A new dating method finally is allowing archaeologists to incorporate rock paintings -- some of the most mysterious and personalized remnants of ancient cultures -- into the tapestry of evidence used ... Researchers have produced a new archaeological tool which could answer key questions in human evolution. The Earth's magnetic field experiences reversals such that north becomes south. Researchers have dated volcanic ash that was formed immediately before ... The precise dating of ancient charcoal found near a skull is helping reveal a unique period in prehistory.About one carbon nucleus in a trillion contains two extra neutrons, giving a mass of 14.This carbon-14 is radioactive and decays with a half-life of 5730 years.
This article is reproduced from Nuclear News, June 19998, and is based on a paper presented at the ANS Winter Meeting, held November 16-20, 1997, in Albuquerquete N. AMS has become an accurate and precise method for dating many types of materials - including such interesting items as the Shroud of Turin and the Dead Sea Scrolls, which will be discussed laterwhere only a small sample can be spared.These conflicting chronologies preclude establishment of a regional pattern of settlement and hinder our understanding of cultural change and ecological impacts on these island ecosystems. The last systematic analysis of radiocarbon dates from archaeological and paleoecological sites throughout East Polynesia, published 17 y ago, was based on 147 radiocarbon dates (5). However, these chronologies continue to be dismissed by some scholars (9, 10) on hypothetical grounds of missing evidence or archaeological invisibility, and in favor of radiocarbon dates on materials (typically unidentified charcoal with high inbuilt age potential) incapable of providing a precise age for the event being dated.Islands of East Polynesia, summarizing the two phases of migration out of West Polynesia (blue shading): first to the Society Islands (and possibly as far as Gambier) between A. ∼10 (orange shading), and second to the remote islands between A. It used a “chronometric hygiene” protocol to exclude dates with high uncertainty and to provide a chronology that proposed initial settlement A. Conflicting estimates for initial colonization in East Polynesia create great uncertainty about the historical framework within which human mobility and colonization, variations in human biology and demography, and the rates and types of human-induced ecological impacts to island ecosystems must be explained.In this video, Dr Fiona Petchey, from the Waikato Radiocarbon Dating Unit based at the University of Waikato, explains the use of standards in the carbon-14 dating process.As well as the sample to be dated, two other standard samples are also analysed – one a modern sample and the other older than 60,000 years with virtually no carbon-14 activity remaining.