Archaeological Chemistry In Archaeological Chemistry; Jakes, K.; ACS Symposium Series; American Chemical Society: Washington, DC, 2002. About the Cover The cover image is from the Toca do Serrote da Bastiana shelter. The photograph is courtesy of Niéde Guidon. The cover was designed by Leroy Corcoran of C&W Associates. In Archaeological Chemistry; Jakes, K.; ACS Symposium Series; American Chemical Society: Washington, DC, 2002. ACS SYMPOSIUM SERIES 831 Archaeological Chemistry Materials, Methods, and Meaning Kathryn A. Jakes, Editor Ohio State University American Chemical Society, Washington, DC In Archaeological Chemistry; Jakes, K.; ACS Symposium Series; American Chemical Society: Washington, DC, 2002. CC 79 .C5A728 2002 c. 1 Archaeological chemistry : materials, methods, and Library of Congress Cataloging-in-Publication Data Archaeological chemistry : materials, methods, and meaning / Kathryn A. Jakes, editor. p. cm.—(ACS symposium series ; 831) Developed from a symposium sponsored by the Division of the History of Chemistry at the 222nd National Meeting of the American Chemical Society, Chicago, Illinois, August 26-30, 2001. Includes bibliographical references and indexes. ISBN 0-8412-3810-3 1. Archaeological chemistry. 2. Archaeology—Methodology. I. Jakes, Kathryn A., 1949- II. American Chemical Society. Division of the History of Chemistry. III. American Chemical Society. Meeting (222nd : 2001 : Chicago, Ill..). IV. Series. CC79.C5 A728 2002 930.1'028—dc21 2002025577 The paper used in this publication meets the minimum requirements of American National Standard for Information Sciences—Permanence of Paper for Printed Library Materials, ANSI Z39.48-1984. Copyright © 2002American Chemical Society Distributed by Oxford University Press All Rights Reserved. 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Foreword The ACS Symposium Series was first published in 1974 to pro vide a mechanism for publishing symposia quickly in book form. The purpose of the series is to publish timely, comprehensive books de veloped from ACS sponsored symposia based on current scientific research. Occasion-ally, books are developed from symposia sponsored by other organizations when the topic is of keen interest to the chem istry audience. Before agreeing to publish a book, the proposed table of con tents is reviewed for appropriate and comprehensive coverage and for interest to the audience. Some papers may be excluded to better focus the book; others may be added to provide comprehensiveness. When appropriate, overview or introductory chapters are added. Drafts of chapters are peer-reviewed prior to final acceptance or rejection, and manuscripts are prepared in camera-ready format. As a rule, only original research papers and original review papers are included in the volumes. Verbatim reproductions of previ ously published papers are not accepted. ACS Books Department In Archaeological Chemistry; Jakes, K.; ACS Symposium Series; American Chemical Society: Washington, DC, 2002. Preface The chapters that comprise this volume provide a cross-section of current research in the area of chemistry applied to archaeological questions. The chapters were first presented as part of the 10th archae ological chemistry symposium, organized by the ACS Division of the History of Chemistry's Subdivision on Archaeological Chemistry, held in Chicago, Illinois, as part of the August 2001 national meeting of the American Chemical Society. The chapters present examples of the use of analytical methods in the study of a variety of archaeological materials. They also discuss the inferences concerning human behavior that can be made based on the patterns observed in the analytical data. Viewed as a whole, the chapters encompass differing viewpoints concerning the definition of nondestructive testing and new developments in determining an object's age and composition. The volume provides a stimulating panoramic view of ongoing research useful to the archaeologist, anthropologist, and chemist. It also may spur interest in the novice reader. As we use chemistry to study the remains of the past, we uncover the traces of human behavior that are embodied in those remains. Kathryn A. Jakes Department of Consumer and Textile Sciences College of Human Ecology Ohio State University 1787 Neil Avenue Columbus, OH 43210-1295 ix In Archaeological Chemistry; Jakes, K.; ACS Symposium Series; American Chemical Society: Washington, DC, 2002. Chapter 1 Archaeological Chemistry: Materials, Methods, and Meaning Kathryn A. Jakes Department of Consumer and Textile Sciences, Ohio State University, 1787 Neil Avenue, Columbus, OH 43210-1295 The chapters that comprise this volume provide a cross section of current research conducted in the area of chemistry applied to archaeological questions. Each presents an example of the chemical analytical investigation of archaeological materials and the use of the analytical data in discerning patterns of human behavior. New developments in dating and compositional analysis are described. Differing views of the definition of "nondestructive" are presented. Archaeology is an eclectic science, drawing from a variety of disciplines in the study of the materials that remain from past human activity. Applying geology, geography, history, anthropology, materials science, and chemistry, among others, we glean new knowledge of past