Papers by Thomas W Stafford, Jr.
Coprolites contain a suite of biomolecules and microfossils, making them incredibly useful palaeo... more Coprolites contain a suite of biomolecules and microfossils, making them incredibly useful palaeoenvironmental and palaeodietary archives. The short-term nature of their production within the human body offers a very high temporal resolution, contrasting with traditional dietary proxies in archaeology such as skeletal C/N isotopes, which give an average lifetime signal. Some of the earliest evidence of human occupation in North America is a coprolite from Paisley Caves (Oregon, USA) which contained ancient human DNA in a matrix dated between 14,170 to 14,340 cal BP. However, there have been debates over the stratigraphic integrity and preservation of the aDNA. This debate is difficult to resolve as there is currently little understanding of the nature of biomolecule taphonomy and movement within the cave environment. Before broader questions of palaeodiet and resource use of these early settlers can be investigated, the identification of coprolite proxies as human or otherwise must be confirmed, and their stratigraphic integrity assessed. This research aims to address these issues by using a novel integration of biogeochemistry and sediment microstratigraphy to investigate the survival and taphonomy of different biomolecules within the cave environment and to understand how these early settlers interacted with their seasonal environment.
Frontiers in Ecology and Evolution
Calibrating human population dispersals across Earth’s surface is fundamental to assessing rates ... more Calibrating human population dispersals across Earth’s surface is fundamental to assessing rates and timing of anthropogenic impacts and distinguishing ecological phenomena influenced by humans from those that were not. Here, we describe the Hartley mammoth locality, which dates to 38,900–36,250 cal BP by AMS 14C analysis of hydroxyproline from bone collagen. We accept the standard view that elaborate stone technology of the Eurasian Upper Paleolithic was introduced into the Americas by arrival of the Native American clade ∼16,000 cal BP. It follows that if older cultural sites exist in the Americas, they might only be diagnosed using nuanced taphonomic approaches. We employed computed tomography (CT and μCT) and other state-of-the-art methods that had not previously been applied to investigating ancient American sites. This revealed multiple lines of taphonomic evidence suggesting that two mammoths were butchered using expedient lithic and bone technology, along with evidence diagn...
Science Advances, 2020
The Clovis complex dates from 13,050 to 12,750 cal yr B.P. during a time of major environmental c... more The Clovis complex dates from 13,050 to 12,750 cal yr B.P. during a time of major environmental change.
Nature Communications, 2020
Large-scale changes in global climate at the end of the Pleistocene significantly impacted ecosys... more Large-scale changes in global climate at the end of the Pleistocene significantly impacted ecosystems across North America. However, the pace and scale of biotic turnover in response to both the Younger Dryas cold period and subsequent Holocene rapid warming have been challenging to assess because of the scarcity of well dated fossil and pollen records that covers this period. Here we present an ancient DNA record from Hall’s Cave, Texas, that documents 100 vertebrate and 45 plant taxa from bulk fossils and sediment. We show that local plant and animal diversity dropped markedly during Younger Dryas cooling, but while plant diversity recovered in the early Holocene, animal diversity did not. Instead, five extant and nine extinct large bodied animals disappeared from the region at the end of the Pleistocene. Our findings suggest that climate change affected the local ecosystem in Texas over the Pleistocene-Holocene boundary, but climate change on its own may not explain the disappear...
Quaternary Science Reviews, 2019
In this study, we explore the Late Pleistocene (LP) vertebrate fauna diversity in southeastern Le... more In this study, we explore the Late Pleistocene (LP) vertebrate fauna diversity in southeastern Lesser Caucasus based on morphological and genetic identification of fossil bones from Karin Tak cave. For the first time in this under-studied region, we used a bulk bone metabarcoding genetic approach to complement traditional morphology-based taxonomic identification hampered by highly fragmented fossil bones. Excellent ancient DNA (aDNA) preservation allowed for a successful species identification of many bone remains and improved paleoenvironmental interpretations for the region. The identification of fossil bones revealed a high diversity of animal taxa inhabiting the region between ca. > 42,000 and 25,683-24,803 calibrated years before present (cal. BP). The reconstructed taxonomic assemblage comprises 29 taxa, including 11 mammalian and three avian families currently inhabiting the region, together with a few taxa that are regionally extinct today. Despite limited temporal resolution, the taxonomic assemblage identified points to faunal continuity in the study region during the LP. This suggests that the transition between warm and humid Marine Isotope Stage (MIS) 3 and cold and arid MIS 2 did not cause a dramatic change in the faunal makeup of the region.
