MAPPING ELEMENT TRENDS USING GIS: A CASE STUDY FROM THE KAROO, SOUTH AFRICA

Haaskraal rock shelter in the Upper Karoo region in the central plateau of South Africa came into use at about AD 100-200 by preceramic hunter foragers and was used intermittently until the late AD 1800s. During that time its occupants witnessed the appearance of ceramics, livestock, then Dutch trekboers. The shelter's densely packed fill of stone artifacts, pottery, faunal remains and, later on, European items has been the subject of intensive study for two decades, resulting in dozens of papers on various aspects. One major research thrust has been the chemical fingerprinting (by INAA) of all 37 hornfels outcrops within a 7.5 km radius of the shelter. The goal of this program was to seek elemental matches between hornfels tools at the shelter and specific local outcrops within an 8 km radius of the shelter. A mass of elemental data has been assembled for each outcrop, resulting in a database of eleven short half-life elements on a total of 724 hornfels specimens. Elemental readings are then mapped via Arc-View 8.0 in order to determine spatial trends. The goal of this exercise will be to locate those elements that define clusters of neighboring outcrops. The potential of this research remains very great. If clusters of adjacent hornfels outcrops can be chemically fingerprinted, this will open up the possibility of source-studies on the hundreds of Stone Age assemblages of all ages including Acheulian , Middle Stone Age, and various Holocene industries found on the same piece of landscape.