pre-Clovis Occupation Research Articles

Behind the Bears Ears: Exploring the Cultural and Natural Histories of a Sacred Landscape

Behind the Bears Ears: Exploring the Cultural and Natural Histories of a Sacred Landscape

ACCELERATOR MASS SPECTROMETRY DATING OF MEADOWCROFT ROCKSHELTER MAIZE

ABSTRACTThe Meadowcroft Rockshelter in southwestern Pennsylvania is best known for its pre-Clovis occupation. Potentially important for later times is the recovery of maize macrobotanical remains from higher strata dating as early as the 4th century BC based on radiometric radiocarbon (14C) dates on wood charcoal. These remains have been considered to be potentially as old as the earliest microbotanical evidence for maize in Michigan, New York and Québec recovered from directly dated charred cooking residues adhering to pottery. The results of accelerator mass spectrometry (AMS) dating 17 samples from maize specimens from all Meadowcroft strata producing maize, indicate that the specimens originated from historical use of the shelter, most likely after AD 1800. These results further emphasize the need to obtain direct dates on maize macrobotanical remains recovered from early contexts prior to the development and common use of AMS dating.

The age of the opening of the Ice-Free Corridor and implications for the peopling of the Americas

SignificanceThe Ice-Free Corridor (IFC) has long played a key role in hypotheses about the peopling of the Americas. Earlier assessments of its age suggested that the IFC was available for a Clovis-first migration, but subsequent developments now suggest a pre-Clovis occupation of the Americas that occurred before the opening of the IFC, thus supporting a Pacific coastal migration route instead. However, large uncertainties in existing ages from the IFC cannot preclude its availability as a route for the first migrations. Resolving this debate over migration route is important for addressing the questions of when and how the first Americans arrived. We report cosmogenic nuclide exposure ages that show that the final opening of the IFC occurred well after pre-Clovis occupation.

Pre-Clovis occupation of the Americas identified by human fecal biomarkers in coprolites from Paisley Caves, Oregon

When and how people first settled in the Americas is an ongoing area of research and debate. The earliest sites typically only contain lithic artifacts that cannot be directly dated. The lack of human skeletal remains in these early contexts means that alternative sources of evidence are needed. Coprolites, and the DNA contained within them, are one such source, but unresolved issues concerning ancient DNA taphonomy and potential for contamination make this approach problematic. Here, we use fecal lipid biomarkers to demonstrate unequivocally that three coprolites dated to pre-Clovis are human, raise questions over the reliance on DNA methods, and present a new radiocarbon date on basketry further supporting pre-Clovis human occupation.

Fladmark + 40: What Have We Learned about a Potential Pacific Coast Peopling of the Americas?

Forty years ago, Knut Fladmark (1979) argued that the Pacific Coast offered a viable alternative to the ice-free corridor model for the initial peopling of the Americas—one of the first to support a “coastal migration theory” that remained marginal for decades. Today, the pre-Clovis occupation at the Monte Verde site is widely accepted, several other pre-Clovis sites are well documented, investigations of terminal Pleistocene subaerial and submerged Pacific Coast landscapes have increased, and multiple lines of evidence are helping decode the nature of early human dispersals into the Americas. Misconceptions remain, however, about the state of knowledge, productivity, and deglaciation chronology of Pleistocene coastlines and possible technological connections around the Pacific Rim. We review current evidence for several significant clusters of early Pacific Coast archaeological sites in North and South America that include sites as old or older than Clovis. We argue that stemmed points, foliate points, and crescents (lunates) found around the Pacific Rim may corroborate genomic studies that support an early Pacific Coast dispersal route into the Americas. Still, much remains to be learned about the Pleistocene colonization of the Americas, and multiple working hypotheses are warranted.

