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The Zagros foreland basin is an important sedimentary archive for the tectonic and paleoclimatic evolution of the Zagros Mountains and the entire Neotethyan Arabia-Iran collision zone. By combining new geochemical high-resolution whole rock XRF data with clay mineralogy and soluble salt geochemistry we propose an evolution of the sedimentary environment in the Lurestan arc from the Serravallian to the early Pleistocene, closing a gap in understanding the complex exhumation history of the central Zagros mountain belt. An increase in ultramafic sedimentary input indicates a shift from provenance 1 to provenance 2 by ophiolite exhumation at ca.10 Ma in the Imbricated Zagros north of the Lurestan arc. Our data further indicates that the sedimentary environment of parts of the Lahbari Mb within the Lurestan arc represents a piedmont deposition of finegrained alluvial fans and siltstones with aeolian contribution deposited under hyper-arid climate conditions. These represent provenance shift 3 and were likely sourced from evaporites of the underlying Gachsaran Fm and fluvial deposits of the Lower Aghajari Mb (provenance 1 and provenance 2), uplifted by the Mountain Front Flexure at around 5.6 Ma. Combining XRF whole rock data with clay mineral data refines formation conditions of the clay minerals in the foreland basin such as palygorskite, which is revealed to be authigenic in origin in the Lower Aghajari Mb. as a function of varying Mg-content due to variations of erosion of the ultramafic and mafic rocks in the Imbricate Zagros belt. Palygorskite in the Lahbari Member is likely both inherited from the Neogene Gachsaran evaporites as well as of authigenic origin. [ABSTRACT FROM AUTHOR]

The Zagros Mountain belt in Iran comprises an extensive record of Mesozoic and Cenozoic deposits uplifted by collision of the Arabian and Iranian continental plates. This area has been shown to provide important information to decipher the climatic history of Western Asia, especially regarding the evolution of deserts in Mesopotamia and Northern Arabia. In a high-resolution geological record of 84 samples, we combine clay mineralogy and micropalaeontological observations to refine the late Neogene climate record in Northern Arabia. We investigated a 2.6-km-thick sedimentary profile from the Simply Folded Zagros Mountain belt spanning ca. 10.2 myrs from the late Middle Miocene (Serravallian) to earliest Pleistocene (Gelasian) comprising floodplain sediments and saline mudstones with a strong aeolian contribution. The clay fraction < 2 µm reveals palygorskite, smectite, illite, chlorite and the zeolite mineral erionite. Using clay mineralogy, arid conditions during the Serravallian and early Tortonian in Northern Arabia are identified, followed by semi-arid conditions during the late Tortonian. Clay mineralogy suggests a transition to sustained arid conditions during the early Messinian and provides a more complex picture on a previously proposed period of hyperaridity (NADX) in Northern Arabia penecontemporaneous with the apex of the Messinian salinity crisis. [ABSTRACT FROM AUTHOR]

Dating fossil hominids and reconstructing their environments is critically important for understanding human evolution. Here we date the potentially oldest hominin, Graecopithecus freybergi from Europe and constrain the environmental conditions under which it thrived. For the Graecopithecus-bearing Pikermi Formation of Attica/Greece, a saline aeolian dust deposit of North African (Sahara) provenance, we obtain an age of 7.37–7.11 Ma, which is coeval with a dramatic cooling in the Mediterranean region at the Tortonian-Messinian transition. Palaeobotanic proxies demonstrate C4-grass dominated wooded grassland-to-woodland habitats of a savannah biome for the Pikermi Formation. Faunal turnover at the Tortonian-Messinian transition led to the spread of new mammalian taxa along with Graecopithecus into Europe. The type mandible of G. freybergi from Pyrgos (7.175 Ma) and the single tooth (7.24 Ma) from Azmaka (Bulgaria) represent the first hominids of Messinian age from continental Europe. Our results suggest that major splits in the hominid family occurred outside Africa. [ABSTRACT FROM AUTHOR]