Late-glacial – early Holocene vegetation, climate, and fire at Sutherland Pond, Hudson Highlands, southeastern New York, U.S.A.

1997 ◽  
Vol 75 (3) ◽  
pp. 431-439 ◽  
Author(s):  
Terryanne E. Maenza-Gmelch

Accelerator mass spectrometry dated pollen, plant-macrofossil, and charcoal records from Sutherland Pond (41°23′29″N, 74°02′16″W), located in the Black Rock Forest, provide a detailed account of forest history during the late-glacial – Holocene transition in the Hudson Highlands, lower Hudson Valley, southeastern New York. Pollen assemblages dating more than 12 600 radiocarbon years before present (years BP) are dominated by herbaceous and shrub types (Salix, Betula, Alnus, Ericaceae, Cyperaceae, Gramineae, and Tubuliflorae), with some arboreal types (Pinus and Picea), apparently representing an open landscape possibly with scattered trees. At 12 600 years BP increased organic deposition and pollen influx and the first occurrence of macrofossils indicate dramatic environmental change. Mixed assemblages of boreal and temperate taxa (Picea, Abies, Betula papyrifera, Quercus, Ostrya – Carpinus, and Fraxinus) are evident from 12 600 to 11 200 years BP. Low charcoal influx suggests that fire was a minor component of early woodland development beginning around 12 600 years BP. A Picea–Abies–Alnus assemblage, suggesting a cool climatic episode, dominates between 11 200 and 10 120 years BP, with rapid onset and termination each occurring within 150 years. Fire activity is also low during this colder interval. Warmer conditions, reestablished by 10 120 years BP, are inferred from expansion of Pinus strobus and increasing Quercus and Ostrya–Carpinus, followed by replacement of B. papyrifera by Betula populifolia and increased charcoal influx. Key words: late glacial, pollen, plant macrofossils, fire, accelerator mass spectrometry radiocarbon dating, New York.

Radiocarbon ◽  
2001 ◽  
Vol 43 (2B) ◽  
pp. 1007-1019 ◽  
Author(s):  
M J C Walker ◽  
C Bryant ◽  
G R Coope ◽  
D D Harkness ◽  
J J Lowe ◽  
...  

This paper outlines a dating program designed to test the reproducibility of radiocarbon dates on different materials of Late-Glacial age (plant macrofossils, fossil beetle remains, and the “humic” and “humin” chemical fractions of limnic sediments) using a combination of radiometric (beta counting) and accelerator mass spectrometry (AMS) techniques. The results have implications for the design of sampling strategies and for the development of improved dating protocols, both of which are important if a high-precision 14C chronology for the Late-Glacial is to be achieved.


Radiocarbon ◽  
2000 ◽  
Vol 42 (3) ◽  
pp. 323-333 ◽  
Author(s):  
Barbara Wohlfarth ◽  
Göran Possnert

The Swedish varve chronology, or Swedish Time Scale, is an annual chronology based upon the successive correlation of more than 1000 varve-thickness diagrams. The Late Glacial-Early Holocene varved clays were deposited as glaciolacustrine sediments in the Baltic Sea during the recession of the Scandinavian ice sheet. Formation of varved clays continued throughout the Holocene and is still going on in the estuary of River ångermanälven in northern Sweden. Accelerator mass spectrometry (AMS) radiocarbon measurements, which have been performed on terrestrial plant macrofossils extracted from the varved clays, show—in comparison with other annual chronologies—that several hundreds of varve years are missing in the varve chronology. These findings are supported by, among others, pollen stratigraphic investigations on time-equivalent varve year intervals. If an effort were undertaken to evaluate the erroneous parts, the Swedish Time Scale would have the potential of becoming a continuous annual chronology.


Radiocarbon ◽  
2019 ◽  
Vol 62 (4) ◽  
pp. 891-899 ◽  
Author(s):  
Adam Sookdeo ◽  
Bernd Kromer ◽  
Ulf Büntgen ◽  
Michael Friedrich ◽  
Ronny Friedrich ◽  
...  

ABSTRACTAdvances in accelerator mass spectrometry have resulted in an unprecedented amount of new high-precision radiocarbon (14C) -dates, some of which will redefine the international 14C calibration curves (IntCal and SHCal). Often these datasets are unaccompanied by detailed quality insurances in place at the laboratory, questioning whether the 14C structure is real, a result of a laboratory variation or measurement-scatter. A handful of intercomparison studies attempt to elucidate laboratory offsets but may fail to identify measurement-scatter and are often financially constrained. Here we introduce a protocol, called Quality Dating, implemented at ETH-Zürich to ensure reproducible and accurate high-precision 14C-dates. The protocol highlights the importance of the continuous measurements and evaluation of blanks, standards, references and replicates. This protocol is tested on an absolutely dated German Late Glacial tree-ring chronology, part of which is intercompared with the Curt Engelhorn-Center for Archaeometry, Mannheim, Germany (CEZA). The combined dataset contains 170 highly resolved, highly precise 14C-dates that supplement three decadal dates spanning 280 cal. years in IntCal, and provides detailed 14C structure for this interval.


Radiocarbon ◽  
1995 ◽  
Vol 37 (1) ◽  
pp. 75-79 ◽  
Author(s):  
Irena Hajdas ◽  
Susan D. Ivy-Ochs ◽  
Georges Bonani

Radiocarbon dating of varved lake sediments shows that, during the Late Glacial (10–12 kyr bp), the offset between the 14C and the absolute time scales was ca. 1 kyr. Varve counting and accelerator mass spectrometry (AMS) dating were used to build absolute and 14C time scales of sediments from two lakes—Soppensee, Switzerland and Holzmaar, Germany. The resulting chronologies extend back to ca. 12.9 kyr cal bp (12.1 kyr bp) in the case of Soppensee and to ca. 13.8 kyr cal BP (12.6 kyr bp) in the Holzmaar record. They compare well with each other but differ significantly from the 14C-U/Th chronology of corals (Bard et al. 1993; Edwards et al. 1993).


