Age of ancient stone tools on Flores, Indonesia, provides new clues in the trail of the "Hobbit"
Roskilde, Denmark – Scientists examining the history of early human occupation of Southeast Asia have dated a newly discovered stone tool
site on the island of Flores, Indonesia. The data show that human occupation occurred much earlier than previously thought, adding weight to controversial theories about the origin of the small-bodied hominin Homo floresiensis – nicknamed the "Hobbit". It raises the possibility that evidence for the primitive ancestors of Homo floresiensis may one day be found on the island.
Writing in the journal Nature, researchers from the University of Wollongong (Australia), Roskilde University (Denmark), and the Geological Survey Institute of Indonesia present evidence that early hominins were living on this eastern Indonesian island by at least 1 million years ago, far earlier than previously believed. The island is the home of the Liang Bua Cave where in 2003 fossil remains of Homo floresiensis were first discovered.
Recent joint Indonesian-Australian archeological excavations in the Soa Basin of central Flores produced in situ stone tools sealed beneath volcanic deposits. High precision dating of these volcanic deposits at the Quaternary Dating Laboratory, Roskilde University has provided a minimum age for the stone tools, suggesting that the artifacts must be at least one million years old.
“This result has major implications for our understanding of the arrival and evolution of hominins on the island,” said Adam Brumm of the University of Wollongong, the study’s lead author. “H. floresiensis, which lived on Flores until as recently as 17,000 years ago, appears to represent a direct link to more primitive, early hominins that first appeared in Africa around two million years ago. Its presence on the Indonesian archipelago seems to conflict with the prevailing idea that the more advanced Homo erectus was the first human species to leave Africa and colonize other parts of the planet. ”
Michael Storey and PhD Student Gitte Margrethe Jensen at Roskilde University used the latest technology to precisely date volcanic ash layers that directly blanket the deposit containing the stone tools. The volcanic ash was erupted explosively from one of the many volcanoes in the Indonesian archipelago.
“There are a lot of researchers working on unraveling the anthropological conundrum thrown up by the discovery of Homo floresiensis,” said Michael Storey, Director of the Quaternary Dating Laboratory. “Now that it is clear that hominins reached Flores far earlier than previously thought it's important that we start to look at even older sedimentary sequences on the island, in the 1-2 million year range, if we really want to find out what is going on there.”
To establish the age of the archeological site the scientists measured the amount of argon gas trapped within volcanic minerals of the ash deposits. This dating method, performed using a revolutionary new mass spectrometer at the Quaternary Dating Laboratory, renders extremely precise ages in geological time frames, based on radioactive decay of potassium to argon trapped in the volcanic material. The Quaternary Dating Laboratory, Department of Environmental, Social and Spatial Change, Roskilde University was established by a grant from the Villum Kann Rasmussen Foundation in 2005.
Press enquiries about the Quaternary Dating Laboratory can be directed to: Michael Storey, Director of the Quaternary Dating Laboratory, Department of Environmental, Social and Spatial Change, Roskilde University Denmark on +45 46 74 23 08 (Office); +45 21 16 85 63 (Mobile) or e-mail storey(at)ruc.dk. website: www.QUADLAB.dk