scholarly journals RESOLVING TIME AMONG NON-STRATIFIED SHORT-DURATION CONTEXTS ON A RADIOCARBON PLATEAU: POSSIBILITIES AND CHALLENGES FROM THE AD 1480–1630 EXAMPLE AND NORTHEASTERN NORTH AMERICA

Radiocarbon ◽  
2020 ◽  
pp. 1-23 ◽  
Author(s):  
Sturt W Manning ◽  
Jennifer Birch ◽  
Megan Anne Conger ◽  
Samantha Sanft
Keyword(s):  
North America ◽  
Short Duration ◽  
Calibration Curve ◽  
Phase Duration ◽  
Stratigraphic Sequence ◽  
Archaeological Evidence ◽  
Northeastern North America ◽  
Wide Range ◽  
Stratigraphic Sequences ◽  
Calendar Dates

ABSTRACT Reversals and plateaus in the radiocarbon (14C) calibration curve lead to similar 14C ages applying to a wide range of calendar dates, creating imprecision, ambiguity, and challenges for archaeological dating. Even with Bayesian chronological modeling, such periods remain a problem when no known order—e.g., a stratigraphic sequence—exists, and especially if site durations are relatively short. Using the reversal/plateau AD 1480–1630 and the archaeology of northeastern North America as our example, we consider possible strategies to improve chronological resolution across such reversal/plateau periods in the absence of stratigraphic sequences, including uses of wood-charcoal TPQs from even very short wiggle-matches, and site phase duration constraints based on ethnohistoric and archaeological evidence.

4D archaeology

Antiquity ◽  
2002 ◽  
Vol 76 (293) ◽  
pp. 784-787
Author(s):  
Patrick Ashmore
Keyword(s):  
Tree Rings ◽  
Calibration Curve ◽  
Archaeological Sites ◽  
Wide Range ◽  
Abundant Evidence ◽  
Main Period ◽  
Calendar Dates

IntroductionBy far the commonest absolute date estimates come from radiocarbon ages converted to dates by comparing them with the ages of tree rings of known date. There are still many problems with the technique. The quoted errors attached to most of the dates obtained between 1950 and around 1982 have to be increased by factors between 1.4 and 4 (Baillie 1990; Ashmore et al. 2000). There are plateaux in the calibration curve which mean that some ages correspond to an unacceptably wide range of calendar dates. Many archaeological sites contain pieces of charcoal much older than the main period of activity on them. Many charcoal dates obtained before about 1999 were from bulk samples and some demonstrably reflect mixing of charcoal of very different age, providing a meaningless date somewhere in between (Ashmore 1999a). There is now fairly abundant evidence that dates from poorly preserved bone, whether buried or cremated, can be centuries out. The marine effect, which has been assumed to make all Scottish shell dates 405 years too old, may fluctuate (Harkness 1983; Cook & Dugmore pers. comm.). The bones of people who ate food from marine sources show the marine effect and calculation of the required change to an age measured by a laboratory depends on a measurement of the strength of the marine effect at the time the person lived (Barrett et al. 2000). Some dates from residues on pots seem to represent accurately the time they formed; others for unknown reasons do not.

scholarly journals Contact-Era Chronology Building in Iroquoia: Age Estimates for Arendarhonon Sites and Implications for Identifying Champlain's Cahiagué

2019 ◽  
Vol 84 (4) ◽  
pp. 684-707 ◽  
Author(s):  
Sturt W. Manning ◽  
Jennifer Birch ◽  
Megan Anne Conger ◽  
Michael W. Dee ◽  
Carol Griggs ◽  
...  
Keyword(s):  
North America ◽  
Calibration Curve ◽  
Radiocarbon Dating ◽  
Time Frame ◽  
The Other ◽  
Radiocarbon Dates ◽  
Relative Dating ◽  
North American Archaeology ◽  
Calendar Dates ◽  
Age Estimates

