Strontium isotopes reveal distant sources of architectural timber in Chaco Canyon, New Mexico.
09 Oct 2001-Proceedings of the National Academy of Sciences of the United States of America (National Academy of Sciences)-Vol. 98, Iss: 21, pp 11891-11896
TL;DR: The use of trees from both the Chuska and San Mateo mountains, but not from the San Pedro Mountains, as early as A.D. 974 suggests that selection of timber sources was driven more by regional socioeconomic ties than by a simple model of resource depletion with distance and time.
Abstract: Between A.D. 900 and 1150, more than 200,000 conifer trees were used to build the prehistoric great houses of Chaco Canyon, New Mexico, in what is now a treeless landscape. More than one-fifth of these timbers were spruce (Picea) or fir (Abies) that were hand-carried from isolated mountaintops 75–100 km away. Because strontium from local dust, water, and underlying bedrock is incorporated by trees, specific logging sites can be identified by comparing 87Sr/86Sr ratios in construction beams from different ruins and building periods to ratios in living trees from the surrounding mountains. 87Sr/86Sr ratios show that the beams came from both the Chuska and San Mateo (Mount Taylor) mountains, but not from the San Pedro Mountains, which are equally close. Incorporation of logs from two sources in the same room, great house, and year suggest stockpiling and intercommunity collaboration at Chaco Canyon. The use of trees from both the Chuska and San Mateo mountains, but not from the San Pedro Mountains, as early as A.D. 974 suggests that selection of timber sources was driven more by regional socioeconomic ties than by a simple model of resource depletion with distance and time.
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TL;DR: Radiogenic isotopes have wide application to chemical stratigraphy, geochronology, provenance studies, and studies of temporal changes in Earth surface processes as discussed by the authors, and they can be used for stratigraphic correlation and to assess changes through Earth history in processes such as tectonic uplift, climate change, biogeochemical cycling, ocean circulation, crustal growth, and surface water evolution.
338 citations
Cites background from "Strontium isotopes reveal distant s..."
...Applications of strontium isotopes to ecosystems have also revealed the sources and extent of cycling of cations (English et al., 2001; Kennedy et al., 2002)....
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TL;DR: In this paper, the authors analyzed 87Sr/86Sr of water, bedrock, soils, and plants across a broad geographic region to test the potential of this method in the ancient Maya area.
278 citations
TL;DR: In this paper, the authors discuss the conclusions of current research at Chaco including definitions of the Chaco region, recent fieldwork, histories of Chaco archaeology, chronology, paleoenvironmental reconstruction, demography, political organization, outlier communities, economic organization, social organization, ritual, violence, and the post-Chacoan reorganization.
Abstract: Current research on Chaco Canyon and its surrounding outlier communities is at an important juncture. Rather than trying to argue for the presence or absence of complexity, archaeologists working in the area are asking different questions, especially how Chacoan political, economic, ritual, and social organization were structured. These lines of inquiry do not attempt to pigeonhole Chaco into traditional neoevolutionary types, but instead seek to understand the historical trajectory that led to the construction of monumental architecture in Chaco Canyon and a large part of the northern Southwest in the 10th through 12th centuries. This review discusses the conclusions of current research at Chaco including definitions of the Chaco region, recent fieldwork, histories of Chaco archaeology, chronology, paleoenvironmental reconstruction, demography, political organization, outlier communities, economic organization, social organization, ritual, violence, and the post-Chacoan reorganization. Although many issues are hotly debated, there is a growing concensus that power was not based in a centralized political organization and that ritual organization was a key factor in the replication of Chacoan architecture across a vast regional landscape. Exactly how ritual, social, and political organization intersected is a central question for Chaco scholars. The resolution of this problem will prove to be of interest to all archaeologists working with intermediate societies across the globe.
113 citations
TL;DR: In this article, Strontium, oxygen, and carbon isotope data from archaeological human tooth enamel from Nasca trophy heads from Aja, Cahuachi, Cantayo, Majoro Chico and Paredones, and from individuals buried in Nasca cemeteries at Cahuachina, Chico, and Majorco Chico elucidate the geographic origins and paleodiet of trophy heads in the Nazca Drainage.
106 citations
TL;DR: In this paper, an isotope package9 map of the Isle of Skye in the Inner Hebrides is presented. The map is based on a study undertaken on the island in the UK, and reduces the complexity of geological and isotope data into five main 87 Sr/86 Sr packages.
