Search

The Ruwai skarn deposit is located in the Schwaner Mountain complex within the central Borneo gold belt and is currently considered the largest Zn skarn deposit in Indonesia. The deposit has been known to host Zn-Pb-Ag mineralization in the form of massive sulfide ore bodies; however, the occurrence of Ag-bearing minerals has not been identified yet. This study documents the mineralogical characteristics of several Bi-Ag sulfosalts and sulfoarsenides, as well as their chemical compositions. Ten Bi-Ag sulfosalts were identified, including native bismuth, tetrahedrite, cossalite, tsumoite, bismuthinite, joseite-B, Bi6Te2S, Bi-Pb-Te-S, Bi-Ag-S, and Bi-Te-Ag. Three sulfoarsenides were identified, including arsenopyrite, glaucodot, and alloclasite. The occurrence of Bi-Ag sulfosalts is typically associated with massive sulfide mineralization, although tsumoite can also be found associated with massive magnetite. In terms of sulfoarsenides, both arsenopyrite and glaucodot are associated with massive sulfide mineralization, whereas alloclasite is associated with massive magnetite mineralization. The Bi-bearing minerals are characterized by irregular, bleb-like texture or patch morphology, and occur either as free grains or inclusions within sulfides, such as galena or pyrite. Tetrahedrite typically has an anhedral shape with a rim or atoll texture surrounding sphalerite or galena. In contrast, sulfoarsenides are typically found as euhedral–subhedral grains where glaucodot typically is rimmed by arsenopyrite. Both Bi-Ag sulfosalt and sulfoarsenides were formed during the retrograde stage under high oxidation and a low sulfidation state condition. The ore-forming temperature based on arsenopyrite geothermometry ranges from 428 °C to 493 °C. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Rutile from orogenic gold deposits was analysed. • Rutile from gold deposits is enriched in Sb compared to unmineralised rocks. • We propose rutile as indicator mineral for orogenic gold deposits. • Zr-in-rutile yielded geologically implausible temperature. Abstract In our study we explore the applicability of rutile as a pathfinder for orogenic gold deposits, which are an important source of this metal worldwide. We analysed rutile associated with orogenic Au deposits from three different Precambrian terranes, the Capricorn Orogen, the Barberton Greenstone Belt and the Ashanti Belt, all of which formed under greenschist conditions and share similarities in the style of mineralisation. Microtextural evidence from scanning electron microscopy and electron back-scatter diffraction indicates that rutile formed during the main deformation and alteration stage in these rocks, and is therefore related to mineralisation. We used electron microprobe and laser ablation ICP-MS to investigate the trace element compositions of rutile and we compared our results to other gold deposits. We find that hydrothermal rutile from gold deposits contains certain trace element characteristics, in particular high Sb concentrations (up to ∼1500 ppm in Au deposits of the Capricorn Orogen), that are distinct from rutile from non-mineralised rocks of various petrogenetic origin. Other elements, such as W and Sn, are found to be more enriched in rutile from other rock types, namely felsic magmatic rocks and hydrothermal veins, and are therefore not diagnostic of Au mineralisation in this type of deposits. We also find that the presence of sub-µm-scale inclusions – in particular Zr-(Si, Th)-bearing phases, sulfide minerals and native Au – can severely affect analyses of this type of rutile and compromise the applicability of Zr-in-rutile geothermometry. [ABSTRACT FROM AUTHOR]

