Constraints on mechanisms for the growth of gully alcoves in Gasa crater, Mars, from two-dimensional stability assessments of rock slopes

Okubo, C. H.; Tornabene, L. L.; Lanza, N.

doi:10.1016/j.icarus.2010.09.025

Cited by 23 publications

(12 citation statements)

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“…One notable exception might be Gasa crater, which is located within an older impact crater. Impact melt and impact breccia might therefore be the dominant bedrock lithology in Gasa crater [ Okubo et al , ]. Note that although the original bedrock material is probably volcanic in origin, crater walls are likely partly covered by allogenic and fall‐back breccias, such as observed on Meteor crater on Earth [ Kumar et al , ].…”

Section: Resultsmentioning

confidence: 99%

“…The alcove backweathering rates are probably larger than the erosion rates because (1) crater walls are highly susceptible to backweathering and (2) crater erosion is more a “grain by grain” process, whereas backweathering spans grain by grain to large failures [e.g., Krautblatter et al , ], which together result in a higher net rate. This explanation is supported by Okubo et al [], who show that the pattern of fracturing around the crowns (upper parts) of the gully alcoves of Gasa crater is indicative of landsliding.…”

Section: Discussionmentioning

confidence: 99%

“…Accordingly, the occurrence of dense fractures on impact crater walls and evidence for erosion along these fractures are found on Mars Exploration Rover images [e.g., Squyres et al , ]. Moreover, the pattern of fracturing around many gully alcoves is indicative of landsliding, for instance, on the pole‐facing gully alcoves of Gasa crater [ Okubo et al , ].…”

Section: Introductionmentioning

confidence: 99%

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Recent (Late Amazonian) enhanced backweathering rates on Mars: Paracratering evidence from gully alcoves

2015

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Abstract Mars is believed to have been exposed to low planet-wide weathering and denudation since the Noachian. However, the widespread occurrence of alcoves at the rim of pristine impact craters suggests locally enhanced recent backweathering rates. Here we derive Late Amazonian backweathering rates from the alcoves of 10 young equatorial and midlatitude craters. The enhanced Late Amazonian Martian backweathering rates (10 −4 -10 −1 mm yr −1 ) are approximately 1 order of magnitude higher than previously reported erosion rates and are similar to terrestrial rates inferred from Meteor crater and various Arctic and Alpine rock faces. Alcoves on initially highly fractured and oversteepened crater rims following impact show enhanced backweathering rates that decline over at least 10 1 -10 2 Myr as the crater wall stabilizes. This "paracratering" backweathering decline with time is analogous to the paraglacial effect observed in rock slopes after deglaciation, but the relaxation timescale of 10 1 -10 2 Myr compared to 10 kyr of the Milankovitch-controlled interglacial duration questions whether a paraglacial steady state is reached on Earth. The backweathering rates on the gullied pole-facing alcoves of the studied midlatitude craters are much higher (∼2-60 times) than those on slopes with other azimuths and those in equatorial craters. The enhanced backweathering rates on gullied crater slopes may result from liquid water acting as a catalyst for backweathering. The decrease in backweathering rates over time might explain the similar size of gullies in young (<1 Ma) and much older craters, as alcove growth and sediment supply decrease to low-background rates over time.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Recent (Late Amazonian) enhanced backweathering rates on Mars: Paracratering evidence from gully alcoves

2015

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“…Source areas for these movements cannot usually be identified, although occasionally failure scars are present. Crown fractures have been identified in the alcoves of Gasa crater (Okubo et al, 2011), where the gullies are particularly active (Dundas et al, 2017b), suggesting slope instability as a trigger for movement. Because activity in classic gullies is so sporadic there are only ~40 examples where timing can be constrained to within less than 3 months and the activity tends to occur in winter during defrosting at that latitude (Dundas et al, 2017b).…”

Section: Compositional Datamentioning

confidence: 99%

“…In considering the cascade of sediments relatively little work has focussed on establishing terrestrial analogues and understanding the processes in the erosional part of martian gullies (i.e., the alcoves). A notable exception is the study by Okubo et al (2011) who examined the potential triggers of landslides in alcoves to supply sediment to martian gullies in Gasa crater. However, these authors did not consider the fate of the sediments postfailure.…”

Section: Future Directionsmentioning

confidence: 99%

Martian gullies: a comprehensive review of observations, mechanisms and insights from Earth analogues

Conway

Haas

Harrison

2018

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Characteristic landforms and geomorphic features associated with impact structures: Observations at the Dhala structure, north‐central India

Singh

Pati

Sinha

et al. 2021

Earth Surf Processes Landf

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Geomorphological study of some of the just more than 200 known terrestrial impact structures has demonstrated that despite extensive degradation, important geomorphological keys, such as drainage pattern, topographic signatures, erosional landforms, and depositional features, can still be assessed. They can provide possible indicators to assist in the recognition of further impact structures, especially on Precambrian shields and cratonic landmasses. This study documents the surface features and landforms of the Paleoproterozoic, about 11 km diameter Dhala impact structure in India. The Dhala structure has an estimated age that is constrained stratigraphically between 1.7 and 2.5 Ga. This structure is deeply eroded, and barely has a morphological resemblance to other known terrestrial or extraterrestrial impact structures.We have analyzed the operative surface-forming processes for the Dhala area.We demand to continue the in-depth study of all terrestrial impact structures, especially the pre-Paleozoic ones, so that geomorphological criteria can be rigorously constrained and applied in conjunction with a priori remote sensing and field data to support the identification of new structures prior to their ultimate confirmation using diagnostic evidence of shock metamorphism.

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Constraints on mechanisms for the growth of gully alcoves in Gasa crater, Mars, from two-dimensional stability assessments of rock slopes

Cited by 23 publications

References 72 publications

Recent (Late Amazonian) enhanced backweathering rates on Mars: Paracratering evidence from gully alcoves

Recent (Late Amazonian) enhanced backweathering rates on Mars: Paracratering evidence from gully alcoves

Martian gullies: a comprehensive review of observations, mechanisms and insights from Earth analogues

Characteristic landforms and geomorphic features associated with impact structures: Observations at the Dhala structure, north‐central India

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