Provenance of eolian dust from Oligocene-Miocene transition in the eastern equatorial Pacific (IODP Exp. 320 Site U1333)
Abstract
We measured the chemical and mineralogical components of eolian particles at IODP Exp. 320 Site U1333B (10°30.996‧N, 138°25.159‧W; 4853 m water depth) in the eastern equatorial Pacific in order to identify the their provenance. Based on the shipboard biostratigraphic and paleomagnetic data, age of the studied interval is estimated to be from Oligocene (25.4 Ma) to Miocene (19.3 Ma). 87Sr/86Sr ratios of eolian sediments are problematic to trace the provenance due to high Ba contents. ɛNd values (-6.08 to -8.6) are similar to those of typical eolian particles delivered from the Southern Hemisphere. REE components of our samples are similar to those of eolian dusts from Australia and South America, but it is difficult to distinguish the sources between Australia and South America. Minerals of detrital particles consist mainly of quartz, feldspar and illite with minor of chlorite, kaolinite and smectite, corresponding to those of loess. Particularly low smectite/(smectite+illite) ratios (less than 0.4) reflect illite - enriched eolian particles from Australia. Considering the paleolocation of ITCZ (intertropical convergence zone), our results suggest that eolian dust at Site U1333 in the eastern equatorial Pacific had been transported from Australia under the influence of westerly winds during 19.3 - 25.4 Ma.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFMPP13A2064L
- Keywords:
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- 4924 PALEOCEANOGRAPHY / Geochemical tracers