Staff Research

Staff at PRI regularly publishes research in scientific journals. We've selected a few of our favotites here, but see our staff page for a full list for each individual's publications.

Reconstruction of woodland vegetation and firewood exploitation in Nine Mile Canyon, Utah, based on charcoal and pollen analysis

Peter Kováčik, Linda Scott Cummings
Quaternary International
Volume 463, Part B, 10 January 2018, Pages 312-326

Anthracological (charcoal) and pollen analysis conducted on samples from multiple sites in Nine Mile Canyon, Utah, western United States of America, were used to reconstruct the woodlands of this region and interpret firewood exploitation during the Formative period ( AD 200–1300). The pollen record identifies constituents of the paleoenvironment of this region, reflecting species that grew in the vicinity of the site and in the broader area. Wood charcoal reflects various trees and shrubs that were used as fuel or for construction by the prehistoric occupants settled in Nine Mile Canyon. Pollen results elucidate a portion of the spectrum of wood taxa, which varies in different parts of the canyon, depending on elevation and the canyon's topography. While micro-charcoal analysis has a long and rich tradition in association with pollen analysis, anthracological analysis is different in that it focuses on macroscopic pieces of archaeological charcoal. Here, anthracology, using SEM imagery, helps define local woody taxa by identifying macroscopic pieces of archaeological charcoal. These two analytical tools build a complementary record of local woodland vegetation through aerial pollen transport and fuel wood selection. While the pollen record is affected by aerial transport, the anthracological assemblages, in most cases, reflect species growing in the vicinity of the prehistoric settlements, but can be affected by natural transport within the drainage. Recovery of Douglas-fir (Pseudotsuga menziesii) charcoal from the lower portions of the canyon, containing steep walls and natural conditions not favorable for Douglas-fir growth, indicates presence of drift-wood or debris-flow deposits.

New Archaeological Evidence for an Early Human Presence at Monte Verde, Chile

Tom D. Dillehay, Carlos Ocampo, José Saavedra, Andre Oliveira Sawakuchi, Rodrigo M. Vega, Mario Pino, Michael B. Collins, Linda Scott Cummings, Iván Arregui, Ximena S. Villagran, Gelvam A. Hartmann, Mauricio Mella, Andrea González, George Dix
PLoS One

Questions surrounding the chronology, place, and character of the initial human colonization of the Americas are a long-standing focus of debate. Interdisciplinary debate continues over the timing of entry, the rapidity and direction of dispersion, the variety of human responses to diverse habitats, the criteria for evaluating the validity of early sites, and the differences and similarities between colonization in North and South America. Despite recent advances in our understanding of these issues, archaeology still faces challenges in defining interdisciplinary research problems, assessing the reliability of the data, and applying new interpretative models. As the debates and challenges continue, new studies take place and previous research reexamined. Here we discuss recent exploratory excavation at and interdisciplinary data from the Monte Verde area in Chile to further our understanding of the first peopling of the Americas. New evidence of stone artifacts, faunal remains, and burned areas suggests discrete horizons of ephemeral human activity in a sandur plain setting radiocarbon and luminescence dated between at least ~18,500 and 14,500 cal BP. Based on multiple lines of evidence, including sedimentary proxies and artifact analysis, we present the probable anthropogenic origins and wider implications of this evidence. In a non-glacial cold climate environment of the south-central Andes, which is challenging for human occupation and for the preservation of hunter-gatherer sites, these horizons provide insight into an earlier context of late Pleistocene human behavior in northern Patagonia.

Prehistoric deforestation at Chaco Canyon?

W. H. Wills, Brandon L. Drake and Wetherbee B. Dorshow
Proceedings of the National Academy of Sciences
2014 August, 111 (32) 11584-11591

Ancient societies are often used to illustrate the potential problems stemming from unsustainable land-use practices because the past seems rife with examples of sociopolitical “collapse” associated with the exhaustion of finite resources. Just as frequently, and typically in response to such presentations, archaeologists and other specialists caution against seeking simple cause-and effect-relationships in the complex data that comprise the archaeological record. In this study we examine the famous case of Chaco Canyon, New Mexico, during the Bonito Phase (ca. AD 860–1140), which has become a prominent popular illustration of ecological and social catastrophe attributed to deforestation. We conclude that there is no substantive evidence for deforestation at Chaco and no obvious indications that the depopulation of the canyon in the 13th century was caused by any specific cultural practices or natural events. Clearly there was a reason why these farming people eventually moved elsewhere, but the archaeological record has not yet produced compelling empirical evidence for what that reason might have been. Until such evidence appears, the legacy of Ancestral Pueblo society in Chaco should not be used as a cautionary story about socioeconomic failures in the modern world.

