Source of ore fluids at the Kalahari Goldridge deposit, Kraaipan greenstone belt, South Africa: evidence from Sr, C and O isotope signatures in carbonates

The Kalahari Goldridge deposit is located in the Archaean Kraaipan greenstone belt in the north-west province of South Africa. Gold mineralization in this deposit is hosted within banded iron formation which is flanked by a mafic schist in the footwall and clastic metasedimentary units in the hanging wall. Data from carbonate minerals from mineralized veins and bulk rock from the A and D zone ore bodies have helped to define the ultimate origin of the ore-forming fluids and their migration history. Carbon isotope ratios of carbonates from both the A and D zone ore bodies have tight clustering from −7.6 to −5.3‰ that indicates a unique origin for the ore-forming fluids associated with the mineralization at Kalahari Goldridge. The δ¹⁸O values of the carbonates have been influenced by temperature gradients and variable degrees of fluid–rock interaction promoting oxygen isotope exchange between ore fluid and host rocks. Minimum ⁸⁷Sr/⁸⁶Sr ratio values of 0.70354 in mineralized veins are most consistent with ore-forming fluids being relatively pristine with a mantle origin. Strontium and the corresponding ore-forming fluids were most likely derived from mantle-derived magmatic rocks probably represented by the meta-basaltic rocks that underlie the ferruginous package in the Kraaipan greenstone belt. Strontium isotopic composition of vein carbonates show considerable variation in ⁸⁷Sr/⁸⁶Sr ratios ranging from 0.70354 to 0.73914. This is consistent with an ore fluid composition that has been modified by the addition of radiogenic Sr possibly during passage of fluid through siliciclastic country rock concomitant with the observed hydrothermal alteration.     

Stable isotope palaeodietary study of humans and fauna from the multi-period (Iron Age,Viking and Late Medieval) site of Newark Bay,Orkney

We report here on stable carbon and nitrogen isotope measurements of human and faunal bone collagen from the Iron Age, Viking Age, and Late Medieval site of Newark Bay, Orkney, Scotland. We found a wide range of results for humans in both δ¹³C (−15.4‰ to −20.3‰) and δ¹⁵N (8.6‰–15.6‰) values. The enriched carbon and nitrogen values indicate the consumption of significant amounts of marine protein, which is very unusual for post-Mesolithic (e.g. 4000 cal BC) UK and European populations. Also of interest is a statistically significant difference in δ¹³C (t = −2.48, p = 0.011) and δ¹⁵N (t = −2.44, p = 0.011) values, and therefore diets, between adult males and females at this site, with males (δ¹³C = −17.8 ± 1.2‰, δ¹⁵N = 13.2 ± 1.6‰) having, on average, a higher proportion of marine protein than females (δ¹³C = −18.9 ± 1.1‰, δ¹⁵N = 11.8 ± 1.8‰). The weaning age of the sub-adults was difficult to interpret due to the large isotopic variation in the adult females, but nearly all individuals between birth and 1.25 years have elevated δ¹⁵N values indicating that they were breastfed to some extent.     

One world,one place

Este artículo rastrea la historia del World Archaeological Congress desde una perspectiva sudafricana-una posición estratégica apropiada, dado que el WAC se formó entorno al tema del apartheid y la relación entre el estudio del pasado y la política del presente. Mientras el apartheid fue una cuestión bien definida, los asuntos que el WAC ha tenido que afrontar con posterioridad no han resultado tan sencillos, e incluso en ocasiones han llevado a la incertidumbre. El concepto de Una Arqueología Mundial que el WAC adopta puede ser visto como una serie continua de meditaciones ligadas con una propuesta fundacional. Sin embargo este mundo ha cambiado. Las nuevas tecnologías de información y comunicación suponen el fin de las distancias que en el pasado supusieron un factor limitador para los movimientos mundiales progresistas. En pocos a?os, la red de banda ancha tendrá un coste bastante inferior en todas las ciudades del mundo. Las organizaciones mundiales que luchan contra intereses establecidos serán redes flexibles que se organizarán entorno a cuestiones locales, compartiendo al mismo tiempo la información y los recursos a nivel global. De este modo se abren grandes oportunidades para los movimientos mundiales que enlazan, a una y al mismo tiempo, las complejidades de las circunstancias locales y las oportunidades de las alianzas globales.

