Stoss‐side mud‐drapes: deposits of interdune pond margins

Purvis, Kevin

doi:10.1111/j.1365-3091.1991.tb01860.x

Cited by 18 publications

(17 citation statements)

References 4 publications

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“…During the dry season, deflation surfaces are present bordering the stoss side of the barchan dune. They are similar to those described by Purvis (1991) on the coast of Tunisia. These surfaces are between 18 and 23 m wide, and exhibit trough cross-bedding, dipping N240° to N270°.…”

Section: Sector Isupporting

confidence: 81%

Coastal dune fields at the São Francisco River strandplain, northeastern Brazil: morphology and environmental controls

Barbosa

Domínguez²

2004

Earth Surf Processes Landf

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Extensive coastal dune fields occur on the Quaternary strandplain associated with the São Francisco River mouth. Two different generations of dunes are identified. One is inactive, already fixed by vegetation, comprising parabolic dunes. The other generation is active, bordering the present-day shoreline and transgressing over the inactive dune field. Three morphological provinces in the active coastal dune fields are recognized. On the updrift side of the São Francisco River mouth, they are: (a) sand-sheet with shrub coppice and shadow dunes; (b) isolated dunes of the barchan-transversal type up to 5 m high, and interdune areas; and (c) a 23 m high compound dune, with superimposed small dunes. The same provinces are recognized on the downdrift side of the river mouth, with two important exceptions: the barchan-transversal and compound dunes are replaced, respectively, by (i) zibar-type dunes up to 5 m high, and (ii) a 19 m high precipitation dune, which is associated with numerous blowouts. The prevailing eastern winds from August to January favour the development of the aeolian bedforms and the migration of dunes. The shoreline orientation almost transversal to the winds and the great supply of finegrained sediments contribute to the formation of barchan-transversal types and compound dunes in the updrift side. On the other hand, in the downdrift side the shoreline orientation is almost parallel to the prevailing winds. This fact, in association with a coarser grain size in the beachface, favours the formation of zibar-type and precipitation dunes with numerous blowouts. The rate of migration of individual dunes is about 20 to 24 m per year. This study suggests that the aeolian sedimentation is a relatively recent phenomenon at the Quaternary strandplain of the São Francisco River. The first generation of dune fields initiated some time after 3000 years BP and the second generation originated some centuries ago.

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Section: Sector Isupporting

confidence: 81%

Coastal dune fields at the São Francisco River strandplain, northeastern Brazil: morphology and environmental controls

Barbosa

Domínguez²

2004

Earth Surf Processes Landf

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“…The occurrence of these mud drapes in aeolian dunes has previously been reported both from the stoss side of aeolian dunes (e.g. Purvis, 1991) and from toesets and bottomsets of lee side aeolian dunes (e.g. Gradziński & Jerzykiewicz, 1974; Langford & Chan, 1989; Mountney & Thompson, 2002; Stanistreet & Stollhofen, 2002).…”

Section: Interdunesmentioning

confidence: 77%

Aeolian sand sea development along the mid‐Cretaceous western Tethyan margin (Spain): erg sedimentology and palaeoclimate implications

