Warren D. Sharp

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During the last glacial period, large millennial-scale temperature oscillations--the 'Dansgaard/Oeschger' cycles--were the primary climate signal in Northern Hemisphere climate archives from the high latitudes to the tropics. But whether the influence of these abrupt climate changes extended to the tropical and subtropical Southern Hemisphere, where changes(More)
We present a high-resolution, 116,000-year carbon stable isotope record from a stalagmite from southern Brazil, which has been precisely dated using the U-series method. Evaluation of carbon and oxygen isotope ratios together with the speleothem growth history suggest that the carbon isotopic composition of the speleothem is primarily controlled by biogenic(More)
Trace element ratios in the Bt2 stalagmite from Botuverá cave, Southern Brazil, are explored as a proxy for changes in the local rainfall recharge during the last 116 ky. BP Mg/Ca and Sr/Ca ratios, measured with an electron microprobe, are significantly positively correlated with one another throughout the entire record, and vary in a way that is very(More)
The Hawaiian-Emperor bend has played a prominent yet controversial role in deciphering past Pacific plate motions and the tempo of plate motion change. New ages for volcanoes of the central and southern Emperor chain define large changes in volcanic migration rate with little associated change in the chain's trend, which suggests that the bend did not form(More)
In proto-historic Hawaii (1500-1795 A.D.), as in many other evolving polities, temples functioned as centers for control over production and the extraction of surplus food and goods. Thorium-230 dates (uncertainty +/- approximately 10 years) on branch coral dedicatory offerings from temples in the Kahikinui district (Maui) indicate that its temple system(More)
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