Author: Kurt Rademaker.
This July 2019 our group began a new field project in the Puna of Junín, supported by a Faculty Initiatives Fund from the Michigan State University College of Social Science. The field team included Kurt Rademaker and Emily Milton from MSU, Katherine Moore (U. of Pennsylvania), Sarah Meinekat (U. of Tübingen), and Brett Furlotte (U. of Saskatchewan). Peter Kaulicke (Pontifical Catholic U. of Lima) is our national collaborator. The project was authorized by the Peruvian Ministry of Culture (RDN No. 273-2019).
We conducted new mapping, photography, and excavations at two classic limestone cave sites - Pachamachay, originally excavated in the 1970s, and Panaulauca, excavated in the early 1980s. Based on published radiocarbon dates, both sites date back at least to the Early Holocene, between 11,300 and 9400 years ago.
Pachamachay (4300 meters above sea level, or masl) is the better known of these two sites (see John Rick's 1980 book "Prehistoric Hunters of the High Andes," Academic Press). Rick interpreted both sites as base camps used by groups of hunter-gatherers living year-round in the Puna of Junín, subsisting on abundant herds of the wild camelids called vicuña, as well as plentiful edible plant resources. Both cave sites are among the richest Preceramic (predating pottery) archaeological sites known from the South American Andes - hence the base camp interpretation - and animal and plant indicators suggested these sites were occupied during multiple seasons of the year. Pachamachay was especially rich in stone tools and debitage (the waste products produced during stone tool manufacture), yet almost no animal remains were found, interpreted as resulting from site cleaning. Rick developed a detailed typology of stone projectile point forms at Pachamachay using the many examples his team recovered.
By contrast, the 1980s excavations at Panaulauca (4150 masl) revealed abundant faunal remains, which Katherine Moore studied extensively for her Ph.D. thesis (also see her 1989 paper "Measures of Mobility and Occupational Intensity in Highland Peru"). In fact, in a recent review of Andean hunter-gatherer archaeological sites, Kate and I concluded that Panaulauca has the richest sequence of faunal remains of any hunter-gatherer site known in the Andes Mountains (see Rademaker & Moore 2018, "Variation in Occupation Intensity of Early Forager Sites of the Andean Puna").
Located in central Peru where rainfall is abundant and vegetation is lush, these sites are ideal for comparing with Cuncaicha rockshelter in more arid southern Peru, where our group has been working since 2010. Cuncaicha is the other richest hunter-gatherer site in the Andes Mountains (Rademaker & Moore 2018), and it dates back to about 12,000 years ago. Why were these three sites used as base camps by early Andean settlers? Were their ways of life - their subsistence, mobility, and settlement patterns - similar or different? Could these early Andean people have been related to each other in some way?
Beyond addressing these questions, our 2019 work was motivated by advances in archaeological methods. Techniques for dating sites and studying site formation processes have come a long way since the 1970s and 1980s, and new investigations at these classic sites sites promise to shed light on initial human settlement of the high Andes and human-environment interactions over the past 10,000 years. The two main goals of our 2019 fieldwork were to (1) obtain new accurate ages for both sites using accelerator mass spectrometry (AMS) radiocarbon dating of organic remains from the base of the site sediments, and (2) evaluate stratigraphic integrity and continuity in both sites through geoarchaeological analysis of the sediment sequences. These first steps establish a basic chronology and formation history for each site, which further field and lab analyses can build upon.
In very limited (1 m2) areas at each site we removed sediment to the base of cultural deposits within previously excavated trenches from the 1970s and 1980s. This involved removal of 5-10 cubic meters of sediment in each site, no easy task at over 4000 m elevation! We then cleaned and photographed wall profiles and carefully sampled mammal bone and carbonized plant remains from the wall profiles for AMS dating at the U. of Arizona. Ph.D. student Sarah Meinekat collected plaster sections of sediment from profiles for detailed examination of microstratigraphy, which she will carry out at the U. of Tübingen in Germany. At Pachamachay from new excavation of only 1 m3, we recovered about 150 kilograms of stone tools and debitage, more than 50 in situ projectile points and other formal tools, red ochre and other minerals. Finally, we backfilled the excavations to protect the sites. And we did it all in less than three weeks. It was a tough but outstanding field season!
In the coming months we will be working on photographing the stone tools, getting new radiocarbon dates, and studying the stratigraphy. We invite you to check out the gallery of images from the 2019 fieldwork, and we'll post updates in early 2020...