Radiocarbon dating of east america lake levels warwick university speed dating

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Determining the biomass fraction of mixed waste fuels: a comparison of existing industry and Parry, S.

Dissolution rates of primary minerals as a function of depth and age deduced from field observations.

Benson and his colleagues used several methods to date the petroglyphs, including determining when the water level the Winnemucca Lake subbasin -- which back then was a single body of water connecting the now-dry Winnemucca Lake and the existing Pyramid Lake -- reached the specific elevation of 3,960 feet.

The elevation was key to the study because it marked the maximum height the ancient lake system could have reached before it began spilling excess water over Emerson Pass to the north.

Living roots magnify the response of soil organic carbon decomposition to temperature in temperate grassland. G., Galy, V., Gaillardet, J., Dellinger, M., Bryant, C., O'Regan, M., Grcke, D.

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Because the sand record extends beyond 4700 years we are able to determine that a ~190 yr and ~600 cycle of lake level fluctuation extends back at least 6600 years, and perhaps further.

During the last prehistoric expansion of modern humans, Polynesians from the Samoa-Tonga area dispersed through more than 500 remote, subtropical to subantarctic islands of East Polynesia (a cultural region encompassing the islands of New Zealand, Chathams, Auckland, Norfolk, Kermadecs, Societies, Cooks, Australs, Gambier, Tuamotu, Marquesas, Line, Rapa Nui, and Hawaii), an oceanic region the size of North America (Fig. The timing and sequence of this expansion, debated vigorously since Europeans rediscovered the islands of East Polynesia (1, 2) and most intensively with the advent of radiocarbon dating (3, 4), remains unresolved. This analysis shortened East Polynesian prehistory just at the time when accelerator mass spectrometry (AMS) radiocarbon dating became available for very small samples (e.g., individual seeds).

On many islands, irreconcilable long and short settlement chronologies coexist that vary by more than 400–1,000 y (4). 600–950 in the central, northern, and eastern archipelagos, and no earlier than A. Subsequent studies using precise AMS dating of short-lived materials alone have generally supported short chronologies (4, 6–8).

Co-authors on the study included Eugene Hattori of the Nevada State Museum in Carson City, Nev., John Southon of the University of California, Irvine and Benjamin Aleck of the Pyramid Lake Paiute Tribe Museum and Visitor's Center in Nixon, Nev. Benson sampled the carbonate into which the petroglyphs were incised and the carbonate that coated the petroglyphs at the base of the limestone boulder.

The radiocarbon dates on the samples indicated the carbonate layer underlying the petroglyphs dated to roughly 14,800 ago.

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