Her findings were first brought into the spotlight in 1986 with a publication in the British magazine "Nature", in which she claimed to have discovered 32,000-year-old hearths and human artifacts. Although such early dates have not been generally accepted, Guidon and her colleagues have shown that the area was occupied by Paleoindian and Archaic rock art cultures subsisting on broad-spectrum hunting and gathering. In 1988 she began a partnership with the Brazilian Institute of Environment and Renewable Natural Resources (IBAMA), to facilitate the continuation of her excavations.