“...In the place where Musters Lake is there was a large marshland with abundant grass and animals for hunting”. Ancient levels of Musters Lake and their archaeological implications in the Lower Sarmiento Valley (Chubut Province, Argentina)

Abstract

The Lower Sarmiento Valley is in south center Chubut, in the Patagonian steppe. The lakes Colhué Huapi and Musters are located in it, at a distance of approximately 20 km from each other. Archaeological research carried out since 2007 revealed differences in the archaeological signs of both lakes, particularly at the end of the Late Holocene. In the former lake, the signs are strong with clear evidence of exploitation of river resources. In the second lake, the signs are weak with little evidence of exploitation of such resources. The following explanatory hypotheses have been evaluated: 1) research biases; 2) differences in archaeological visibility; 3) post-depositional alterations; 4) impact of the collecting processes; 5) differences in lake productivity; and 6) the possibility that part of the archaeological record is currently submerged due to the existence of lower levels for Lake Musters during the Late Holocene. After further evaluation, the first five alternatives have been discarded. There was no previous information about the levels of Lake Musters being lower than the current ones. Thanks to the collaboration with artisanal fishermen and underwater surveys, it has been possible to detect the presence of submerged shrub remains in a living position. Samples of these were taken, one of which was dated at 320 years 14C BP. This indicates that the lake had lower levels during the Late Holocene, which can potentially explain the differences in the archaeological record between both lakes.