The Middle Pleistocene Al Mahrúqah Formation in the Murzuq Basin, northern Sahara, Libya evidence for orbitally-forced humid episodes during the last 500,000 years

Micromorphological approach to polycyclic pedogenesis on the Messak Settafet plateau (central Sahara): Formative processes and palaeoenvironmental significance

“…Furthermore, the U/Th dating of 236 k YBP (Cremaschi, 1998) on CaCO 3 concretions from a 2B horizon in the area of wadi Berjuj suggests a Middle Pleistocene pedogenetic phase too, during which the mobilization of calcite in the soil occurred. This age determination points to a humid phase corresponding to the MIS 7, substantially in accordance with the deposition of several lacustrine carbonatic terraces in the region, recently dated by Geyh and Thiedig (2008) between 260 and 205 k YBP. Besides this chronological correspondence, Pleistocene pedogenetic phases on the Messak Settafet plateau should occur synchronously with the formation of lake deposit in the adjoining areas, such as in the Murzuq region (Thiedig et al, 2000;Geyh and Thiedig, 2008) and along the wadi Shati (Petit-Maire, 1982).…”

“…Recent palaeoenvironmental investigations have shown that Middle and Late Pleistocene interglacials may have been wetter than today (Thiedig et al, 2000;Drake et al, 2008;Geyh and Thiedig, 2008;Gallala et al, 2010), and higher water availability also is recorded for the Early and Middle Holocene (Cremaschi, 1998(Cremaschi, , 2002Zerboni, 2006Zerboni, , 2007Zerboni, , 2008Cremaschi and Zerboni, 2009;Cremaschi et al, 2010). Geyh and Thiedig (2008) identified several lacustrine terraces accumulated in the SW Fezzan during humid episodes at N420, 380-290, 260-205, and 140-125 k YBP, roughly coincident with the MIS (Marine Isotope Stage) 9, MIS 7, and MIS 5.5 interglacial periods; moreover, after Termination 1, a last phase of surface aquifers reactivation occurred during the Holocene African Humid Period, dating in the region of 9.8-5 uncal. k YBP (Cremaschi, 2002;Zerboni, 2006Zerboni, , 2007Cremaschi and Zerboni, 2009;Cremaschi et al, 2010).…”

Geomorphological Map of the Tadrart Acacus Massif and the Erg Uan Kasa (Libyan Central Sahara)

“…The meteorological stations closest to the study area indicate that the mean annual temperature is between 228 and 258C, and the mean annual rainfall is between 0 and 10 mm (Walter & Lieth, 1960). During the Pleistocene interglacials and interstadials, the region was wetter than today (Drake et al, 2008;Geyh & Thiedig, 2008;Petit-Maire, 1982;Zerboni et al, 2011), and higher water availability is also recorded for the Early and Middle Holocene (Cremaschi & Zerboni, 2009;Cremaschi, Zerboni, Spötl, & Felletti, 2010).…”

Geomorphological Map of the Messak Settafet and Mellet (Central Sahara, SW Libya)

“…The Middle and Late Pleistocene interglacials may have been wetter than today (Petit-Maire, 1982;Drake et al, 2008;Geyh and Thiedig, 2008;Zerboni et al, 2011), and higher water availability is also recorded for the Early and Middle Holocene (Cremaschi and Zerboni, 2009;Cremaschi et al, 2010). In the region, Petit-Maire (1982) and Geyh and Thiedig (2008) identified several humid episodes corresponding to lacustrine sedimentation, and roughly coincident with the MIS (Marine Isotope Stage) 9, 7, and 5.5 interglacial periods; moreover, a last phase of surface aquifer reactivation occurred during the Holocene African Humid Period (e.g., Cremaschi and Zerboni, 2009;Cremaschi et al, 2010).…”