Rodríguez‐López¹,

Meléndez²,

Boer

et al. 2008

Sedimentology

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The existence of a mid‐Cretaceous erg system along the western Tethyan margin (Iberian Basin, Spain) was recently demonstrated based on the occurrence of wind‐blown desert sands in coeval shallow marine deposits. Here, the first direct evidence of this mid‐Cretaceous erg in Europe is presented and the palaeoclimate and palaeoceanographic implications are discussed. The aeolian sand sea extended over an area of 4600 km2. Compound crescentic dunes, linear draa and complex aeolian dunes, sand sheets, wet, dry and evaporitic interdunes, sabkha deposits and coeval extradune lagoonal deposits form the main architectural elements of this desert system that was located in a sub‐tropical arid belt along the western Tethyan margin. Sub‐critically climbing translatent strata, grain flow and grain fall deposits, pin‐stripe lamination, lee side dune wind ripples, soft‐sediment deformations, vertebrate tracks, biogenic traces, tubes and wood fragments are some of the small‐scale structures and components observed in the aeolian dune sandstones. At the boundary between the aeolian sand sea and the marine realm, intertonguing of aeolian deposits and marine facies occurs. Massive sandstone units were laid down by mass flow events that reworked aeolian dune sands during flooding events. The cyclic occurrence of soft sediment deformation is ascribed to intermittent (marine) flooding of aeolian dunes and associated rise in the water table. The aeolian erg system developed in an active extensional tectonic setting that favoured its preservation. Because of the close proximity of the marine realm, the water table was high and contributed to the preservation of the aeolian facies. A sand‐drift surface marks the onset of aeolian dune construction and accumulation, whereby aeolian deposits cover an earlier succession of coastal coal deposits formed in a more humid period. A prominent aeolian super‐surface forms an angular unconformity that divides the aeolian succession into two erg sequences. This super‐surface formed in response to a major tectonic reactivation in the basin, and also marks the change in style of aeolian sedimentation from compound climbing crescentic dunes to aeolian draas. The location of the mid‐Cretaceous palaeoerg fits well to both the global distribution of other known Cretaceous erg systems and with current palaeoclimate data that suggest a global cooling period and a sea‐level lowstand during early mid‐Cretaceous times. The occurrence of a sub‐tropical coastal erg in the mid‐Cretaceous of Spain correlates with the exposure of carbonate platforms on the Arabian platform during much of the Late Aptian to Middle Albian, and is related to this eustatic sea‐level lowstand.

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“…13). Micaceous silty sandstones with mud flakes (Purvis, 1991) and clasts indicate an extra‐erg fluvial supply of sediment, whereas current ripples indicate fluvial transport to the south‐west along interdune corridors. Silcrete and freshwater limestone deposits together with structures such as wave ripples and desiccation cracks all indicate interdune ponding of water and gradual desiccation (Driese, 1985).…”

Section: Discussionmentioning

confidence: 99%

Stratigraphic evolution of an aeolian erg margin system: the Permian Cedar Mesa Sandstone, SE Utah, USA

2004

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The Permian Cedar Mesa Sandstone of south‐east Utah is a predominantly aeolian succession that exhibits a complex spatial variation in sedimentary architecture which, in terms of palaeogeographic setting, reflects a transition from a dry erg centre, through a water table‐controlled aeolian‐dominated erg margin, to an outer erg margin subject to periodic fluvial incursion. The erg margin succession represents a wet aeolian system, accumulation of which was controlled by progressive water table rise coupled with ongoing dune migration and associated changes in the supply and availability of sediment for aeolian transport. Variation in the level of the water table relative to the depositional surface determined the nature of interdune sedimentary processes, and a range of dry, damp and wet (flooded) interdune elements is recognized. Variations in the geometry of these units reflect the original morphology and the migratory behaviour of spatially isolated dry interdune hollows in the erg centre, locally interconnected damp and/or wet interdune ponds in the aeolian‐dominated erg margin and fully interconnected, fluvially flooded interdune corridors in the outer erg margin. Relationships between aeolian dune and interdune units indicate that dry, damp and wet interdune sedimentation occurred synchronously with aeolian bedform migration. Temporal variation in the rates of water‐table rise and bedform migration determined the angle of climb of the erg margin succession, such that accumulation rates increased during periods of rapidly rising water table, whereas sediment bypassing (zero angle of climb) occurred in the aftermath of flood events in response to periods of elevated but temporarily static water table. During these periods in the outer erg margin, the expansion of fluvially flooded interdunes in front of non‐climbing but migrating dunes resulted in the amalgamation of laterally adjacent interdunes and the generation of regionally extensive bypass (flood) supersurfaces. A spectrum of genetic depositional models is envisaged that accounts for the complex spatial and temporal evolution of the Cedar Mesa erg margin succession.

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Stoss‐side mud‐drapes: deposits of interdune pond margins

Cited by 18 publications

References 4 publications

Coastal dune fields at the São Francisco River strandplain, northeastern Brazil: morphology and environmental controls

Coastal dune fields at the São Francisco River strandplain, northeastern Brazil: morphology and environmental controls

Aeolian sand sea development along the mid‐Cretaceous western Tethyan margin (Spain): erg sedimentology and palaeoclimate implications

Stratigraphic evolution of an aeolian erg margin system: the Permian Cedar Mesa Sandstone, SE Utah, USA

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