Abstract: The potential of 87 Sr/ 86 Sr isotope composition for tracking and determining the origin of material, whether it is humans, animals, water or wine can be fully realized only if high-quality reference datasets are available against which to compare the unknowns. This is currently not the case. Despite the rapid increase in 87 Sr/ 86 Sr-based provenance studies of biosphere materials there are no well-documented maps available. Most researchers resort to generating reference maps from a variety of geological datasets plus the analysis of sparse ’environmental9 samples. A major reason for this lack of reference material is the investment needed to undertake systematic sampling and analysis over large areas. A further problem is associated with the choice of proxy material, as organisms differ in their habitat and exploitation of resources. In this paper various approaches to isotope biosphere sampling are considered, some of the problems are assessed, the precision required for the study of human populations is discussed, and a first attempt is made to condense all of the available information into an ’isotope package9 map. The work is based on a study undertaken on the Isle of Skye, in the Inner Hebrides, and reduces the complexity of geological and isotope data into five main 87 Sr/ 86 Sr packages: Package 1 (northern area) = 0.705–0.7092; Package 2 (NE coast) = 0.7082–0.7102; Package 3 (granitic rocks) = 0.716–0.720; Package 4 (metamorphic rocks) = 0.7092–0.7188; Package 5 (seawater) = 0.7092 ± 0.005% (2σ). The approach of trying to constrain the isotope composition of certain areas and/or lithologies offers the possibility of extrapolating to other similar areas without having to sample at the original density.
105 citations
Cites methods from "Strontium isotopes reveal distant s..."
...Strontium isotopes are increasingly being used as a tool for archaeological and environmental migration and provenance studies (Beard & Johnson 2000; English et al. 2001; Price et al. 2004, 2006; Bentley & Knipper 2005a; Bentley 2006; Evans et al. 2006; Price & Gestsdottir 2006; Dufour et al. 2007; Montgomery et al. 2007a; Stein et al. 2009; Heier et al. 2009)....
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...…isotopes are increasingly being used as a tool for archaeological and environmental migration and provenance studies (Beard & Johnson 2000; English et al. 2001; Price et al. 2004, 2006; Bentley & Knipper 2005a; Bentley 2006; Evans et al. 2006; Price & Gestsdottir 2006; Dufour et al.…...
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References
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TL;DR: A montane grassland restoration project in northern New Mexico is described that was justified and guided by an historical sequence of aerial photographs showing progressive tree invasion during the 20th century, and a south- western network of fire histories illustrates the power of aggregating historical time series across spatial scales.
Abstract: Applied historical ecology is the use of historical knowledge in the man- agement of ecosystems. Historical perspectives increase our understanding of the dynamic nature of landscapes and provide a frame of reference for assessing modern patterns and processes. Historical records, however, are often too brief or fragmentary to be useful, or they are not obtainable for the process or structure of interest. Even where long historical time series can be assembled, selection of appropriate reference conditions may be com- plicated by the past influence of humans and the many potential reference conditions encompassed by nonequilibrium dynamics. These complications, however, do not lessen the value of history; rather they underscore the need for multiple, comparative histories from many locations for evaluating both cultural and natural causes of variability, as well as for characterizing the overall dynamical properties of ecosystems. Historical knowledge may not simplify the task of setting management goals and making decisions, but 20th century trends, such as increasingly severe wildfires, suggest that disregarding history can be perilous. We describe examples from our research in the southwestern United States to illustrate some of the values and limitations of applied historical ecology. Paleoecological data from packrat middens and other natural archives have been useful for defining baseline conditions of vegetation communities, determining histories and rates of species range expansions and contractions, and discriminating between natural and cultural causes of environmental change. We describe a montane grassland restoration project in northern New Mexico that was justified and guided by an historical sequence of aerial photographs showing progressive tree invasion during the 20th century. Likewise, fire scar chronologies have been widely used to justify and guide fuel reduction and natural fire reintroduction in forests. A south- western network of fire histories illustrates the power of aggregating historical time series across spatial scales. Regional fire patterns evident in these aggregations point to the key role of interannual lags in responses of fuels and fire regimes to the El Nino-Southern Oscillation (wet/dry cycles), with important implications for long-range fire hazard fore- casting. These examples of applied historical ecology emphasize that detection and expla- nation of historical trends and variability are essential to informed management.
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TL;DR: In this paper, the authors predict a wide array of biogeographic phenomena, including soil carbon pools, vegetation physiognomy, species range, and plant and animal diversity, by modulating the frequency, magnitude, and spatial scales of natural disturbances.
