T188 Eolian Processes and Landscape Evolution (Posters)

Tuesday, 24 September 2019
9:00 AM - 6:30 PM
Hall AB, North Building

HYPOTHESIS TESTING FOR THE ORIGIN OF CRATER-LIKE FEATURES NEAR GREAT SAND DUNES, COLORADO

Paper number: T188-24
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

For decades, residents of Crestone, Colorado have pondered the origin of a ~100 m diameter crater-like feature south of their town. The primary theory suggested a small meteorite impact formed the feature, but geological and geophysical surveys have yielded no conclusive evidence of an impactor or other signatures of a collision sufficient to produce a crater of the observed scale. Recent airborne laser altimetry surveys have produced high-resolution digital terrain models of the San Luis Valley. Shaded relief maps of these DTM’s revealed similar crater-like features distributed over a unique unit of eolian sand. Mapping these features shows spatial correlation with the maximum estimated shoreline elevation for Pleistocene Lake Alamosa, suggesting the paleolake’s hydrology played a role in their formation. Evidence of Pleistocene alpine glaciation is also found upslope of this unit of crater-like features, suggesting a paleoclimate that was cold and wet enough to support periglacial activity at relatively low elevations (<2500 m). Quaternary lakeshore processes, the eolian sediments in the valley, and climate change could have all played a role in the formation of these geomorphic features. We define tests for the hypotheses of extraterrestrial, eolian, or periglacial origin such as geologic setting, rim/depression geometry, spatial density, mineralogy, and subsurface structure. These tests are applied to previously acquired geological data and considered in recommendations for future remote, field, and/or lab studies. Understanding the origin of these crater-like features may have implications for the ongoing study of spatiotemporal evolution of surface processes on both Earth and Mars.

Geological Society of America Abstracts with Programs. Vol. 51, No. 5

doi: 10.1130/abs/2019AM-340856

© Copyright 2019 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.