Early Human Settlement of Northeastern North America

This paper summarizes current evidence for earliest human occupation of northeastern North America during the late Pleistocene and early Holocene. We review evolution of the region's landscapes and evidence of archaeological chronologies as context for understanding human settlement of the region. Current data support limited evidence for pre-Clovis occupation south of the Laurentide glacial margin, followed by a significant temporal gap prior to early Paleoindian settlement of the region. Despite differences in sub-regional data sets, mapping of site distributions and assemblage data do support the notion of variation in lifeways between Paleoindian populations occupying formerly glaciated parts of the Northeast in the late Pleistocene, versus contemporary groups in lands south of the Laurentide glacial margin. Through time, the greatest differences in Paleoindian land use and technology occur between the Younger Dryas and early Holocene.

Pre-Clovis occupation 14,550 years ago at the Page-Ladson site, Florida, and the peopling of the Americas.

Stone tools and mastodon bones occur in an undisturbed geological context at the Page-Ladson site, Florida. Seventy-one radiocarbon ages show that ~14,550 calendar years ago (cal yr B.P.), people butchered or scavenged a mastodon next to a pond in a bedrock sinkhole within the Aucilla River. This occupation surface was buried by ~4 m of sediment during the late Pleistocene marine transgression, which also left the site submerged. Sporormiella and other proxy evidence from the sediments indicate that hunter-gatherers along the Gulf Coastal Plain coexisted with and utilized megafauna for ~2000 years before these animals became extinct at ~12,600 cal yr B.P. Page-Ladson expands our understanding of the earliest colonizers of the Americas and human-megafauna interaction before extinction.

Sandia cave reconsidered

Review of the controversy surrounding the excavation of Sandia cave, New Mexico, and infrared Raman laser studies of the existing specimens from the site suggests the probability of a pre-Clovis occupation at the site. Pleistocene fauna attributed by Hibben to his Folsom layer quite probably belong to Haynes and Agogino’s more recently defined Unit F. This was apparently the original locus of the Sandia points, and it has produced pre-Clovis dates.

Pre-Clovis Lithic Technology at the Debra L. Friedkin Site, Texas: Comparisons to Clovis through Site-Level Behavior, Technological Trait-List, and Cladistic Analyses

AbstractHumans first left Siberia and colonized the Americas perhaps around 16,000 years ago, and the Clovis archaeological complex in North America has traditionally been linked to this migratory pulse. Archaeologists searching for evidence of Clovis technological antecedents have focused their attention on the Beringian and Siberian archaeological records. Growing evidence for the pre-Clovis occupation of North America provides a possible alternative source for the origins of Clovis. In this paper, we present new data on the pre-Clovis lithic assemblage from the Debra L. Friedkin site, Texas, and compare Clovis and pre-Clovis lithic technological signatures. We show that while Clovis and pre-Clovis share some important technological traits, they also differ in important ways. We conclude that the pre-Clovis assemblage from Debra L. Friedkin cannot be called “Clovis,” but it could represent a technological antecedent of Clovis.

Identifying stone tool cut marks and the pre-Clovis occupation of the Paisley Caves

Analysis of taphonomic processes observable in undoubtedly cultural Younger Dryas-age faunal collections at the Paisley Caves establishes what cultural bone modification looks like in post-Clovis deposits at the site. Clearly stating the criteria by which these bones have been identified as culturally modified by stone tools, we apply the same criteria to bones found at the noncultural paleontological site of Mineral Hill Cave, Nevada, and find no cases of stone-tool-cut-marked bones. Applying these same criteria to bones recovered from pre-Clovis stratigraphic contexts at the Paisley Caves resulted in the identification of two cut-marked specimens, a mountain sheep (Ovis canadensis) mandible and a small artiodactyl rib that were both found in close proximity to human coprolites and artifacts. Directly radiocarbon dated prior to the beginning of the Clovis era (ca. >13,100 cal B.P.), these specimens increase the number of culturally modified items recovered from preClovis contexts and support previous DNA studies indicating that the northern Great Basin was occupied at least a mil lennium before Clovis points became widespread throughout North America. Dos cortar huesos marcados, una oveja de montana (Ovis canadensis) mandibula y un segmento pequeno artiodactyl ambos fueron encontrados en las proximidades de coprolitos humanos y artefactos en las cavernas Paisley, Oregon. Directamente radiocarbono fechado antes del comienzo de la era Clovis (ca. > 13.100 cal B.P.), estas muestras de aumentar el numero de elementos culturalmente modificados recuperados de pre-Clovis contextos y apoyar los estudios previos de ADN que indican la gran cuenca norte fue ocupado por lo menos un milenio antes de Clovis tecnologia se extendio a lo largo de America del Norte.

