T158 Geologic Research at Mount Rainier and Other Cascade Volcanoes: Ideal Natural Laboratories for Cutting-Edge Research with Implications to Life Safety and Infrastructure Protection in the Pacific Northwest (Posters)

Monday, 23 October 2017
9:00 AM - 6:30 PM
Halls 4EF

IDENTIFYING INFLUENCES ON GLACIAL MELTWATER HYDROCHEMISTRY USING LABORATORY SIMULATIONS OF SUBGLACIAL CHEMICAL EROSION

Paper number: T158-1
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

Nisqually Glacier is a six-kilometer-long valley glacier on the southern flank of Mount Rainier, Washington. Analysis of Nisqually Glacier meltwater consistently yields low concentrations of sulfate and chloride ions. This goal of this study is to determine the influence of subglacial chemical erosion of bedrock on meltwater hydrochemistry. Hand samples representing bedrock near Nisqually Glacier were crushed to a rock flour, and suspended in deionized water and snowmelt for forty-eight hours in a cold room. The hand samples were identified as andesite and diorite through analysis of thin sections. Sediment mixed with snowmelt leached up to 0.53 ± 0.74 mg/L of sulfate and 0.45 ± 0.03 mg/L of chloride.These concentrations are a small fraction of concentrations measured in Nisqually Glacier meltwater. High uncertainty and the lack of a relationship between sediment concentration and leached constituents warrant further experimental trials. Despite high uncertainty, our results suggest that Nisqually Glacier meltwater could be influenced by Mount Rainier’s hydrothermal system. Future experiments will test this hypothesis.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-307707

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