Collaborative/RUI: Late-Quaternary Glacial and Paleoclimate History of the Uinta Mountains, Northeastern Utah

摘要：温塔山脉保存完好，记录了晚更新世高山冰川的范围和活动。然而，这一记录尚未在大范围尺度上进行详细研究，末次冰期极大期（Last GlacialMaximum， LGM）和随后的消冰期（deglacialmaximum）的时间也尚未确定。在温塔山脉记录晚第四纪冰期的时空范围是有必要的，有几个原因。首先，该山脉的位置——位于年代久远的高山冰川地区的中心，毗邻博纳维尔湖盆地的东部边缘——为研究博纳维尔湖对犹他州东北部古气候和冰川的区域影响提供了巨大的潜力。其次，乌塔山脉的方向提供了一个独特的机会来研究在一个山脉内南北流动的大型冰川的记录。最后，冰碛的良好保存和不稳定巨石的抗岩性为宇宙表面暴露定年提供了理想的目标。本文拟采用传统与先进研究方法相结合的方法，对乌塔山晚第四纪冰川和古气候记录进行研究，以达到以下目的：1)确定LGM期间和之后乌塔山冰川的范围和时间。这项工作将包括：(1)对尤因塔山脉南侧的地表地质进行详细的野外和航空摄影测绘；(2)对尤因塔山脉西部、中部和东部冰川融化期间沉积的冰碛进行宇宙成因地表暴露测年；(3)对山脉南北斜坡上被消退的冰碛筑坝的湖泊沉积物岩心进行检索和研究。2)利用温塔山脉的冰川记录重建更新世晚期古气候。因为冰川的范围是温度和降水的函数，冰川记录是气候变化的极好代用物。我们将使用最新更新世冰川的地貌记录来验证基于气候输入参数模拟冰川生长的数值模拟实验；这将为确定温塔山脉的LGM古气候提供一个独特的方法。更广泛的影响本建议中概述的研究将产生超越追求核心科学目标的好处。首先，它将进一步推进阿什利国家森林（ANF）和威斯康星大学麦迪逊分校之间的持续关系。由于国家森林的公共利用和更密集的管理，ANF的主管对林地的地质历史产生了更大的兴趣，并在过去的8年里支持了研究生在尤塔山脉的研究（例如，Douglass, 2000; Munroe, 2001; Carson, 2003），并继续支持当前的研究生研究（B. labs，本研究；见支持信）。第二，博士生B. labs将参加新的NSF研究性教学与学习整合中心（CIRTL），这是一个由NSF赞助的项目，在威斯康星大学麦迪逊分校启动，旨在培养下一代大学科学教授。他将参加CIRTL的课程和研讨会，重点是有效利用研究方法在大学课堂上传播科学知识。实验室将是第一批获得证书的研究生之一，承认为学术界的职业生涯做准备，并将nsf -威斯康星大学麦迪逊分校的合作成果带入美国高等教育体系。最后，J. Munroe（米德尔伯里学院）在他的研究生工作的基础上，开始将本科生纳入他目前对该地区晚第四纪历史的研究中。拟议的研究为三名地质学专业的大四学生提供了机会，以追求总体研究目标的各个方面的本科论文（见RUI影响声明了解更多信息）。

ABSTRACTThe Uinta Mountains contain a well-preserved record of alpine glacier extents and behavior during the latestPleistocene. Yet, this record has not been studied in detail at the range-wide scale, and the timing of the Last GlacialMaximum (LGM) and subsequent deglaciation have not been determined. Documenting the spatial and temporalextent of late-Quaternary glaciation in the Uinta range is warranted for several reasons. First, the location of the range - central among well-dated alpine glacial localities and adjacent to the eastern edge of the Lake Bonneville basin - provides great potential for examining the regional effect of Lake Bonneville on paleoclimate and glaciation in northeastern Utah. Second, the orientation of the Uinta range provides a unique opportunity to study a record of large glaciers that flowed both north and south within a single mountain range. Finally, the excellent preservation of moraines and resistant lithology of erratic boulders provides ideal targets for cosmogenic surface-exposure dating. We propose to use a combination of conventional and advanced research methods to study the late-Quaternary glacial and paleoclimate record of the Uinta Mountains in pursuit of the following goals:1) Determine the extent and timing of glaciation in the Uinta Mountains during and since the LGM. Thiseffort will involve (1) detailed field and air photograph mapping of the surficial geology of the south flank ofthe Uinta Mountains (2) cosmogenic surface-exposure dating of moraines deposited during the LGM in thewestern, central, and eastern Uintas and (3) retrieval and study of lake sediment cores from lakes dammed by recessional moraines across the north and south slopes of the range.2) Reconstruct the latest Pleistocene paleoclimate from glacial records across the Uinta Mountains. Becausethe extents of glaciers are a function of temperature and precipitation, glacial records are excellent proxies of climate change. We will use the geomorphic records of latest Pleistocene glaciers to validate numericalmodeling experiments that simulate glacier growth based on climate input parameters; this will allow for aunique determination of LGM paleoclimate in the Uinta Mountains.Broader ImpactsThe research outlined in this proposal will yield benefits beyond pursuit of the core scientific objectives. First, it will further the ongoing relationship between the Ashley National Forest (ANF) and UW-Madison. Due to rising public use and more intensive management of National Forests, supervisors of the ANF have developed a greater interest in the geologic history of forest land and have supported graduate student research in the Uinta Mountains for the past 8 years (e.g., Douglass, 2000; Munroe, 2001; Carson, 2003) and continue to support current graduate research (B. Laabs, this study; see letter of support). Second, Ph.D. student B. Laabs will participate in the new NSF Center for the Integration of Research Teaching and Learning (CIRTL), an NSF-sponsored program that was launched at the UW-Madison to prepare the next generation of college science professors. He will participate in CIRTL courses and workshops focused on the effective use of research methods to disseminate scientific knowledge in the college classroom. Laabs will be among the first graduate students to receive a certificate acknowledging preparation for a career in academia and bring the fruits of this NSF-UW-Madison partnership into the U.S. higher education system. Finally, J. Munroe (Middlebury College) has built upon his graduate work in the Uintas and has begun including undergraduates in his current research on the late Quaternary history of the area. The proposed research provides the opportunity for three senior geology majors to pursue undergraduate theses on facets of theoverall research objectives (see RUI impact statement for more information).