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Résumé Le r?le de l'apartheid et de la localisation de Cape Town sont des éléments utilisés dans le survol du développement du Congrès Mondial de l'Archéologie et du mouvement One World Archaeology depuis 1986. à l'époque un boycott académique a empêché la participation des Sud-africains au congrès de Southampton durant lequel fut formaliser le CMA. Le terme un monde, une place, caractérise la proposition d'adopter une nouvelle approche et l'opportunité de repositionner le mouvement One World Archaeology. L'approche un monde, une places'oriente sur le concept de place, de sites locaux d'engagements et de connections entre la question de l'identité, le patrimoine culturel, l'interprétation historique et les droits humains. Un accès élargis aux nouvelles technologies de communication peut faciliter cette approche et offrir le potentiel de se préoccuper de la diversité des localisations et rendre possible le développement d'un réseau de communication stratégique d'une ≪archéologie engagée.

     

Archaeological ethnography: Conversations around Kruger National Park

Este artículo esboza las posibilidades para una práctica mixta, a la que yo denomino etnografía arqueológica, que enlaza la arqueología y antropología sociocultural. Mi trabajo de campo se ha realizado en los límites del Parque Nacional Kruger con individuos de la comunidad de Malatji, y también con ecologistas sociales, guardas del parque, intérpretes y agentes del patrimonio que trabajan en el parque nacional. La investigación contribuye y evalúa críticamente el centralísmo del patrimonio arqueológico de Sudáfrica y sus múltiples papeles en la formulación de nuevas subjetividades en la nación cosmopolita y postcolonial.

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Résumé Cet article illustre la possibilité d'utiliser l'ethnographie archéologique comme pratique hybride permenttant de faire le pont entre l'archéologie et l'anthropologie socioculturelle. Mon travail de terrain se déroule à la limite du Parc National Kruger avec des individus de la communauté Malatji et aussi des spécialistes en écologie sociale, des agents de la conservation, des guides interprètes et des représentants du patrimoine employés du parc national. Cette recherche entend contribuer et faire une évaluation critique de la centralité du patrimoine archéologique en Afrique du sud et de ses r?les multiples dans la formation d'une nouvelle subjectivité dans la nation cosmopolite postcoloniale.

     

Fighting or Dancing: Archaeology and Folklore Traces

The connections between archaeology and traditions or folklore may be thought of as a dance, in which archaeological traces complement or constitute elements of folklore, and traces of folklore complement and constitute archaeological interpretation. On the other hand, archaeology and folklore may engage in competition about the “true” past(s). In this paper I will explore the tensions between these perspectives, and the tensions between archaeology and many forms of folklore.     

Optical dating of alluvial deposits at the orogenic front of the andean precordillera (Mendoza,Argentina)

Well constrained numerical ages of alluvial fan sediments are key to understanding the chronology of alluvial episodes and tectonic activity at the front of the Andean Precordillera. We tested the application of radiocarbon and optically stimulated luminescence (OSL) dating in the distal part of an alluvial fan five kilometers north of Mendoza. For OSL dating a large number of aliquots (n > 70) — each composed of ∼50 quartz grains — were measured in order to obtain reliable burial ages despite scattered dose distributions. Owing to a feldspar contamination in all samples, an infrared stimulation was inserted before each OSL measurement, which reduced the feldspar OSL signal successfully. By using the minimum age model we obtained stratigraphically consistent burial ages of alluvial deposits in a depth profile. The uppermost ∼1 m of sediment is composed of debris flow deposits buried 770±76 years ago. Three plant remnants used for radiocarbon dating from the same layer, however, yielded ages younger than 350 years, which are interpreted to underestimate the depositional age. Underneath the debris flow, a major unconformity cuts a series of distal alluvial fan sediments with interstratified floodplain deposits, which are composed of sandy and calciterich silt layers, respectively. Three samples from this unit which were distributed over one meter of sediment thickness yielded statistically concordant OSL ages of 12.3±1.2 ka, 12.3±1.2 ka, and 11.7±1.1 ka. The deposition of these sediments during the latest Pleistocene coincides with a phase of cool and humid climate, which occurred before the alluvial fan propagated farther into the foreland. The overlying debris flow sediments are associated with alluvial fan incision during the arid Late Holocene.     

