scholarly journals Component age estimates for the Hell Gap Paleoindian site and methods for chronological modeling of stratified open sites - Response to commentary by C. Vance Haynes

2018 ◽  
Vol 90 (1) ◽  
pp. 248-250
Author(s):  
Spencer R. Pelton ◽  
Marcel Kornfeld ◽  
Thomas Minckley ◽  
Mary Lou Larson
Keyword(s):  
Age Estimates ◽  
Hell Gap

Component age estimates for the Hell Gap Paleoindian site and methods for chronological modeling of stratified open sites

2017 ◽  
Vol 88 (2) ◽  
pp. 234-247 ◽  
Author(s):  
Spencer R. Pelton ◽  
Marcel Kornfeld ◽  
Mary Lou Larson ◽  
Thomas Minckley
Keyword(s):  
North America ◽  
North American ◽  
Young Age ◽  
Archaeological Sites ◽  
Historic Landmark ◽  
Northwestern Plains ◽  
Archaeological Knowledge ◽  
Late Paleoindian ◽  
Age Estimates ◽  
Hell Gap

AbstractThe Hell Gap National Historic Landmark, located on the northwestern plains of Wyoming, is one of the most important Paleoindian archaeological sites in North America because it contains a stratified sequence of occupations spanning nearly the entirety of the Paleoindian period. Although Hell Gap is central to archaeological knowledge concerning North American Paleoindian chronology, consistently assigning component ages has been problematic due to conflicting radiocarbon determinations from individual strata, stratigraphic age reversals in age-depth relationships, and other issues related to the stratified open campsite. Toward resolving the Hell Gap chronology, we devised a procedure for correcting age-depth relationships for incorporation in chronostratigraphic models and then used the Bayesian age-depth modeling qprocedures in Bchron to estimate the ages of 11 stratified components present at Hell Gap Locality 1. We present these age estimates and discuss their significance to Paleoindian chronology. Notable aspects of our chronology include a revised age estimate for the Goshen complex, the identification of three Folsom components spanning the entirety of the Folsom temporal range, and relatively young age estimates for the Late Paleoindian Frederick/Lusk component(s) at Locality 1. More broadly, our study demonstrates a procedure for creating chronometric models of stratigraphically complicated open stratified sites of any type.

scholarly journals Age biases the judgment rather than the perception of an ambiguous figure

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ambroos Brouwer ◽  
Xuxi Jin ◽  
Aisha Humaira Waldi ◽  
Steven Verheyen
Keyword(s):  
Young Woman ◽  
Social Group ◽  
Positive Relationship ◽  
Ambiguous Figure ◽  
Anchor Effect ◽  
Cognitive Penetrability ◽  
The Difference ◽  
Age Estimates

AbstractOlder participants who are briefly presented with the ‘my wife/mother-in-law’ ambiguous figure estimate its age to be higher than young participants do. This finding is thought to be the result of a subconscious social group bias that influences participants’ perception of the figure. Because people are better able to recognize similarly aged individuals, young participants are expected to perceive the ambiguous figure as a young woman, while older participants are more likely to recognize an older lady. We replicate the difference in age estimates, but find no relationship between participants’ age and their perception of the ambiguous figure. This leads us to conclude that the positive relationship between participants’ age and their age estimates of the ambiguous ‘my wife/mother-in-law’ figure is better explained by the own-age anchor effect, which holds that people use their own age as a yard stick to judge the age of the figure, regardless of whether the young woman or the older lady is perceived. Our results disqualify the original finding as an example of cognitive penetrability: the participants’ age biases their judgment of the ambiguous figure, not its perception.

scholarly journals Molecular clocks in ancient proteins: Do they reflect the age at death even after millennia?

2021 ◽  
Author(s):  
Nina Sophia Mahlke ◽  
Silvia Renhart ◽  
Dorothea Talaa ◽  
Alexandra Reckert ◽  
Stefanie Ritz-Timme
Keyword(s):  
Protein Degradation ◽  
Forensic Medicine ◽  
Molecular Clocks ◽  
Post Mortem ◽  
Age At Death ◽  
Morphological Examination ◽  
Dental Tissues ◽  
Ancient Proteins ◽  
Age Estimates ◽  
Age At Death Estimation

AbstractAge at death estimation in cases of human skeletal finds is an important task in forensic medicine as well as in anthropology. In forensic medicine, methods based on “molecular clocks” in dental tissues and bone play an increasing role. The question, whether these methods are applicable also in cases with post-depositional intervals far beyond the forensically relevant period, was investigated for two “protein clocks”, the accumulation of D-aspartic acid (D-Asp) and the accumulation of pentosidine (Pen) in dentine. Eight teeth of skeletons from different burial sites in Austria and with post-depositional intervals between c. 1216 and c. 8775 years were analysed. The results of age at death estimation based on D-Asp and Pen in dentine were compared to that derived from a classical morphological examination. Age at death estimation based on D-Asp resulted consistently in false high values. This finding can be explained by a post-mortem accumulation of D-Asp that may be enhanced by protein degradation. In contrast, the Pen-based age estimates fitted well with the morphological age diagnoses. The described effect of post-mortem protein degradation is negligible in forensically relevant time horizons, but not for post-depositional intervals of thousands of years. That means that the “D-Asp clock” loses its functionality with increasing post-depositional intervals, whereas Pen seems to be very stable. The “Pen-clock” may have the potential to become an interesting supplement to the existing repertoire of methods even in cases with extremely long post-depositional intervals. Further investigations have to test this hypothesis.

