Between Westerlies and the Intertropical Convergence Zone: a high-resolution paleoclimate and paleoenvironment study of Holocene sediments of the Layla lakes, Saudi Arabia

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The Arabian Peninsula underwent strong aridification during the Holocene towards the present-day hot arid climate. Consequently, the savannah-like landscape with local surface water disappeared that had provided humans with a connection between Africa and the Fertile Crescent. This transition is documented only from marginal settings, and open questions about the timing and the climatic framework still exist. The fundamental hypothesis is that decreasing insolation prevented the Intertropical Convergence Zone to penetrate further into central Arabia during summer. Because of the lack of climate archives this has not yet been constrained for central Arabia, and the role of Westerly precipitation during winter remains unclear. Until the 1990s, groundwater-fed lakes existed in sinkholes approx. 300 km south of Riyadh near the town of Layla. Intensive groundwater abstraction caused lake levels to sink and exposed a unique laminated lacustrine climate archive for the middle and late Holocene in the centre of the Arabian Peninsula where such archives are missing. We propose a multi-proxy approach that combines analyses of sediment facies, mineralogy, geochemistry, palynology, diatoms, ostracods, and stable isotopes and to establish a robust chronology to retrieve environmental information. We expect fundamental new insights into the aridification of the Arabian Peninsula during the middle and late Holocene and into atmospheric circulation dynamics at the transition between Westerlies and the Intertropical Convergence Zone, an area where paleoclimate information is still missing.