Dating desert pavements – First results from a challenging environmental archive

Abstract

Desert pavements are widespread landforms of arid environments. They consist of a monolayer of clasts at the surface, associated with an underlying unit of eolian fines. In some situations, buried desert pavements can be observed, which is interpreted as a change in the environmental conditions. Therefore, it is believed that desert pavements represent important paleoenvironmental sediment archives, especially for arid environments, where natural archives of past environments are rare. To better understand the formation process of desert pavements and to enable the paleoenvironmental interpretation of these valuable sediment archives, reliable chronologies are of crucial importance. Thus, OSL dating was applied to samples from well-developed desert pavements in two different study areas, the Cima Volcanic Field, eastern Mojave Desert, USA, and the desert of northeastern Badia, Jordan.To test the suitability of the sediments for OSL dating, the luminescence characteristics of the fine-and coarse-grain quartz fraction are described and compared. Finally, first OSL ages are presented.2

OSL Age Determination of Archaeological Stone Structures Using Trapped Aeolian Sediments: A Case Study from the Negev Highlands, Israel

“…In this study, no signal component fitting was carried out. However, the signal decay rates are very similar to decay rates of coarse grain samples from Jordan, which were measured with the same instrumental configuration (Fuchs et al., ). In that study, it was confirmed that the signal was strongly dominated by the fast component, which is a crucial precondition for the use of the SAR protocol.…”

Environmental history recorded in aeolian deposits under stone pavements, Mojave Desert, USA

“…The fine-grain quartz fraction (4-11 µm) was extracted by sedimentation and etched with 34 % pre-treated H 2 SiF 6 for several days. For details see Fuchs et al (2015). Between 16 and 20 aliquots (mask size 4 mm) were measured for the coarse-grain samples and 7 aliquots for the fine-grains samples.…”

“…This subsequent emplacement (and admixture to the fine-grained matrix by closing of the cracks after thorough soil wetting) of coarse grains is also supported by the comparably high overdispersion or scatter in individual De values (broad kernel density estimate curves in Figure 6A). For a detailed discussion on these issues see Fuchs et al (2015). Since the fine grain ages of section P 3 are interpreted as representing primary deposition of sediment, these are used as age control for the correlated sections and serve as base for the following interpretation.…”

Late Quaternary aeolian sand deposition sustained by fluvial reworking and sediment supply in the Hexi Corridor — An example from northern Chinese drylands

“…Such an effective trapping of distinct silt and sand units from bypassing air flow (~1 m/ka at maximum) is considered unlikely. For comparison, dated fine aeolian sediments in the Mojave Desert, USA, and in northern Jordan (Fuchs et al, 2015) reveal much lower accumulation rates beneath a desert pavement. Thus, the accretionary process seems to be a minor contributor to the underlying deposits.…”