ABSTRACTAncient DNA (aDNA) sequencing has enabled unprecedented reconstruction of speciation, mig... more ABSTRACTAncient DNA (aDNA) sequencing has enabled unprecedented reconstruction of speciation, migration, and admixture events for extinct taxa1. Outside the permafrost, however, irreversible aDNA post-mortem degradation2 has so far limited aDNA recovery within the ˜0.5 million years (Ma) time range3. Tandem mass spectrometry (MS)-based collagen type I (COL1) sequencing provides direct access to older biomolecular information4, though with limited phylogenetic use. In the absence of molecular evidence, the speciation of several Early and Middle Pleistocene extinct species remain contentious. In this study, we address the phylogenetic relationships of the Eurasian Pleistocene Rhinocerotidae5-7 using ˜1.77 million years (Ma) old dental enamel proteome sequences of a Stephanorhinus specimen from the Dmanisi archaeological site in Georgia (South Caucasus)8. Molecular phylogenetic analyses place the Dmanisi Stephanorhinus as a sister group to the woolly (Coelodonta antiquitatis) and Merck...
Science Advances, 2019
14C dates disprove Holocene survival of Pleistocene megafauna in the Pampas and show humans hunte... more 14C dates disprove Holocene survival of Pleistocene megafauna in the Pampas and show humans huntedMegatheriumat 12,600 CAL BP.
Quaternary Science Reviews, 2018
Genetic analysis of Paleoamerican human remains suggests that people first entered the Americas s... more Genetic analysis of Paleoamerican human remains suggests that people first entered the Americas sometime between ∼14,000 and ∼16,000 years ago. Evaluation of these data requires unequivocal archaeological evidence in a solid geological context that is well dated. Accurately determining the age of late Pleistocene sites is thus crucial in explaining when and how humans colonized the Americas. There are, however, significant challenges to dating reliability, especially when vertebrate fossils (i.e. bones, teeth and ivory) are often the only datable materials preserved at sites. We re-dated vertebrate fossils associated with the North American butchering sites of Wally's Beach (Canada), La Prele [also known as Fetterman (Wyoming)], Lindsay (Montana), and Dent (Colorado). Our work illustrates the crucial importance of sample chemical preparation in completely removing contaminants derived from sediments or museum curation. Specifically, our work demonstrates that 2 chromatographic methods, e.g. preparative High Performance Liquid Chromatography and column chromatography using XAD resins, are currently the only efficient methods for removing environmental and museum-derived contaminants. These advanced techniques yield demonstrably more accurate AMS 14 C measurements that refine the ages of these four sites and thereby contribute to advancing our understanding of human dispersals across North America during the late Pleistocene.
Stones, Bones, and Profiles: Exploring Archaeological Context, Early American Hunter-Gatherers, and Bison, 2016
stones and bones are the fundamental building blocks of prehistory, especially the deep hominin p... more stones and bones are the fundamental building blocks of prehistory, especially the deep hominin prehistory. The only thing that survives from the earliest humans, except in rare instances of the humans themselves, is stones and bones in that order. it was in this context that the late archaeologist Glynn isaac (1977) characterized the archaeology of the earliest humans as "squeezing blood from stones." stones and bones must, however, be placed in context, and that largely comes from profiles or rather stratigraphy. stones, bones, and profiles thus constitute the three building blocks of much of the early archaeology from the appearance of earliest humans to the advent of the neolithic or its equivalents on various continents. so it is no wonder that this book, dedicated to two prominent scholars whose careers focused on the earliest americans, the Paleoindians, is about stones, bones, and profiles. in fact, tools and tool making from raw stone material and the remains of food residues, or one of these, are what we find at nearly all Paleoindian sites in western north america. Where we find them and in what contexts are key to understanding the implications of these remains for reconstructing the lifeways of ancient peoples. and by and large, other items are rare or absent, except in a few cases, and often these are likewise made of either stone or bone. We are referring to such things as bone tools (needles, awls, gaming pieces, and others), ornaments (beads), and possibly in a few instances
Advances in AMS physics and organic geochemistry have revolutionized our ability to establish abs... more Advances in AMS physics and organic geochemistry have revolutionized our ability to establish absolute chronologies on vertebrate fossils. Highly purified collagen, which provides extremely accurate 14C ages, can be extracted from single bones and teeth as small as 50 mg. Combined with measurement precisions of ±15 to 25 years for ages of < 20,000 yr, the direct AMS 14C technique enables fossil deposits to be chronologically dissected at the level of single animals. Analysis of data from a variety of sites in the United States indicates that most excavation levels (analysis units) as small as 10 cm can be time averaged by several thousand years at a minimum, even with the greatest care in excavation and processing of sediments. Time averaging of this magnitude has important implications for fine-scale paleoecological analysis of faunas, especially when compared to high-resolution climate records like those derived from speleothems, ice cores, or marine cores. To this end, we prop...
