Giant Desiccation Polygons of Great Basin Playas

Neal, James T.; Langer, Arthur M.; Kerr, Paul F.

doi:10.1130/0016-7606(1968)79[69:gdpogb]2.0.co;2

Cited by 135 publications

(80 citation statements)

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“…Illite and kaolinite were the dominate clays present in all of the samples tested. Lucerne Dry Lake sediments appear to be slightly coarser than the results reported from 11 other cracked playas by Neal et al (1968). We report their results in Table 5.…”

Section: Xrd Analysis Of the Hermit Formation Lucerne Dry Lake And Ocontrasting

confidence: 63%

Sand injectites at the base of the Coconino Sandstone, Grand Canyon, Arizona (USA)

Whitmore

Strom²

2010

Sedimentary Geology

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Section: Xrd Analysis Of the Hermit Formation Lucerne Dry Lake And Ocontrasting

confidence: 63%

Sand injectites at the base of the Coconino Sandstone, Grand Canyon, Arizona (USA)

Whitmore

Strom²

2010

Sedimentary Geology

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“…Dans la plupart des cas, les polygones ainsi formés présentent un diamètre relativement faible, ne dépassant pas quelques mètres, ce qui permet de les différencier de ceux liés aux coins de glace (Black, 1976). Cependant, il arrive qu'ils atteignent des dimensions nettement plus élevées : supérieures à 10 m, parfois même 100 m et plus (Knechtel, 1951 ;Willden et Mabey, 1961 ;Neal et al, 1968). Mais, dans tous les exemples traités, les formations touchées présentent une très forte teneur en argiles et carbonates ainsi qu'une capacité de rétraction élevée, ce qui n'est pas le cas des dépôts des Valets composés principalement de graviers et de sables.…”

Section: Interprétation -Discussionunclassified

Présence d’un réseau de grands polygones au sud de l’estuaire de la Gironde (France) : interprétation et implications paléoclimatiques

Texier¹

2007

gpq

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Une photographie aérienne prise à basse altitude a permis de repérer un réseau de grands polygones au sud de l'estuaire de la Gironde (France). Ses caractéristiques morphométriques ansi que celles de son contexte topographique et sédimentaire permettent d'exclure une origine liée à des phénomènes de dessiccation, de dissolution différentielle, d'haloturbation ou de tension. Il résulte vraisemblablement de contractions thermiques et constitue un nouveau témoignage de la présence d'un pergélisol en Médoc et dans les environs de Bordeaux (45° latitude Nord). Lors de son développement, vraisemblablement contemporain du dernier Pléniglaciaire, les températures moyennes annuelles de l'atmosphère ne devaient pas dépasser dans cette région -8°C.

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“…(For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) meters (El Maarry et al, 2010, 2012Harris, 2004;Neal et al, 1968;Weinberger, 1999), teepee structures from chemical precipitates (Dixon, 2009;Shaw and Thomas, 1989), or patterned ground from thermal cycling or ice-related processes (Chan et al, 2008;Korteniemi and Kreslavsky, 2012;Levy et al, 2009;Mangold et al, 2004;Mellon, 1997). There are no obvious vertical structures in the sediment beneath the scalloped layer edges, however, so that direct evidence for any of these mechanisms is lacking.…”

Section: Interpretation Of Fine-textured Depositsmentioning

confidence: 99%

Sedimentology and climatic environment of alluvial fans in the martian Saheki crater and a comparison with terrestrial fans in the Atacama Desert

Morgan

Howard

Hobley

et al. 2014

Icarus

110

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a b s t r a c tThe deflated surfaces of the alluvial fans in Saheki crater reveal the most detailed record of fan stratigraphy and evolution found, to date, on Mars. During deposition of at least the uppermost 100 m of fan deposits, discharges from the source basin consisted of channelized flows transporting sediment (which we infer to be primarily sand-and gravel-sized) as bedload coupled with extensive overbank mud-rich flows depositing planar beds of sand-sized or finer sediment. Flow events are inferred to have been of modest magnitude (probably less than $60 m 3 /s), of short duration, and probably occupied only a few distributaries during any individual flow event. Occasional channel avulsions resulted in the distribution of sediment across the entire fan. A comparison with fine-grained alluvial fans in Chile's Atacama Desert provides insights into the processes responsible for constructing the Saheki crater fans: sediment is deposited by channelized flows (transporting sand through boulder-sized material) and overbank mudflows (sand size and finer) and wind erosion leaves channels expressed in inverted topographic relief. The most likely source of water was snowmelt released after annual or epochal accumulation of snow in the headwater source basin on the interior crater rim during the Hesperian to Amazonian periods. We infer the Saheki fans to have been constructed by many hundreds of separate flow events, and accumulation of the necessary snow and release of meltwater may have required favorable orbital configurations or transient global warming.

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Giant Desiccation Polygons of Great Basin Playas

Cited by 135 publications

References 0 publications

Sand injectites at the base of the Coconino Sandstone, Grand Canyon, Arizona (USA)

Sand injectites at the base of the Coconino Sandstone, Grand Canyon, Arizona (USA)

Présence d’un réseau de grands polygones au sud de l’estuaire de la Gironde (France) : interprétation et implications paléoclimatiques

Sedimentology and climatic environment of alluvial fans in the martian Saheki crater and a comparison with terrestrial fans in the Atacama Desert

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