The Sunda arc of Indonesia is an excellent example of how volcanic processes at convergent plate margins affect the distribution of metals and control the distribution of ore deposits. In this paper, we report microtextural observations and microanalytical data (SEM-EDS and LA-ICP-MS) of silicate and sulfide melt inclusions from fresh samples of volcanic rocks from the 2008 eruption of Mt. Krakatau and 1963 eruption of Mt. Batur, Sunda arc, Indonesia that bear implications on the concentration and transport of Cu and other chalcophile elements in mafic-intermediate magmas in arc settings. These multi-phase inclusions contain glass, amphibole and plagioclase, together with co-trapped apatite, magnetite, sulfides and lobed, drop-like Fe-oxide. We observed two stages of sulfide formation: 1) early-formed sulfide globules (pyrrhotite and intermediate solid solution), which derived from an immiscible sulfide melt and only occur as inclusions in phenocrysts; and 2) late-formed, irregular Cu-rich sulfides (intermediate solid solution to bornite), which were deposited in the presence of an aqueous fluid, and are contained as fluid phase precipitates in vapour bubbles of melt inclusions and in vesicles, as well as finely dispersed grains in the groundmass. Microtextural observations and X-ray elemental maps show that interaction between sulfide globules and aqueous fluid resulted in partial oxidation and transfer of Cu between the fluid and the sulfide phase. A compilation of whole-rock analyses from the Sunda arc indicates that Cu reaches ~ 250–300 ppm in mafic samples (SiO 2 ≤ 52 wt.%), and then suddenly drops with progressive fractionation to < 50 ppm in intermediate-felsic samples. This behaviour can be explained by sulfide melt exsolution or degassing and scavenging of Cu occurring at various stages of magma fractionation (at MgO ~ 8–2.5 wt.%). These trends can be effectively modelled by sulfide saturation during fractional crystallisation at oxygen fugacities varying from fO 2 = FMQ + 0.8 to FMQ + 1.4. In contrast, LA-ICP-MS analyses of whole multi-phase melt inclusions hosted in olivine, pyroxene and plagioclase indicate variable Cu and S contents (Cu up to ~ 6000 ppm), which do not correlate with fractionation indicators (e.g. SiO 2 , MgO, Rb), consistent with co-trapping of Cu S phases with silicate melt. The highest Cu concentrations, Cu/S and incompatible trace elements (e.g. Rb) were measured in plagioclase, which crystallised over a wider range of melt compositions in comparison with olivine and pyroxene, and preferentially contains late-formed Cu-rich sulfides. These results underline the importance of mafic-intermediate magmas as sources of Cu in magmatic-hydrothermal ore deposits, and suggest that S-rich fluid is of primary importance in the transport of Cu in arc settings. [ABSTRACT FROM AUTHOR]

The Barberton Greenstone Belt of southern Africa hosts several Mesoarchaean gold deposits. The ores were mostly formed in greenschist facies conditions, and occur as hydrothermal alteration zones around extensional faults that truncate and post-date the main compressional structures of the greenstone belt. Ore deposition was accompanied by the intrusion of porphyries, which has led to the hypothesis that gold may have been sourced from magmas. Because the transport of Au in the hydrothermal fluids is widely believed to have involved S complexes, tracing the origin of S may place strong constraints on the origin of Au. We measured multiple S isotopes in sulfide ore from Sheba and Fairview mines of the Barberton Greenstone Belt to distinguish “deep” S sources (e.g. magmas) from “surface” S sources (i.e. rocks of the volcano-sedimentary succession that contain S processed in the atmosphere preserved as sulfide and sulfate minerals). Ion probe (SIMS) analyses of pyrite from ore zones indicate mass-independent fractionation of S isotopes (Δ 33 S = −0.6‰ to +1.0‰) and the distribution of the analyses in the Δ 33 S–δ 34 S space matches the distribution peak of previously published analyses of pyrite from the entire volcano-sedimentary succession. Notwithstanding that the H 2 O–CO 2 components of the fluids may have been introduced from a deep source external to the greenstone belt rocks, the fact that S bears an atmospheric signature suggests the hypothesis that the source of Au should also be identified in the supracrustal succession of the greenstone belt. Our findings differ from conclusions of previous studies of other Archaean shear-hosted Au deposits based on mineralogical and isotopic evidence, which suggested a magmatic or mantle source for Au, and imply that there is no single model that can be applied to this type of mineralisation in the Archaean. [ABSTRACT FROM AUTHOR]

In order to define the cathodoluminescence (CL) properties of magmatic topaz and its relation with trace-element composition, we studied topaz phenocrysts from the Ary-Bulak ongonite massif, Russia using a wide array of analytical techniques. Scanning electron microscopy CL panchromatic images reveal strong variations, which define micrometre-scale euhedral growth textures. Several truncations of these growth textures occur in single grains implying multiple growth and resorption events. The CL spectra of both CL-bright and -dark domains have a major peak in the near-ultraviolet centred at 393 nm. Cathodoluminescence images taken after several minutes of electron bombardment show decreasing emission intensity. Electron microprobe analyses indicate high F concentrations (average OH/(OH+F)=0.04 calculated by difference, 100 wt.% - total from electron probe microanalyses), consistent with what has been found previously in topaz-bearing granites, and the OH stretching vibration (~3653 cm-1) was detected in Raman spectra. Laser ablation inductively-coupled plasma mass spectrometry traverses performed across the CL textures detected trace elements at ppm to thousands of ppm levels, including: Fe, Mn, Li, Be, B, P, Nb, Ta, W, Ti, Ga, light rare-earth elements, Th and U. Lithium, W, Nb and Ta appear to be correlated with CL intensity, suggesting a role for some of these elements in the activation of CL in topaz. In contrast, no clear correlation was found between CL intensity and F contents, despite the fact that the replacement of OH for F is known to affect the cell parameters of topaz. [ABSTRACT FROM AUTHOR]