A Historical Sketch on the Concepts of Archaeological Association, Context, and Provenience

The archaeological concepts of association, context, and provenience have been known by archaeologists since the early nineteenth century, but the terms have not been used. Provenience is empirical and absolute; an association and a context are inferential and relative. These fundamental concepts have seldom been the subject of thoughtful discussion except when a particular association or context has implications far beyond the particular instance under study, such as in the context of considerations of claims for a pre-Clovis occupation of North America. Introductory archaeology textbooks published over the past 100 years do not always introduce the terms and sometimes fail to define them. Future discussion of the concepts should include several examples of what qualifies as evidence of an association or context, how the inference of an association or context was derived, and descriptions of analytical techniques used to determine if an inferred temporal association is valid.

Large scale mitochondrial sequencing in Mexican Americans suggests a reappraisal of Native American origins

BackgroundThe Asian origin of Native Americans is largely accepted. However uncertainties persist regarding the source population(s) within Asia, the divergence and arrival time(s) of the founder groups, the number of expansion events, and migration routes into the New World. mtDNA data, presented over the past two decades, have been used to suggest a single-migration model for which the Beringian land mass plays an important role.ResultsIn our analysis of 568 mitochondrial genomes, the coalescent age estimates of shared roots between Native American and Siberian-Asian lineages, calculated using two different mutation rates, are A4 (27.5 ± 6.8 kya/22.7 ± 7.4 kya), C1 (21.4 ± 2.7 kya/16.4 ± 1.5 kya), C4 (21.0 ± 4.6 kya/20.0 ± 6.4 kya), and D4e1 (24.1 ± 9.0 kya/17.9 ± 10.0 kya). The coalescent age estimates of pan-American haplogroups calculated using the same two mutation rates (A2:19.5 ± 1.3 kya/16.1 ± 1.5 kya, B2:20.8 ± 2.0 kya/18.1 ± 2.4 kya, C1:21.4 ± 2.7 kya/16.4 ± 1.5 kya and D1:17.2 ± 2.0 kya/14.9 ± 2.2 kya) and estimates of population expansions within America (~21-16 kya), support the pre-Clovis occupation of the New World. The phylogeography of sublineages within American haplogroups A2, B2, D1 and the C1b, C1c andC1d subhaplogroups of C1 are complex and largely specific to geographical North, Central and South America. However some sub-branches (B2b, C1b, C1c, C1d and D1f) already existed in American founder haplogroups before expansion into the America.ConclusionsOur results suggest that Native American founders diverged from their Siberian-Asian progenitors sometime during the last glacial maximum (LGM) and expanded into America soon after the LGM peak (~20-16 kya). The phylogeography of haplogroup C1 suggest that this American founder haplogroup differentiated in Siberia-Asia. The situation is less clear for haplogroup B2, however haplogroups A2 and D1 may have differentiated soon after the Native American founders divergence. A moderate population bottle neck in American founder populations just before the expansion most plausibly resulted in few founder types in America. The similar estimates of the diversity indices and Bayesian skyline analysis in North America, Central America and South America suggest almost simultaneous (~ 2.0 ky from South to North America) colonization of these geographical regions with rapid population expansion differentiating into more or less regional branches across the pan-American haplogroups.

