Coupled 230Th/234U-ESR analyses for corals: A new method to assess sealevel change

Although coupled 230Th/234U-ESR analyses have become routine for dating teeth, they have never been used for corals. While the ESR age depends on, and requires assumptions about, the time-averaged cosmic dose rate, over(D, -)cos (t), 230Th/234U dates do not. Since over(D, -)cos (t) received by corals depends on the attenuation by any intervening material, over(D, -)cos (t) response reflects changing water depths and sediment cover. By coupling the two methods, one can determine the age and a unique over(D, -)cos, coupled (t) simultaneously. From a coral's water depth and sedimentary history as predicted by a given sealevel curve, one can predict over(D, -)cos, sealevel (t) . If over(D, -)cos, co

ESR analyses for teeth from the open-air site at Attirampakkam, India: Clues to complex U uptake and paleoenvironmental change

In open-air sites, diagenetic alteration makes teeth difficult to analyze with electron spin resonance (ESR). Despite strong diagenetic alteration, three ungulate teeth from Pleistocene fluvial sediment in the open-air Paleolithic site at Attirampakkam, Tamil Nadu, India, were analyzed using standard and isochron ESR. Diagenetic alteration features in two teeth indicated rapid submergence in quiet saline to hypersaline water, following a short subaerial exposure, while the third remained constantly buried under reducing conditions. Geochemical signatures and ESR data all indicate that the teeth experienced at least three independent U uptake events during diagenesis, including two that occurred long after burial