perhaps be supplied by some of the local rivers (Ti/Al ~0.049-0.106) and not exclusively by Saharan dust. The data and statistical models do not offer support for the presence of any significant Orinoco source.

Original languageEnglish (US)
Pages (from-to)159-162
Number of pages4
JournalGeology
Volume38
Issue number2
DOIs
StatePublished - Feb 2010

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basin
river
sediment
shelf sediment
interglacial
eolian deposit
regional pattern
sediment trap
upper crust
chemical composition
dust

ASJC Scopus subject areas

  • Geology

Cite this

Martinez, N. C., Murray, R. W., Thunell, R. C., Peterson, L. C., Muller-Karger, F., Lorenzoni, L., ... Varela, R. (2010). Local and regional geochemical signatures of surface sediments from the Cariaco Basin and Orinoco Delta, Venezuela. Geology, 38(2), 159-162. https://doi.org/10.1130/G30487.1

Local and regional geochemical signatures of surface sediments from the Cariaco Basin and Orinoco Delta, Venezuela. / Martinez, N. C.; Murray, R. W.; Thunell, R. C.; Peterson, Larry C; Muller-Karger, F.; Lorenzoni, L.; Astor, Y.; Varela, R.

In: Geology, Vol. 38, No. 2, 02.2010, p. 159-162.

Research output: Contribution to journalArticle

Martinez, NC, Murray, RW, Thunell, RC, Peterson, LC, Muller-Karger, F, Lorenzoni, L, Astor, Y & Varela, R 2010, 'Local and regional geochemical signatures of surface sediments from the Cariaco Basin and Orinoco Delta, Venezuela', Geology, vol. 38, no. 2, pp. 159-162. https://doi.org/10.1130/G30487.1
Martinez, N. C. ; Murray, R. W. ; Thunell, R. C. ; Peterson, Larry C ; Muller-Karger, F. ; Lorenzoni, L. ; Astor, Y. ; Varela, R. / Local and regional geochemical signatures of surface sediments from the Cariaco Basin and Orinoco Delta, Venezuela. In: Geology. 2010 ; Vol. 38, No. 2. pp. 159-162.
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