T142 Glacier-Landscape Interactions, Loess Paleoclimatology, and Interdisciplinary Quaternary Science II: In Memory of Stephen C. Porter

Monday, 23 October 2017
1:30 PM - 5:30 PM
Chelan 4

DIGGING DEEPER IN QUATERNARY SCIENCE: THE IMPORTANCE OF PAIRING SEDIMENTOLOGICAL AND GEOMORPHOLOGICAL OBSERVATIONS IN UNDERSTANDING GLACIAL LANDSCAPE EVOLUTION

Paper number: T142-10
Program: Technical Sessions
Time: 3:35 PM – 3:50 PM

Authors

  • Cianna Wyshnytzky Presenting Author
    U.S. Department of Agriculture Natural Resources Conservation Service, Brigham City, UT

Abstract

Metaphorically and literally, we must dig deeper than the surface expression of landforms to best understand landscape evolution. Recent research in the European Alps highlights how this can be particularly important in glacial ice-front settings, where specific processes of moraine formation may be foremost influenced by non-climatic factors.

Closely-spaced minor moraines allow observations of moraine formation and ice fluctuations on short timescales, helping to better understand glacier retreat and predict geomorphological effects. Some minor moraines can be classified as annual moraines given sufficient chronological control, which implies a seasonal climatic driver of minor ice-front fluctuations and extremely detailed chronologies. This leads to annual moraines being utilized as very specific and short-term records of glacier fluctuations. However, such research is sparse in high-mountain settings. This study presents the sedimentological results of minor moraines at two settings in the Alps. Minor moraines at Schwarzensteinkees, Austria, formed as push and combined push and freeze-on moraines. The existence of a former proglacial lake appears to have exerted the primary control on minor moraine formation. Minor moraines at Silvrettagletscher, Switzerland, exist primarily on reverse bedrock slopes. The presence of these bedrock slopes, and in some areas controlled moraines, appear to exert the primary controls on minor moraine formation, resulting in four formation mechanisms.

These findings show that climate may only play a small role in minor moraine formation at these study sites, echoing similar findings from another glacier in the Alps. Valley geometry and pre-existing geomorphology play a large, if not dominant, role in minor moraine formation and are at odds with a primarily-climatic control of minor moraine formation in lowland settings. Important details of moraine formation would have been missed without sedimentological investigation. This concept is not exclusive to moraines; interdisciplinary Quaternary science should be the goal, especially in environments in which we cannot actively observe landform formation. This presentation serves as an example of why we should be using all the puzzle pieces we can gather for the most robust conclusions of landscape evolution.

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

doi: 10.1130/abs/2017AM-297005

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