Replies

Did you see this article?

-------------------------------------------------------------------------------- Feature: Chinese hominid challenges out-of-Africa origin of modern man

-------------------------------------------------------------------------------- Story Filed: Friday, October 11, 2002 8:03 AM EST

Oct 11, 2002 (Xinhua via COMTEX) -- The limited capacity of the commonly-used radiocarbon, or carbon-14 method, which could date back no further than 50,000 years, had previously rendered it impossible to achieve an accurate dating of the human fossils.

Through the use of the new thermal ionization mass spectrometer, which measures the rate of decay in radioactive uranium (TIMS U- series dating), a more accurate and larger dating range can be achieved, said Wang, who is also a senior researcher with the Guangxi Museum of Nature.

The scientists dated "Liujiang Man" by measuring the rate of decay of uranium by counting the number of thorium atoms, but instead of dating the fossils, which are porous, they dated the sediments, which better retain uranium, above and below the fossils.

"Referring to the excavation record in 1958, we confirmed that the Liujiang Hominid was discovered in sedimentary breccia fragments in the middle layer, whose age is the same as that of the fossils," Wang said.

The estimated age of "Liujiang Man" challenges the 15-year-old "out of Africa" theory that holds that modern humans first appeared in eastern Africa about 150,000 years ago, migrated out of the continent between 35,000 and 89,000 years ago, and moved across the globe to sweep aside populations, with no inter- breeding.

There are still dissident scientists who insist on the multi- regional evolution model which holds that modern man descended from several indigenous archaic human populations in the Old World, such as the Neanderthals who resided in Europe or from the so- called Java man or from the Peking man in Asia.

This alternative theory, called multi-regionalism, also holds that our ancestors emigrated from Africa 1.5 million years ago, but differs in that it holds that different branches in several different regions -- what is now Africa, Europe, east Asia and west Asia -- evolved simultaneously into modern humans through interbreeding between the regions.