Hypotheses for the Origin of Galaxias Chaos: Mass Movements, Lava Flow Morphology, Stratigraphy, and Ground-Volatile Interactions in Northern Elysium, Mars
Abstract
Galaxias Chaos, a region of chaotic terrain on the northern flank of Elysium Mons, is the subject of an ongoing morphology study. Initial research utilizing Viking imagery concentrated on lobate flow structures north of Elysium Mons and west of Hecates Tholus, approaching the Elysium/northern plains boundary. Most of these features are accepted by researchers as lava flows emitted from Elysium Mons; however, some flows have been hypothesized as lahars or jokelhaups. Flows were mapped and measured: Their dimensions correspond roughly to similar features in other regions of Mars. Diverse width behavior as a function of downflow distance was observed; for some flows, considerable variation in width was noted. Current efforts focus on topographic analyses. Regridded MOLA (Mars Orbital Laser Altimeter) data is being used to generate maps, contours, and cross-sections of the Chaos and environs. The relationship of the flow unit to the chaotic terrain along the boundary is being studied in the light of several hypotheses regarding chaos formation. A model is proposed featuring an overlying protective lava cap over a contact between two basements: a southern Elysium flow unit, which is volatile depleted and/or resistant to collapse, and a northern plains unit, volatile rich and/or mechanically weak. The northern unit, where unprotected, forms knobby plains by volatile/mass depletion; where covered by a veneer of lava, grooved plains result. Alternate models under consideration include successive weathering along joints. This research may reveal the roll of mass movements in the evolution of the Northern Plains/Southern Highlands boundary.
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2002
- Bibcode:
- 2002AGUSM.P41A..03P
- Keywords:
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- 5400 PLANETOLOGY: SOLID SURFACE PLANETS;
- 5499 General or miscellaneous;
- 6225 Mars;
- 6297 Instruments and techniques;
- 1625 Geomorphology and weathering (1824;
- 1886)