21 Drainage Basin Evolution, Fluvial Geomorphology, and Fluvial Processes of the Great Plains, Great Lakes, and Upper Mississippi River Basin

Monday, 18 May 2020
1:30 PM - 5:30 PM
Lake Superior Ballroom L

A SEDIMENTOLOGICAL CHARACTERIZATION OF HURON MOUNTAIN STREAMS FOR APPLICATION TO FUTURE ECOLOGICAL STUDIES

Paper number: 21-1
Program: Theme Sessions
Time: 1:30 PM – 1:50 PM

Authors

Abstract

The Huron Mountain region of Michigan’s Upper Peninsula provides a pristine environment for interdisciplinary studies across ecology and geology. A preliminary analysis of multiple rivers within two separate watersheds links hydrologic setting to its impact on aquatic plants and dragonflies. Characterizing the sedimentology of these diverse fluvial environments was done via Wolman pebble counts and dry sieving of the bed load samples to determine grain-size distributions, while geomorphic analysis of river dimensions and velocity as well as documentation of obvious aquatic vegetation and emergent rocks within the bed load helped to further frame which areas will best suit future efforts. Streams with steeper gradients and coarser average grain size, such as the Pine River, appeared to hold more emergent cobble and boulders, on which dragonfly larval hatching might occur. Depth and velocity of the rivers had an apparent link to prevalence of aquatic plants observed. Bed material of the streams showed linkage to its provenance, either the Jacobsville Sandstone or Precambrian basement rock. Comparisons of randomized pebble counts over time show sand dominance in some stretches of the Salmon-Trout River, likely reflecting nearby anthropogenic activity and land use. Overall, grain-size showed a wide range, depending on the river. In general, sediment load of the river has the potential to affect water chemistry and nutrients available to the biota in this ecological setting, while emergent material provides habitat and shelter during the lifecycle of various insects. Temporal changes in sediment and bed composition have potential to be reflected in ecological changes. With an expectation to begin biological sampling of insects and aquatic vegetation as the next phase, the familiarity of the riparian environment through this study will prove worthwhile.

Geological Society of America Abstracts with Programs. Vol. 52, No. 5

doi: 10.1130/abs/2020NC-348153

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