Biology letters, 2015
Hippidions were equids with very distinctive anatomical features. They lived in South America 2.5... more Hippidions were equids with very distinctive anatomical features. They lived in South America 2.5 million years ago (Ma) until their extinction approximately 10 000 years ago. The evolutionary origin of the three known Hippidion morphospecies is still disputed. Based on palaeontological data, Hippidion could have diverged from the lineage leading to modern equids before 10 Ma. In contrast, a much later divergence date, with Hippidion nesting within modern equids, was indicated by partial ancient mitochondrial DNA sequences. Here, we characterized eight Hippidion complete mitochondrial genomes at 3.4-386.3-fold coverage using target-enrichment capture and next-generation sequencing. Our dataset reveals that the two morphospecies sequenced (H. saldiasi and H. principale) formed a monophyletic clade, basal to extant and extinct Equus lineages. This contrasts with previous genetic analyses and supports Hippidion as a distinct genus, in agreement with palaeontological models. We date the...
The Journal of Geology, 2014
JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, a... more JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact
Quaternary Science Reviews, 2008
Sedimentary records from California's Northern Channel Islands and the adjacent Santa Barbara Bas... more Sedimentary records from California's Northern Channel Islands and the adjacent Santa Barbara Basin (SBB) indicate intense regional biomass burning (wildfire) at the Ållerød-Younger Dryas boundary (w13.0-12.9 ka) (All age ranges in this paper are expressed in thousands of calendar years before present [ka]. Radiocarbon ages will be identified and clearly marked '' 14 C years''.). Multiproxy records in SBB Ocean Drilling Project (ODP) Site 893 indicate that these wildfires coincided with the onset of regional cooling and an abrupt vegetational shift from closed montane forest to more open habitats. Abrupt ecosystem disruption is evident on the Northern Channel Islands at the Ållerød-Younger Dryas boundary with the onset of biomass burning and resulting mass sediment wasting of the landscape. These wildfires coincide with the extinction of Mammuthus exilis [pygmy mammoth]. The earliest evidence for human presence on these islands at 13.1-12.9 ka (w11,000-10,900 14 C years) is followed by an apparent 600-800 year gap in the archaeological record, which is followed by indications of a larger-scale colonization after 12.2 ka. Although a number of processes could have contributed to a post 18 ka decline in M. exilis populations (e.g., reduction of habitat due to sea-level rise and human exploitation of limited insular populations), we argue that the ultimate demise of M. exilis was more likely a result of continental scale ecosystem disruption that registered across North America at the onset of the Younger Dryas cooling episode, contemporaneous with the extinction of other megafaunal taxa. Evidence for ecosystem disruption at 13-12.9 ka on these offshore islands is consistent with the Younger Dryas boundary cosmic impact hypothesis [Firestone, R.