• Multiple S isotopes analysed in pyrite nodules from a Mesoarchaean volcanic lake. • 36S-depleted isotope compositions reflect mass-independent fractionation in a dense volcanic plume. • The terrestrial setting allowed instantaneous trapping and preservation of atmospheric S. Archaean supracrustal rocks carry a record of mass-independently fractionated S that is interpreted to be derived from UV-induced photochemical reactions in an oxygen-deficient atmosphere. Experiments with photochemical reactions of SO 2 gas have provided some insight into these processes. However, reconciling experimental results with the multiple S isotopic composition of the Archaean sedimentary record has proven difficult and represents one of the outstanding issues in understanding the Archaean surface S-cycle. We present quadruple S isotope data (32S, 33S, 34S, 36S) for pyrite from Mesoarchaean carbonaceous sediments of the Dominion Group, South Africa, deposited in an acidic volcanic lake, which help reconcile observations from the Archaean sedimentary record with the results of photochemical experiments. The data, which show low Δ 33 S/ δ 34 S ratios (mostly ≪ 1) and very negative Δ 36 S/ Δ 33 S ratios (−4 and lower), contrast with the composition of most Archaean sedimentary sulfides and sulfates, having Δ 36 S/ Δ 33 S ∼ − 1 (the so-called 'Archaean reference array'), but match those of modern photochemical sulfate aerosols produced in the stratosphere, following super-large volcanic eruptions, and preserved in Antarctic ice. These data are also consistent with the results of UV-irradiation experiments of SO 2 gas at variable gas pressure. The S isotope composition of the Dominion Group pyrite is here interpreted to reflect the products of photolysis in a low-oxygen-level atmosphere at high SO 2 pressure during large volcanic eruptions, mixed with Archaean 'background' (having a composition broadly similar to the Archaean reference array) S pools. It is inferred that high sedimentation rates in a terrestrial basin resulted in an instantaneously trapped input of atmospheric S during short-lasted depositional intervals, which faithfully represents transient photochemical signals in comparison with marine sedimentary records. [ABSTRACT FROM AUTHOR]

The 3.45 Ga old felsic volcanic rocks from the Barberton Greenstone Belt of southern Africa include a submarine succession of felsic lavas and volcaniclastic rocks and shallow subvolcanic intrusions. Sea floor alteration strongly affected rock compositions shortly after emplacement, making comparisons with coeval intrusions challenging. We analysed well-preserved quartz-hosted melt inclusions from the felsic rocks, which offers a unique opportunity to gain insight into pre-alteration melt compositions. Melt inclusion compositions are then compared with whole-rock analyses to evaluate the significance of the volcanic complex in the context of Archaean felsic magmatism in the Barberton Greenstone Belt. Whole-rock immobile trace element concentrations, including high-field strength and rare earth elements, indicate strong similarities with coeval tonalite–trondhjemite–granodiorite intrusions. These same geochemical characteristics distinguish these rocks from other Archaean felsic rocks in the Barberton Greenstone Belt (e.g. the 3.54 Ga Theespruit Formation), which have characteristically higher Th, Nb and REE. Low CaO (≤ 1 wt.%) and relatively high Nb and Th (mostly ≤ 9 and ≤ 13 ppm, respectively) in comparison with least altered whole-rock samples, and the presence of negative Eu anomalies are consistent with the melt inclusions being relatively evolved, rather than representing primitive compositions. Melt inclusion analyses suggest the presence of two melts with varying K 2 O/Na 2 O. Melt inclusions from extrusive samples, which contain remnants of K-feldspar phenocrysts, have K 2 O/Na 2 O > 1 by weight, whereas subvolcanic intrusions, which contain Na-rich plagioclase, have K 2 O/Na 2 O < 1. Moderately high Cl contents (Cl ≤ 0.7 wt.%) of melt inclusions may record interaction of the melting protolith with sea water prior to melting. We speculate that the varying K 2 O/Na 2 O in the felsic volcanic rocks was due to melting of a greenstone succession heterogeneously affected by sea floor alteration. [ABSTRACT FROM AUTHOR]

