ESH - Late Quaternary Climate Change and Biotic Responses inthe Bonneville Basin and Vicinity, Northeastern Great Basin

9709502罗德州犹他州西部和内华达州东部的邦纳维尔盆地拥有世界上最著名的晚更新世古环境记录之一，但我们对该地区陆地生物群历史的了解落后于我们对湖泊水位或区域古气候的了解。最近，从大盐湖沙漠周围的山脉中收集了大量古老的袋鼠亚种，提供了丰富的动植物化石来源，可以追溯到过去5万年。根据这项建议，将对这些蚊子样本进行一系列分析。从这些中层采集的样品将进行放射性碳测年，以得出中层的长期年代学。将识别植物大型化石、花粉、昆虫遗骸和脊椎动物区系元素，以重建生物随时间的分布。将检查气孔密度以及氢和碳的稳定同位素浓度，以确定某些植物类群(樟子松)在冰川-间冰期周期期间因气候和大气化学变化而产生的水分利用效率的变化。将使用粪便颗粒作为替代措施来评估在同一时间段内毛尾木对气候变化的身体大小的假设变化。当这些数据集整合在一起时，这一中期记录将被用来识别和确定过去50,000年来单一区域生态系统内植被群落、昆虫和脊椎动物分类群的分布以及动植物分类群的生理和形态随着气候和大气二氧化碳浓度的急剧变化而发生的重大变化。这些数据将为该区域的古气候估计提供基础，以补充和交叉核对来自Bonneville盆地的其他古气候替代数据和气候模型结果，有助于利用现有的地质和生物系统对气候变化和反应进行最详细和最准确的陆地长期记录。

9709502 Rhode The Bonneville Basin of western Utah and eastern Nevada has one of the best known late Pleistocene paleoenvironmental records in the world, but our understanding of the history of terrestrial biota in the region lags behind our understanding of lake levels or regional paleoclimates. Recently a large number of ancient packrat middens have been collected from the mountains surrounding the Great Salt Lake Desert, providing a rich source of fossil plant and animal remains dating through the last 50,000 years. Under this proposal, a series of analyses of these midden samples will be undertaken. Samples from these middens will be radiocarbon dated to derive a long term chronology of midden strata. Plant macrofossils, pollen, insect remains, and vertebrate faunal elements will be identified, to reconstruct biotic distributions through time. Stomatal density and concentrations of stable isotopes of hydrogen and carbon will be examined to determine changes in water use efficiency of certain plant taxa (limber pine) in response to changes in climate and atmospheric chemistry during the glacial-interglacial cycle. Postulated changes in body size of the bushy-tailed woodrat in response to climate change during this same time period will be evaluated using fecal pellets as a proxy measure. When these data sets are integrated together, this midden record will be used to identify and date major shifts in vegetation associations, the distribution of insect and vertebrate taxa, and changes in physiology and morphology of plant and animal taxa in response to dramatic changes in climate and atmospheric CO2 concentration, within a single regional ecosystem during the last 50,000 years. These data will provide the basis for paleoclimatic estimates in the region to complement and cross-check other paleoclimatic proxy data and climate model results from the Bonneville Basin, contributing to one of the most detailed and well dated long-term terrestrial records of climate change and responses b y geological and biological systems available.