Doctoral Dissertation Research: Analyses of Clast Fabrics in Periglacial Mass-Movement Deposits

冰缘过程是指在接近冰川的条件下发生的过程，无论是在冰川边缘，还是在气候几乎冷到足以支持冰川作用的地区。在威斯康星州西南部的无流区和阿巴拉契亚山脉北部超出更新世冰川范围的部分地区，以及阿拉斯加中部和北部的地区，冰缘过程对景观产生了重大影响。长期以来，第四纪科学家一直试图区分各种冰缘过程的影响，但明确的证据线很少，而且在冰缘环境中识别物质消耗形式的标准分析程序尚未得到很好的发展。这篇博士论文的研究过程将集中在三个不同地点的崩积层中“碎屑织物”（由岩石碎片组成的材料）方向的比较。其中两个地点（一个在阿拉斯加中部，另一个在纽约西南部和宾夕法尼亚州西北部）是先前研究确定的似乎是以前冰川周围事件遗迹的地层的地方。第三个地点（在阿拉斯加东部）是一个冰川周围作用仍然活跃的地点。从这些地点提取的材料所得到的数据将与其他沉积和环境数据一起进行分析，以便评估在冰缘环境中运行的现有沉积物运输过程模型的有效性。该研究项目将从多个角度提供有价值的新见解。方法上的进步应通过改进查明和比较矿床内部和之间的方位变化的新统计方法来实现。冰川周围环境中作用过程的基础知识也将得到发展，将化石证据与活动过程联系起来的努力可能会产生特殊的价值。作为博士论文改进奖，该奖项也将提供支持，使有前途的学生建立一个强大的独立研究生涯。

Periglacial processes are those processes that operate in near-glacial conditions, whether along the margins of glaciers or in areas where the climates are almost cold enough to support glaciation. In locales like the Driftless Area of southwestern Wisconsin and parts of the northern Appalachians just beyond the limits of Pleistocene glaciation, and in locales like those of central and northern Alaska, periglacial processes have had significant impacts on the landscape. Quaternary scientists long have attempted to differentiate between the effects of various periglacial processes, but unambiguous lines of evidence are rare, and standard analytic procedures to identify forms of mass- wasting in periglacial environments have not been well developed. This doctoral dissertation research process will focus on comparisons of the directional orientation of "clast fabrics" (materials consisting of rock fragments) within colluvium from three different sites. Two of these sites (one in central Alaska and one in southwestern New York and northwestern Pennsylvania) are locales where previous studies have identified formations that appear to be relics of previous periglacial episodes. The third site (in eastern Alaska) is a site where periglacial processes are still active. Data derived from material extracted from these sites will be analyzed with other sedimentary and environmental data in order to assess the validity of extant models of sediment-transport processes operating in periglacial environments. This research project will provide valuable new insights from a number of perspectives. Methodological advances should be realized through refinement of new statistical approaches for identifying and comparing orientational variations within and between deposits. Fundamental knowledge of the processes operating in periglacial environments also will be advanced, with special value likely to result from efforts to relate fossil evidence to active processes. As a doctoral dissertation improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.