Chemical zoning of pyrites can record the evolution of mineralising fluids at widely varying P–T conditions ranging from diagenesis to medium-grade metamorphism. If preserved, zoning can reveal growth textures, brecciation and veining, resorption and recrystallisation events, thus shedding light on the processes that contributed to ore formation. Chemical zoning of sulfides is invisible in optical microscopy, but can be studied by chemical etching, high-contrast back-scattering electron images, and elemental imaging. In this study we compared micro-PIXE and WDS-EPMA elemental maps on the chemically zoned pyrites in mineralised vein-bearing samples from the Sheba and Fairview gold mines in the Barberton Greenstone Belt, South Africa. Elemental images show complex distribution of trace elements, suggesting multiple events of pyrite crystallisation and gold deposition. EPMA maps show fine-scale variations reflecting growth and recrystallisation textures marked, in particular, by variations of As, Ni, and Co. In PIXE maps, gold occurs both as finely-distributed and discrete inclusions, suggesting incorporation in the pyrite structure as solid solution, and deposition as electrum inclusions, respectively. Micro-PIXE and EPMA provide complementary information, forming together a powerful tool to obtain information on chemical zoning of pyrites in ore deposits. [ABSTRACT FROM AUTHOR]

Concentrically laminated pyrite is a relatively common, although volumetrically minor, component of auriferous conglomerates in the Archaean (ca. 3.0–2.7 Ga) Witwatersrand Basin of South Africa. This type of pyrite contains high amounts (several tens of ppm) of Au, but the origin of the pyrite is debated, and the timing of Au deposition in these grains is not known. In order to constrain the formation of pyrite, we have studied concentrically laminated pyrite and other coexisting types of pyrite (inclusion-rich, massive pyrite) by analysing the contents and distribution of Au and other trace elements by laser ablation ICP-MS, the S and Fe isotope composition by SIMS, and the mineral inclusions by scanning electron microscope and laser Raman spectroscopy. Trace element maps indicate that concentrically laminated pyrite is enriched in Sb, Mn, Au, Ag, Tl, Cu, Mo, Mn, and contains two types of gold: finely dispersed Au (“invisible gold”, with Au/Ag ~ 0.1 and likely of primary origin) and Au inclusions with Au/Ag ~ 10 of secondary origin. The study of mineral inclusions revealed the presence of muscovite, chlorite, fine-grained carbonaceous matter, monazite, Ti-oxides, and quartz. Iron and multiple S isotopes suggest that concentrically laminated pyrite and inclusion-rich pyrite were formed from two separate pools of S and Fe with different isotope characteristics. Sulfur was derived from atmospheric S that had undergone mass-independent isotope fractionation to form SO 4 2− with negative Δ 33 S that constituted concentrically laminated pyrite, and elemental S with positive Δ 33 S that formed inclusion-rich pyrite. Iron pools were derived from partial oxidation of Fe 2 + , so that concentrically laminated pyrite formed from a low-δ 56 Fe residual Fe 2 + (average + 0.2‰) and inclusion-rich pyrite formed from a high-δ 56 Fe Fe 3 + pool (average + 2.7‰). Biological activity may have been involved in the reduction of SO 4 2− , causing a wide spread of δ 34 S values (~ 25‰, S reducing microorganisms), as well as in the partial oxidation of Fe 2 + (anaerobic photosynthetic Fe reducers or photosynthetic O 2 producers), and in the formation of pyrite from Fe 3 + (dissimilatory Fe reducers). We propose that concurrent biogenically-mediated pyrite formation and Au trapping suggest that microbial activity was responsible for the accumulation of Au and other trace elements (e.g. Sb, Mn, Ag, Tl, Cu, Mo, Mn) which are commonly enriched in organic matter-rich sediments. [ABSTRACT FROM AUTHOR]

Textural, mineralogical and geochemical data on F-rich rhyolite (ongonite) from the Ary-Bulak massif of eastern Transbaikalia help constrain the formation of magmatic topaz. In these rocks, topaz occurs as phenocrysts, thus providing compelling evidence for crystallisation at the orthomagmatic stage. Cathodoluminescence images of topaz and quartz reveal growth textures with multiple truncation events in single grains, indicative of a dynamic system that shifted from saturated to undersaturated conditions with respect to topaz and quartz. Electron microprobe and Raman analyses of topaz indicate near-pure F composition [Al2 SiO4 F2], with very limited OH replacement. Laser ablation ICP-MS traverses revealed the presence of a large number of trace elements present at sub-ppm to hundreds of ppm levels. The chemical zoning of topaz records trace element fluctuations in the coexisting melt. Concentrations of some trace elements (Li, Ga, Nb, Ta and W) are correlated with cathodoluminescence intensity, thus suggesting that some of these elements act as CL activators in topaz. The study of melt inclusions indicates that melts with different F contents were trapped at different stages during formation of quartz and topaz phenocrysts, respectively. Electron microprobe analyses of glass in subhedral quartz-hosted melt inclusions indicate F ≤ 1.2 wt.%, whereas irregular-shaped melt inclusions hosted in both topaz and quartz have F ≤ 9 wt.%. Cryolithionite [Na3Li3 Al2F12] coexists with glass in irregular inclusions, implying high Li contents in the melt. The very high F contents would have increased the solubility of Nb, Ta and W in the melt, thus allowing progressive concentration of these elements during magma evolution. Crystallisation of Nb-Ta-W-oxides (W-ixiolite and tantalite-columbite) may have been triggered by separation of cryolithionite, which would have caused F and Li depletion and consequent drop in the solubility of these elements. [ABSTRACT FROM AUTHOR]