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802 citations
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21 Sep 1972
TL;DR: In this paper, the Rubidium-Strontium Isochron method was used to measure the geologic time of a given sample, which was then used to calculate the initial 87Sr/86Sr ratio of the sample.
Abstract: I. The Geochemistry of Rubidium and Strontium.- 1. Introduction.- 2. Rubidium.- 3. Strontium.- 4. The Rubidium/Strontium Ratio.- 5. Summary.- II. Measurement of Geologic Time by the Rubidium-Strontium Method.- 1. Introduction.- 2. Radioactive Decay of 87Rb to 87Sr.- 3. The Half-life of 87Rb.- 4. The Growth of Radiogenic 87Sr in Rocks and Minerals.- 5. The Rubidium-Strontium Isochron Method of Dating.- 6. A Useful Approximation.- 7. Analytical Methods.- 8. Summary.- III. Uses of Strontium Isotopes in Petrogenesis.- 1. Introduction.- 2. Evolution of Strontium in the Continental Crust and the Upper Mantle.- 3. Applications to Petrology.- 4. Summary.- IV. Volcanic Rocks.- 1. Introduction.- 2. The Strontium Isotopic Data for Volcanic Rocks.- a) General Comment.- b) Basaltic Rocks from Oceanic Islands.- c) Sea-Floor Basalts.- d) Andesites of Volcanic Arcs.- e) Antarctic and Tasmanian Dolerites.- 3. Variations in the Initial 87Sr/86Sr Ratio among and within Geologic Provinces.- a) Oceanic Islands.- b) Continental Volcanic Rocks.- 4. Possible Causes of Variations in Isotopic Composition among Cogenetic Rocks.- 5. Summary.- V. Granitic Rocks.- 1. Introduction.- 2. The Granite Problem.- 3. Observed Initial 87Sr/86Sr Ratios of Granitic Rocks.- 4. Interpretation and Discussion of Initial 87Sr/86Sr Ratios of Granites.- a) Granites with Initial Ratios within the Basalt Field.- The Salisbury Pluton, North Carolina.- b) Granites with High Initial 87Sr/86Sr Ratios.- The Heemskirk Granite, Western Tasmania.- c) Granites with Intermediate Initial 87Sr/86Sr Ratios.- The Isle of Skye.- Phanerozoic Batholiths of North America.- 5. Summary.- VI. Alkalic Rocks and Carbonatites.- 1. Introduction.- 2. Carbonatites.- 3. Alkalic Rocks.- a) Potassic Rocks.- b) Sodic Rocks.- c) Comparison of North American and African Alkalic Rocks.- 4. Summary.- VII. Ultramafic and Related Rocks.- 1. Introduction.- 2. 87Sr/86Sr Ratios of Ultramafic Rocks.- a) The Layered Gabbro-Norite-Peridotite Association in Major Intrusions.- Anorthosites.- b) The Alpine-Type Peridotite-Serpentinite Association.- c) Ultramafic Rocks in Differentiated Basic Sills and in Minor Intrusions.- d) Kimberlites.- e) Ultramafic Nodules.- 3. Summary.- VIII. Sedimentary Rocks and the Oceans.- 1. Introduction.- 2. Marine Carbonate Rocks and the Oceans.- 3. Marine Evaporites.- 4. Dating of Detrital Sedimentary Rocks.- 5. Glauconite.- 6. Nonmarine Carbonate Rocks.- 7. Summary.- IX. Isotopic Homogenization of Strontium in Open Systems.- 1. Introduction.- 2. Contact Metamorphism.- 3. Regional Metamorphism.- 4. Open-System Behavior of Total-Rock Samples.- 5. Chemical Weathering.- 6. Summary.- X. Meteorites.- 1. Introduction.- 2. Rubidium and Strontium in Stony Meteorites.- 3. The Ages of Stony and Iron Meteorites.- 4. The Initial 87Sr/86Sr Ratios of Stony Meteorites.- 5. Summary.- XI. The Moon.- 1. Introduction.- 2. Lunar Basalt.- 3. Initial 87Sr/86Sr Ratios.- 4. Luny Rock 1 and Sample 12013.- 5. The Soil.- 6. Luna 16.- 7. Summary.- XII. The Evolution of the Isotopic Composition of Terrestrial Strontium.- 1. Introduction.- 2. Evolution of Strontium in the Mantle.- 3. Initial 87Sr/86Sr Ratios of Gabbro and Basalt.- 4. Continental Growth.- 5. Summary.- References for Appendix.- Author Index.
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