Diet,nutritional status and oral health in hunter‐gatherers from the central‐northern coast of Patagonia and the Chubut river lower valley,Argentina

Archaeological research in central‐northern Patagonia (Atlantic coast and lower the valley of Chubut river) showed that this area was used since at least the Middle Holocene. Stable isotope analyses (¹³C and ¹⁵N) of human bone samples indicate that hunter‐gatherers living in that area had a terrestrial‐marine diet including guanaco meat, land plants, mollusks and pinnipeds. Despite this general trend, intersite variability and changes through time were noted, especially after the late Holocene. These results have been reinforced by archaeofaunal, technological and bioarchaeological records. In this paper, three hypotheses are examined: (a) the diet of these populations was complete and rich enough to ensure good health status and avoid nutritional deficiencies; (b) carbohydrate consumption increased progressively after 1000 BP, when pottery technology was adopted and (c) this kind of mixed diet would have been qualitatively more nutritious than that of other populations of the region, which would have resulted in better nutritional and healthy conditions. These three hypotheses are compared with dental results obtained from 563 permanent teeth from 45 individuals (34 adults and 11 juveniles from both sexes), rescued from burial sites. Indicators of oral health were assessed through the observation of caries, abscesses, wear, pulpar cavity exposure and ante mortem loss. Features of nutritional status such as enamel hypoplasia, porotic hyperostosis and cribra orbitalia were also examined. Given the availability of direct radiocarbon dating for most of the sample, three temporal series were determined: ‘Before 1000 BP’, ‘1000–5000 BP’ and ‘Post‐contact’. No evidence of alimentary stress or iron deficiency was found in individuals from the three series, which accounts for healthy and good nutritional life conditions. After 1000 BP, the results show a progressive increase in the caries percentage and a decrease in abscesses, dental wear and ante mortem losses frequency. This is possibly related to more consumption of processed foods in the last 1000 years. These results were compared with similar studies based on samples from different environments and latitudes of Patagonia. Evidence suggests that mixed diets (marine‐terrestrial) would have been more appropriate and nutritionally complete than exclusively marine or terrestrial diets. Copyright © 2010 John Wiley & Sons, Ltd.     

Twins in prehistory: The case from Olèrdola (Barcelona,Spain; s. IV II BC)

This paper details the discovery of two perinatal individuals interred simultaneously at the archaeological site of Olèrdola, Barcelona, Spain. Information from the excavation and from the subsequent anthropological study of the recovered skeletal and dental remains suggests that these individuals (OL–2000–8245 and OL–2000–8246) are the first documented case of twins in Iberian period. The possibility of a simultaneous perinatal twins burial at Olèrdola raises new questions concerning about the frequency of twins in prehistory and protohistory. Copyright © 2010 John Wiley & Sons, Ltd.     

ANALCIME CRYSTALLIZATION AND COMPOSITIONAL PROFILES—COMPARING APPROACHES TO DETECT POST‐DEPOSITIONAL ALTERATIONS IN ARCHAEOLOGICAL POTTERY*

The approaches of comparative studies and profile measurements, often used in order to detect post‐depositional alterations of ceramics, have been applied simultaneously to two sets of Roman pottery, both of which include altered individuals. As analytical techniques, Neutron Activation Analysis and X‐Ray Diffraction have been used. Both approaches lead to substantially different results. This shows that they detect different levels of alteration and should complement each other rather than being used exclusively. For the special process of a glassy phase decomposition followed by a crystallization of the Na‐zeolite analcime, the results suggest that it changes high‐fired calcareous pottery rapidly, and so fundamentally that the results of various archaeometric techniques can be severely disturbed.     

BAYESIAN ANALYSIS OF PLEISTOCENE CHRONOMETRIC METHODS*

Bayesian analysis of radiocarbon dates on Holocene archaeological sites has become well established. Application to Pleistocene sites dated by multiple techniques would be advantageous. This paper develops the necessary mathematical apparatus in the form of likelihoods for luminescence dating, and uranium‐series dating, and considers the possibility for amino‐acid racemization dating. Application of the new methods is illustrated using the stratigraphic sequences of dates from the sites of Saint‐Césaire and La Chaise‐de‐Vouthon. For application to amino‐acid racemization dating, fuller publication of data is found to be required.     