Abstract: The Fairview and Sheba mines are two of the major gold mines in the Paleoarchean Barberton Greenstone Belt of Southern Africa. At these mines, gold is associated with quartz–carbonate±rutile veins and occurs both as “invisible” gold finely dispersed in sulfides (primarily pyrite and arsenopyrite), and as visible electrum grains hosted in pyrite. Up to approximately 1000ppm Au are contained in pyrite, and up to approximately 1700ppm in arsenopyrite. Mapping of trace element distribution in sulfide minerals using electron microprobe and proton probe techniques revealed multiple events of ore formation and Au mineralisation. At Fairview mine, three stages of pyrite formation were identified, the last of which is associated with arsenopyrite, electrum and other sulfide minerals (sphalerite, chalcopyrite, galena, gersdorffite, and Sb-sulfides). At Sheba mine, pyrite was deposited in two stages, and electrum is associated with the second stage. At both mines, the last stage of sulfide formation is the main stage of Au deposition, and is associated with mobilisation of Au, As, Sb, Cu, Zn, and Ni. The host rock composition seems to have affected the composition of pyrite, since higher Ni and Co concentrations (up to 1.4 and 1.6wt.%, respectively) have been measured in meta-(ultra)mafic host rocks in comparison with chert and metagreywacke. Arsenopyrite is chemically zoned, and has Sb- and S-rich cores and As- and Ni-rich rims. This zoning indicates variations in fluid compositions (decreasing Sb and increasing Ni), and crystallisation conditions (increasing As content for increasing temperature). Geothermometric estimates based on the As content of arsenopyrite (As ≤32at.%) indicate temperatures up to ~420°C for the crystal rims. Petrographic and cathodoluminescence observations of quartz associated with gold mineralisation show only local brittle deformation, and no plastic deformation. This supports the notion that the ore-transporting veins were emplaced late in the deformation history. Variations of cathodoluminescence of quartz are correlated with changing Al contents (Al ≤0.16wt.%), and can be related to fluctuations in the pH of the mineralising fluids. [Copyright &y& Elsevier]

Abstract: The Gawler Range Volcanics (GRV) and the Hiltaba Suite (HS) of South Australia form a silicic-dominated large igneous province (the Gawler SLIP) emplaced in an intracontinental setting during the Mesoproterozoic. Emplacement of the GRV lasted for a short period of time (∼2Ma), and can be separated into two main phases. The first phase (lower GRV) is composed of thick (≤3km) sequences erupted from distinct centres, and includes small to moderate volume (up to >150km3) felsic lavas, ignimbrites, and minor mafic and intermediate lavas. The upper GRV include extensive felsic lavas that are up to >1000 of km3 in volume and >200km across. Using well preserved, quartz-hosted melt inclusions, we investigated the composition of the lower GRV, including major, trace, and volatile elements. The results indicate high concentrations of K2O (≤7–8wt.%), rare earth and high field strength elements, and low concentrations of Ca, Mg, Ni, Cr, Sr and Ba in comparison with felsic continental crust. Overall, melt inclusion compositions match whole-rock geochemical characteristics. We demonstrate that the GRV magma was F-rich (≤1.3wt.%), and had high temperature for a silicic magma. High F concentrations and high temperature would have resulted in lower than usual polymerisation of the melt and relatively low viscosity. These characteristics help explain how very voluminous felsic magma was erupted effusively and emplaced as lavas. Other intracontinental SLIP contain extensive felsic lavas and ignimbrites which appear to share similar geochemical characteristics. We also show that selective alteration caused depletion of whole-rock compositions in some trace elements, namely Pb, U, and Sn. [Copyright &y& Elsevier]

