[Show abstract][Hide abstract] ABSTRACT: Phytolith reference collections are a fundamental prerequisite for accurate interpretation of fossil phytolith assemblages used in reconstructing vegetation histories. As part of a multi-disciplinary research project studying Late Holocene landscape transformations associated with pre-Columbian raised field complexes in the coastal savannas of French Guiana, phytolith production in selected plant species with high environmental and economic significance native to the region was examined. A total of 49 families, 92 genera, and 108 species were analysed. Phytolith abundance in each specimen was rated qualitatively and morphotypes described following modern standards of nomenclature. Of the 92 non-Poaceae species tested, 37 contributed phytoliths that are diagnostic to at least the family level. Two of these are newly-discovered phytolith morphotypes isolated from Protium guianense (Burseraceae) and Thelypteris confluens (Thelypteridaceae [Pteridophyta]) which have not been described previously. This work represents the first systematic undertaking to establish a phytolith reference collection of French Guiana flora. Results reinforce the usefulness of phytolith analysis for distinguishing ecologically significant taxa, and therefore major vegetation formations. The creation of a comprehensive reference collection for French Guiana improves taxonomic resolution and has provided the necessary ground work for the interpretation of palaeoevironmental and archaeological records in the region.
[Show abstract][Hide abstract] ABSTRACT: The relationship between bone mineral density and archaeological bone survivorship has played a critical role in zooarchaeological and taphonomic studies in recent decades. Numerous studies have suggested that higher-density skeletal element portions survive more frequently than lower-density element portions when archaeological assemblages are affected by some taphonomic processes. Interpretations of density mediated destruction have become commonplace in the archaeological literature, and are often used to explain the absence of certain bone elements and element parts in zooarchaeological assemblages. This study explores the effects of rockfall on bovid elements in varied environmental conditions and the differential survivorship of their element parts, and has implications for understanding the taphonomic processes through which bones are subjected to dynamic loading. Actualistic rockfall experiments conducted on twelve samples of frozen, fresh, and semi-dried bovid bones reveal that the generally low-density epiphyseal ends of bone elements resist fracture and analytical deletion with more frequency than the higher-density diaphyses. This evidence suggests that bone density does not correlate with likelihood of breakage or effective archaeological “destruction” when rockfall and other processes that result in dynamic impact are in action. While this research does not question the relationship between bone mineral density and the likelihood for archaeological survivorship as the result of some taphonomic processes, it presents one specific set of taphonomic processes that result in the differential survivorship of low density bone elements parts and the fragmentation and destruction of higher density element parts. This research presents evidence that shows that dynamic impact is a process capable of fragmenting and sometimes destroying high-density elements while low-density elements survive.
Journal of Archaeological Science 11/2012; 39(11):3443–3449.
[Show abstract][Hide abstract] ABSTRACT: The nature and scale of pre-Columbian land use and the consequences of the 1492 "Columbian Encounter" (CE) on Amazonia are among the more debated topics in New World archaeology and paleoecology. However, pre-Columbian human impact in Amazonian savannas remains poorly understood. Most paleoecological studies have been conducted in neotropical forest contexts. Of studies done in Amazonian savannas, none has the temporal resolution needed to detect changes induced by either climate or humans before and after A.D. 1492, and only a few closely integrate paleoecological and archaeological data. We report a high-resolution 2,150-y paleoecological record from a French Guianan coastal savanna that forces reconsideration of how pre-Columbian savanna peoples practiced raised-field agriculture and how the CE impacted these societies and environments. Our combined pollen, phytolith, and charcoal analyses reveal unexpectedly low levels of biomass burning associated with pre-A.D. 1492 savanna raised-field agriculture and a sharp increase in fires following the arrival of Europeans. We show that pre-Columbian raised-field farmers limited burning to improve agricultural production, contrasting with extensive use of fire in pre-Columbian tropical forest and Central American savanna environments, as well as in present-day savannas. The charcoal record indicates that extensive fires in the seasonally flooded savannas of French Guiana are a post-Columbian phenomenon, postdating the collapse of indigenous populations. The discovery that pre-Columbian farmers practiced fire-free savanna management calls into question the widely held assumption that pre-Columbian Amazonian farmers pervasively used fire to manage and alter ecosystems and offers fresh perspectives on an emerging alternative approach to savanna land use and conservation that can help reduce carbon emissions.
