No abstract

No abstract

orrelating the timing of events that occurred in different places, though a C difficult problem in geographic research, is important for understanding the development of human and physical landscapes. This paper focuses on the evolution of natural arid landscapes and prehistoric human activity in drylands over timescales of 1 O 3 to 1 O5 years. Our approach examines the dark rock coatings called rock varnish that are ubiquitous in arid and semiarid areas (Dorn and Oberlander 1982) and attempts to determine whether layers of rock varnish can serve as a natural CIS (geographic information system). Is it possible, in other words, to map these unique layering patterns for the purpose of establishing temporal correlations?Orange and black microlaminations in rock varnish were first recognized by Perry and Adams (1 978) as miniature sedimentary strata with the potential to record environmental change. As we point out below, orange layers record arid climates, while black layers form in humid settings.