Proposing new approaches for dating young volcanic eruptions by luminescence methods

The application of luminescence dating to young volcanic sediments has been first investigated over three decades ago, but it was only with the technical innovations of the last decade that such analyses became viable. While current analytical procedures show promise for dating late Quaternary volcanic events, most efforts have been aimed at unconsolidated volcanic tephra. Investigations into direct dating of lava flows or of non-heated volcanoclastics like phreatic explosion layers, however, remain scarce. These volcanic deposits are of common occurrence and represent important chrono- and volcanostratigraphic markers. Their age determination is therefore of great importance in volcanologic, tectonic, geomorphological and climate studies. In this article, we propose the use of phreatic explosion deposits and xenolithic inclusions in lava flows as target materials for luminescence dating applications. The main focus is on the crucial criterion whether it is probable that such materials experience complete luminescence signal resetting during the volcanic event to be dated. This is argued based on the findings from existing literature, model calculations and laboratory tests.     

Multidisciplinary analysis of a mummified cranium claimed to be that of a medieval execution victim

This article presents a multidisciplinary analysis of a human skull with preserved soft tissue curated by a small museum in Boscastle, Cornwall, UK. The skull lacks a mandible and is coated in a black tar-like substance. Records left by a previous museum curator (now deceased) claimed the skull to be the head of a medieval execution victim. The skull was purportedly recovered from a London church that was destroyed during the Second World War where it had been kept in a carved oak box. If these details are correct, the skull would appear to have been venerated as a relic. The skull and box have been analysed using a range of techniques including computerised tomography, laser scanning, microscopy, infrared spectroscopy and radiocarbon dating. These analyses demonstrated the skull in fact to be that of an Egyptian mummy dating from the Ptolemaic period. Other instances have been noted of parts of Egyptian mummies being presented as European saintly relics, and the ‘Boscastle skull’ would appear to be an example of such. A wider point illustrated by the work presented here is that sufficient application of modern analytical techniques may reveal considerable information regarding human remains which otherwise have little or no provenance. This point strengthens arguments for the retention of such remains by curating institutions.     

Ceramic findings from the archaeological site at Aiano-Torraccia di Chiusi (Siena,Italy): a multi-analytical approach

In 2005, the remains of a Roman villa, dating from the early fourth to the sixth centuries ad, were discovered at the archaeological site of Aiano-Torraccia di Chiusi (Siena, Italy). After being abandoned in the sixth century ad, the complex was occupied by a group of Ostrogothic or Lombardic artisans in the period between the sixth and the seventh centuries ad. Many ceramic remains (coarse pottery and red slip ceramics) from the first to the seventh centuries ad have been discovered on this archaeological site. These findings have been analysed using different analytical techniques (optical microscopy (OM), X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscope-energy dispersive spectroscopy (SEM-EDS), attenuated total reflection Fourier transform infrared (ATR-FTIR), and micro-Raman in order to characterize the ceramic body, the coating, the temper, and to investigate the compositional relationship between the different kinds of ceramics. The use of different techniques on the same samples yielded information at different scales. OM and SEM-EDS yielded interesting information on the coarse pottery: the analyses performed on some minerals and rock fragments suggest that stone tesserae from the Roman villa (in the form of numerous marble fragments) were used in the production of this pottery. Bulk analyses (XRD and XRF) and subsequent micro-analyses (SEM-EDS, ATR-FTIR, and micro-Raman) of the red slip pottery revealed clear chemical, mineralogical and textural differences: some ceramics (the TCC sample group) typically have a Fe-enriched coating while others (the INGR sample group) present a clear difference in grain size but no chemical or mineralogical differences between the ceramic body and the coating.