On the moon and other airless bodies, ballistically emplaced ejecta transitions from a thinning, continuous inner deposit to become discontinuous beyond approximately one crater radius from the crater rim and can further break into discrete rays and secondary craters. In contrast, on Mars, ejecta often form continuous, distinct, and sometimes thick deposits that transition to a low ridge or escarpment that may be circular or lobate. The Martian ejecta type has been variously termed pancake, rampart, lobate, or layered, and in this work we refer to it as abrupt termini ejecta (ATE). Two main formation mechanisms have been proposed, one requiring interaction of the ejecta with the atmosphere and the other mobilization of near-surface volatiles. ATE morphologies are also unambiguously seen on Ganymede, Europa, Dione, and Tethys, but they are not as common as on Mars. We have identified up to 38 craters on Charon that show signs of ATE, including possible distal ramparts and lobate margins. These ejecta show morphologic and morphometric similarities with other moons in the solar system, which are a subset of the properties observed on Mars. From comparison of these ejecta on Charon and other solar system bodies, we find the strongest support for subsurface volatile mobilization and ejecta fluidization as the main formation mechanism for the ATE, at least on airless, icy worlds. This conclusion comes from the bodies on which they are found, an apparent preference for certain terrains, and the observation that craters with ATE can be near to similarly sized craters that only have gradational ejecta.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/627125 |
| Date | 01 1900 |
| Creators | Robbins, Stuart J., Runyon, Kirby, Singer, Kelsi N., Bray, Veronica J., Beyer, Ross A., Schenk, Paul, McKinnon, William B., Grundy, William M., Nimmo, Francis, Moore, Jeffrey M., Spencer, John R., White, Oliver L., Binzel, Richard P., Buie, Marc W., Buratti, Bonnie J., Cheng, Andrew F., Linscott, Ivan R., Reitsema, Harold J., Reuter, Dennis C., Showalter, Mark R., Tyler, G. Len, Young, Leslie A., Olkin, Catherine B., Ennico, Kimberly S., Weaver, Harold A., Stern, S. Alan |
| Contributors | Univ Arizona, Lunar & Planetary Lab, Southwest Research Institute; Boulder CO USA, Department of Earth and Planetary Sciences; The Johns Hopkins University; Baltimore MD USA, Southwest Research Institute; Boulder CO USA, Lunar and Planetary Laboratory; University of Arizona; Tucson AZ USA, Sagan Center; SETI Institute; Mountain View CA USA, Lunar and Planetary Institute; Houston TX USA, Department of Earth and Planetary Sciences at McDonnell Center for the Space Sciences; Washington University; St. Louis MO USA, Lowell Observatory; Flagstaff AZ USA, Department of Earth and Planetary Sciences; University of California; Santa Cruz CA USA, Planetary Systems Branch, Space Sciences and Astrobiology Division; NASA Ames Research Center; Moffett Field CA USA, Southwest Research Institute; Boulder CO USA, Planetary Systems Branch, Space Sciences and Astrobiology Division; NASA Ames Research Center; Moffett Field CA USA, Massachusetts Institute of Technology; Cambridge MA USA, Southwest Research Institute; Boulder CO USA, NASA Jet Propulsion Laboratory; California Institute of Technology; Pasadena CA USA, Department of Earth and Planetary Sciences; The Johns Hopkins University; Baltimore MD USA, Department of Electrical Engineering; Stanford University; Stanford CA USA, Ball Aerospace (retired); Boulder CO USA, NASA Goddard Space Flight Center; Greenbelt MD USA, Sagan Center; SETI Institute; Mountain View CA USA, Department of Electrical Engineering; Stanford University; Stanford CA USA, Southwest Research Institute; Boulder CO USA, Southwest Research Institute; Boulder CO USA, Lowell Observatory; Flagstaff AZ USA, Department of Earth and Planetary Sciences; The Johns Hopkins University; Baltimore MD USA, Southwest Research Institute; Boulder CO USA |
| Publisher | AMER GEOPHYSICAL UNION |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Article |
| Rights | ©2017. American Geophysical Union.All Rights Reserved. |
| Relation | http://doi.wiley.com/10.1002/2017JE005287 |
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