Desert pavement characteristics on wadi terrace and alluvial fan surfaces: Wadi Al-Bih, U.A.E. and Oman

Al-Farraj, Asma; Harvey, Adrian

doi:10.1016/s0169-555x(00)00049-0

Cited by 95 publications

(84 citation statements)

References 21 publications

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“…The sharp mosaic boundaries between young bar and swale units created by the contrast of surface clast dimensions and roughness diminish over time. Additionally, coarse cobbles and gravel weather into smaller clasts (Sharp and Birman, 1963;Al-Faraj and Harvey, 2000). This process explains the decrease in clast size observed in the progression from bars to flattened bars (Table 1).…”

Section: Hypothesized Landform Evolutionmentioning

confidence: 89%

Biogeomorphology of a Mojave Desert landscape — Configurations and feedbacks of abiotic and biotic land surfaces during landform evolution

et al. 2014

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Terrestrial ecosystems can be more holistically understood by investigating the morphology of landscape mosaics, the assemblage of their ecological communities, and the linkages and feedbacks between the mosaics and communities. The overarching objectives of this study were to: (1) study the abiotic and biotic configurations of landform units as mosaics within a Mojave Desert chronosequence; and (2) elucidate their potential feedbacks, interactions, and dynamics during landform evolution. Seven landform units distributed over three geomorphic ages were identified, including: young bars and swales; intermediate-aged flattened bars, flattened swales, and bioturbation units; and old desert pavements and shrub zones. These landform units were characterized according to abiotic and biotic land surface properties. Landform units were statistically distinct and predictable based on a specific suite of abiotic and biotic properties. Vascular plant functional group and biological soil crust community diversity varied with geomorphology, with greatest diversity associated with bars and shrub zones and lowest diversity associated with desert pavements. Biological soil crust communities were controlled by geomorphic age, surface rock size, and protruding rocks with young bar units having the highest abundance and diversity. Perennial forbs were observed in old shrub zones with small rocks and few protruding rocks. A high clast density and a finer-sized clast distribution were found particularly in desert pavements and flattened swales, and generally inhibited biological soil crust and plant cover. Evolutionary trajectories for landforms of a lower piedmont landscape can be dominated by either abiotic and biotic landform processes. These two trajectories are distinctly different and are associated with their own unique linkages, feedbacks, and dynamics of abiotic and biotic land surface properties, producing a highly diverse desert landscape.

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Section: Hypothesized Landform Evolutionmentioning

confidence: 89%

Biogeomorphology of a Mojave Desert landscape — Configurations and feedbacks of abiotic and biotic land surfaces during landform evolution

et al. 2014

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“…To the northwest in the UAE, the steep slopes of the mountain make an abrupt contact with the desert plain. This contact is only softened by stepped marine terraces on the slopes (Ricateau & Richié, 1980;Kusky et al, 2005) and by alluvial fans extending from the mouths of the wadi to the plain (Al-Farraj & Harvey, 2000).…”

Section: Geological Settingmentioning

confidence: 99%

Bat urea-derived minerals in arid environment. First identification of allantoin, C4H6N4O3, in Kahf Kharrat Najem Cave, United Arab Emirates

Audra¹,

Bosák²,

Gázquez³

et al. 2017

IJS

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Abstract:Kahf Kharrat Najem Cave is a small cave in United Arab Emirates (UAE) that hosts a bat colony which is the source of guano deposits and peculiar centimeter-long yellowish stalactites. The mineralogy and geochemistry of these deposits were analyzed using powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopic microanalysis (EDX), scanning electron microscope (SEM), and stable isotope composition (δ 13 C and δ 15 N). Urea CO(NH 2 ) 2 was found to be the main compound of these stalactites, while allantoin C 4 H 6 N 4 O 3 was found to be an accessory urea byproduct. This paper is the first to mention allantoin in a cave environment. We also identified rare sulfate minerals (aphthitalite, alunite) and phosphates that probably correspond to the archerite-biphosphammite series. The occurrence of these rare bat-related minerals is due to the extremely dry conditions in the cave, which accounts for the extraordinary preservation of the guano deposits and allows for the crystallization of these very soluble minerals. cave minerals, allantoin, bat guano, bat urea, Kahf Kharrat Najem Cave, United Arab Emirates

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“…In a sand-dominated parent-material environment such as a distal fan, the initial surface has relatively few clasts with which to form a pavement. In these cases, pavement clasts must first be pushed to the surface vertically and/or distributed horizontally by freeze-thaw, wetting-drying cycles and bioturbation (Springer, 1958;Corte, 1963;Inglis, 1965), or other size-segregative processes, or possibly made available through progressive fracturing of larger clasts (Al-Farraj and Harvey, 2000;McFadden et al, 2005). As the surface gains clast-material coverage, lateral migration serves to interlock and suture the clasts as in the graveldominated case.…”

Section: Role Of Parent-materials Texture In Pavement Formation and Mementioning

confidence: 99%

Desert pavement dynamics: numerical modeling and field‐based calibration

Pelletier

Cline

DeLong

2007

Earth Surf Processes Landf

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Desert pavements are widely used as a relative surface-dating tool because they are progressively better developed on surfaces ranging from thousands to hundreds of thousands of years in age. Recent work, however, has highlighted the dynamic nature of pavements and undermined their use as surface-age indicators. Quade ( To calibrate the model, we conducted surficial geologic mapping and pavementsedimentological analysis on two desert piedmonts. Our study areas include both proximal and distal fan environments, illustrating the role of parent-material texture in controlling the mode of pavement formation. Using available geochronology, our work provides a rigorous calibration of pavement formation rates in our study areas and provides evidence supporting the use of pavements as local relative surface-age indicators over Holocene to late Pleistocene timescales.

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Desert pavement characteristics on wadi terrace and alluvial fan surfaces: Wadi Al-Bih, U.A.E. and Oman

Cited by 95 publications

References 21 publications

Biogeomorphology of a Mojave Desert landscape — Configurations and feedbacks of abiotic and biotic land surfaces during landform evolution

Biogeomorphology of a Mojave Desert landscape — Configurations and feedbacks of abiotic and biotic land surfaces during landform evolution

Bat urea-derived minerals in arid environment. First identification of allantoin, C4H6N4O3, in Kahf Kharrat Najem Cave, United Arab Emirates

Desert pavement dynamics: numerical modeling and field‐based calibration

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