Abstract: Six hundred sixty-two obsidian samples from sources in Oregon were characterized by instrumental neutron activation analysis (INAA) in order to establish the number of geochemical groups present. Neutron irradiations were performed at the Missouri University research reactor (MURR) and gamma-ray spectra were measured with high-purity germanium (HPGe) detectors to determine absolute concentrations for 27 elements.

Thirty-six different geochemical groups were formed. Four groups were found in the Malheur National Forest of Grant County. Six groups were found in Harney County, three of them near the town of Burns. Three correlated groups, part of an extensive ash-flow tuff, were found in the Ochoco National Forest area of Harney County. Seven groups were found at Glass Buttes, Lake County, where x-ray fluorescence (XRF) showed only six groups. Nine groups were found in Lake County. Four groups were found in Newberry Caldera. Previously, based on XRF, it was thought that only two groups existed. A single geochemical group was identified in Klamath County. Two chemical groups were found in Lane County.

Most of the above chemical groups were successfully separated using an abbreviated-INAA procedure (only the elements Na, Mn, and Ba). Only in the Ochoco National Forest was the procedure unsuccessful.

Use of the database on an archaeological problem was demonstrated by analyzing thirty-one artifacts from the Robins Spring site, on Glass Buttes, by procedures in this study. The results indicate the artifacts were made from several of the obsidian sources on Glass Buttes as well as Yreka Butte, a source near Glass Buttes.

Abstract: The present research investigates prehistoric use of near-shore wetland habitats in the Mono Lake basin. Wetland types are stratified into three classes in order to assess the use of these lakeshore habitats through time. The research seeks to identify the role of wetlands in prehistoric lifeways and how this has changed through time.

Project data were recovered through a random stratified surface survey of 10 km² distributed around the near-lakeshore area. Spatial associations of artifacts and debitage were recorded and samples collected for analysis. In addition to techno-morphological analysis, obsidian artifacts were also subject to visual, X-ray fluorescence source, and obsidian hydration analysis.

Results of the analysis suggest thath the near-shore wetlands of Mono Lake basin were subject to varied use during the past, ranging from duration of stay to activity undertaken. This may be due in part to lake elevation fluctuations affecting the habitats, as well as population pressure and diet breadth expansion.

Abstract: Archaeological studies of lithic material procurement and use have traditionally focused on raw material quality and proximity to source as sole indicators for selection of particular materials for stone tool manufacture. Yet this effectively denies the role of human action and belief in the choice of lithic materials. The Glass Mountain obsidian quarry provides evidence of the integration of prehistoric belief systems into toolstone procurement patterns as visible through differential toolstone use in prehistory and the selection of specific raw material types for particuular categories of objects.

Large obsidian bifaces from northern California have long been known as non-utilitarian ceremonial and wealth objects. Despite their uniform and stylized shape, bifaces were manufactured from several different obsidiain sources. Glass Mountain in Siskiyou County, California was one source for black obsidian bifaces. The lithic assemblage at Glass Mountain and X-ray fluorescence data from the surrounding region indicate that this obsidian was used almost entirely for biface production, and was neglected as a source for utilitarian objects. Just as obsidian objects fulfilled utilitarian of non-utilitarian functions, obsidian sources retained special roles within the context of prehistoric cultura and belief systems.

Ultimately, differential use of Glass Mountain obsidian lies in the context of cultural beliefs, which hold it as a special source to be used exclusively for the production of valued objects. Certainly Glass Mountain is not the only obsidian utilized for value objects, but it is unique in that it was used almost entirely for non-utilitarian purposes, while other nearby obsidian was exploited for utilitarian objects. The cultural context of Glass Mountain obsidian utilization varies across and within territorial and geographic boundaries, yet despite cultural differences, the concept of value is intricately linked with Glass Mountain obsidian and the large bifaces made from it. In this sense, the quarry was in itself also an active agent, which gave value to things. It provides evidence for integration of prehistoric belief systems into toolstone procurement and use patterns through the selective use of Glass Mountain obsidian for ceremonial and value objects.

Abstract: Bone Cave is located in the High Lava Plains ofCentral Oregon, just east of Bend. Excavations were conducted at the site to examine the extent of looter disturbance, and to address research questions focused on prehistoric settlement and subsistence. In the excavation of more than 10 m3 ofsediment from six l-x-2 meter test units in the front chamber ofthe lava tube, no undisturbed deposits were encountered.

Due to the disturbed context, analysis ofthe lithic and faunal assemblages was not able to completely answer questions about culture change or ethnic affiliation, although subsistence, site function and chronology were addressed. Obsidian hydration and obsidian characterization studies indicate that the site was probably occupied exclusively during the Early Holocene, prior to the eruption of Mt. Mazama.