Radiocarbon dating is rarely used in historical or contact-era North American archaeology because of idiosyncrasies of the calibration curve that result in ambiguous calendar dates for this period. We explore the potential and requirements for radiocarbon dating and Bayesian analysis to create a time frame for early contact-era sites in northeast North America independent of the assumptions and approximations involved in temporal constructs based on trade goods and other archaeological correlates. To illustrate, we use Bayesian chronological modeling to analyze radiocarbon dates on short-lived samples and a post from four Huron-Wendat Arendarhonon sites (Benson, Sopher, Ball, and Warminster) to establish an independent chronology. We find that Warminster was likely occupied in 1615–1616, and so is the most likely candidate for the site of Cahiagué visited by Samuel de Champlain in 1615–1616, versus the other main suggested alternative, Ball, which dates earlier, as do the Sopher and Benson sites. In fact, the Benson site seems likely to date ~50 years earlier than currently thought. We present the methods employed to arrive at these new, independent age estimates and argue that absolute redating of historic-era sites is necessary to accurately assess existing interpretations based on relative dating and associated regional narratives.

FABRIC OF THE LITHOSPHERE IN NORTHEASTERN NORTH AMERICA

2019 ◽  
Author(s):  
Yiran Li ◽  
◽  
Vadim Levin ◽  
Zhenxin Xie
Keyword(s):  
North America ◽  
Northeastern North America

Early Maize in Northeastern North America: A Comment on Emerson and Colleagues

2021 ◽  
Vol 86 (2) ◽  
pp. 425-427
Author(s):  
John P. Hart ◽  
William A. Lovis ◽  
M. Anne Katzenberg
Keyword(s):  
North America ◽  
Great Lakes ◽  
Empirical Evidence ◽  
River Valley ◽  
Human Bone ◽  
Northeastern North America ◽  
Isotopic Evidence ◽  
St Lawrence River

Emerson and colleagues (2020) provide new isotopic evidence on directly dated human bone from the Greater Cahokia region. They conclude that maize was not adopted in the region prior to AD 900. Placing this result within the larger context of maize histories in northeastern North America, they suggest that evidence from the lower Great Lakes and St. Lawrence River valley for earlier maize is “enigmatic” and “perplexing.” Here, we review that evidence, accumulated over the course of several decades, and question why Emerson and colleagues felt the need to offer opinions on that evidence without providing any new contradictory empirical evidence for the region.

scholarly journals The duration of the active phase on surge-type glaciers: contrasts between Svalbard and other regions

1991 ◽  
Vol 37 (127) ◽  
pp. 388-400 ◽  
Author(s):  
Julian A. Dowdeswell ◽  
Gordon S. Hamilton ◽  
Jon Ove Hagen
Keyword(s):  
Time Series ◽  
North America ◽  
Active Phase ◽  
Aerial Photographs ◽  
Polar Ice ◽  
Phase Duration ◽  
Field Surveys ◽  
The World ◽  
Glacier Surges ◽  
Fast Motion

AbstractMany glaciers in Svalbard and in other glacierized areas of the world are known to surge. However, the time series of observations required to assess the duration of fast motion is very restricted. Data on active-phase duration in Svalbard come from aerial photographs, satellite imagery, field surveys and airborne reconnaissance. Evidence on surge duration is available for eight Svalbard ice masses varying from 3 to 1250 km2. Worldwide, active-phase duration is recorded for less than 50 glaciers. Few observations are available on high polar ice masses. The duration of the active phase is significantly longer for Svalbard glaciers than for surge-type glaciers in other areas from which data are available. In Svalbard, the active phase may last from 3 to 10 years. By contrast, a surge duration of 1–2 years is more typical of ice masses in northwest North America, Iceland and the Pamirs. Ice velocities during the protracted active phase on Svalbard glaciers are considerably lower than those for many surge-type glaciers in these other regions. Mass is transferred down-glacier more slowly but over a considerably longer period. Svalbard surge-type glaciers do not exhibit the very abrupt termination of the active phase, over periods of a few days, observed for several Alaskan glaciers. The duration of the active phase in Svalbard is not dependent on parameters related to glacier size. The quiescent phase is also relatively long (50–500 years) for Svalbard ice masses. Detailed field monitoring of changing basal conditions through the surge cycle is required from surge-type glaciers in Svalbard in order to explain the significantly longer length of the active phase for glaciers in the archipelago, which may also typify other high polar ice masses. The finding that surge behaviour, in the form of active-phase duration, shows systematic differences between different regions and their environments has important implications for understanding the processes responsible for glacier surges.

Sign in / Sign up

Export Citation Format

Share Document