Regional context, internal structure, and microbiological investigation of the Lone Peak Rock Glacier, Big Sky, Montana

• Main Author: Florentine, Caitlyn Elizabeth
• Other Authors: Chairperson, Graduate Committee: Mark L. Skidmore, Mark Skidmore, Marvin Speece, Curtis Link, William Locke, Christina Carr, and Colin Shaw were co-authors of the article, 'The role of geology in rock-glacier distribution and internal structure: a case study from SW Montana' in the journal 'Journal of geophysical research earth surface' which is contained within this thesis., Mark Skidmore and Scott Montross were co-authors of the article, 'Rock-glacier ice as a microbial habitat' in the journal 'Journal of glaciology' which is contained within this thesis.
• Format: Thesis
• Language: English
• Published: Montana State University - Bozeman, College of Letters & Science 2011
• Subjects: Rock glaciers; Permafrost; Ice; Geomicrobiology; Lone; permafrost
• Online Access: https://scholarworks.montana.edu/xmlui/handle/1/1264

This thesis is the first to the author's knowledge to conduct a holistic investigation of the physical, chemical and microbial properties of a rock glacier. The Lone Peak Rock Glacier (LPRG) is located in the Madison Range of southwest Montana on Big Sky Resort property. This thesis focuses on three scales of investigation: regional, landform, and micro. Regional-scale analysis assessed the role of geology and topography as factors in determining rock-glacier distribution in SW Montana above 2000m. Rock glaciers across alpine landscapes in southwest Montana are preferentially distributed according to rock type, with more rock glaciers occurring in intrusive, foliated intrusive and metamorphic catchments relative to the areal proportion of these rock types than in extrusive and sedimentary catchments. This preferential distribution according to catchment geology is likely due to the affect that geology has on topography and provision of talus. Landform-scale analysis focuses on internal structure, flow dynamics and surface topography of the LPRG. The relationship between surface topography and subsurface structure is explained by passive roof duplex faulting. This finding has implications for rock-glacier flow dynamics and the development of transverse ridges, a common surface feature of rock glaciers studied worldwide. Micro-scale analysis characterizes microbiological and geochemical properties of rock-glacier ice and evaluates it as a microbial habitat, exploring potential associations between debris content and microbial activity. Amber ice (containing 0.1% debris by weight) appears to be a more suitable microbial environment than debris-poor ice (containing < 0.01% debris). This finding highlights the importance of debris as a potential nutrient and energy source to enhance microbial viability in rock-glacier ice.