Index of Texas Archaeology Open Access Grey Literature from the Lone Star State, 1998
During our excavations, various media outlets visited the cave and ran several stories on our wor... more During our excavations, various media outlets visited the cave and ran several stories on our work there. These stories helped generate interest in our work within the broad reaches of the federal government, and undoubtedly contributed to the success of some of our funding requests. In particular, I thank Scott Sonner and Sandra Chereb of the Associated Press, as well as Kirk Hansen of Fantastic Caverns in Springfield, Missouri, and Pat Nelson of National Geographic World. Gene Russell of Gene Russell Studios in Elko took the photos that became Figures 6, 20, 21, 23, and 24 of this report. Results of C-14 analysis of charcoal samples collected from Test Pit 2, chamber I. C-14 samples obtained on plant macrofossils and charcoal from Test Pit 3. Number of radiocarbon dates from Mineral Hill Cave associated with general time periods and climatic phases. U-Th ages of stalactite and stalagmite samples from Mineral Hill Cave. The animals identified at Mineral Hill Cave. Correlation of Land Mammal Ages, Marine Isotope Stages, and general climatic terms used in this report. Animals with AMS dates at Mineral Hill Cave subdivided by eight general climatic regimes. Mean metatarsal V measurements of M. inexpectatus, M. trumani, Puma concolor, Panthera onca, A. jubatus, and the Mineral Hill Cave specimen. Proximal phalanx measurements (mm) of Arctodus, Ursus, and the Mineral Hill Cave specimen. Mandibular tooth measurements of Canis lupus, Canis latrans, Vulpes vulpes, and Urocy on cinereoargenteus from Little Box Elder Cave, Jaguar Cave, Mineral Hill Cave, and recent specimens. C-PI114 tooth measurements of recent Canis latrans and Urocyon cinereoargenteus, and the three Vulpes vulpes mandibles from Mineral Hill Cave. Pmi-M 3 tooth measurements of recent Canis latrans and Urocyon cinereoargenteus, and Rancholabrean Canis latrans and Vulpes vulpes mandibles from Jaguar Cave and Mineral Hill Cave. Pm 4 tooth measurements of Canis latrans, Vulpes vulpes, and Urocyon cinereoargenteus from Little Box Elder Cave, Jaguar Cave, Mineral Hill Cave, and recent specimens. M 1 tooth measurements of Canis latrans, Vulpes vulpes, and Urocyon cinereoargenteus from Little Box Elder Cave, Jaguar Cave, Mineral Hill Cave, and recent specimens. M 2 tooth measurements of Canis lupus, Canis latrans, Vulpes vulpes, and Urocyon cinereoargenteus from Little Box Elder Cave, Jaguar Cave, Mineral Hill Cave, and recent specimens. Depth of mandible at Pm 2 of Canis latrans, Vulp es vulpes, and Urocyon cinereoargenteus from Mineral Hill Cave and recent specimens. 5 6 10 24 26 CvJmus columbianus Tundra swan lemmiscus curtatus Sagebrush vole Microtus soo. Meadow vole Corvus corax Raven Neotoma cinerea Bushy-tailed woodrat Gymnorhinus Piftonjay Neotoma leoida Desert woodrat cyanocepha/a Peromyscus maniculatus Deer mouse Pica oica Black-billed masroie Oncorhvnchus clarki Cutthroat trout Turdus mi2ratorius American robin Crotaphytus sp. Collard lizard Zenaida macroura Moumim? dove Gambelia sp. Leopard lizard Cnemidophorus so. Whiptail Phrynosoma Mountain/Pigmy Short hemandezildoufdasi homed lizard Phrvnosoma olatvrhinos Desert homed lizard Uta sp. Side-Blotched lizard Scelooorus sp. Spiny lizard Eumeces sp. Skink Pituoohis melanoleucus Pine-Gopher snake Masticoohis sn. Whiosnake (Coachwhio) Coluber constrictor Racer Rhinocheilus lecontei Long-nosed snake Thamnoohis so. Garter snake Hvosifdena torQuata Night snake Crotalus sp. Rattlesnake Charina bottae Rubber boa cf. ButeoJ;!al/us frarzi/is fragile eagle Aquila chrvsaetos Golden eagle Buteo famaicensis Red-tailed hawk Asio /lammeus Short-eared owl Falco mexicanus Prairie falcon Falco soarverius American kestrel Centrocercus Sage grouse urophasianus cf. Dendragapus Blue grouse obscurus Tympanuchus Sharp-tailed grouse phasianellus 12 CHAPTER2 Paleoenvironmental Context for Mineral Hill Cave Bryan Hocketl General Patterns This chapter explores more fully the paleoenvironmental context of Mineral Hill Cave. This context includes previous research on Pleistocene fauna! assemblages in western North America, as well as past studies of both fauna! and floral remains in the Great Basin, with emphasis on the central and northern Great Basin subregions. As Grayson (1993) summarized, the Great Basin can be defined based on hydrology, physiography, floristic associations, or similarity of prehistoric artifacts. The Great Basin will be defined here hydrographically: it is that region of western North America that exhibits internal drainage basins with no outlet to the sea. This region is also known as the Intermountain West ~use it is roughly bounded to the west by the Sierra Nevada Mountains along the Nevada-California border and to the east by the Wasatch Range in central Utah. The northern boundary is irregular, and is located near the Nevada-Idaho border to the east and southern and central Oregon to ~e west. The southern boundary, also highly trregular, abuts the Colorado Plateau region (Figure 8).
