The Nature of Late Pleistocene Climate Ameliorations in Eastern Beringia

这是一个与来自科罗拉多大学、阿拉斯加大学和沙漠研究所的主要研究人员合作的提案。 西伯利亚、阿拉斯加和加拿大西北部的大部分地区在更新世晚期形成了一个未被冰川覆盖的大陆块，称为白令吉亚。 以前的白令纪古气候研究只得到了定性的温度估计。有必要进行定量估计，以便更好地了解气候变化的程度和区域表现形式。 主要研究人员将试图通过使用热释光（TL）测年法分析昆虫化石、花粉和植物宏体化石来量化古温度。他们将使用化石甲虫分析和古植物学研究的相互气候范围（MCR）方法来估计最温暖（TMAX）和最寒冷月份（TMIN）的平均温度，以及估计平均年温度（MAT）。 他们将在阿拉斯加中部和北方的五个研究地点重建过去的环境，沉积物的年龄从同位素阶段6结束到全新世。 主要研究人员将重点研究末次间冰期之前和期间的样本。 他们将通过TL及其新的变体光子激发发光法测定14万至5万年前的沉积物。将讨论两个研究主题。 第一个主题是研究第6阶段到第5阶段的气候过渡的性质，并确定老乌鸦火山灰在这个序列中的位置。 第二个研究主题是确定末次间冰期白令吉亚气候改善的性质。

OPP-99-19048EliasOPP-00-02362Edwards OPP-00-02361BergerThis is a collaborative proposal with Principal Investigators from the Universities of Colorado, Alaska, and the Desert Research Institute. Large portions of Siberia, Alaska, and northwestern Canada formed an unglaciated land-mass during the late Pleistocene known as Beringia. Previous Beringian paleoclimatic studies have yielded only qualitative temperature estimates. There is a need to develop quantitative estimates to gain a better understanding of the magnitude and regional expression of climate change. The Principal Investigators will attempt to quantify the paleotemperatures through the analysis of fossil insects, pollen, and plant macrofossils using thermoluminescence (TL) dating. They will use the Mutual Climatic Range (MCR) method of fossil beetle analysis and paleobotanical studies to produce estimates of mean temperatures of the warmest (TMAX) and coldest months (TMIN), as well as estimates of mean annual temperature (MAT). They will reconstruct past environments at the five study sites in central and northern Alaska with sediments ranging in age from the end of isotope stage 6 to the Holocene. The Principal Investigators will focus on samples from just before and during the last interglacial interval. They will date sediments from 140-50 thousand years by TL and its newer variant, photon-stimulated-luminescence. Two research themes will be addressed. The first theme is to study the nature of the climatic transition of stage 6 to stage 5 and to determine where the Old Crow tephra fits in this sequence. The second research theme is to determine the nature of climatic amelioration in Beringia during the last interglacial period.