The Nature of Late Pleistocence Climate Ameliorations in Eastern Beringia

OPP-99-19048 Elias OPP-00-02362 Edwards OPP-00-02361 Berger这是与来自科罗拉多大学、阿拉斯加大学和沙漠研究所的首席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晚更新世形成了一块未冰川的陆块，被称为贝林贾。以前的柏林纪古气候研究只给出了定性的温度估计。有必要进行量化估计，以便更好地了解气候变化的规模和区域表现。首席调查人员将尝试通过对昆虫化石、花粉和植物大型化石的热释光(TL)测年分析来量化古温度。他们将使用甲虫化石分析和古植物学研究的相互气候极差(MCR)方法来估计最温暖(Tmax)和最冷的月份(Tmin)的平均温度，以及估计年平均温度(MAT)。他们将重建阿拉斯加中部和北部五个研究地点的过去环境，沉积物的年龄从同位素第六阶段结束到全新世。首席调查员将重点研究上一次间冰期之前和期间的样本。他们将用热释光及其更新的变种--光子激发发光法测定14万至5万年前的沉积物的年龄。将讨论两个研究主题。第一个主题是研究从阶段6到阶段5的气候过渡的性质，并确定老乌鸦山雀在这个序列中的位置。第二个研究主题是确定最后一次间冰期期间贝林贾气候改善的性质。

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.