Pans, Playas and Salt Lakes

Shaw, Paul; Bryant, Robert G.

doi:10.1002/9780470710777.ch15

Cited by 41 publications

(31 citation statements)

References 144 publications

(288 reference statements)

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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%

“…Their level surface implies they are probably composed of fine sediment deposited from suspension. Alluvial fans in enclosed basins typically terminate in nearly level playas that receive fine suspended sediment that is carried beyond the end of the fan (Shaw and Thomas, 1989). Although the higher benches in Saheki crater are spatially limited to bordering the southern crater rim (Fig.…”

Section: Interpretation Of Benchesmentioning

confidence: 99%

“…Being the endpoint for both suspended and dissolved loads, playa sediments are commonly rich in salts concentrated from evaporation of ephemeral shallow lakes or delivered by groundwater (Dixon, 2009;Langer and Kerr, 1966;Shaw and Thomas, 1989;Yechieli and Wood, 2002). Solute-cemented playa deposits are common in the southwestern United States and in the salars of the Atacama Desert.…”

Section: Interpretation Of Benchesmentioning

confidence: 99%

“…In terrestrial enclosed basins, the fan and playa deposits interfinger during basin infilling (e.g., Shaw and Thomas, 1989). The stratigraphy of terminal deposits in enclosed basin centers often alternates between playa and lacustrine sediments, with varying degrees of interbedded and co-deposited chemical precipitates (Pueyo et al, 2001;Smith, 1957Smith, , 1974.…”

Section: Interpretation Of Benchesmentioning

confidence: 99%

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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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Section: Interpretation Of Fine-textured Depositsmentioning

confidence: 99%

Section: Interpretation Of Benchesmentioning

confidence: 99%

Section: Interpretation Of Benchesmentioning

confidence: 99%

Section: Interpretation Of Benchesmentioning

confidence: 99%

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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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“…Large salt lakes (or playas) are a common feature of arid areas, and are particularly widespread in Australia (Shaw & Thomas, 1999). They form a large proportion of inland aquatic ecosystems at a global scale and face a range of threats, not the least being enhanced salinisation and pollution (Williams, 1993(Williams, , 2002.…”

Section: Introductionmentioning

confidence: 99%

Response of fringing vegetation to flooding and discharge of hypersaline water at Lake Austin, Western Australia

Etten

Vellekoop

2009

Hydrobiologia

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Patterns and dynamics of the salt marsh vegetation that surrounds many of the salt lake systems of arid/semi-arid Australia are poorly known. Lake Austin is a very large salt lake with extensive areas of fringing salt marsh; it is located in the arid Yilgarn Region of Western Australia. In this study, the changes in this vegetation over a 4-year period (1998–2002), during which both a major flooding event and addition of hypersaline groundwater from a nearby mining operation occurred, are reported. The monitoring program, based on Before-After-Control-Impact (BACI) principles, was designed to detect impacts of discharging hypersaline water into the lake; however, the flooding event, the result of above average rainfall in early 2000, complicated the results. The rains of 2000 and subsequent inundation of the vegetation immediately fringing the lake bed and major inlet channels resulted in dramatic changes to the species composition of annual and short-lived species and growth of perennial species. Flooding resulted in substantial death and damage to perennial shrubs (particularly Halosarcia fimbriata) due most likely to a combination of several weeks/months of inundation and smothering by macroalgae and Ruppia, with smaller plants and those closer to the lake bed impacted upon to a greater degree. Seed germination and recruitment of new Halosarcia plants was substantial as floodwaters receded with the majority of these seedlings surviving some 2 years after flooding despite the severe drought that followed the flood. Growth rates of seedlings differed substantially and were linked to subtle differences in micro-topography. Recruitment following flooding was also demonstrated in in vitro experiments involving inundated soil cores, provided water was relatively non-saline (conductivity \u3c30 mS cm−1). A conceptual model is proposed to explain changes in fringing vegetation in response to frequency, depth, period and salinity of flooding in relation to micro-topography. Despite the profound effect of flooding, impacts of discharge were identified, with changes in topsoil pH and salinity greater in areas closer to the discharge than those further away. Impacts on vegetation characteristics were not detected

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Estimating aerodynamic roughness over complex surface terrain

et al. 2013

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[1] Surface roughness plays a key role in determining aerodynamic roughness length (z o ) and shear velocity, both of which are fundamental for determining wind erosion threshold and potential. While z o can be quantified from wind measurements, large proportions of wind erosion prone surfaces remain too remote for this to be a viable approach. Alternative approaches therefore seek to relate z o to morphological roughness metrics. However, dust-emitting landscapes typically consist of complex small-scale surface roughness patterns and few metrics exist for these surfaces which can be used to predict z o for modeling wind erosion potential. In this study terrestrial laser scanning was used to characterize the roughness of typical dust-emitting surfaces (playa and sandar) where element protrusion heights ranged from 1 to 199 mm, over which vertical wind velocity profiles were collected to enable estimation of z o . Our data suggest that, although a reasonable relationship (R 2 > 0.79) is apparent between 3-D roughness density and z o , the spacing of morphological elements is far less powerful in explaining variations in z o than metrics based on surface roughness height (R 2 > 0.92). This finding is in juxtaposition to wind erosion models that assume the spacing of larger-scale isolated roughness elements is most important in determining z o . Rather, our data show that any metric based on element protrusion height has a higher likelihood of successfully predicting z o . This finding has important implications for the development of wind erosion and dust emission models that seek to predict the efficiency of aeolian processes in remote terrestrial and planetary environments.

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Pans, Playas and Salt Lakes

Cited by 41 publications

References 144 publications

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

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

Response of fringing vegetation to flooding and discharge of hypersaline water at Lake Austin, Western Australia

Estimating aerodynamic roughness over complex surface terrain

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