Comparison of XRF and PXRF for analysis of archaeological obsidian from southern Perú

Chemical sourcing is becoming an increasingly important component of archaeological investigation. Instruments used for elemental analysis generally must be operated in a controlled laboratory environment. Further, many methods require destruction of a small portion of the objects under investigation. These facts inhibit the application of chemical sourcing studies in a number of research contexts. Use of portable non-destructive instruments would resolve these issues. Sixty-eight obsidian artifacts from the site of Jiskairumoko, in southern Perú, were examined by X-ray fluorescence spectrometry (XRF) and portable X-ray fluorescence spectrometry (PXRF). Results were compared for consistency in terms of source determination and individual element concentrations. Both instruments determined that the same sixty-six artifacts derived from the Chivay obsidian source and both identified the same two artifacts that could not be assigned to source. Individual element comparisons showed significant differences, but these can be resolved through instrument cross calibration, and differences had no bearing on source identification. PXRF was found suitable for determining obsidian sources in southern Perú and for identifying specimens that require more sensitive analytical methods such as, instrumental neutron activation analysis (INAA). Regular use of Chivay at Jiskairumoko suggests consistent trade relationships developed during the Archaic.     

A possible case of metastatic carcinoma in a middle Sican burial from Batán Grande,Perú

The skeleton of a young to middle-aged adult excavated at the base of the Pre-Incaic pyramid of Huaca Las Ventanas, northern coast of Peru, shows an osteoplastic formation on the fifth lumbar vertebra compatible with a diagnosis of metastatic carcinoma, possibly from the prostate gland.     

Imaging Evaluation of Skull Trepanation Using Radiography and CT

Cranial surgery as practised by the prehistoric and present-day traditional medicine man is the oldest known and one of the highest surgical achievements in the history of medicine. This study examines morbidity and mortality of this ancient surgical procedure by re-examining and reviewing reports of 71 completely trepanned skulls from pre-Columbian Peru by three techniques: gross visual observation and palpation; radiography; and CT. The specimens are located in the San Diego Museum of Man and are part of the Hrdlicka collection. Clear distinction can be made by visual observation between skulls with bone regeneration and those without; that is, between patients who survived long enough to allow bone healing and those who died immediately or within a few days of the operation. 64.8 per cent of skulls had complete healing, 12.7 per cent had partial healing and 22.5 per cent had no evidence of healing. Thus, a post-operative survival rate of 77.5 per cent is noted by gross examination. The meaning of completely trepanned skulls with no evidence of healing is questionable, however, some unhealed skulls may represent post-mortem trepanation, suggesting a lower surgical mortality. Both radiography and CT scan demonstrate with considerable accuracy the presence or absence of new bone formation on trepanned skulls. One skull demonstrated evidence of partial bone healing by CT and radiography but not by our gross examination or by that of some anthropologists. Evidence of osteomyelitis was illustrated by CT scan but not by radiography.     

Flotation versus dry sieving archaeobotanical remains: A case history from the Middle Horizon southern coast of Peru

Abstract

During excavations at the site of Casa Vieja located in the Peruvian coastal desert, archaeological plant remains were systematically collected to assess whether it is more productive and informative to sieve sandy sediments in dry environments or to process such samples by water flotation, a persistent methodological concern. At Casa Vieja, dual subsamples were collected and analyzed using both of these procedures. For dry, sandy sediment conditions, each processing strategy was found to yield a different view of the botanical remains. Dry sieving recovers more of the larger plant specimens whereas water flotation yields more of the smaller-sized material. These results should be incorporated into archaeological research designs in the future, especially for desert environments.     

A comprehensive numerical chronology for the pre-Columbian cultures of the Palpa valleys,south coast of Peru

Before the arrival of the Spaniards in Peru in 1532, many different societies flourished in the coastal desert of southern Peru. Of these, one of the best known is the Nasca culture (living in the area between about 260 cal BC and 640 cal BC.), which created the famous geoglyphs on the desert floor. In this paper we present a numerical chronology for the cultural development in the valleys of Palpa, in the northern part of the Nazca region, which spans the time from the Archaic Period (starting there around 3760 cal BC) to the Late Intermediate Period (terminating with the arrival of the Spaniards in 1532 AD). The chronology is based on more than 150 ¹⁴C samples collected by our project from well-documented archaeological excavations of 17 different sites in and around Palpa. Thanks to the advanced AMS-¹⁴C dating technique, demanding only few milligrams of organic material, we could focus on samples of plants, like beans, corn, or reed, representing single years of growth or use, and also on delicate materials like straw from clay bricks (adobe) and textiles. All single ¹⁴C dates were combined to cultural phases using a Bayesian statistical model, implementing the a priori information of the archaeological contexts, and adopting the relative ceramic chronologies available for this area.     

Assessing individual systemic stress through cortisol analysis of archaeological hair

As a product of physiological status and the social and physical environments, stress has significant impact on health and well-being in both ancient and contemporary societies. In bioarchaeological research, stress is characterized using an array of skeletal indicators that record stressful periods during childhood and adulthood. In modern clinical research, exposure to stress can be assessed using systemic cortisol levels that have been shown to fluctuate in response to experienced stress. Analysis of cortisol levels in archaeological hair should enable assessment of stress during a short, but critical, period of an individual's life. For this pilot study, we selected hair samples from ten individuals from five different archaeological sites in Peru, and analyzed them in segments to determine cortisol levels. These data demonstrate that it is possible to observe biogenic patterns of cortisol production, and that individual experiences of stress can be reconstructed for the period of time represented by each hair sample. Analysis of cortisol levels in hair has the potential to be a valuable short-term dynamic stress indicator that will complement paleopathological and biochemical studies of health and stress, and permit the reconstruction of increasingly detailed life histories.     

Through the Glass Darkly: Prehispanic Obsidian Procurement and Exchange in Southern Peru and Northern Bolivia

Recent discovery of the major geological sources of Central Andean obsidian permits a new understanding of the patterns of obsidian procurement and exchange by the Prehispanic societies of southern Peru and northern Bolivia. Based on the trace element analysis of obsidian artifacts from 160 archaeological sites, it can be established that the two major deposits of obsidian were being exploited by 9400 BP, and that volcanic glass was being transported over long distances throughout Andean prehistory. Inhabitants of the Cuzco region acquired most obsidian from the Alca source in central Arequipa, while those in the high plateau surrounding Lake Titicaca obtained most obsidian from the Chivay source in southern Arequipa. Obsidian evidence suggests close ties between the Cuzco and Circum-Titicaca regions throughout prehistory, except during the Middle Horizon (ca. 1400–1050 BP), when the expansion of the Huari and Tiahuanaco states disrupted this pattern.     

THE FOUNDING ABYSS OF COLONIAL HISTORY: OR "THE ORIGIN AND PRINCIPLE OF THE NAME OF PERU"

The name of "Peru" and the entities and beings it names first appeared "in an abyss of history" on "the edge of the world" in the early 1500s. In this essay I ask what hermeneutical truths or meanings the strange event that made the name of Peru both famous and historical holds for—and withholds from—any understanding of the meaning of colonial history. By way of a reading of Inca garcilaso de la Vega's rendering, in Los Comentarios Reales de los Incas (1609) of "the origin and principle of the name of Peru," I suggest that Peru's name is itself an inaugural event that marks the founding void or abyss of colonial and postcolonial history, which is to say, of modern global history. This événemential void is not unoccupied, however. It is inhabited by another founding, mythopoetic figure of history: "the barbarian" whose speech is registered in the historian's text.