Real‐time quadrupole mass spectrometer analysis of gas in borehole fluid samples acquired using the U‐tube sampling methodology

Sampling of fluids in deep boreholes is challenging because of the necessity of minimizing external contamination and maintaining sample integrity during recovery. The U‐tube sampling methodology was developed to collect large volume, multiphase samples at in situ pressures. As a permanent or semi‐permanent installation, the U‐tube can be used for rapidly acquiring multiple samples or it may be installed for long‐term monitoring applications. The U‐tube was first deployed in Liberty County, TX to monitor crosswell CO₂ injection as part of the Frio CO₂ sequestration experiment. Analysis of gases (dissolved or separate phase) was performed in the field using a quadrupole mass spectrometer, which served as the basis for determining the arrival of the CO₂ plume. The presence of oxygen and argon in elevated concentrations, along with reduced methane concentration, indicates sample alteration caused by the introduction of surface fluids during borehole completion. Despite producing the well to eliminate non‐native fluids, measurements demonstrate that contamination persists until the immiscible CO₂ injection swept formation fluid into the observation wellbore.     

Fracture sealing and fluid overpressures in limestones of the Jabal Akhdar dome,Oman mountains

Fractures are important conduits for fluid flow in the Earth's crust. To better understand the spatial and temporal relations among fracturing, fracture sealing, and fluid flow, we have studied fractures, faults, and veins in a large dome (Jabal Akhdar) in the Oman mountains. Our work combines the results of meso‐ and microstructural analyses and stable isotope analyses. Seven generations of fractures and veins have been identified in the carbonate‐dominated dome. The earliest generations of veins developed during extension and subsidence of the Mesozoic basin. These veins formed in the inclined segments of bedding‐parallel stylolites and in extensional fractures that are perpendicular to bedding (#1 and #2, respectively). These extension‐related veins are truncated by bedding‐parallel veins (#4) that formed during top‐to‐north bedding‐parallel shear of both the northern and southern limbs of the dome. These veins are consistent with a change in stress regime and may be related to an earlier generation of strongly deformed pinch‐and‐swell veins (#3) that are exposed locally on the southern limb of the dome. Normal faults contain a set of en‐echelon tension gashes (#5) and veins emplaced in dilational jogs along the fault planes (#6). In the northern part of the dome, veins (#7) associated with thrusts post‐date the normal faults. Samples of veins and their host rocks were analyzed to provide information on fluid‐rock interaction in the dome and the scale(s) of fluid movement. Oxygen isotope values range from +16.2 to +29.3‰; carbon isotope values range from 0 to +3.6‰. The results of the structural and isotopic analyses are consistent with the early veins (#2–#5) having precipitated from overpressured fluid in a isotopically rock‐buffered system. During normal faulting (#5 and #6), a more open system allowed external fluid to infiltrate the dome at drained conditions and precipitate the youngest sets of veins (#6 and #7).     

Precipitation of lead–zinc ores in the Mississippi Valley‐type deposit at Trèves,Cévennes region of southern France

