Geo-archeological interpretation of Acheulian calc-pan sites at Doornlaagte and Rooidam (Kimberley, South Africa)

Abstract

Two Acheulian occupation sites of the Kimberley District, Doornlaagte and Rooidam, are found geologically sealed and in semi-primary context within complex sequences of calcareous and arenaceous sediments. The sedimentary columns are analyzed and interpreted in terms of sedimentology and stratigraphy, indicating major occupation along the margins of shallow, seasonal lakes; sporadic visits to the fluctuating shoreline are also indicated thereafter, until the Doornlaagte playa began to dry out, and at Rooidam until the whole depression was submerged. The evolution of the related calcareous pans is discussed and attributed to cycles of alternating erosion (aeolian, chemical and fluvial) and deposition (lacustrine and colluvial, including reworked aeolian components). In addition to pedogenetic “calcretes,” most of the limestones of the pan sedimentary sequences are lacustrine in origin. Palaeosols also include fersiallitic soils. The various geomorphologic events indicate repeated and appreciable environmental changes during the mid-Pleistocene. The detailed climatic oscillations recorded at Doornlaagte and Rooidam cannot be correlated, and the latter site is appreciably younger, with a provisional Th U date of 115,000 BP for the late Acheulian (“Fauresmith”) occupation.