A timeline in stone
In the arid Patagonian steppe, a rocky outcrop called Alero El Puesto 1 (AEP-1) holds a stratified record of deep time. This open-air site, part of the Piedra Museo locality, contains evidence that fundamentally challenged previous models for the peopling of the Americas. Systematic excavations, led by archaeologist Laura Miotti starting in 1995, uncovered stone tools directly associated with the remains of extinct Pleistocene megafauna. Radiocarbon dating of charcoal and bone collagen from the lowest occupation layers places humans at this spot around 12,900 years ago.
The animal remains belong to species that vanished at the end of the last ice age. Evidence points to the butchering of the American horse (Hippidion saldiasi) and the giant ground sloth (Mylodon darwinii). Cut marks and percussion fractures on the bones of these large animals show that early inhabitants processed carcasses on-site. More than 80% of the identifiable bones in the oldest layers belong to these extinct species, showing their importance to the hunter-gatherers who occupied the area. The discoveries at Piedra Museo provide clear, dated evidence of human interaction with megafauna in South America thousands of years before the "Clovis-first" culture appeared in North America.
A hunter's toolkit
The artifacts left behind at Piedra Museo document a sophisticated stone tool technology. The hunter-gatherers used local raw materials, including chalcedony and chert, to craft their implements. Among the most significant finds are distinctive "fishtail" projectile points, also known as Fell 1 points. These spear tips, with their carefully shaped stemmed bases for hafting, represent a technology found at early Paleo-Indian sites across South America.
Excavations at the AEP-1 rockshelter revealed a well-preserved sequence of occupation layers, with the earliest human evidence found in stratigraphic units 5 and 6. In addition to projectile points, the lithic collection includes various scrapers and blades designed for processing hides and other materials. This toolkit was highly adapted for a mobile, big-game hunting lifestyle in the cool, open tundra-steppe environment of late Pleistocene Patagonia. The presence of this technology so early in southern Patagonia demonstrates a rapid human expansion into the farthest reaches of the continent.