The influence of climatic change on the Late Bronze Age Collapse and the Greek Dark Ages

Brandon L.Drake
Journal of Archaeological Science
Volume 39, Issue 6, June 2012, Pages 1862-1870

Between the 13th and 11th centuries BCE, most Greek Bronze Age Palatial centers were destroyed and/or abandoned. The following centuries were typified by low population levels. Data from oxygen-isotope speleothems, stable carbon isotopes, alkenone-derived sea surface temperatures, and changes in warm-species dinocysts and formanifera in the Mediterranean indicate that the Early Iron Age was more arid than the preceding Bronze Age. A sharp increase in Northern Hemisphere temperatures preceded the collapse of Palatial centers, a sharp decrease occurred during their abandonment. Mediterranean Sea surface temperatures cooled rapidly during the Late Bronze Age, limiting freshwater flux into the atmosphere and thus reducing precipitation over land. These climatic changes could have affected Palatial centers that were dependent upon high levels of agricultural productivity. Declines in agricultural production would have made higher-density populations in Palatial centers unsustainable. The ‘Greek Dark Ages’ that followed occurred during prolonged arid conditions that lasted until the Roman Warm Period.

Assessing the applicability of portable X-ray fluorescence spectrometry for obsidian provenance research in the Maya lowlands

Adam J.Nazaroff, Keith M.Prufer, and Brandon L.Drake
Journal of Archaeological Science
Volume 37, Issue 4, April 2010, Pages 885-895

Recent innovations in portable energy-dispersive X-ray fluorescence (PXRF) spectrometry have increased its utility for the geochemical characterization of obsidian artifacts for archaeological provenance research. However, concerns over the utility of PXRF instrumental analyses have been raised, focused on the validity and reliability of the geochemical data produced. Here we adopt the framework of Richard Hughes (On Reliability, Validity, and Scale in Obsidian Sourcing Research, 1998), whereby reliability addresses instrument stability and issues of measurement while validity pertains to an instrument’s ability to discern geochemical source provenance. This is done in order to test the utility of PXRF instruments for archaeological provenance research. k-Means cluster analysis was used to test the accuracy of PXRF through statistical comparison of data acquired via laboratory and portable energy-dispersive XRF instruments. Multivariate analysis was employed to demonstrate obsidian source representation at two Classic Maya archaeological sites in southern Belize – Uxbenká and Ek Xux – and to test the validity of data obtained from a PXRF instrument in answering archaeological research questions pertaining to regional interactions between lowland Maya polities. Results suggest that portable XRF instruments produce internally consistent results. However, data acquired from a PXRF instrument are not statistically equivalent to other XRF instruments. This is to say that while PXRF is not a reliable technique, it is valid for questions pertaining to geochemical source representation.

Illustrated Phytoliths from Assorted Food Plants

Linda Scott Cummings
Phytolith Systematics
1992 pp 175-192

Various food plants were examined for phytoliths. Identification of cultivation or availability of food plants may rest with recovery of phytoliths from the edible or even inedible portions of the plants. Recovery of phytoliths from coprolites represents the edible portions, and may be used to identify plants that contributed to the diet. Occasionally another portion of the plant produces yet another type of phytolith, which might be recovered from plant parts that decay in place when examining sites such as garden plots.

Environmental constraints of human settlement in an evolving holocene alluvial system, the lower Mississippi valley

  • M. J. Guccione, R. H. Lafferty III, L. Scott Cummings
  • Geoarchaeology
  • Volume 3, Issue 1 1988 Pages 65–84
The lower Mississippi River has aggraded throughout the Holocene, resulting in stratification of cultural materials. Determination of this landscape evolution adds a temporal dimension to a model of human settlement. Sites most likely to be settled are high, well-drained surfaces near a stream. In the middle Holocene, conditions began to be suitable for settlement near Big Lake, Arkansas. A stream developed on the flood plain adjacent to a braided stream terrace. Flooding of the terrace formed a natural levee composed of well-drained, fertile, loam that was better suited for agriculture, if it existed at this time, and a living substrate than terrace sand to the west and backswamp clay to the east. Water and aquatic food sources were nearby. Open swamp conditions, present during middle Holocene, diminished by Late Holocene as bottomland arboreal habitats were becoming reestablished. This ideal environment has been intensely exploited for the past 3000 years, despite the temporary inconvenience of flooding.