lifeways. The chemist who undertakes an investigation of an object from an archaeological site can make a unique contribution to archaeology, often providing new information that is not apparent to the naked eye. We learn which foods people ate and the tools people used, also uncovering facts about how these materials were gathered locally or traded from afar. We are fascinated as we examine objects formed by early artisans, learning about how they were made and speculating about why they were made in a particular manner. We are connected to our predecessors on this planet as we learn what they knew, as we try to see what they saw, as we speculate about the things they valued. Spurred by the connection between us and the past, we probe the objects that embody clues to the past. Even as the world advances, we continue to be curious about those who have gone before us. © 2002 American Chemical Society 1 In Archaeological Chemistry; Jakes, K.; ACS Symposium Series; American Chemical Society: Washington, DC, 2002. 2 On first appraisal, the chapters that comprise this volume may appear to be a disparate group. The common thread that unites them is their use of chemical analytical methods to examine archaeological materials and their assessment of the information derived from these analyses to discern patterns of past human behavior. The chapters were first presented as part of the tenth archaeological chemistry symposium organized by the Division of History of Chemistry's Subdivision on Archaeological Chemistry and held as part of a national meeting of the American Chemical Society. Individually each provides an example of the current work being conducted in the area of chemistry applied to archaeological questions. Viewed as a whole they reflect the interdisciplinary nature of archaeological chemistry. Many different types of archaeological materials are discussed and many different chemical analytical methods are employed in the study of these materials. New developments in isotopic dating methods and in compositional analysis are described. The chapters also include some differing views of the definition of "nondestructive". Methods of Analysis The methods described in the first chapters of this book reflect continued efforts by the archaeological chemist to glean data from artifacts while incurring the least possible sample destruction. They also present differing viewpoints concerning the definition of "nondestructive". Although there is general consensus among the authors that there should be no apparent destruction of the artifact in question, some differences can be seen in approach to this goal. Ciliberto (2) describes nondestructive analytical techniques as those which "allow analytical informatidn to be obtained with no damage whatsoever to the sample or in some cases, the object in question. All visible alterations are avoided, and the object remains aesthetically unimpaired." Archaeology is destructive by nature; some alteration is incurred when an object is excavated and brought into a new environment. Subsequent examination can incur damage to the recovered materials, causing fading of colors, for example. While Ciliberto (7) argues that there are "numerous fragments and leftover pieces" available for analysis of archeological objects, in some cases very little remains, and we strive to derive the most information possible from the smallest sample possible. New analytical methods help us achieve this goal, providing a vast amount of information from very small amounts of material. Two different approaches to the goal of nondestructive analysis are presented in these chapters. Either a very small sample is removed for subsequent examination or a very small amount of material is extracted from the bulk object. Is it best to remove a micro-sized sample, smaller than can be perceived by the naked eye? An assumption must be made in subsequent analyses that the results of the examination of small areas are representative of the object as a whole. On the other hand, if a very small amount of a component of the object in question can be removed from the entire object, the extract will provide a clue to the overall composition of the artifact. The extraction, In Archaeological Chemistry; Jakes, K.; ACS Symposium Series; American Chemical Society: Washington, DC, 2002. 3 however, will affect the chemistry of the entire object, even if only slightly. As the science of archaeological chemistry proceeds and new developments allow more information to be gleaned from ever smaller amounts of analyte, it will be important that any methods used in examination of the object be well documented. In an innovative approach to obtaining the carbon for radioisotopic dating, Steelman and Rowe describe plasma chemical extraction of carbon from bulk organic objects. They tested the effects of the procedure on a peyote button, a clothing label, a sample of bone, and a sample of Third International Radiocarbon Intercomparison (TIRI) standard wood. The extraction process is "nondestructive in that it extracts only organic material" from the samples studied; the objects remain visibly unaffected by the treatment. The method is supported in the close match between the dates they obtained for the TIRI wood and charcoal samples and those obtained by other laboratories in the conventional manner. The plasma extraction procedure