Multiple lines of evidence for possible Human population decline/settlement reorganization during the early Younger Dryas
Introduction
Considerable interest has emerged about the potential effects of abrupt, large-scale climate change on plant and animal populations as well as humans, in part because of growing concerns about potential impacts of modern global warming. Since the end of the last Glacial Maximum ca. 18,000 cal BP, the most pronounced extended climate perturbation following the onset of rapid deglaciation was the Younger Dryas (YD) cooling episode. This began abruptly at ca. 12,900 cal BP (all dates are in calendar or calibrated years before present or BP, unless otherwise noted) and persisted for about 1300 years. Various hypotheses have been proposed to explain the abrupt cooling reversal at the onset of the YD, including shifts in continental meltwater outflow (Kennett and Shackleton, 1975, Broecker et al., 1989, Broecker et al., 2010, Carlson, 2007); outburst flooding (Teller, 1988, Murton, 2010); related changes in thermohaline circulation (Broecker et al., 1989, Alley, 2000); and cosmic impact (Firestone et al., 2007). These hypotheses are the subject of ongoing debate and will not be addressed here. It is well accepted that the onset of the YD led to widespread biotic changes in many parts of the Northern Hemisphere, although specific regional biotic and human responses are not well constrained. Investigations into the YD have led to appreciable recent debate about whether or not a significant decline and/or reorganization in human populations occurred at the onset of the YD ca. 12,900 cal BP (cf., Firestone et al., 2007, Anderson et al., 2008a, Anderson et al., 2008b, Anderson et al., 2009, Anderson et al., 2010, Buchanan et al., 2008, Collard et al., 2008, Meltzer, 2009, Holliday and Meltzer, 2010, Meltzer and Holliday, 2010, Steele, 2010). This paper explores what happened to human populations in North America during the YD using three somewhat interrelated lines of evidence: (1) Paleoindian projectile point frequency data; (2) changes in Paleoindian usage patterns of lithic quarries, and (3) summed probability analyses (SPA) of radiocarbon dates related to human activity. The primary focus of this contribution has been to compile and evaluate data using these approaches to determine whether or not the evidence is consistent with changes in human population at the onset of the YD.
Section snippets
Climate and culture change: basic assumptions
An extensive literature documents how changes in climate affect biotic communities and human societies. Climate parameters such as the type, rate, and magnitude of change help shape the degree of cultural change and may even produce human population bottlenecks. Of particular importance to early human societies was the potential effect of such change on food supplies, and whether this affected the incidence and intensity of epidemics, civil unrest, or warfare (e.g., Fagan, 2000, Fagan, 2004,
Analysis results (1): Clovis and post-Clovis projectile point frequencies in North America
Paleoindian projectile points occur across North America within a number of geographically widespread and variable stylistic horizons (Fig. 1). The ‘Clovis horizon’ is dated to ca. 13,050 to 12,900 cal BP, just prior to the YD onset, and is marked by classic Clovis points, which typically have flat to weakly indented bases and fluting only partly along the blade (Morrow, 1996, Tankersley, 2004, Waters and Stafford, 2007, Meltzer, 2009). This point style was replaced during the early part of the
Analysis results (2): southeastern quarry assemblages
The documentation of Clovis and immediate post-Clovis use of quarry sites in the southeastern U.S. has not been an easy task, and reflects decades of collection and excavation by avocational and professional archaeologists. For the southeastern U.S., records were compiled of archaeological assemblages from eleven major stone quarry sites that were used extensively during the Clovis period and for most of prehistory thereafter. These represent major known quarry sites used by Clovis populations
Analysis results (3): summed probability analyses
