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It has been hypothesised that in sand seas where multiple dune generations occur, each generation represents a distinct terrestrial response to contrasting palaeoatmospheric circulation conditions (Lancaster N, Kocurek G, Singhvi A, Pandey V, Deynoux M, Ghienne J-F et al. (2002) Late Pleistocene and Holocene dune activity and wind regimes in the western Sahara Desert of Mauritania. Geology 30: 991–994). However, reconstructing dunefield accumulation and preservation chronologies has often utilised a limited suite of samples because of the difficulties realised in accessing unconsolidated aeolian sands, which has limited the capacity to test this hypothesis. In the eastern United Arab Emirates, artificial excavation for quarrying and construction have generated a unique opportunity to examine and sample the internal structures of dune systems, and to generate data to test the hypothesis of dune generational development. This paper presents new data and chronologies from a multigenerational analysis of dune accumulation in the northeast dunefield of the Rub’ al-Khali. A complex developmental history during the Holocene is revealed, which does not fully conform to the notion of each dune generation forming in distinct palaeoclimatic phases, since the age ranges represented in the accumulation of secondary dunes is also found within a longer suite of accumulation ages from the underlying megaridges. [ABSTRACT FROM AUTHOR]

Abstract: The northeastern sector of the Rub'' al-Khali desert in the eastern United Arab Emirates (UAE) is dominated by large NE–SW trending dune ridges orientated perpendicular to the currently prevailing northwesterly wind regime. In this study, extensive use has been made of artificially exposed sections through these major dune ridges that reveal internal sedimentary structures and allow an intensive, high-resolution sampling programme to be carried out. Here, we present the optical dating results for samples from 7 sections. The results indicate that dune activity and preservation occurred within the periods 7–3ka, 16–10ka and 22–20ka with evidence of earlier preservation during marine oxygen isotope stages MIS 3 and 5, with net accumulation rates in the range 2.2–25m.ka−1. In several instances, hiatuses in the preserved record of dune accumulation coincide with stratigraphic bounding surfaces visible in the exposed section profiles with associated truncation of internal sedimentary structures. Caution must be exercised when interpreting such gaps in the recorded accumulation chronologies of these dunes since these may simply constitute phases of low preservation potential rather than phases of low aeolian activity. Other factors such as sediment supply and availability in relation to sea-level dynamics may be significant and are also considered. [Copyright &y& Elsevier]

An early-to mid-Holocene humid phase has been identified in various Arabian geo-archives, although significant regional heterogeneity has been reported in the onset, duration and stability of this period. A multi-proxy lake and dune record from Wahalah in the United Arab Emirates (UAE) documents significant variations in hydrology, biological productivity and landscape stability during the first half of the Holocene. These data reveal that post-Last Glacial Maximum dune emplacement continued into the earliest part of the Holocene, with the onset of permanent lacustrine sedimentation at the site commencing ∼8.5 ka cal. BP. A long-term shift towards more arid conditions is inferred between ∼7.8 and 5.9 ka cal. BP, with intermittent flooding of the basin and distinct phases of instability throughout the catchment area. This transition is linked to the southwards migration of the Intertropical Convergence Zone (ITCZ) and associated weakening of monsoon rains. A peak in landscape instability is recorded between ∼5.9 and 5.3 ka cal. BP and is marked by a pronounced increase in regional dune emplacement. These variations are considered alongside the record of human settlement raising important questions about the interactions between population demographics, climate and environment in southeast Arabia during the Neolithic. [ABSTRACT FROM AUTHOR]