Firn Accumulation Processes in Taylor Dome, Vostok and Siple Dome Ice Using Cosmogenic 14 C and 10Be as Tracers

9909484 Lal该奖项是为了支持三年的资助，以开发南极洲几个地点沉积的上层冰层中发生的积雪和物理过程的历史，使用宇宙成因的原位碳-14（14 C）和宇宙成因的铍-10（10 Be）作为放射性示踪剂。 拟议的研究出现在最近的研究宇宙成因原位14 C在GISP 2全新世和几个南极冰样品，其中显示显着差异的14 C浓度的样品，相比，理论上的预期值。 GISP 2样品中的14 C含量与预期的相当，但南极样品中的14 C含量不足30-50%或更多。 这些结果表明，在缓慢积累的冰样本中（例如南极洲），注入的宇宙射线14 C以某种方式部分丢失，但在高积累区域的样本中定量保留。 这些结果表明，宇宙成因的14 C沉积后，其浓度下降，在积雪由于过程，如重结晶，升华/蒸发和再沉积。 为了量化这些过程，还将测量冰样品中的大气宇宙成因10 Be。 由于~（10）Be和~（14）C对土壤固化过程有不同的响应，对它们的同时研究有助于阐明这些过程的性质和重要性。 来自泰勒穹、沃斯托克和西普尔穹的样本都将被研究。

9909484LalThis award is for support for three years of funding to develop a history of snow accumulation and physical processes occurring in the upper layers of ice deposited at several sites in Antarctica, using cosmogenic in-situ Carbon-14 (14C) and cosmogenic Beryllium-10 (10Be) as radiotracers. The proposed research emerges from recent studies of cosmogenic in-situ 14C in GISP2 Holocene and several Antarctic ice samples, which revealed marked differences in the 14C concentrations in the samples, compared to the theoretically expected values. The GISP2 samples have about the expected amount of 14C but the Antarctic samples are deficient by 30-50% or more. These results suggest that in slowly accumulating ice samples (such as occur in Antarctica), the cosmic ray implanted 14C is somehow partially lost, but quantitatively preserved in samples from areas of high accumulation. These results suggest that after deposition of the cosmogenic 14C, its concentration is decreased in firn due to processes such as recrystallization, sublimation/evaporation and redeposition. In order to quantify these processes, the atmospheric cosmogenic 10Be in ice samples will also be measured. Since 10Be and 14C have different responses to the firnification processes, their simultaneous study can help to elucidate the nature and importance of these processes. Samples from Taylor Dome, Vostok and Siple Dome will all be studied.