The Effects of Snowmelt Percolation on Stratified Pollen Records: A Cooler Study
Temperate valley glaciers may contain unique paleoecological records with the possibility of very high-resolution pollen analysis. However, little is known about the effects of meltwater percolation on pollen found in snow and glacial ice. Previous studies have suggested that pollen is relatively im...
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The Aquila Digital Community
2013
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| Online Access: | https://aquila.usm.edu/masters_theses/472 https://aquila.usm.edu/context/masters_theses/article/1535/viewcontent/Ewing_Michael_Edward_May_2013_Redacted.pdf |
| Summary: | Temperate valley glaciers may contain unique paleoecological records with the possibility of very high-resolution pollen analysis. However, little is known about the effects of meltwater percolation on pollen found in snow and glacial ice. Previous studies have suggested that pollen is relatively impervious to meltwater percolation due to grain size and, thus, resists transport. However, investigations on McCall Glacier in the Brooks Range of northeast Alaska reveal a disparity between the large amounts of pollen in the surface snow and firn, and dearth of pollen in the glacial ice core samples. The purpose of this study is to investigate if meltwater percolation can effectively transport pollen in a way that results in reduced pollen concentrations in deeper layers of the glacier. To do this, an experiment was conducted in Fairbanks, Alaska from February 28-March 2, 2012 using nine Styrofoam coolers filled with natural snow accumulation. The coolers were stratified into three groups: Snow/Flat (SF), Snow/Tilted (ST), and Ice/Tilted (IT). All coolers were spiked at the surface with 104,242 Lycopodium marker spores, melted to two-thirds the original volume, and the remaining snow profile was sampled in 5cm increments (except the IT stratum) and tested for spore concentrations. Meltwater was collected throughout the process and examined. Results indicate both strong vertical and horizontal spore transport due to meltwater percolation. Peak spore concentrations occurred in the bottommost snow layers and/or meltwater in eight of nine coolers, and provide evidence of effective transport of pollen via meltwater percolation and runoff. |
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