Glacial and Interglacial Climate Variability in Guaymas Basin (Gulf of California)
Abstract
We tested for interaction between long and short climate cycles to reconstruct records of interannual to decadal variability. Marine varved sediments are one of the few archives with the necessary resolution. The latest Quaternary in sediment core MD02-2515 (65m, 7 to 38 kyr) from the Gulf of California is predominantly varved with few bioturbated intervals (e.g. the Younger Dryas). The material is therefore ideally suited to test for interaction between all scales of climate variability, from orbital scales (glacial/interglacial) via millennial (D/O cycles) to interannual oscillations (ENSO). The Guaymas Basin allows reconstruction not only of regional upwelling and precipitation but also of ocean circulation in the North Pacific (intermediate water) and equatorial Pacific (subsurface water). A varve age model has been compiled, supported by radiocarbon dates, correlation of ∂15Norg data with the GISP-record and backscatter electron imagery, allowing estimation of biogenic and lithogenic fluxes at annual to near annual resolution. During the last glacial the rates of opal, TOC and lithogenic material were 2-3 times higher than during the Holocene, indicating that total mass fluxes control the export production of carbon. Dysoxia in the basin is mainly controlled by regional productivity (as opposed to intermediate water circulation) as seen from a strong correlation between opal and ∂13C in benthic foraminifers. The distribution pattern of opal does not correlate with typical North Atlantic patterns (e.g. D/O cycles). Annual resolution records of opal content and ∂15N in laminated intervals from the last glacial, Bolling/Allerod, and Holocene all show ENSO-like variability but there is no consistent change in strength or frequency.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFMPP31B1326T
- Keywords:
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- 4901 PALEOCEANOGRAPHY / Abrupt/rapid climate change;
- 4922 PALEOCEANOGRAPHY / El Nino;
- 4924 PALEOCEANOGRAPHY / Geochemical tracers;
- 4926 PALEOCEANOGRAPHY / Glacial