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dc.contributor.authorCole, Hank M.
dc.contributor.authorAndrews-Hanna, Jeffrey C.
dc.date.accessioned2017-07-13T18:44:09Z
dc.date.available2017-07-13T18:44:09Z
dc.date.issued2017-05
dc.identifier.citationThe anatomy of a wrinkle ridge revealed in the wall of Melas Chasma, Mars 2017, 122 (5):889 Journal of Geophysical Research: Planetsen
dc.identifier.issn21699097
dc.identifier.doi10.1002/2017JE005274
dc.identifier.urihttp://hdl.handle.net/10150/624714
dc.description.abstractWrinkle ridges are among the most common tectonic structures on the terrestrial planets and provide important records of the history of planetary strain and geodynamics. The observed broad arches and superposed narrow wrinkles are thought to be the surface manifestation of blind thrust faults, which terminate in near-surface volcanic sequences and cause folding and layer-parallel shear. However, the subsurface tectonic architecture associated with the ridges remains a matter of debate. Here we present direct observations of a wrinkle ridge thrust fault where it has been exposed by erosion in the southern wall of Melas Chasma on Mars. The thrust fault has been made resistant to erosion, likely due to volcanic intrusion, such that later erosional widening of the trough exposed the fault plane as a 70km long ridge extending into the chasma. A plane fit to this ridge crest reveals a thrust fault with a dip of 13 degrees (+8 degrees, -7 degrees) between 1 and 3.5km depth below the plateau surface, with no evidence for listric character in this depth range. This dip is significantly lower than the commonly assumed value of 30 degrees, which, if representative of other wrinkle ridges, indicates that global contraction on Mars may have been previously underestimated.
dc.description.sponsorshipNASA Planetary Geology and Geophysics program [NNX17AD470]; Southwest Research Instituteen
dc.language.isoenen
dc.publisherAMER GEOPHYSICAL UNIONen
dc.relation.urlhttp://doi.wiley.com/10.1002/2017JE005274en
dc.rights© 2017. American Geophysical Union. All Rights Reserved.en
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/
dc.subjectMarsen
dc.subjecttectonicsen
dc.subjectfaulten
dc.subjectwrinkle ridgeen
dc.titleThe anatomy of a wrinkle ridge revealed in the wall of Melas Chasma, Marsen
dc.typeArticleen
dc.contributor.departmentUniv Arizona, Lunar & Planetary Laben
dc.identifier.journalJournal of Geophysical Research: Planetsen
dc.description.note6 month embargo; First published: 21 May 2017en
dc.description.collectioninformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.en
dc.eprint.versionFinal published versionen
dc.contributor.institutionDepartment of Geophysics; Colorado School of Mines; Golden Colorado USA
dc.contributor.institutionDivision of Space Sciences; Southwest Research Institute; Boulder Colorado USA
refterms.dateFOA2017-11-22T00:00:00Z
html.description.abstractWrinkle ridges are among the most common tectonic structures on the terrestrial planets and provide important records of the history of planetary strain and geodynamics. The observed broad arches and superposed narrow wrinkles are thought to be the surface manifestation of blind thrust faults, which terminate in near-surface volcanic sequences and cause folding and layer-parallel shear. However, the subsurface tectonic architecture associated with the ridges remains a matter of debate. Here we present direct observations of a wrinkle ridge thrust fault where it has been exposed by erosion in the southern wall of Melas Chasma on Mars. The thrust fault has been made resistant to erosion, likely due to volcanic intrusion, such that later erosional widening of the trough exposed the fault plane as a 70km long ridge extending into the chasma. A plane fit to this ridge crest reveals a thrust fault with a dip of 13 degrees (+8 degrees, -7 degrees) between 1 and 3.5km depth below the plateau surface, with no evidence for listric character in this depth range. This dip is significantly lower than the commonly assumed value of 30 degrees, which, if representative of other wrinkle ridges, indicates that global contraction on Mars may have been previously underestimated.


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