Preliminary optical and radiocarbon age determinations for Upper Pleistocene alluvial sediments in the southern Anti Atlas Mountains, Morocco

Abstract

This paper presents the first results of a 14 C and optical luminescence dating project on extensive alluvial silt formations in the southern Anti Atlas Mountains in southern Morocco. The silts comprise three members: basal silts, an inter-silt fluvial gravel member and a top silt member and are incised by the rivers. Top silt dates are: 11 340-11 940, 12 670-13 130 cal. yr BP, and 10.6 ± 0.7 ka (OSL). OSL dates for the inter-silt gravels are 29.6 ± 2.0 ka and for the bottom silts is 45.0 ± 3.7 ka. The sediments correlate with Soltanian stratigraphies known elsewhere in Morocco. To cite this article:

Fluvio‐lacustrine sedimentation in the Agadir‐Tissint Feija (Anti‐Atlas, Morocco): A promising palaeoclimate archive for the last glacial cycle in northwest Africa

“…A U/Th age from calci‐mudstones in a stratigraphically higher interval within S1 (51.3 ± 0.1 kyr) is located just above the maximum flooding interval and is consistent with an earlier OSL age given by Thorp et al. () in sector 3 indicating an age of ca 45 ± 3.7 kyr in S1, although the precise location of this OSL analysis in our measured section is uncertain. In sector 2, two new U/Th ages bracket the succession.…”

“…Finally, another U/Th date (11.8 ± 0.6 kyr) at the top of S3 in sector 2 (Figure ) is consistent within uncertainties with an OSL age of 10.6 ± 0.7 kyr provided by Thorp et al. () found 0.4 cm below the top of S3. They characterize the age of the latest stage of sedimentation in the depocentre.…”

“…(a) Digital elevation model of south‐western Morocco showing the Anti‐Atlas and its surrounding areas. The five feijas identified in southern Morocco are indicated (modified after Thorp et al., ). Topographic profiles reveal that feijas constitute the first lowlands southward of the Anti‐Atlas.…”

Palaeoclimate in the Saharan and Arabian Deserts during the Middle Palaeolithic and the potential for hominin dispersals

“…The evidence for this humid period comes from a range of humid proxies, with lacustrine sediments from the Chott el Djerid in southern Tunisia (Causse et al, 2003), tufa from Kharga Oasis (Blackwell et al, 2012) and Wadi Abu Had-Dib (Hamdan, 2000) in Egypt, calcrete from Ras el Wadi in northern Libya (Giraudi, 2005), travertine from Oued Noun in Morocco (Weisrock et al, 2006(Weisrock et al, , 2008, fluvial sediments from Wadi Zewana in northern Libya (Rowan et al, 2000), as well as Oued Noun (Weisrock et al, 2006) and Tassint in Morocco (Thorp et al, 2002). Thus there is evidence for humidity in the eastern Sahara and along its northern margins at this time, but no evidence in Arabia (Fig.…”

“…The 37 ka peak consists solely of sites on the northern margins of the Moroccan Sahara, with travertines and fluvial sediments from Oued Noun and a travertine from Imouzzer (Weisrock et al, 2008). Evidence for Saharan humidity at 44 ka is more widespread being provided by spring tufas from the east-central Sahara in Kharga Oasis (Sultan et al, 1997) and Wadi Abu Had-Dib (Hamdan, 2000) in Egypt as well as from fluvial activity in the semi-arid belt on the northern margins of the Sahara in Libya (Rowan et al, 2000), southern Tunisia (White et al, 1996) and Morocco (Thorp et al, 2002;Weisrock et al, 2008) (Fig. 5B).…”