Radiocarbon ◽  
2014 ◽  
Vol 56 (1) ◽  
pp. 95-108 ◽  
Author(s):  
Minna Väliranta ◽  
Markku Oinonen ◽  
Heikki Seppä ◽  
Sanna Korkonen ◽  
Sari Juutinen ◽  
...  

Four fen peat sequences in northern Finland were dated by the accelerator mass spectrometry (AMS) radiocarbon method in order to study past peatland dynamics and carbon accumulation patterns. Initially, plant macrofossils were used for dating. However, the dates were severely disordered, with marked inversions in all sequences. In one 140-cm peat core, for example, all ages fell within a ∼1000-yr time window. Following these unreliable results, a few bulk peat samples were dated to help assess if any of the plant macrofossil-derived dates were reliable. Bulk dates did not help to solve the problem. This study evaluates the possible sources of error but is unable to single out one clear cause. It is probable that many factors related to the fen environment, such as flooding and root intrusion, may have contributed to the errors. Peat plant macrofossils and bulk peat samples are considered to be reliable dating materials, but the examples given herein highlight the difficulties that can be associated with AMS dating of peat samples.


Radiocarbon ◽  
2015 ◽  
Vol 57 (5) ◽  
pp. 943-954 ◽  
Author(s):  
Joshua D Reuther ◽  
Jason S Rogers ◽  
Julie Rousseau ◽  
Patrick S Druckenmiller

The Colorado Creek section of Alaska is an important paleontological site first excavated and reported on in the early 1980s and 1990s. The remains of two individual mammoths (the “Upper” and “Lower”), and elements of horse, bison, and caribou make this a unique faunal assemblage for a region in interior western Alaska, and the western edge of eastern Beringia. The mammoth remains were the only portions of the faunal assemblage radiocarbon dated in the 1980s. The Upper mammoth ages were widespread between 13,000 and 16,200 BP with the older dates being more accepted for the death of the individual. A single age on the Lower mammoth was produced at 22,880 14C yr BP. New accelerator mass spectrometry (AMS) dates generally confirm the accepted ages for the two mammoths and provide more precise ages of 16,200 ± 50 and 22,710 ± 90 14C yr BP for the Upper and Lower mammoths, respectively. AMS dates on caribou and horse are similar to ages on the Upper mammoth and show an overlap in their ecological ranges in interior western Alaska between 16,000 and 17,000 14C yr BP during the Late Glacial, similar to other areas of the state. The sole AMS date on bison produced an infinite 14C age (>43,500 14C yr BP), considerably older than the Upper and Lower mammoths’ remains, and indicates that older deposits are present at the site. A dearth of dated Quaternary paleontological specimens from western Alaska hinders our understanding of this region's paleoecology. This study enhances our conception of the geographic and chronological spread of late Pleistocene large terrestrial mammals in Alaska and Beringia.


2009 ◽  
Vol 72 (2) ◽  
pp. 301-308 ◽  
Author(s):  
Eric C. Grimm ◽  
Louis J. Maher ◽  
David M. Nelson

AbstractAlthough the carbon-reservoir problem with bulk-sediment radiocarbon dates from lakes has long been recognized, many synoptic studies continue to use chronologies derived from such dates. For four sites in central North America, we evaluate chronologies based on conventional radiocarbon dates from bulk sediment versus chronologies based on accelerator mass spectrometry (AMS) radiocarbon dates from terrestrial plant macrofossils. The carbon-reservoir error varies among sites and temporally at individual sites from 0 to 8000 yr. An error of 500–2000 yr is common. This error has important implications for the resolution of precise event chronologies.


Radiocarbon ◽  
2007 ◽  
Vol 49 (1) ◽  
pp. 123-129 ◽  
Author(s):  
Yaroslav V Kuzmin

The problem of a hiatus at about 6100–5300 BP (about 4900–4200 cal BC) in the prehistoric chronology of the Cis-Baikal region in Siberia is discussed. Based on a critical evaluation of existing evidence, there was no discontinuity found in the cultural sequence between the Kitoi and Serovo/Glazkovo complexes of the Neolithic, and the proposed “hiatus” may be an artifact based on underestimation of solid data. Conventional 14C dates are presented that were generated in the 1980s to early 2000s for Cis-Baikal prehistoric burial grounds, and were later dated by the accelerator mass spectrometry (AMS).


Radiocarbon ◽  
2021 ◽  
pp. 1-12
Author(s):  
G Quarta ◽  
M Molnár ◽  
I Hajdas ◽  
L Calcagnile ◽  
I Major ◽  
...  

ABSTRACT The application of accelerator mass spectrometry radiocarbon (AMS 14C) dating in forensics is made possible by the use of the large excursion of the 14C concentration in the post-WWII terrestrial atmosphere due to nuclear testing as a reference curve for data calibration. By this approach high-precision analyses are possible on samples younger than ∼70 years. Nevertheless, the routine, widespread application of the method in the practice of forensics still appears to be limited by different issues due to possible complex interpretation of the results. We present the results of an intercomparison exercise carried out in the framework of an International Atomic Energy Agency (IAEA) CRP-Coordinated Research Project between three AMS laboratories in Italy, Hungary, and Switzerland. Bone and ivory samples were selected with ages spanning from background (>50 ka) to 2018. The results obtained allow us to assess the high degree of reproducibility of the results and the remarkable consistency of the experimental determinations.


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