Further investigation of possible changes in North American human populations during the last deglacial interval from about 14,000 to 11,000 cal BP used summed probability analyses (SPA). This analysis relies on changes in the frequencies of radiocarbon dates from cultural sites (e.g., Rick, 1987, Housley et al., 1997, Gkiasta et al., 2003, Miller and Kenmotsu, 2004, Gamble et al., 2005, Thomas, 2008, Buchanan et al., 2008, Blockley and Pinhasi, 2011). The procedure involves calibrating
A test of SPA in North America
SPA was first used to test whether or not a long hypothesized decline in human and bison populations on the Great Plains during the Altithermal, or Atlantic period, an extended period of warming during the Mid-Holocene from ∼9000–5000 cal BP, whose effects varied from region to region (Reeves, 1973, Frison, 1978:201; Wedel, 1986, Mayewski et al., 2004, Anderson et al., 2007), could be identified. Available dates from the Canadian Archaeological Radiocarbon Database (CARD, 2005) were divided
Younger Dryas SPA results for North America
The same 14C dates published by Buchanan et al. (2008) and spanning from ∼14,000 to 11,000 cal BP and including the YD interval, were used to analyze multiple regions of North America (Fig. 9). Contrary to Buchanan et al. (2008) and as supported by Steele (2010), there is an abrupt decline at the YD onset at or close to 12,900 cal BP, followed a few hundred years later by a distinct rebound that continued for several hundred years. The decline at the YD onset was more than 50%, similar in
SPA results for North America
Buchanan et al. (2008) recognized a decline in 14C summed probabilities at ∼12,800 cal BP, approximately the time of the YD onset or slightly later, but interpreted that decline as relatively minor, essentially no more significant from other fluctuations observed from ∼13,000 to 9500 cal BP. To evaluate whether or not the decline observed in many areas after ∼12,900 cal BP represented noise, a test was conducted in which the radiocarbon database was divided into several different regions and
SPA results on other continents
Using the radiocarbon databases in Table 2, Table 3, SPA were conducted with cultural 14C dates for other parts of the Northern Hemisphere (Fig. 11) to determine whether or not a decline occurred at the onset of the YD. These results (Fig. 12) are similar to those in North America in some but not all areas (i.e., the Mideast). Apparent population declines or plateaus associated with the YD onset appear in all continental areas north of the equator.
Europe displays a drop in 14C summed
Conclusions
All three datasets, projectile points, quarries, and SPA data, indicate that a major human population decrease (bottleneck), or alternatively population reorganizations (i.e., dramatic changes in settlement patterning), occurred over broad areas of North America at the onset of the YD cooling episode ∼12,900 cal BP. The SPA results provide evidence that similar declines or changes occurred across much of remainder of the Northern Hemisphere with the exception it, seems, of the Middle East. In
Acknowledgments
The authors wish to thank Stuart J. Fiedel, Ted Goebel, Erik Johanson, Shane Miller, Kenneth E. Sassaman, Thomas W. Stafford, Jr., Stephen J. Yerka, and two anonymous reviewers for their advice and comments during the the preparation of this paper. The research reported herein was facilitated by interactions with numerous colleagues in recent years, whose openness and assistance is deeply appreciated. Those interested in furthering the work with PIDBA are encouraged to submit primary data for
References (108)
The Younger Dryas cold interval as viewed from central Greenland
Quaternary Science Reviews
(2000)- et al.
A revised chronology for the adoption of agriculture in the Southern Levant and the role of lateglacial climatic change
Quaternary Science Reviews
(2011) - et al.
Wildfire and abrupt ecosystem disruption on California’s northern channel islands at the Allerod–Younger Dryas boundary (13.0–12.9 ka)
Quaternary Science Reviews
(2008) - et al.
Holocene climate variability
Quaternary Research
(2004) Clovis biface technology at the Topper site, South Carolina: evidence for variation and technological flexibility
Journal of Archaeological Science
(2010)Radiocarbon dates as data: quantitative strategies for estimating colonization front speeds and event densities
Journal of Archaeological Science
(2010)- et al.
