RUI Collaborative Proposal: Climate and Chronology of the Last Glacial-Interglacial Transition, North-Central Great Basin, U.S.A.

该奖项是根据2009年《美国复苏和再投资法案》(公法111-5)提供资金的。美国西部更新世冰川记录的最新发展揭示了落基山脉北部、中部、南部和科罗拉多高原中部之间最后一次冰川-间冰期转变(GIT；时间约为17-10ka)开始时的空间差异。这种变化可能反映了极地急流位置和伴随的风暴路径的变化造成的这些地区降水量的差异，或者可能反映了大盆地雨积湖作为顺风山脉湿润来源的重要性。在确定大盆地中北部冰川和湖泊波动的范围、时间和年表方面，该项目填补了美国西部冰川和古气候历史理解方面的广泛空间空白，并为用于验证区域气候模型的气候记录提供了亟需的补充。智力价值：大盆地中北部的许多山脉和山间山谷都有丰富的证据表明，在最后一次大地震期间，冰川和洪水湖发生了波动。然而，在这一过渡期间，冰川和湖泊对气候变化的反应时间几乎是未知的，而在这段深刻的气候变化期间，温度和/或降水变化的性质也鲜为人知。利用该地区的冰川和洪水湖记录来推断最新更新世期间的气候变化是当前非常感兴趣的，原因有几个。首先，大盆地的位置位于美国西部内陆冰川和洪水湖地区的中心位置，这为研究对气候敏感的小型冰川和湖泊对北美冰盖消退和伴随着区域尺度大气环流重组而产生的气候变化的反应提供了巨大的潜力。其次，冰川和洪水湖沉积的良好保存为宇宙成因地表暴露测年和光激发发光(OSL)测年提供了理想的靶标。最后，最后一次GIT期间，山脉冰川靠近封闭盆地的洪泛湖，这为冰川和湖泊物质平衡的联合数值模拟提供了一个罕见的环境，可以用来设定对古温度和降雨量的狭窄限制。更广泛的影响：这项研究是由两所以本科生为主的机构的教职员工进行的，现场和分析工作的所有方面都得到了来自米德尔伯里学院和纽约州立大学Geneseo的学生研究人员的帮助。通过该项目制作的地图由内华达州矿业和地质局出版，娱乐用户可以获得这些受欢迎地区的冰川历史。正在为内华达州矿业和地质局网站开发EarthCach网站，以提供有关研究地区受欢迎地区的地质和第四纪历史的信息。此外，测绘和所有其他结果都提供给美国农业部林业局、土地管理局和国家公园管理局，它们管理着几乎所有拟议的研究区域。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Recent developments in the understanding of Pleistocene glacial records in the western U.S. reveal spatial variability in the onset of the last glacial-interglacial transition (GIT; the time ~17-10 ka) among the northern, middle, southern Rocky Mountains, and the central Colorado Plateau. Such variability may reflect differences in precipitation among these areas caused by shifts in the location of the polar jet and accompanying storm tracks, or possibly the importance of Great Basin pluvial lakes as moisture sources for downwind mountain ranges. In determining the extent, timing, and chronology of glacier and lake fluctuations in the north-central Great Basin, this project fills a broad spatial gap in the understanding of glacial and paleoclimate history in the western U.S., and provides a much needed addition to climate records used to validate regional climate models. Intellectual Merit: Numerous mountain ranges and intermountain valleys in the north-central Great Basin contain abundant evidence of glacier and pluvial-lake fluctuations during the last GIT. However, the timing of glacier and lake responses to climate changes during this transition is virtually unknown in this region, and the nature of temperature and/or precipitation changes during this interval of profound climate change is poorly understood. Using glacier and pluvial-lake records from this region to infer climate changes during the Latest Pleistocene is of great current interest for several reasons. First, the location of the Great Basin, central among well-dated glacial and pluvial-lake locales in the interior western U.S., provides significant potential for examining the response of climate-sensitive, small glaciers and lakes to climate changes associated with the retreat of North American ice sheets and accompanying reorganization of regional-scale atmospheric circulation. Second, the excellent preservation of glacial and pluvial-lake deposits provides ideal targets for cosmogenic-surface exposure dating and optically-stimulated luminescence (OSL) dating. Finally, the proximity of mountain glaciers to closed-basin pluvial lakes during the last GIT affords a rare setting in which combined numerical modeling of glacier and lake mass balance can be used to set narrow limits on paleo-temperature and precipitation. Broader Impacts: This research is carried out by faculty from two predominantly undergraduate institutions, and all aspects of field and analytical work are aided by student researchers from Middlebury College and SUNY Geneseo. Maps produced through this project are published by the Nevada Bureau of Mining and Geology, making the glacial history of these popular areas available to recreational users. EarthCache sites are in development for the Nevada Bureau of Mining and Geology website to provide information about the geology and Quaternary history of popular localities in the study area. Additionally, mapping and all other results are provided to the USDA-Forest Service, the Bureau of Land Management, and the National Park Service, which manage nearly all of the proposed study areas.