Lithic reduction activities at the site appear to have been limited to late-stage bifacial reduction and tool resharpening. There is no evidence ofany early stage core reduction, or large flake or flake tool manufacture. The limited tool assemblage, consisting primarily ofwell-worked bifacial fragments, supports this conclusion. Lithic debitage was sourced to more local obsidian sources while the tools were mostly produced from distant and unknown sources, suggesting long-term tool curation and retooling at the site using local material.

The large faunal assemblage contains approximately 91 percent rabbit remains. The small amount of medium sized mammal bone fragments, along with a portion of the rabbit remains, exhibit clear cut marks indicative ofbutchering activity. The site appears to have served as a processing location for large-scale hunts or drives specifically targeting rabbits during the Early Holocene. If the site served such a specialized function, then it implies some degree of logistical organization during the Early Archaic. Communal rabbit drives also suggest a level ofpolitical organization not generally associated with the Early Archaic in the Great Basin.

Disturbed sites such as Bone Cave are able to produce valuable information if the proper analytical methods are used. A combination of lithic and faunal analysis can reveal site function, chronology, lithic use and reduction strategy, and subsistence practices, even in the absence ofcontextual information and formal tool assemblages.

Abstract: This dissertation examines spatio-temporal patterns of obsidian use on the Volcanic Tableland and their implications for long-term change in lithic technology and regional settlement ranges in the western Great Basin. The core of the study ia a massive set of obsidian source and hydration data, fostered by the use of existing artifact collections and new materials recovered through survey and excavation.

Shifts in flakes stone technology occur with the introduction of the bow-and-arrow. At the Newberry/Haiwee transition (1400 B.P.), the switch from Elko dart points to Rosegate arrow points was accompanied by changes in the roles and forms of bifaces, cores, and flake tools. Also, projectile points are shown to be useful time markers in the Great Basin, using hydration data and point types as proxy measures.

Throughout its prehistory, the Tableland was occupied by groups entering mainly through the north and northeast. Early and middle Holocene occupations (ca. 8500-4000 B.P.) centered on Fish Slough. Visitors came from extreme distances north and south, stopping only briefly. Between 4000-1400 B.P., occupations shifted to the plateau, people hailing from shorter distances to the north/northeast. Habitations were extended or repeated enough to produce middens and focused on dryland plants and animals. More recent occupations (ca. 1400-200 B.P.) targeted plateau sites, and reused sites at Fish Slough, emphasizing the bulk procurement and processing of dryland seend. Ricegrass was gathered while green and "flash-burned" to remove chaff, the seeds ground on bedrrock with two-handed manos. Visitors had restricted northern territories, making settlement moves between western Nevada, the Mono Basin, and Long Valley. The presence of Owens Valley groups was limited, the terminal prehistoric pattern (200 B.P.-Contact) showing near exclusive use by northern populations. Major sites were again reoccupied and used to process seed plants in bulk. Late Holocene settlement systems including the Tableland saw the kind of spatial circumscription commonly ascribed to the Owens Valley settlement regime. This suggests other populations in eastern California/western Nevada experienced conditions of growth and competition, the effects of which led to subsistence intensification across the Inyo-Mono region.

Abstract: This thesis explores the complex dynamics of lithic raw material procurement systems within the context of changing patterns of social, political, and economic interaction among prehistoric settlers of the Pajarito Plateau, New Mexico. Isopleth maps are generated for the archaeological distributions of locally available obsidian, basalt, and chert at several hundred sites within the study area. I distinguish differences between specialized, seasonally-occupied sites and residential structures, and calculate how procurement patterns shifted through time. Instead of examining broad trends in procurement and exchange over spaces measured on a scale of hundreds of kilometers, this investigation addresses small-scale variations in procurement patterns. The large number of sites used for analysis provides a high-resolution portrait of these patterns, the details of which show how physiographic relief and social boundaries may have shaped procurement behavior across the study area. I found that social boundaries functioned to restrict access to certain raw material sources and that these divisions were in place earlier than previously thought. In addition, the analysis revealed that obsidian procurement was increasingly emphasized at two discrete settlement clusters relative to neighboring groups signalling the emergence of more specialized production, probably to serve a growing trade relationship known to exist between Puebloan and Plains groups to the east.