Background. Despite the introduction of screening bases intrapartum prophylaxis, Streptococcus agalactiae is still an important etiological agent of perinatal infections. The increasing rate of resistance and the differences in resistance pattern among countries suggest that a program of surveillance at the institutional level is important in determining optimal prophylaxis. In contrast, knowledge on GBS epidemiology in Italy is limited, and no data are available in the Southern region of the country. We sought to determine the occurrence of resistance to macrolides and clindamycin of GBS isolates in pregnant and nonpregnant women. Methods. Between 2005 and 2008, 1346 vaginal and 810 rectovaginal swabs were obtained frompregnant and not-pregnant women. Results. The occurrence of macrolides and clindamycin resistance was 16.5% in 2005 increasing up to 69.9% in 2008. A high percentage of isolates was resistant to tetracycline through all the study period with no statistically significant annual. Conclusions. In our cohort, an increase of in vitro resistance of GBS to macrolides and clindamycin is clearly evident. The discordance with reports from different countries emphasize the crucial role of microbiological methods in setting possible therapeutic strategies. [ABSTRACT FROM AUTHOR]

Abstract: Silicic-dominated large igneous provinces (SLIP) represent vast amounts of magma (≥105 km3) erupted onto the Earth''s surface or injected into the crust over short time spans, and are important components of the continental crust. The conditions of formation and evolution of these large magmatic provinces and their magma chambers are still poorly constrained. In this contribution, we examine cathodoluminescence textures and trace element (Al, Ti, Fe) zoning of quartz in a Mesoproterozoic SLIP, the Gawler Range Volcanics (GRV), South Australia. We describe intra-granular textures such as truncation of growth textures and reverse zoning (rimwards increase of Ti content). These characteristics of quartz, together with remelting of already crystallised portions of the magma chamber (felsic enclaves), suggest a complex history of crystallisation and resorption, and fluctuating magma temperature. Titanium-in-quartz geothermometry indicates that adjacent quartz zones record temperature variations (ΔT) up to 70°C in volcanic units. We also report contrasting (non-correlatable) zoning patterns amongst quartz crystals, each indicating different crystallisation conditions. The juxtaposition of quartz crystals with contrasting zoning patterns is consistent with a dynamic regime (convection, stirring, overturning) of the GRV magma chamber. These results point to pulsating magmatic conditions, compatible with a non-linear evolution of the GRV magma chamber. Heat, necessary to explain both intra-granular and infra-granular textural variations, may have been provided in different pulses by underplating of mafic magma. [Copyright &y& Elsevier]

Abstract: Rhyolites of the Mesoproterozoic Gawler Range Volcanics (GRV) of South Australia are characterised by high concentrations of some trace elements (REE, Y, HFSE, Rb and F, in particular). Whole rock geochemical data suggest that these elements were incompatible during magma crystallisation. Accessory minerals (fluorite, zircon, REE-F-carbonate, Ti oxide, apatite, and titanite) can account for most of the trace element content of the rocks. These minerals occur in vesicles, micromiaroles, lithophysal vugs and in interstices between major mineral phases (quartz and feldspar as both phenocrysts and groundmass). Such textural evidence indicates that accessory minerals crystallised late in the history of the magma and that they were deposited from a volatile-rich (fluid) phase. These features are explained by the following sequence of events: 1) F dissolved in the magma lowered the crystallisation temperature of accessory minerals, causing trace elements (REE, Y, and HFSE) to behave as incompatible elements. 2) Protracted crystallisation of major mineral phases (quartz, feldspar, and oxides) formed a volatile- and trace element-enriched residual liquid. 3) A volatile element (H2O, F, and CO2)-rich phase (late-stage magmatic fluid) evolved from the magma. High concentration of fluorine and other complexing agents in this phase allowed trace elements to be transported in solution. 4) Accessory minerals crystallised from such a phase in vesicles, micromiaroles and interstices between the major mineral phases. [Copyright &y& Elsevier]

To examine how the subsequent childbearing of HIV-infected mothers enrolled in the European Collaborative Study (ECS) has changed over time and identify factors predictive of further childbearing. Prospective cohort study. Centres in nine European countries included in the ECS, enrolled between end 1986 and November 2003. HIV-infected women (3911): 3693 with only one and 218 with subsequent live births. Univariable and multivariable logistic regression analyses to obtain odds ratios (OR) and 95% confidence intervals (CI). Kaplan–Meier (KM) analyses to estimate cumulative proportions of women having a subsequent live birth. Subsequent live birth. In multivariable analysis adjusting for time period, ethnicity, maternal age and parity, black women were more likely [adjusted odds ratio (AOR) 2.45; 95% CI, 1.75–3.43], and women>30 years less likely (AOR 0.54, 0.37–0.80), to have a subsequent live birth. Time to subsequent live birth significantly shortened over time, with an estimated 2% of women having a subsequent live birth within 24 months of enrolment pre-1989 versus 14% in 2000–2003 ( P< 0.001). Estimated time to subsequent live birth was shorter for black than for white women ( P< 0.001). The likelihood of subsequent live births substantially increased after 1995 and birth intervals were shorter in women on HAART and among black women. Numbers are currently too small to address the issue of advantages and disadvantages in the management of subsequent deliveries. [ABSTRACT FROM AUTHOR]

