Andrew Gustin

Andrew Gustin

Research

IU Geologic Field Station Willow Creek Demonstration Watershed 2010-2011

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Description

Rock glaciers are periglacial deposits which typically contain coarse boulders. These deposits flow downslope, similar to a glacier, due to the presence of an ice–core and/or an interstitial ice matrix. For my master‘s research, I outlined all identifiable rock glacier deposits in the Tobacco Root Range using remote sensing techniques. A few high–priority sites were selected based on location, morphology, and apparent age. Twenty–five of these deposits were physically visited during the summers of 2009 and 2010.

Plot of age-assigned lichen diameter data showing lichen growth rates
Plot of age-assigned lichen diameter data showing lichen growth rates. Max and average lichen diameter versus age, showing lichen growth rates for the Tobacco Root Mountains.
plot of average max lichen diameter versus average lichen cover for each site (with site number labels). The trend is used to help determine the relative age of the deposits.
Plot of average max lichen diameter versus average lichen cover for each site (with site number labels). The trend is used to help determin the relative age of the deposits.

The relative age of each deposit was assessed using well–established techniques such as lichenometry and other measures of boulder weathering. Fracture measurements and orientations were also recorded on the contributing headwall above the rock glacier.

Using this data as well as topoclimatic information derived from zonal extractions in GIS (slope, aspect, elevation, and radiation reduction), I aim to further understand the impact that these different factors have on the development and morphology of rock glaciers. I also hope to develop a generalized view of the regional climatic conditions during the different stades of the Neoglacial period and earlier.

Polar plot showing glacier elevation (x and y axis) and rock glacier aspect (outer axis), in addition to rock glacier area (relative size of circles) for all sites identified in the Tobacco Root Mountains
Polar plot showing rock glacier elevation (x and y axis), and rock glacier aspect (outer axis), in addition to rock glacier area (relative size of circles) for all sites identified in the Tobacco Root Mountains.
Polar plot showing rock glacier elevation (x and y axis), rock glacier aspect (outer axis), and ratio of rock glacier area to rock-shed area (relative size of circles) for selected sites in the Tobacco Root Mountains
Polar plot showing rock glacier elevation (x and y axis), rock glacier aspect (outer axis), and ratio of rock glacier area to rock-shed area (relative size of circles) for selected sites in the Tobacco Root Mountains.