| PALEOCEANOGRAPHY |
Eastern Equatorial Pacific Deglacial Atmospheric Dust Flux Data
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McGee, D., F. Marcantonio, and J. Lynch-Stieglitz. 2007. Deglacial changes in dust flux in the eastern equatorial Pacific.
Earth and Planetary Science Letters, 257(1-2), 215-230.
| Data Coverage |
North: 7.2 * South: -2.98 |
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West: -110.57 * East: -109.75 |
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Altitude: -3860 m |
Start Year: 14C yr BP
* End Year: 14C yr BP
Data: Please Cite Data Contributors!
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Summary: Atmospheric dust levels may play important roles in feedbacks linking continental source areas, tropical convection, marine
productivity, and global climate. These feedbacks appear to be particularly significant in the tropical Pacific, where variations
in local convection and productivity have been demonstrated to have impacts on climate at higher latitudes. Modeling of past
dust levels and related feedbacks has been limited, however, by a paucity of observational data. In this study we present
a temporal and spatial survey of dust fluxes to the eastern equatorial Pacific over the past 30 kyr. Glacial and Holocene
fluxes of 232Th, a proxy for continental material, were calculated by normalization to 230Th from a north¿south transect of
cores along 110°W between 3°S and 7°N (ODP sites 848¿853). Fluxes were 30¿100% higher during the last glacial, suggesting
increased dustiness in both hemispheres during the glacial period. In both time periods, dust fluxes decrease towards the
south, reflecting scavenging of Northern Hemisphere dust by precipitation at the ITCZ. The Holocene meridional dust flux gradient
between 7°N and 3°S is characterized by a steep drop in dust levels at the southern edge of the modern range of the ITCZ,
while the gradient is shallower and more nearly linear during the last glacial. This change may indicate that the glacial
ITCZ in this region was a less effective barrier to inter-hemispheric dust transport, most likely due to a decrease in convective
intensity and precipitation during the last glacial; alternatively, the change in gradient may be explained by increased variability
in the location of the glacial ITCZ. Our data do not appear to require a mean southerly displacement of the glacial ITCZ,
as suggested by the results of other studies.
More Info on Paleoceanography Data |
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Parameters: delta C13 PDB (Globigerinoides sacculifer); Thorium-232 (ng/g); delta O18 PDB (Globigerinoides sacculifer); Thorium-230 (ng/g); Uranium-238 (ng/g)
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Complete XML Record: noaa-ocean-5592
(Last Revised: 2010-03-11 )
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