This letter is a follow up to your March 10, 1999 letter regarding the ARPA permit submitted by D... more This letter is a follow up to your March 10, 1999 letter regarding the ARPA permit submitted by Dr. Gary,Hucldebe,"r;,,"and myself, for on-site geological excavations at the Kennewick Site, Washington. Your 3110/99 letter noted that the permit application was still under review. Because an additional two months have elapsed, I'm asking what is the status of the decision process and when you and I will expect a reply from your headquarters.
PaleoAmerica
Paisley Caves in Oregon has become well known due to early dates, and human presence in the form ... more Paisley Caves in Oregon has become well known due to early dates, and human presence in the form of coprolites, found to contain ancient human DNA. Questions remain over whether the coprolites themselves are human, or whether the DNA is mobile in the sediments. This brief introduces new research applying an integrated analytical approach combining sediment micromorphology and lipid biomarker analysis, which aims to resolve these problems.
Proceedings of the National Academy of Sciences of the United States of America, Jul 18, 2018
Found in 1968, the archaeological site of Anzick, Montana, contains the only known Clovis burial.... more Found in 1968, the archaeological site of Anzick, Montana, contains the only known Clovis burial. Here, the partial remains of a male infant, Anzick-1, were found in association with a Clovis assemblage of over 100 lithic and osseous artifacts-all red-stained with ochre. The incomplete, unstained cranium of an unassociated, geologically younger individual, Anzick-2, was also recovered. Previous chronometric work has shown an age difference between Anzick-1 and the Clovis assemblage (represented by dates from two antler rod samples). This discrepancy has led to much speculation, with some discounting Anzick-1 as Clovis. To resolve this issue, we present the results of a comprehensive radiocarbon dating program that utilized different pretreatment methods on osseous material from the site. Through this comparative approach, we obtained a robust chronometric dataset that suggests that Anzick-1 is temporally coeval with the dated antler rods. This implies that the individual is indeed t...
American Antiquity
Contemporaneity of people and the American mastodon (Mammut americanum) at Big Bone Lick, Kentuck... more Contemporaneity of people and the American mastodon (Mammut americanum) at Big Bone Lick, Kentucky, has been extensively debated for more than two hundred years. Newly interpreted stratigraphic excavations and direct AMS ¹⁴C measurements on mastodon bones from Big Bone Lick, Kentucky, indicate that the megafauna are a palimpsest of fossils spanning at least 1,200 calendar years (11,020 ± 30 to 12,210 ± 35 RC yr B.P.). The radiocarbon evidence indicates that mastodons and Clovis people overlapped in time; however, other than one fossil with a possible cut mark and Clovis artifacts that are physically associated with but dispersed within the bone-bearing deposits, there is no incontrovertible evidence that humans hunted Mammut americanum at the site.
Radiocarbon, 1987
Bone would seem to be an ideal material for14C dating because this calcified tissue contains 20 w... more Bone would seem to be an ideal material for14C dating because this calcified tissue contains 20 weight per cent protein. Fossil bone, however, can lose most of its original organic matter and frequently contains contaminants having different14C ages. Numerous14C dates on bone have been available to archaeologists and geologists but many age determinations have been inaccurate despite over 30 years of research in the field following the first14C age determinations on bone (Arnold & Libby, 1951). This situation remained unchanged until simple pretreatments were abandoned and more bone-specific fractions were isolated. The ideal solution is to use accelerator mass spectrometer14C dating, which facilitates the use of milligram-sized amounts of highly purified compounds—an approach impossible to pursue using conventional14C decay-counting methods.
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Papers by Thomas W Stafford, Jr.