The study of the peopling of the Americas has been transformed in the past decade by astonishing progress in paleogenomic research. Ancient genomes now show that Native American ancestors were formed in Siberia or the Amur region by admixture of ca. 15–30% Ancient North Eurasian genes with those of East Asians. The Anzick infant, buried with Clovis bifaces at 12,900 cal BP, belonged to a group that was ancestral to later Native Central and South Americans. Fishtail points, derived from Clovis, mark the arrival and rapid expansion of Clovis-descended Paleoindians across South America, also evident in the sharp increase of radiocarbon dates, continent-wide, at 13,000–12,500 cal BP. In both North and South America, extinction of most genera of megafauna was virtually simultaneous with Paleoindian expansion. Human hunting must have been involved, perhaps in concert with other indirect impacts. Contrary to the alternative bolide impact theory, there is no evidence of a dramatic human population decline after 12,800 cal BP. Ancient genomes show that divergent lithic traditions after 13,000 cal BP need not be attributed to a separate Pacific Rim migration stream. Several recent finds raise the possibility that pre-Clovis people might have reached the Americas before 20,000 cal BP, but these precursors must have either failed to thrive, or were ultimately replaced by proto-Clovis or Clovis people. Consilient paleogenomic and archaeological data indicate that initial colonization by Paleoindian ancestors of living Native Americans occurred after 14,500 cal BP.

Wasted tires are the great source of fuel and valuable components but could be a cause of environmental and land pollution. This study shows the detailed method for the determination of radiocarbon isotope (14C) concentration in tires and their pyrolysis products. Samples are taken from truck and passenger car tires in the form of shredded rubber, pyrolysis oil and recovered carbon black. Liquid scintillation counting (LSC) and accelerator mass spectrometry (AMS) techniques were used for the investigation at Gliwice Radiocarbon and Mass Spectrometry Laboratory, and National Laboratory for Age Determination, Trondheim, Norway. The results are in good agreement. Radiocarbon concentration of the rubber varies significantly because of its complex structure and composition within the tires. The 14C concentration values were found to be higher in pyrolytic oil compared to rubber, and greater in truck tires rather than car tires.

In this paper we present dating of archaeological samples from Croatia only performed since our last reports (Obelić et al. 2011; Horvatinčić et al. 2012). Liquid scintillation radiometric measurement technique with benzene synthesis (LSC-B) and accelerator mass spectrometry (AMS) technique were applied.

Corrections are made to Stuart Fiedel’s (2022) recent errors and misrepresentations related to the late Pleistocene sites of Monte Verde and Huaca Prieta and to South American Fishtail projectile points.

Brzezie in the Pleszew region was first mentioned in archaeological literature, as the location where a treasure of gold artifacts dating back to the 3rd period of the Bronze Age was discovered in 1876. Archaeological research has been conducted there almost continuously since 1985. The result of many years of fieldwork is the discovery of 363 late Bronze Age and Early Iron Age graves, as well as 50 burials of the Przeworsk culture from the era of Roman influence. In the last few years, further research has been conducted by archeologist Grzegorz Szczurek. After comprehensive geophysical prospecting, the extent of the necropolis was established, and more graves were excavated. For the first time, materials for radiocarbon and luminescence dating were also collected to determine the absolute chronology for this archaeological site. Four samples were dated in the Poznań radiocarbon laboratory, and five luminescence tests were conducted in the Gliwice luminescence laboratory. Due to the complete thermo-destruction of collagen in human bones, age determination was based on carbonate fractionation. In one case, a piece of charcoal was selected for dating purposes. Considering uncertainties and the fact that both methods date different events, the results reveal concurrence, giving a 1000–500 BC range.

During the Late Pleistocene (MIS 5e-2), the brown bear Ursus arctos was widespread in the Czech Republic. From this time interval, the species was recorded in 51 Czech localities, including 10 open-air and 41 cave sites. A total of 18 radiocarbon dates obtained from the material showed the presence of the species in this territory 46–12.6 kyr ago during the Late Pleistocene, but most of the dates are concentrated between 45.7 and 29.3 kyr. Later, its occurrence continued into the Holocene. Three dates confirmed the presence of U. arctos just before and during the LGM. However, during the coolest part of the GS-2.1b interval (about 20.9–19.0 kyr), the species was not recorded in the territory of the Czech Republic. A large, broad-toothed, highly carnivorous priscus ecomorph adapted to live in open grasslands occurred during the Late Pleistocene, while the arctos ecomorph was rarely recorded from that period. The post-LGM time (17.5–14.7 kyr) was characterised by increasing numbers of brown bear dates on the territory of the Czech Republic. It was also a period of progressive afforestation and the disappearance of the priscus ecomorph. The latest occurrence of the priscus ecomorph in the territory of the Czech Republic was represented by a robust mandible from the Býčí skála Cave, dated at 15.4–14.9 kyr.

A new system for preparing 14C samples was established for a compact accelerator mass spectrometer (GXNU-AMS) at Guangxi Normal University. This sample preparation system consists of three units: a vacuum maintenance unit, a CO2 purification unit, and a CO2 reduction unit, all of which were made of quartz glass. A series of radiocarbon (14C) preparation experiments were conducted to verify the reliability of the system. The recovery rate of graphite obtained was more than 80%. The carbon content in the commercial toner and wood sample was linearly fitted to the CO2 pressure in the measurement unit of the system. The results showed a good linear relationship, indicating that the reliability of the sample preparation system. AMS measurements were conducted on a batch of standard, wood, and dead graphite samples prepared using this system. The results showed that the beam current of 12C- for each sample was more than 40 μA, the carbon contamination introduced during the sample preparation process was ∼ 2 × 10–15, and that the new sample preparation system is compact, low-contamination, and efficient and meets the GXNU-AMS requirements for 14C samples.