Proceedings of the National Academy of Sciences 04/2012; 109(17):6473-8.
[Show abstract][Hide abstract] ABSTRACT: Zooarchaeologists have often employed studies of bone fracture morphology as a means of understanding past human cultural activity, and various methodological approaches have been developed for analyzing archaeological broken bone assemblages. It is widely understood that bones degrade over time, however, few studies have attempted to define and quantify the rate at which bones degrade and fracture morphologies change. This study examines degradation in frozen bones (−20°C) and bones exposed to hot (40°C) dry conditions. These two simulated environmental conditions represent extreme real-world climates, and allow for an actualistic understanding of the rates of degradation that bones experience in nature. When frozen, bones degrade slowly but significantly, and demonstrate measurable differences in samples frozen for 1, 10, 20, 40, and 60 weeks. In hot, dry conditions, bones degrade very quickly, and demonstrate measurable differences after 1, 3, 7, 14, and 21 days. These data allow for a more detailed understanding of the relationship between the cultural and natural processes that result in bone fracture, and the time period during which bones can be expected to maintain fresh fracture characteristics. This research also has implications for understanding human subsistence and survival strategies and for interpreting the archaeological record.
Journal of Archaeological Science - J ARCHAEOL SCI. 02/2012;
[Show abstract][Hide abstract] ABSTRACT: Horse domestication revolutionized transport, communications, and warfare in prehistory, yet the identification of early domestication processes has been problematic. Here, we present three independent lines of evidence demonstrating domestication in the Eneolithic Botai Culture of Kazakhstan, dating to about 3500 B.C.E. Metrical analysis of horse metacarpals shows that Botai horses resemble Bronze Age domestic horses rather than Paleolithic wild horses from the same region. Pathological characteristics indicate that some Botai horses were bridled, perhaps ridden. Organic residue analysis, using delta13C and deltaD values of fatty acids, reveals processing of mare's milk and carcass products in ceramics, indicating a developed domestic economy encompassing secondary products.
[Show abstract][Hide abstract] ABSTRACT: This paper presents a phytolith analysis of selected native plants and modern surface soils from southeastern Uruguay. A modern phytolith reference collection was established based on 60 Poaceae species, 22 non-Poaceae monocotyledonous species, 17 species of herbaceous dicotyledons, 9 woody dicotyledonous species, and 2 species of fern. Nine modern surface soil samples were analyzed from the most representative vegetation units of the region, including wetlands, wet prairies, upland prairies, riparian forest, and palm forest. Of the 50 non-Poaceae plant species analyzed, 25 contribute diagnostic phytoliths at different taxonomic levels corresponding to all the major ecological zones of southeastern Uruguay. Patterns of phytolith production and morphology were concordant with those observed in related taxa studied from other regions of the world. The modern soil analysis revealed significant patterns that differentiate a number of specific habitats, showing that distinct vegetational units may be discriminated by the phytolith signatures they produce. These results reinforce the utility of using phytoliths as significant indicators for vegetation units dominated both by monocotyledonous and dicotyledonous plant species, and demonstrate the potential of phytolith analysis for paleoecological and archeological reconstruction in this region.
[Show abstract][Hide abstract] ABSTRACT: This article presents the results of ongoing instrumental neutron activation analyses (INAA) conducted on archaeological artifacts from the Formative period of northwestern Argentina (NWA). These studies are part of a wider archaeological project that seeks to understand the structure of the social landscape of the period by examining domestic and burial evidence from a wide range of villages across the area known as the southern Calchaquí valleys. Elemental data is discussed in the light of its potential contribution to reassess past social interaction strategies in the region.
Journal of Archaeological Science 01/2009; 36(9):1955-1964.
[Show abstract][Hide abstract] ABSTRACT: Dental enamel hypoplasias are increasingly being used in epidemiological studies as indicators of health within both modern and prehistoric populations. This symptom of growth disruption is used here to examine possible changes in health occurring at the transition between the Bronze Age and Iron Age in Jordan, through examination of enamel hypoplasias in skeletal remains from two tombs at the archaeological site of Pella. A small but not statistically significant difference in the prevalence and frequency of hypoplastic defects was found between the two time periods. These results suggest that the political and economic changes occurring at this time were not sufficiently stressful to cause a dramatic deterioration in health at the onset of the Early Iron Age.
HOMO - Journal of Comparative Human Biology 02/2007; 58(3):211-20.
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