Abstract: Archaeologists have been undecided for years on the purpose or intent of ancient lithic caches that have been discovered throughout the landscape in various parts of the world. These caches have varied by morphology, typology, size, and location. This dissertation discusses a brief history of lithic caches, their possible meanings and purposes, and examines four lithic caches that were discovered in the United States of America, for any possible relationships and similarities. These four lithic caches are concentrated on Idaho's south central Snake River Plain within a range of 110 km of each other. Non-professionals discovered three caches; another was professionally excavated. The Cedar Draw and China Creek Caches have never been placed into the archaeological history record and are catalogued and analyzed here for the first time. Even though the caches were found at different elevations and landscapes they were all located near a water source that provided visibility of the surrounding terrain. No debitage was found directly at the sites, and osteological evidence was not present. The artifacts in the Simon Cache and the China Creek Cache appear to be made from exotic materials procured from a non-local stone sources suggesting long distance movement or trade. Both caches were discovered near possible ancient trade routes. The Cedar Draw Cache and the Rock Creek Cache exhibit the same morphology and typology. A strong probability exists that they were manufactured from the same ignimbrite material source. The four caches vary in age from the Clovis culture (11,200 B.P. to 10,900 B.P.) to approximately 3,000 B.P.

Abstract: Recent studies of the Late Archaic period in the Great Basin have identified major changes in settlement, subsistence, and technology compared to those seen during the Middle Archaic. The concern of this study is whether the Late Archaic at the Birch Creek Site (35ML181) is marked by a significant change in adaptive strategy, as it appears to be in much of the Great Basin. This thesis uses the sediments encountered and material recovered from the 2006 excavations of the Birch Creek Site, including datable samples, ancient pollen, ground and chipped stone tools and debitage, faunal remains, and evidence of ceramic technology as evidence of the adaptive strategy of Late Archaic people at the Birch Creek Site. The Late Archaic component was expected to be structured differently from earlier materials if it were created by a new group of people practicing a new adaptice strategy beginning during the Late Archaic. Comparisons of Late Archaic artifact assemblages to previously studied materials from the Middle Archaic component of the Birch Creek Site were used to determine if a discontinuity in adaptive strategy exists. Material evidence of settlement, subsistence, and technological organization do not reflect direct continuity, nor do they indicate an abrupt shift, in adaptive strategies. The adaptive strategy duing the Late Archaic occupation of the Birch Creek Site appears to be a product of relatively local conditons related to subsistence and tool raw material resources, with some indications of wider regional interactions.

Abstract: Identifying lithic sources is central to understanding toolstone use by prehistoric hunter-gatherer groups. The distribution of archaeological materials in relation to geologic sources creates a spatial pattern of use that varies through time. These patterns of distribution in conjunction with analysis of technological organization can be used to infer behavior, especially levels of mobility. This thesis presents geochemical data from a wide-scale sourcing study in the Bonneville basin of western Utah and eastern Nevada. Results of this investigation are presented, including discussion of newly identified geologic source groups and further characterization of previously identified sources, outcome of X-ray fluorescence analysis on approximately 600 fine-grained volcanic (FGV) artifacts from a host of open sites in the Old River Bed delta and from caves/rockshelters including Danger Cave, Bonneville Estates Rockshelter, and Camels Back Cave, and a brief look at how the inhabitants of this region varied FGV-toolstone use through time.

Abstract: This study examines igneous toolstone procurement and mobility strategies during the Archaic Period (9,000 B.P. - 2,400 B.P.) on the Coconino Plateau, Arizona. Relying on X-ray fluorescence analysis to determine the geologic source of 271 diagnostic projectile points, I investigate obsidian and fine-grained volcanic (FGV) source preferences and small-scale mobility patterns surrounding the San Francisco and Mt. Floyd Colcanic Fields. Included in this study is a sampling survey designed to provide a comparative geochemical source libraary (n=355) for the region. The baseline survey served to ascertain the various performance characteristics of each raw material. These performance characteristics were then used as a foundation for a procurement model intended to explain the highly slective and patterned procurement behavior exhibited by the hunter-gatherers that occupied the area. I adapted the lithics-based model, termed the procurement preference model (PPM), from subsistence-based diet breadth models.

Archaic Period bands occupying the Coconino Plateau exploited only a handful of the lithic source options available in the research area. I assert that hunter-gatherers optimized procurement decisions and sought to maximize rate of energy return by choosing the highest-quality lithic materials. I further argue hunter-gatherers practiced a disembedded procurement strategy once within the study area. Lastly, the specific igneous toolstone sources comprising the optimal set of lithic sources remained unchanged throughout the 6,600 years of the Archaic, although the overall percentage of the entire optimal set increased as observed in the projectile point sample. Thus, I conclude lithic source procurement became more specialized over time.

