Last millennium development and dynamics of vegetated linear dunes inferred from ground‐penetrating radar and optically stimulated luminescence ages |
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| Authors: | Joel Roskin Dan G Blumberg Itzhak Katra |
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| Institution: | 1. Department of Geography and Environmental Development, Ben‐Gurion University of the Negev, , Beer‐Sheva, 84105 Israel;2. Department of Maritime Civilizations and the Leon Recanati Institute for Maritime Studies (RIMS), University of Haifa, , Haifa, 31905 Israel |
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| Abstract: | Using ground‐penetrating radar, optically stimulated luminescence dating, particle‐size distribution and morphological analysis, the study of the construction phases of a vegetated linear dune in the arid north‐western Negev dunefield of Israel during the last millennium improves current knowledge about vegetated linear dunes that developed in the late Pleistocene. Vertical accretion in rapid pulses forming horizontally bedded units along the axis of vegetated linear dunes, regardless of their age, was found to be characteristic of vegetated linear dunes. The combination of the unique topographic feature of a longitudinal 5 m step‐like fall in dune crest elevation with the substantial narrowing of dune width constitutes a distinct morphological marker for interpreting local dune growth and stabilization of the last, albeit localized, dune mobilization episode at ca 0·5 ka. Evidence for lateral dune migration was not observed. Where local sediment supply exists, short episodes of powerful winds within the Holocene (with recurrence intervals separated by hundreds of years) can lead to the construction of vegetated linear dunes. The spatially constrained extent of such young dunes in the north‐western Negev may be due to limited sand availability because most of the Negev dunes were stable during the Holocene. These findings imply that vegetated linear dune construction can occur in glacial and interglacial (including Holocene) environments in semi‐arid to arid climates if certain conditions are met. In times of increased wind power during the Anthropocene, a period characterized by simultaneous rises in the human impact on the landscape and in climate variability (i.e. drought), local growth of vegetated linear dunes can be expected. This study demonstrates that ground‐penetrating radar is a reliable tool for interpreting the shallow internal structure of young vegetated linear dunes. |
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| Keywords: | Aeolian climate dune internal structure ground‐penetrating radar optically stimulated luminescence stratigraphy vegetated linear dune growth |
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