• Mesoarchaean carbonaceous shales interpreted as lake sediments. • Rock alteration minerals indicate acidic conditions. • Depleted δ 13 C values are compatible with methane recycling or acetogenesis. The antiquity of life in marine environments has been demonstrated, with examples of microfossils and stromatolites extending back to at least 3.5 billion years ago (Ga). In contrast, emerged land was likely a more challenging environment during the Archaean, and only sparse evidence of life in non-marine environments has so far been identified. Here we document the abundance of isotopically light carbon (with δ 13 C values from −46.6 to −31.3‰), diagnostic of a biogeochemical methane cycle or acetogenesis, in shale and sandstone deposited in ∼3 billion-years-old acidic volcanic lakes on the Kaapvaal Craton of southern Africa. A distinctive Al-rich mineral assemblage with abundant pyrophyllite in lacustrine sedimentary rocks bears similarity to modern volcanic rocks affected by circulation of hot acidic fluids. This is compounded with an enrichment of Ni, Mo, W, As and Cu in whole-rock analyses of sedimentary rocks, which is also observed in geothermal areas of modern volcanic environments. Analysis of early diagenetic pyrite in these sedimentary rocks indicates high nutrient level in the lake, which might reflect hydrothermal input with leaching of volcanic material. Despite the restricted and ephemeral nature of volcanic lakes, a highly productive and complex ecosystem established itself in this environment. Volcanic lakes during the Mesoarchaean thus served as an ecological niche for the development and diversification of microbial life on emerged continental landmasses. [ABSTRACT FROM AUTHOR]

• U–Pb and trace elements of rutile from polymetamorphic Proterozoic succession analysed. • Detrital and metamorphic-hydrothermal rutile generations identified. • Mechanisms of element mobilisation in rutile evaluated. • Geological history of the Capricorn Orogen recorded in multiple rutile generations. The trace element composition of rutile is widely used to constrain the temperature and timing of geological events, the provenance of detrital grains and as a potential indicator of proximal ore mineralisation. Understanding the processes of trace element mobility in rutile is therefore paramount to the successful application of rutile geochemistry to geological research. Using a combination of electron backscattered diffraction and laser-ablation split-stream ICP-MS, we studied the microtextures, trace-element contents and U–Pb isotopes of rutile from the siliciclastic rocks of the Mesoproterozoic Edmund Group, Capricorn Orogen (Western Australia). The Capricorn Orogen experienced multiple tectonothermal events during the Proterozoic under conditions spanning from low- to high-grade metamorphism. Rutile textures, U–Pb ages, trace-element variations and calculated Zr-in-rutile temperatures reveal different generations of rutile, including detrital or metamorphic-hydrothermal grains. U–Pb age data of detrital rutile indicate a wide span of ages (ca. 2.7–1.7 Ga) of the source rocks and Cr-Nb compositions point to metamafic, metapelitic and granitic origins for this rutile. The youngest detrital ages of 1.68 Ga constrain the maximum depositional age of the sedimentary package. The comparison of age spectra across the stratigraphy indicates a change in provenance, with sourcing from circa 1.7 Ga rocks during early stages of deposition, followed by unroofing of older basement during deposition of the youngest units of the Edmund Group. Partial resetting of detrital rutile is observed in the increase of 207Pb/206Pb ratios, accompanied by a decrease of Zr-in-rutile calculated temperatures. Lower-temperature metamorphic-hydrothermal rutile yielded imprecise Mesoproterozoic ages (1.3–1.1 Ga). This rutile has significant variations of Zr/Hf and Nb/Ta extending to values both lower and higher than primitive mantle, which may record crystallisation from, or interaction with hydrothermal fluids. Partial remobilisation of trace elements in metamorphic-hydrothermal rutile is demonstrated by sub-grain domains with sharp geochemical variations and by evidence of element diffusion at grain margins. Orders of magnitude differences in trace element concentrations (including Nb, Cr and Zr) in metamorphic-hydrothermal rutile grains suggest thorough investigation of rutile textures needs to be carried out prior to using the trace element concentrations in rutile for provenance and Zr-in-rutile temperature studies. [ABSTRACT FROM AUTHOR]