Estimating growth of tropical tunas in the Indian Ocean using tag-recapture data and otolith-based age estimates

2015 ◽  
Vol 163 ◽  
pp. 58-68 ◽  
Author(s):  
J. Paige Eveson ◽  
Julien Million ◽  
Fany Sardenne ◽  
Gaël Le Croizier
Keyword(s):  
Indian Ocean ◽  
The Indian Ocean ◽  
Age Estimates

scholarly journals Dating of Prehistoric Burial Mounds by 14C Analysis of Soil Organic Matter Fractions

Radiocarbon ◽  
2003 ◽  
Vol 45 (1) ◽  
pp. 101-112 ◽  
Author(s):  
Søren M Kristiansen ◽  
Kristian Dalsgaard ◽  
Mads K Holst ◽  
Bent Aaby ◽  
Jan Heinemeier
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Science ◽  
Ams Dating ◽  
Buried Soil ◽  
Archaeological Artifacts ◽  
Burial Mounds ◽  
Organic Matter Fractions ◽  
Age Estimates ◽  
Organic Remains

Dating of prehistoric anthropogenic earthworks requires either excavation for archaeological artifacts or macroscopic organic matter suitable for 14C analysis. Yet, the former, in many cases, is undesirable and the latter is difficult to obtain. Here we present a soil science procedure, which has the potential to overcome these problems. It includes careful sampling of buried former soil surfaces, acid-alkali-acid fractionation of soil organic matter (SOM), and subsequent 14C AMS dating. To test the procedure, soil from one of the largest known burial mounds in Scandinavia, Hohøj, and 9 other Danish burial mounds were sampled. The 14C dates from extracted SOM fractions were compared to reference ages obtained by other methods. We show that humic acid fractions in 7 of the 10 mounds had the same age as the reference, or were, at maximum, 280 yr older than the reference ages. The best age estimates were derived from an organic-rich layer from the upper cm of buried soil or sod. Differences among SOM fraction ages probably indicate the reliability of the dating. Hohøj dated to approximately 1400 BC and, thus, was up to 500 yr older than other dated Scandinavian mounds of comparable size. The remaining investigated burial mounds were dated to between 1700 and 1250 BC. We conclude that combined sampling of buried soil surfaces, SOM fractionation, and 14C analysis allows for dating of archaeological earthworks when minimal disturbance is required, or if no macroscopic organic remains are found.

Age determination and growth of orange roughy (Hoplostethus atlanticus): a comparison of annulus counts with radiometric ageing

1995 ◽  
Vol 52 (2) ◽  
pp. 391-401 ◽  
Author(s):  
David C. Smith ◽  
Simon G. Robertson ◽  
Gwen E. Fenton ◽  
Stephen A. Short
Keyword(s):  
Age Determination ◽  
Percentage Reduction ◽  
Age At Maturity ◽  
Otolith Growth ◽  
Two Stage ◽  
Orange Roughy ◽  
Mass Growth ◽  
Hoplostethus Atlanticus ◽  
Age Estimates ◽  
Radiometric Data

Ages of orange roughy (Hoplostethus atlanticus) determined by two methods (counting annuli on the surface of whole and in longitudinally sectioned otoliths) were similar up to maturity. Beyond maturity, age estimates from sectioned otoliths exceeded those from whole otoliths. Maximum recorded age was 125 years for an individual 41 cm standard length (SL), and age at maturity was estimated to be 25 years (30–32 cm SL). These are consistent with ages estimated previously by radiometric methods. Results demonstrated a two-stage linear relationship between otolith weight and age that confirmed the two-stage otolith mass growth model previously used in radiometric ageing. However, in the radiometric analyses the reduction in otolith growth was arbitrarily estimated at 45% of the immature rate whereas annuli data demonstrated a reduction after maturity to 62% of the immature rate. The new estimates of otolith mass growth rate were incorporated into the radiometric data and ages recalculated, which reduced age estimates for 38–40 cm SL fish from 77–149 to 59–101 years. The radiometric data were also recalculated using only the percentage reduction in otolith growth after maturity, giving the radiometric age of 125 ± 9 years for the oldest fish.

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