From the Introduction: The research that is reported in this project deals primarily with obsidian characterization. I have gone beyond this topic, though, in presenting an overview of the many other geological, geomorphological and archaeological properties of this natural glass. The project, as a result, is divided into five distinct, but interrelated parts, in addition to an extensive bibliography and a number of appendices.

This part, the first one, is an introduction to the rest of the project. It will give the reader a general idea of the structure that I used to organize this paper and of what I intended to achieve through the research that is reported. Topics touched on here will be discussed in greater detail in later sections.

Part Two of this project is concerned with providing an overview of the many geological and geomorphological characteristics and properties of obsidian. This includes its geographic distribution, the forms in which it occurs, how it is transported after extrusion, its macroscopic and microscopic properties and its chemical composition. An understanding of these characteristics provides a step towards comprehending how the physical and geochemical properties of obsidian may be studied and how the results can be utilized in archaeological problem-solving.

Part Three describes the ways in which analysis of the petrographic, optical and geochemical properties of obsidian can be applied to archaeological studies. Specifically, I will discuss obsidian characterization methods, the ways in which characterized obsidian can be used to infer prehistoric contact networks and obsidian geochronologic techniques.

Part Four comprises the main body of the project, a systematic investigation of some of the attributes of obsidian that may be used to characterize, or distinguish, a particular geologic source of glass. In Part Four, I will describe the ten Oregon sources that were sampled for this research and the different ways in which they were successfully and unsuccessfully "fingerprinted" or characterized. All of the sampled obsidian sources were known or suspected to be prehistoric quarry sites.

Abstract: This research integrates the analysis of obsidian geochemistry with investigation on the effects of forest fires on obsidian artifacts in surface assemblages. The first component of this project investigated the nature of heat altered obsidian at a prehistoric quarry sites following the 1996 Dome Fire in the Jemez Mountains of northern New Mexico. Burned artifacts were examined to discern indicators of heat alteration in obsidian and to measure the impact of fire on obsidian hydration (OH) bands. Descriptive categories developed to encompass a range of fire effects are provided here as a tool for identifying heat-altered obsidian in archaeological contexts. Measurement of obsidian hydration in artifacts collected from across the site demonstrated substantial loss and alteration of OH information, as well as positive correlation of OH loss/alteration with degree of burn severity.

The second component of the project investigated the role of obsidian geochemistry in fire effects, especially obsidian vesiculation. Intrasource and intersource geochemical analyses of obsidian trace element composiiton were integrated with analysis of major/minor elements, and with analysis of the water content as a volatile constituent. Results show elemental homogeneity among the Dome area Obsidian Ridge/Rabbit Mountains obsidians of the Cerro Toledo Rhyolite (CTR), demonstrate a cogenic realtionship among geographically separate CTR deposits, and confirm that these obsidians are chemically distinct from Valles Rhyolite (VR) glasses as Cerro del Medio. Analyses of obsidian water content using loss-on-ignition (LOI) and infrared spectroscopy (FTIR) demonstrate the efficacy o both techniques for archaeological applications. Water contents were found to be low in VR samples, but high and variable in CTR samples. These results accord with the expectation of higher and more variable water contents in glasses from pyroclastic deposits, as compared with lower water contents in glasses from extrusive volcanic contexts This study provides a new example in which obsidian water content is high and variable within a single chemical type. This example provides support for the inclusion of water contents as a compositional variable in the OH dating model and demonstrates the utility of integrating analysis of both elemental and volatile composition into archaeological practices of obsidian geochemical analyses.

Abstract: Despite several decades of archaeological work in both the western Great Basin and the Sierra Nevada foothills, little is known about how prehistoric populations used the high elevation areas between these two regions. This thesis involved the investigation of six high elevation sites at Taboose Pass in Kings Canyon National Park, California. Through a combination of surface collection, limited test excavation, two distinct archaeological patters were identified. The first is an earlier (ca-3500 B.P.-1350 B.P.) limited-use pattern characterized by dense lithic scatters related to obsidian procurement by groups living on the western slope of the Sierra Nevada. The second pattern is a later (ca. 1350 B.P.-historic contact) intensive-use pattern with rock ring features, midden soil, and a variety.

