Ice preservation and landscape erosion during glacial retreat on Earth and Mars

Active glacial environments exhibit characteristic landforms due to the interplay of ice, climate, soil, and rock. These landforms are used as indicators of past and present climate conditions, and the base of knowledge established by studying glacial morphologies on Earth has been applied to aid interpretation of ice-rich or ice-remnant landforms on Mars. We focus on how glaciers and glacial landforms act to erode their surrounding landscape when they are active, and how they are preserved on the landscape when climate changes and ice retreats. This includes specific study of glaciers, debris-covered glaciers, rock glaciers, and cirques because glaciers act to erode landscapes, and landscapes contribute debris that can preserve glacier ice. We contextualize lobate debris aprons and glacier-like forms on Mars with debris-covered glaciers on Earth in order to put the latest research on both planets in a perspective aimed at maximizing process-based understanding of glacier evolution and ice preservation. While we primarily focus on processes controlling active debris-covered glaciers, a key to understanding glacier change through time is to consider individual landforms in context with the full-system environment in which they are found. We discuss process-based progressions and relationships between glacial landforms as understood on Earth; for example, the development of clean-ice glaciers, debris-covered glaciers, rock glaciers, moraines, and talus may be determined as a function of ice movement and debris input.

Building from our current knowledge of Mars, we show results from preliminary investigations of previously unmapped ice-remnant forms in Eastern Hellas and the Deuteronilis/Protonilus/Nilosyrtis Mensae regions that we have found using the recently available Context Camera (CTX) image mosaic (http://murray-lab.caltech.edu/CTX/). These landforms are newly identified small components of the martian glacial system, that are different from, but likely related to, glacier-like forms and recessional glacier-like forms. We also search for the cirque signature of ice erosion on Mars, and discuss how the timing of glacial, deglacial, and paraglacial activity may be further constrained by evaluating the existence and distribution of all possible components of a glacial landsystem. Interpretations of Mars from remote sensing alone can be evaluated against targeted interpretations on Earth using both remote sensing and field studies. In particular we will share on recent work studying debris sources and glacier evolution at Mt. Rainier, Washington state. By applying terrestrial understanding to Mars we aim to evaluate how present-day martian landforms are informative of past activity and conditions during times when orbital parameters, climate, and water-ice distribution were different.