The Trèves zinc–lead deposit is one of several Mississippi Valley‐type (MVT) deposits in the Cévennes region of southern France. Fluid inclusion studies show that the ore was deposited at temperatures between approximately 80 and 150°C from a brine that derived its salinity mainly from the evaporation of seawater past halite saturation. Lead isotope studies suggest that the metals were extracted from local basement rocks. Sulfur isotope data and studies of organic matter indicate that the reduced sulfur in the ores was derived from the reduction of Mesozoic marine sulfate by thermochemical sulfate reduction or bacterially mediated processes at a different time or place from ore deposition. The large range of δ³⁴S values determined for the minerals in the deposit (12.2–19.2‰ for barite, 3.8–13.8‰ for sphalerite and galena, and 8.7 to ?21.2‰ for pyrite), are best explained by the mixing of fluids containing different sources of sulfur. Geochemical reaction path calculations, based on quantitative fluid inclusion data and constrained by field observations, were used to evaluate possible precipitation mechanisms. The most important precipitation mechanism was probably the mixing of fluids containing different metal and reduced sulfur contents. Cooling, dilution, and changes in pH of the ore fluid probably played a minor role in the precipitation of ores. The optimum results that produced the most metal sulfide deposition with the least amount of fluid was the mixing of a fluid containing low amounts of reduced sulfur with a sulfur‐rich, metal poor fluid. In this scenario, large amounts of sphalerite and galena are precipitated, together with smaller quantities of pyrite precipitated and dolomite dissolved. The relative amounts of metal precipitated and dolomite dissolved in this scenario agree with field observations that show only minor dolomite dissolution during ore deposition. The modeling results demonstrate the important control of the reduced sulfur concentration on the Zn and Pb transport capacity of the ore fluid and the volumes of fluid required to form the deposit. The studies of the Trèves ores provide insights into the ore‐forming processes of a typical MVT deposit in the Cévennes region. However, the extent to which these processes can be extrapolated to other MVT deposits in the Cévennes region is problematic. Nevertheless, the evidence for the extensive migration of fluids in the basement and sedimentary cover rocks in the Cévennes region suggests that the ore forming processes for the Trèves deposit must be considered equally viable possibilities for the numerous fault‐controlled and mineralogically similar MVT deposits in the Cévennes region.     

Chemical and isotopic signatures of Na/HCO3/CO2‐rich geofluids,North Portugal

Geochemical and isotopic studies have been undertaken to assess the origin of CO₂‐rich waters issuing in the northern part of Portugal. These solutions are hot (76°C) to cold (17°C) Na–HCO₃ mineral waters. The δ²H and δ¹⁸O signatures of the mineral waters reflect the influence of altitude on meteoric recharge. The lack of an ¹⁸O‐shift indicates there has been no high temperature water–rock interaction at depth, corroborating the results of several chemical geothermometers (reservoir temperature of about 120°C). The low ¹⁴C activity (up to 9.9 pmC) measured in some of the cold CO₂‐rich mineral waters (total dissolved inorganic carbon) is incompatible with the presence of ³H (from 1.7 to 4.1 TU) in those waters, which indicates relatively short subsurface circulation times. The δ¹³C values of CO₂ gas and dissolved inorganic carbon range between ?6‰ and ?1‰ versus Vienna‐Peedee Belemnite, indicating that the total carbon in the recharge waters is being diluted by larger quantities of CO₂ (¹⁴C‐free) introduced from deep‐seated (upper mantle) sources, masking the ¹⁴C‐dating values. The differences in the ⁸⁷Sr/⁸⁶Sr ratios of the studied thermal and mineral waters seem to be caused by water–rock interaction with different granitic rocks. Chlorine isotope signatures (?0.4‰ < δ³⁷Cl < +0.4‰ versus standard mean ocean chloride) indicate that Cl in these waters could be derived from mixing of a small amount of igneous Cl from leaching of granitic rocks.     

Mid‐Holocene Development of Mangrove Communities Featuring Rhizophoraceae and Geomorphic Change in the Richmond River Estuary,New South Wales,Australia

This paper describes the hitherto unreported occurrence of mid‐Holocene mangrove deposits in the Richmond River estuary, southeastern Australia, thereby providing evidence for changes in the distribution and composition of mangrove communities within a subtropical estuarine system during the Holocene. Stratigraphic, radiocarbon and palynological evidence indicates that widespread development of mangrove communities took place in the upstream reaches of the Richmond River estuary during the period 7000 to 6000 years BP. These communities maintained their habitat through substrate aggradation under the conditions of a moderate sea‐level rise, in contrast to other estuaries within the region, which generally experienced the submergence of intertidal substrates. Mangrove species belonging to the family Rhizophoraceae, most likely Bruguiera gymnorrhiza and Rhizophora stylosa, dominated these communities, in strong contrast to contemporary communities, which are dominated by Avicennia marina. Moreover, these mid‐Holocene communities were located a considerable distance upstream of the contemporary occurrences of Rhizophoraceae species within the estuary. The changes in the spatial distribution and composition of mangrove communities parallel the large‐scale evolution of the estuary driven by sea‐level variation. Shallow, buried Pleistocene terraces probably contributed to the regionally unique aggradational response of the mangrove communities and their substrates to a sea‐level rise during mid‐Holocene times.