holds a great potential for dating organic archaeological artifacts. Although a sample may have to be removed from an object, the extraction procedure itself leaves no visible effect on the sample and additional tests can be performed. In exploring the question of the earliest date for human presence in Brazil, Steelman and coworkers apply the plasma chemical procedure to extract carbon from both the pigments of a rock painting from Toca do Serrote de Bastiana and the accretions covering its surface. The accretions were found to contain both monohydrate of calcium oxalate and calcium carbonate. The radiocarbon age of the oxalate carbon was determined to be 2540 ± 60 B.P. while the radiocarbon age of carbon extracted from the pigment was determined to be 3730 ± 90 B.P. These ages are much more recent than the 30,000-40,000 B.P. age determined by electron spin resonance and mennoluminescence of the accretions, but are consistent with dates of other pictographs in the same shelter. In another approach to extraction of a small amount of material from the bulk of an object, Reslewic and Burton extract lead from intact samples of majolica using ethylenediaminetetraacetic acid (EDTA). Lead isotope ratios of the EDTA extracts, detennined by inductively coupled plasma mass spectrometry, are used to study the provenience of majolica. Their data agree with previous studies indicating that only a few production centers supplied New Spain with majolica in the 18th century. While more work needs to be done to determine the lead isotope ratio differences among geologic deposits and thereby identify distinct majolica groups, their EDTA extraction method holds a significant potential for the study of lead glazed pottery, and serves as a model for the concept of the use of chelating agents to extract components from archaeological materials with minimal effect on the objects. Speakman and his colleagues describe the application of inductively coupled plasma mass spectrometry (ICP-MS) to the elemental analysis of obsidian, chert, pottery and painted and glazed surfaces. Only a very small area is affected in the laser ablation sampling, usually 1000 um by 1000 urn by 30 um. Their method is "virtually nondestructive" since the ablated area is not visible to the naked eye. Because ICP-MS has a lower detection limit than other In Archaeological Chemistry; Jakes, K.; ACS Symposium Series; American Chemical Society: Washington, DC, 2002. 4 common techniques, it is an ideal method for elemental analysis of materials with widely variable and yet localized composition. Materials Characterization Several chapters in this volume present work conducted on the characterization of materials recovered from archaeological sites or of modern material prepared for comparative purposes. Chemical and physical attributes such as elemental composition, molecular structure, or isotopic ratios are determined and classification systems are developed that distinguish different members of a class. For example, Lambert and his coworkers examined modern and ancient plant resins employing solid-state carbon-13 nuclear magnetic resonance. They focus on the resins from Africa and the Americas, expanding on the classifications derived from results of infrared (IR) spectroscopy and gas chromatography-mass spectrometry (GC-MS). Thereby the composition of ancient artifacts can be used to determine their biological or geographic origin and inferences concerning exchange of resins or resinous objects also can be speculated. In a complementary paper, Lampert and her colleagues use GC and GC-MS to examine plant resins of Southeast Asia. They also identify characteristics of residues of archaeological resins coating the surfaces of ceramic potsherds, and are able to distinguish differences in chromatograms of resins from different plant genera. Radiocarbon dates of the resinous coatings of sherds from only one of the two sites under study agree with other known dates for these sites. Similar work in characterization of materials is described in Chapter 8, in which Karklins et al. use neutron activation analysis to examine 290 glass beads and fragments from a glassmaking house in Amsterdam. The elemental composition, color, and pattern of the beads forms the basis by which beads found in sites in northeastern North America can be traced to their origins in Amsterdam. In Chapter 9, silk fibers from textiles recovered from the marine site of a wrecked ship are described by Srinivasan and Jakes. These seemingly fragile fibers are well preserved despite 130 years of submersion in the deep ocean. Not only can these textiles provide information about the people who traveled on the fated ship in 1857, they serve as models of the survival of fragile textiles in marine sites and thereby may encourage exploration and recovery. Taking a different route to materials characterization, Hayes and Schurr use an experimental archaeological approach to develop a method for classification of archaeological maize and bone. They prepare comparative sets of maize and bone heated to different temperatures for differing periods of time and in conditions that include or exclude oxygen. Using Electron Spin Resonance (ESR), they are able to determine the maximum heating temperature In Archaeological Chemistry; Jakes, K.; ACS Symposium Series; American Chemical Society: Washington, DC, 2002.