ABSTRACT
The methods used in Holocene research are numerous and they vary in different desert regions. Continuous high-resolution records of Holocene palaeoenvironments in the deserts of the world are difficult to construct because biomass production, which can serve as source of proxy records, is low under dry open-air conditions. Where available organic material is formed in exposed sites like lakes it is unlikely to be preserved in the long term in arid zones. Desert lake sediments are often interrupted and increased productivity during wet phases is often responsible for poor uniformity and continuity of biological data records. In deserts like the Sahara, lake sediments have nevertheless received much attention. Alternatively, many palaeoenvironmental studies in arid areas focus on cave shelter inclusions, e.g. in the North American Southwest where urine-impregnated packrat middens have been studied extensively. By responding to the orbital precession cycle, deserts in different hemispheres reacted out of phase with each other during the Early and Mid-Holocene. Smaller scale variability superimposed on this broad pattern is observed, but global correlation of these cycles has up to now not been possible.