Mitochondrial Population Genomics Supports a Single Pre-Clovis Origin with a Coastal Route for the Peopling of the Americas

It is well accepted that the Americas were the last continents reached by modern humans, most likely through Beringia. However, the precise time and mode of the colonization of the New World remain hotly disputed issues. Native American populations exhibit almost exclusively five mitochondrial DNA (mtDNA) haplogroups (A-D and X). Haplogroups A-D are also frequent in Asia, suggesting a northeastern Asian origin of these lineages. However, the differential pattern of distribution and frequency of haplogroup X led some to suggest that it may represent an independent migration to the Americas. Here we show, by using 86 complete mitochondrial genomes, that all Native American haplogroups, including haplogroup X, were part of a single founding population, thereby refuting multiple-migration models. A detailed demographic history of the mtDNA sequences estimated with a Bayesian coalescent method indicates a complex model for the peopling of the Americas, in which the initial differentiation from Asian populations ended with a moderate bottleneck in Beringia during the last glacial maximum (LGM), around approximately 23,000 to approximately 19,000 years ago. Toward the end of the LGM, a strong population expansion started approximately 18,000 and finished approximately 15,000 years ago. These results support a pre-Clovis occupation of the New World, suggesting a rapid settlement of the continent along a Pacific coastal route.

Luminescence dating of sand deposits related to late Pleistocene human occupation at the Cactus Hill Site, Virginia, USA

Optically stimulated luminescence (OSL) ages, obtained primarily using single grains, are reported for 13 sediment samples from the Cactus Hill site, a culturally stratified sand dune in Virginia. The site has drawn interest because of a blade level, potentially representing an early occupation of humans in North America, a few centimeters below a Clovis artifact layer. Pre-Clovis occupation in North America is disputed. Most of the ages are drawn from quartz grains, but the quartz at this site appears to saturate at a young age, so analysis on potassium feldspar grains was also performed on the deepest samples. Geologic evidence suggests deflation, small-scale turbation, and low accretion rates have compressed and slightly mixed some of the deposits. The diameters of OSL sampling tubes therefore cover long time spans for many samples, so a minimum age is determined statistically for the top of sampling volumes. The derived ages, with one exception, are in the correct stratigraphic order and are broadly in agreement with radiocarbon ages. This seems to confirm the overall integrity of the strata and places the deposit containing the pre-Clovis artifacts at about 18 ka. Further evaluation and constraint of the ages is provided by Bayesian analysis.

Distinguishing between naturally and culturally flaked cobbles: A test case from Alberta, Canada

AbstractDistinguishing between naturally and culturally produced, simply flaked cobbles has been a problem for proponents of a pre‐Clovis occupation in the Americas. Several sites in Alberta have been assigned a pre‐Clovis status based on the presence of simply flaked cobbles found in Late Pleistocene till deposits. Historically, these types of assemblages have been assigned a cultural status based on subjective criteria and appeals to the analyst's expertise. To determine the archaeological status of two such assemblages from Alberta (Varsity Estates and Silver Springs), they were compared to a known natural assemblage and two known cultural assemblages. Chi‐square testing was used to evaluate several lithic attributes. Only those attributes that statistically differentiated between natural and cultural assemblages were used for further analyses. All cobbles were then scored using these attributes. A point was awarded when a statistically significant attribute of human‐manufacture was present. These points were then totaled, providing an aggregate score for each cobble. These scores were plotted to determine whether the test assemblages had closer affinities with the known natural or known cultural assemblages. The results indicate that the proposed pre‐Clovis assemblages have closer affinities to known natural assemblages than to cultural assemblages. Our results suggest that these sites provide no evidence for a pre‐Clovis occupation in the Americas. © 2004 Wiley Periodicals, Inc.