From the Abstract: Geochemical characterization methods are commonly used in the reconstruction of prehistoric raw material use and procurement systems. Trace element studies of lithic source materials and artifacts, specifically those made of obsidian, can reveal important information about the environmental and cultural factors which influence the prehistoric distribution of raw material. The current investigation use geochemical characterization methods and data to document and evaluate the distribution of geologic and artifact obsidian that originates from the Silver Lake/Sycan Marsh (SL/SM) obsidian source. This large and prehistorically significant source is located in western Lake County, Oregon. Few source descriptions or artifact distribution studies exist for SL/SM obsidian. However, over the past decade, a significant increase in the use of geochemical characterization methods has generated a wealth of data for Oregon obsidian sources. This thesis synthesizes the results of the geochemical characterization analysis of 392 geologic obsidian specimens collected from the SL/SM source area and 1,938 SL/SM obsidian artifacts recovered from over 200 sites in Oregon, Washington and California. The artifact analytical data were derived from previously characterized artifact collections compiled and archived in an extensive database. A subset of artifacts were characterized for the purpose of this study.

From the Abstract: Over the last 30 years, obsidian has served archaeologists by providing a means to estimate age in one capacity or another. An ultimate objective of this thesis was to reexamine both absolute and relative dating approaches.

Two lines of action were pursued in this endeavor. First, an extensive review of studies on glass surface reactions was undertaken, with the intent to synthesize the information gathered, and assess both its pertinence to the obsidian hydration process and its implications regarding dating issues. Secondly, accelerated hydration experiments were conducted, reacting California North Coast Ranges obsidians, with the intent to evaluate the application of the experimental method for both absolute and relative dating purposes.

From the review of studies on glass surface reactions, it was found that glass scientists have made considerable advances recently in their understanding of glass weathering kinetics. Many factors, working synergetically, have been shown to affect both mechanisms and rates of reaction, reflecting the complexity of glass weathering processes. As the literature search indicates, such factors as solution pH, solution composition, glass surface area-to-solution volume (SA/V), relative humidity, and temperature, all affect experimentally determined rates of reaction. The extent of their significance to naturally hydrating obsidian, in archaeological site contexts, needs to be assessed to fully evaluate implications to obsidian dating in its absolute chronometric capacity.

From accelerated hydration experiments, designed primarily to investigate the replicability of test results, it was found that some variability between results occurred. This variability was attributed to small differences in condition such as non-standardized flake sizes (affecting SA/V ratios), and differences in solution composition (deionized water vs. silica saturated solutions). Although it was determined that test results appear to be reproducible if all factors are held constant, the appropriateness of applying condition-specific rate constants (derived from these high-temperature essentially closedsystem experiments) to field conditions was questioned.

I conclude, based on the review of glass surface reaction studies and accelerated hydration experiments, that the absolute dating of obsidian remains less than secure. From a more practical standpoint, until problematic issues are resolved, perhaps a relative dating approach has more merit. An investigation was conducted exploring the potential of accelerated hydration experiments to enhance this approach. A proposed application is suggested to obtain relative calibrations of hydration measurements between sources, allowing temporal ordering and providing a means to make cross-source comparisons of obsidians exposed to similar temperature histories and conditions.

Abstract: Regional studies of obsidian artifacts in the south-central Andes have shown thath over 90% of the analyzed obsidian artifacts from the Lake Titicaca Basin belong to a single geochemical obsidian type. A decade ago researchers identified the geologic origin of this obsidian as the Chivay/Cotallalli source, located 180km west of Lake Titicaca above the Colcaa Valley in Arequipa at 71.5355º S, 15.6423º W (WGS84), and at 4972 meters above sea level. This research project focused on the obsidian source and adjacent lands within one day's travel from the source. The project included a 33km² survey, 8 test units, and in-depth lithic attribute analysis. Mobile GIS (Arcpad) was used extensively during survey. A substantial quarry pit and an obsidian workshop were examined closely, as were consumption sites in nearby areas. The results of this study found that the earliest diagnostic materials at the source date to he Middle Archaic (8000-6000 BCE) and that intensification of obsidian production occurred earlier than previously recognized, at circa 3300 BCE. Increased obsidian production appears to have been focused on the acquisition of large (>20cm) and homogeneous obsidian nodules, although the formal tools produced with obsidian were predominantly small projectile points. It is argued that the acquisition of large, homogeneous nodules was prioritized because the production potential of large nodules was highest, and because obsidian was associated with competitive display among early aggrandizers. The timing and economic associations of obsidian production and circulation suggest that the possession of large obsidian pieces in the Titicaca Basin was a demonstration of social connections to distant resources, and to regional trade networks that emerged with regular camelid caravan transport networks. Obsidian artifacts were not niherently "prestige goods"; rather, it is suggested here that obsidian was the least-perishable of a number of cultural goods distributed by an expanding network of caravans that linked communities in the region. The acquisition and consumption of these cultural goods was a demonstration of economic connections and cultural influence during the dynamic period of incipient social inequity between the Terminal Archaic (3300-2000 BCE) through the Middle Formative (1300-500 BCE).