A note on the use of temporal frequency distributions in studies of prehistoric demography
Journal of Archaeological Science
(2007) Pleistocene human occupation of the southeastern United States: research directions for the early 21st century
Comment
Current Anthropology
(2010)- et al.
The distribution of fluted Paleoindian projectile points: update 1998
Archaeology of Eastern North America
(1998)
Environmental and chronological considerations
The earliest Americans (Paleoindian) theme study for the Eastern United States
Paleoindian database of the Americas: update 2005
Current Research in the Pleistocene
Southeastern data inconsistent with Paleoindian demographic reconstruction
Proceedings of the National Academy of Sciences
PIDBA (Paleoindian Database of the Americas) 2010: current status and findings
Archaeology of Eastern North America
Facing environmental crisis
Near East 14C database
CalPal Neolithic database
What’s the point: model forms and attributes of Paleoindian bifaces in the New England-Maritimes region
Archaeology of Eastern North America
The mysterious 14C decline
Radiocarbon
Routing of meltwater from the Laurentide ice sheet during the Younger Dryas episode
Nature
Putting the Younger Dryas cold event into context
Quaternary Science Reviews
The Sinclair site (40Wy111): a Clovis quarry along the Buffalo River in Wayne County, Tennessee
Current Research in the Pleistocene
Paleoindian demography and the extraterrestrial impact hypothesis
Proceedings of the National Academy of Sciences
Geochemical proxies of North American freshwater routing during the Younger Dryas cold event
Proceedings of the National Academy of Sciences
Reply to Anderson et al., Jones, Kennett and West, Culleton, and Kennett, et al.: further evidence against the extraterrestrial impact hypothesis
Proceedings of the National Academy of Sciences, USA
Clovis Blade Technology: A Comparative Study of the Keven Davis Cache, Texas
The nature of Clovis blades and blade cores
Evidence for Pre-Clovis occupation at the Gault Site (41BL323), central Texas
Current Research in the Pleistocene
Wells Creek: an early man site in Stewart County, Tennessee
Archaeology of Eastern North America
Variability in the archaeological record of northeastern early Paleoindians: a view from southern Ontario
Archaeology of Eastern North America
The Little Ice Age: How Climate Made History
The Long Summer: How Climate Changed Civilization
The mysterious onset of the Younger Dryas
Quaternary International
Is more precise dating of Paleoindian expansion feasible?
Radiocarbon
Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling
Proceedings of the National Academy of Sciences, USA
A stone’s throw from Kimmswick: Clovis period research in Kentucky
Prehistoric Hunters of the High Plains
The archaeological and genetic foundations of the European population during the Late Glacial: implications for “agricultural thinking”
Cambridge Archaeological Journal
The Flint Run Paleoindian Complex: A Preliminary Report 1971 through 1973 Seasons. Occasional Paper No. 1
Neolithic transition in Europe: the radiocarbon record revisited
Antiquity
The early Holocene occupation of the southeastern United States: a geoarchaeological summary
Recognition of the Redstone fluted point in the South Carolina Paleoindian point data base
Current Research in the Pleistocene
Instrument-assisted fluting as a technochronological marker among North American Paleoindian points
Current Research in the Pleistocene
Cited by (95)
Discerning invention/innovation processes in artifact design change: Is it time to rethink drifting attributes?
2024, Journal of Archaeological Science: ReportsComprehensive refutation of the Younger Dryas Impact Hypothesis (YDIH)
2023, Earth-Science ReviewsClimatic factors and human population changes in Eurasia between the Last Glacial Maximum and the early Holocene
2023, Global and Planetary ChangeConcept and global context of the glacial landforms from the Younger Dryas Stadial
2022, European Glacial Landscapes: The Last DeglaciationClimate change, environment pollution, COVID-19 pandemic and mental health
2021, Science of the Total EnvironmentChronology and environmental context of the early prehistoric peopling of Kamchatka, the Russian North Far East
2021, Quaternary Science Reviews