A premature burial: comments on Grayson and Meltzer's “Requiem for overkill”

In a recent JAS article (“A requiem for North American overkill”), Donald Grayson and David Meltzer [39] attack Paul Martin’s “overkill” hypothesis that humans caused America’s Terminal Pleistocene megafaunal extinctions. This is one of three similar recent articles by these authors [37–39] in which, by scrupulous evaluation of the archaeological record, they have reduced the list of unambiguous instances of human interactions with now-extinct mammals in North America to 14 proboscidean kill sites. We applaud their informed skepticism about the evidence, especially since one of us (Haynes) wrote a set of strict standards that Grayson and Meltzer used in their analyses. Regrettably, they did not exercise the same critical scrutiny and caution when they evaluated purported evidence of pre-Clovis occupation in South America [24,76]. Although their critical assessment of the Late Pleistocene archaeological record is laudable, Grayson and Meltzer unfortunately make numerous mistakes, indulge in unwarranted ad hominem rhetoric, and thus grossly misrepresent the overkill debate. In this comment, we first briefly address those aspects of their papers that represent mere theatrical posturing, and then we turn our attention to their more serious errors of fact and interpretation. First, the theater. A phrase repeated or paraphrased in each of the articles is that overkill is “a faith-based policy statement rather than a scientific statement about the past, an overkill credo rather than an overkill hypothesis” ([39], p. 591). By thus denying the very scientific legitimacy of the overkill hypothesis, Grayson and Meltzer seek to preclude any further serious engagement with its advocates. Science is not advanced by such dogmatic dismissal of competing hypotheses. Also theatrical but unfounded are three points Grayson and Meltzer [39] chose to emphasize in their article summary: (1) overkill has been rejected for western Europe (it has decidedly not been rejected by knowledgeable experts, such as A.J. Stuart [100] and colleagues [101]), (2) Paul Martin is the only reason overkill is still discussed for North America and Australia (also wrong—see, for example, the recent work of Alroy [6,7], Flannery [27–29], and O’Connell [85]), and (3) “there is virtually no evidence” to support overkill, which, as we show in this reply, is absolutely wrong. In fact, we think there is far more support for overkill than for climate change as the principal cause of the extinctions.

The Peopling of the New World: Present Evidence, New Theories, and Future Directions

The prevailing archaeological consensus on Paleoindian origins and colonization of the Americas has been shaken by recent wide acknowledgment of pre-Clovis occupation at Monte Verde, Chile, and by claims that ostensibly non-Mongoloid skeletal remains might represent a precursor population. Recent mitochondrial DNA studies have been interpreted by some as indicating an earlier and more complex peopling of the continent. This paper reviews the current archaeological and biological evidence, in America and northern Asia, for the origins of Native Americans, assesses models of the colonization process in the light of new data and a revised chronology, and suggests avenues for future research.

New Perspectives on the Clovis vs. Pre-Clovis Controversy

We consider the Clovis vs. pre-Clovis debate from three perspectives: migration models; petroglyph and surface-artifact ages; and scientific method. First, we test the hypothesis that a Clovis migration can account for the temporal and spatial distribution of South American Paleoindian sites “accepted” by Clovis-first advocates. Using a Clovis-first model, site ages are underpredicted by approximately 1,500 years, suggesting that the Clovis hypothesis cannot be reconciled with accepted empirical data. Second, we present North American accelerator mass spectrometry (AMS)14C minimum-limiting ages from petroglyphs and surface artifacts that demonstrate continued support for a pre-Clovis occupation of the dryland west, as well as a Beringian entry into the hemisphere. Third, the debate has been confounded by a widespread misstatement of the problem. Though Clovis occupation is a “solved” issue, the competing hypotheses are whether the first migration was Clovis or pre-Clovis; the presence of Clovis sites is simply a necessary prediction of both migration theories. The empirical implications of the Clovis-first hypothesis are virtually untested. Scientifically evaluating the first peopling controversy requires scrutinizing the empirical test implications and logical coherency of both competing hypotheses.