The response of the water table in coastal aeolian systems to changes in sea level

Kocurek, Gary; Robinson, Neville I.; Sharp, John M.

doi:10.1016/s0037-0738(00)00137-8

Cited by 61 publications

(53 citation statements)

References 14 publications

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“…For these Earth examples, dry-system dunes accumulated during low-stands, but sand availability was apparently terminated with the onset of marine transgression. Subsequent deflation occurred to the rising water table, which was the inland response to the marine transgression (see Kocurek et al 2001). Continued rise of the water table allowed for the accumulation of sabkha and related deposits overlying the surface.…”

Section: Marsmentioning

confidence: 99%

Source-to-Sink

Kocurek¹,

Ewing²

2012

Sedimentary Geology of Mars

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Eolian dune fields on Earth and Mars evolve as complex systems within a set of boundary conditions. A source-to-sink comparison indicates that although differences exist in sediment production and transport, the systems largely converge at the dune-flow and pattern-development levels, but again differ in modes of accumulation and preservation. On Earth, where winds frequently exceed threshold speeds, dune fields are sourced primarily through deflation of subaqueous deposits as these sediments become available for transport. Limited weathering, widespread permafrost, and the lowdensity atmosphere on Mars imply that sediment production, sediment availability, and sand-transporting winds are all episodic. Possible sediment sources include relict sediments from the wetter Noachian; slow physical weathering in a cold, water-limited environment; and episodic sediment production associated with climatic cycles, outflow events, and impacts. Similarities in dune morphology, secondary airflow patterns over the dunes, and pattern evolution through dune interactions imply that dune stratification and bounding surfaces on Mars are comparable to those on Earth, an observation supported by outcrops of the Burns formation. The accumulation of eolian deposits occurs on Earth through the dynamics of dry, wet, and stabilizing eolian systems. Dry-system accumulation by flow deceleration into topographic basins has occurred throughout Martian history, whereas wetsystem accumulation with a rising capillary fringe is restricted to Noachian times. The greatest difference in accumulation occurs with stabilizing systems, as manifested by the north polar Planum Boreum cavi unit, where accumulation has occurred through stabilization by permafrost development. Preservation of eolian accumulations on Earth typically occurs by sediment burial within subsiding basins or a relative rise of the water table or sea level. Preservation on Mars, measured as the generation of a stratigraphic record and not time, has an Earth analog with infill of impact-created and other basins, but differs with the cavi unit, where preservation is by burial beneath layered ice with a climatic driver.

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Section: Marsmentioning

confidence: 99%

Source-to-Sink

Kocurek¹,

Ewing²

2012

Sedimentary Geology of Mars

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“…The colour of these units could indicate inheritance of ferruginous coatings due to limited aeolian transportation of this sand following deflation from the reddened parent material. It is envisaged that vegetation cover was reduced at this time due to a regional lowering of the water table in response to the rapidly falling sea-levels during MIS 2 (Kocurek et al, 2001).…”

Section: Evolution Prior To Mismentioning

confidence: 99%

The formation and evolution of the barrier islands of Inhaca and Bazaruto, Mozambique

et al. 2006

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“…In order to avoid this problem and to make the model more realistic, we consider that the sand hill has a constant profile in the upwind backshore area, which has a width of Δx ≈ 25 m. Whereas in reality the sand surface close to the beach and water table may have profiles much more complex than in the model depicted in Fig. 5 ( Kocurek et al, 2001), modeling of the detailed process leading to the accumulation of sand at the backshore and the formation of the sand beach is out of the scope of the present work. Indeed, using different profiles for the sand beach or different values of Δx does not change the results presented in the next section, provided there is a sufficient amount of sand above the water level that serves as an upwind source of sand for the dune field.…”

Section: Simulations Of Coastal Dune Fieldsmentioning

confidence: 99%

“…The dynamics of the water table in some aeolian sand systems is connected with seasonal variations in climate and rainfall , and has been modeled by many different authors (de Castro Ochoa and Muñoz-Reinoso, 1997; Kocurek et al, 2001). However, quantitatively little is known about dune field morphodynamics in the presence of a varying groundwater level.…”

Section: Introductionmentioning

confidence: 99%

Model for a dune field with an exposed water table

Luna¹,

Parteli²,

Herrmann³

2012

Geomorphology

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Aeolian transport in coastal areas can be significantly affected by the presence of an exposed water table. In some dune fields, such as in Lençóis Maranhenses, northeastern Brazil, the water table oscillates in response to seasonal changes of rainfall and rates of evapotranspiration, rising above the ground during the wet season and sinking below in the dry period. Understanding dune mobility in an environment with a varying groundwater level is essential for the study of long-term evolution of many dune fields. Here we apply a model for aeolian dunes to study the genesis of coastal dune fields in the presence of an oscillating water table. We find that the morphology of the field depends on the time cycle, T w , of the water table and the maximum height, H w , of its oscillation. Our calculations show that long chains of barchanoids alternating with interdune ponds, such as those found at Lençóis Maranhenses, arise when T w is of the order of the dune turnover time, whereas H w dictates the growth rate of dune height with distance downwind.

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The response of the water table in coastal aeolian systems to changes in sea level

Cited by 61 publications

References 14 publications

Source-to-Sink

Source-to-Sink

The formation and evolution of the barrier islands of Inhaca and Bazaruto, Mozambique

Model for a dune field with an exposed water table

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