Landscape development and the evidence for early human occupation in the inter-Andean tropical lowlands of the Magdalena River, Colombia

This dissertation presents the results of a decade of investigations in the Middle Magdalena Valley designed to understand the landscape development and the nature of early human occupations. The Magdalena River is the most prominent corridor through the Andean mountains in northern South America. Since 1990 stratified open sites were located during CRM projects. Six were tested (three with small excavations). These sites located in the paleo-floodplain at ca. 150 m asl. have provided a preceramic cultural sequence spanning the last 5000 to 10,400 years. The deposits contained stone artifacts and charcoal to variable depths; in the summit of the paleo-terrace early deposits are buried in the Bt horizon from ca. 40 cm to 80 cm below the surface but in the interior small Cano Regla valley deposits reach 120 cm in depth.; A tightly clustered series of radiocarbon dates place the earliest occupations in the Late Pleistocene. The older dates come from lower cultural layers of the sites La Palestina (10,400 BP, 10,230 BP, 10,260 BP and 10,300 BP), San Juan de Bedout (10,350 BP) and Nare (10,350 BP and 10,400 BP). Raw material is abundant, particularly chert and milky quartz cobbles. Thousands of waste flakes, many the product of bipolar flaking, were recovered as well as a number of expedient tools made on flakes. Other tools were fashioned from large flakes by unifacial and bifacial retouch. Bifacially flaked points varied considerably in size (4 to 16 cm) and shape, although triangular contracting stemmed forms were the most common. Biface edges were reduced using controlled percussion and, in the final stage, pressure retouch. A hundred plano-convex scrapers were recovered that are remarkably uniform in size and shape. Palestina, Penones and Nare sites have bifacial thinning flakes from the bottom of the occupation and fragments of projectile points appeared in Penones in the level dated to 6000 B.P.; Geoarchaeological evidence confirms important depositional activity of a braided Magdalena River during the Early Holocene period. Early inhabitants camped around beaches and islands, near streams, and swamps. Although no faunal remains were preserved in the Middle Magdalena sites, lithic artifacts suggest hunting activities and faunal preparation. They probably captured aquatic mammals (manatee), riverine fauna (fish, caiman, turtle), and medium sized terrestrial mammals.