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The Dingcun locality 54:100 site was first excavated in 1950 s and has since yielded abundant stone artefacts and the famous ‘Dingcun human’ fossils, including three teeth and a parietal fragment. The Dingcun teeth has been regarded as a potential evidence of early emergence and development of ‘modern’ anatomic characters, making them key to understanding the origin and evolution of our species. However, there has been considerable debate regarding the chronology of the Dingcun site. Here we establish a new chronology for the site, based on optical dating of the fossil-bearing sediments and U-series dating of fauna fossils from the cultural layers. Our study shows that the age of the Dingcun human fossil ranges from 298,000 to 225,000 years ago (at 95.4 % confidence interval). This new dating result suggest that the Dingcun hominins represent a Late Middle Pleistocene population in East Asia who had borne some modern dental traits. ....
The peopling of Sahul (the combined landmass of New Guinea and Australia) is a topic of much debate. The Kimberley region of Western Australia holds many of Australia's oldest known archaeological sites. Here, we review the chronological and archaeological data available for the Kimberley from early Marine Isotope Stage 3 to the present, linking episodes of site establishment and the appearance of new technologies with periods of climatic and sea-level change. We report optical ages showing human occupation of Widgingarri 1, a rockshelter located on the Kimberley coast of northwest Australia, as early as 50,000 years ago, when the site was located more than 100 km from the Late Pleistocene coastline. We also present the first detailed analysis of the stone artefacts, including flakes from ground stone axes, grinding stones and ground haematite recovered from the deepest excavated layer. The high proportion of flakes from ground axe production and resharpening in the earliest occup ....
Frontiers | Paleoseismological Findings at a New Trench Indicate the 1714 M8.1 Earthquake Ruptured the Main Frontal Thrust Over all the Bhutan Himalaya frontiersin.org - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from frontiersin.org Daily Mail and Mail on Sunday newspapers.
Abstract Volcanic sediments are generally difficult to date using luminescence dating methods, but many important archaeological and palaeoanthropological sites are located in volcanic regions. Here we present an improved dating procedure for grains with composite mineralogies deposited at Liang Bua, the type locality of Homo floresiensis in Indonesia, using the post-infrared infrared stimulated luminescence (pIRIR) signal. Individual mineral grains that emit detectable pIRIR signals are composed of a range of feldspar varieties, quartz, clay minerals, heavy minerals and volcanic glass, rendering the isolation of individual potassium-rich feldspar grains infeasible. We investigate the luminescence behaviour of these composite mineral grains in detail, including their thermal stability, anomalous fading and dose-response characteristics. A standardised growth curve is developed to enable more time-efficient measurements, together with a ‘micro-aliquot’ approach in which eac ....
Abstract In optical dating of feldspars, it is commonly supposed that potassium (K)-rich feldspar grains have been isolated for luminescence measurements by means of density separation. The K and rubidium (Rb) concentrations of these grains deliver a significant internal beta dose rate. K and Rb concentrations of 12.5 ± 0.5 wt% and 400 ± 100 ppm, respectively, are typically assumed for dose rate and age calculation, but this assumption may be wrong. Thorium (Th) and uranium (U) also contribute to the beta and alpha components of the internal dose rate. We investigated the K, Rb, Th and U concentrations of individual luminescent feldspar grains in four sediment samples from Liang Bua in Indonesia to determine single-grain internal dose rates and appropriate sample-average internal dose rates. The composition of the ‘K-rich’ feldspar fraction was investigated using X-ray diffraction spectrometry (XRD), which found that this fraction was heavily contaminated in each sample ....