Extensive valley glacier deposits in the northern mid-latitudes of Mars: Evidence for Late Amazonian obliquity-driven climate change |
| |
| Institution: | 1. Department of Geological Sciences, Brown University, Providence, RI 02912, USA;2. Department of Earth Sciences, Boston University, Boston, MA 02215, USA;1. Charles University in Prague, Faculty of Mathematics and Physics, Mathematical Institute, Sokolovská 83, Praha 8, Karlín, CZ 186 75, Czech Republic;2. Université de Nantes, LPG-Nantes, UMR 6112, 2 chemin de la Houssinière, F-44322 Nantes, France;3. CNRS, LPG-Nantes, UMR 6112, F-44322 Nantes, France;1. School of Computing and Information Science, University of Maine, Orono, ME 04469 USA;2. Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912 USA;1. UCD School of Geography, University College Dublin, Belfield, Dublin 4, Ireland;2. UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland;3. Dept. of Physical Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA, UK;4. Planetary Science Institute Tucson, 1700 E. Fort Lowell, Suite 106, Tucson, AZ 85719, United States;1. Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, United States;2. Rubenstein School for Environment and Natural Resources and the Gund Institute of Ecological Economics, University of Vermont, Burlington, VT 05405, United States |
| |
| Abstract: | Understanding spin orbital parameter-driven climate change on Mars prior to ～ 20 Ma ago requires geological evidence because numerical solutions for that period are chaotic and non-unique. We show geological evidence that lineated valley fill at low mid-latitudes in the northern hemisphere of Mars (～ 37.5° N) originated through regional snow and ice accumulation and underwent glacial-like flow. Breached upland craters and theater-headed valleys reveal features typical of erosion in association with terrestrial glaciers. Parallel, converging and chevron-like lineations in potentially ice-rich deposits on valley floors indicate that flow occurred through constrictions and converged from different directions at different velocities. Together, these Martian deposits and erosional landforms resemble those of intermontaine glacial systems on Earth, particularly in their major morphology, topographic shape, planform and detailed surface features. An inferred Late Amazonian age, combined with predictions of climate models, suggest that the obliquity of Mars exceeded a mean of 45° for a sustained period. During this time, significant transfer of ice occurred from ice-rich regions (e.g., the poles) to mid-latitudes, causing prolonged snow and ice accumulation there and forming an extensive system of valley glaciers. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