• New data on volcanology, petrology and geochemistry of ca. 2.2 Ga Machadodorp Member. • Machadodorp Member is more extensive than previously thought. • Geochemistry suggests a depleted mantle source, a unique case in the Kaapvaal craton. • Modelling suggests a shallow magma source, rifting can explain melting process. • Bushveld Complex possibly exploited the rifting structures during its intrusion. The Neoarchean to Paleoproterozoic (ca. 2.65–2.06 Ga) Transvaal Supergroup of the Kaapvaal Craton is dominated by clastic and chemical sedimentary rocks, with few strata-bound igneous units. Two ca. 2.2 Ga igneous units in its upper part (Pretoria Group), the Machadodorp Member of the Silverton Formation and the Mashishing dyke swarm, have so far only been recognized in the eastern part of the Transvaal subbasin. As these units are near-contemporaneous with an early Paleoproterozoic geochemical excursion to higher Th/Nb ratios compared to both older and younger igneous units, they probably mark a change in the geodynamic evolution of the craton. In the present contribution, we provide new data on the igneous units within the Silverton Formation (one lava and 5 sills) from a borehole (BB11) in the south-western part of the Transvaal subbasin. Two of these igneous units are particularly interesting because they show strong geochemical similarities to the Machadodorp Member and Mashishing dyke swarm, which are thus more spatially extensive than previously thought. In combination with existing data, our results further show that the Machadodorp Member corresponds to two separate, possibly not co-magmatic, igneous events, as documented by low- and high-Th basalts. The low-Th lavas show flat mantle-normalized REE and multi-element patterns, along with depleted Nd and Hf isotopic signatures, which are unusual among Precambrian magmatic rocks in the craton. This signature can be explained by partial melting of a depleted spinel peridotite incorporated into the subcratonic lithospheric mantle (SCLM) by a prior subduction event. A failed rifting event can have triggered melting of such a shallow source in a cratonic context. Even though comparable in age, the high-Th ca. 2.2 Ga Mashishing dyke swarm comes from a very different source, likely a part of the SCLM that had experienced subduction-related fluid metasomatism around the Archean – Proterozoic transition. About 150 million years later, the Bushveld Complex possibly exploited the same rifting structures during its intrusion. [ABSTRACT FROM AUTHOR]

[Display omitted] • Framboidal pyrite contains measurable amounts of trace elements (As, Au, Ag, etc.) • Cooked carbonaceous matter is rich in Fe and S and depleted in metallic elements. • Pyrite and carbonaceous matter textures evolve with increasing metamorphic grade. • Trace element removal during transformation of framboidal pyrite to euhedral pyrite. • Removal of trace elements except Se from pyrite by pressure solution. The Cretaceous Luk Ulo Complex (LUC) in Central Java, Indonesia, hosts orogenic gold-type ores with S derived from metapelite. The host rock consists of accreted metapelite, metamorphosed under temperature up to 510 ± 30 °C. We investigated the textural and chemical evolution of pyrite and carbonaceous matter (CM), and analyzed the hosts phases for trace elements (TEs) such as As, Pb, Cu, Sb, Te, Ag, Zn, Bi, Se, Hg, and Au, with the aim of documenting the behavior of these elements during prograde metamorphism and evaluate the implications on gold mineralization. With increasing metamorphic grade, the texture and chemical composition of pyrite evolved through different stages: 1) framboidal pyrite and pyrite nodules in the sedimentary–diagenetic facies, 2) anhedral–subhedral pyrite in sub-greenschist facies (SGSF), 3) euhedral pyrite in lower greenschist facies (LGSF), 4) elongated pyrite in middle greenschist facies (MGSF), and 5) replacement of pyrite by pyrrhotite in upper greenschist facies (UGSF). The framboidal pyrite and pyrite nodules contain measurable TEs. Recrystallization of such pyrite into euhedral pyrite in LGSF resulted in significant depletion of TEs, except for Se, by pressure-solution. With increasing metamorphic grade, the recrystallization of organic matter to "cooked" CM in LGSF was accompanied by significant depletion in most TEs, with only Fe and S being retained. The transformation of cooked CM into graphite in MGSF, and of elongated pyrite into pyrrhotite in UGSF resulted in further removal of remaining TEs. These observations and the absence of para -amphibolite in the LUC suggest that remobilization of TEs and S from sedimentary pyrite and CM might have occurred in the LGSF, much earlier than previously proposed (UGSF-amphibolite transition). [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Invasive procedures for fetal karyotyping: no cause of subsequent gestational hypertension or pre-eclampsia," by P. Lindgren and colleagues in the 2010 issue.

The trend to have children even if one or both parents suffer from chronic diseases is influenced by personal, psycho-organic and social factors. The Authors face the moral and professional dilemma of honouring a woman's intentions, or persuading her to interrupt her pregnancy to prevent damage to her health. [ABSTRACT FROM AUTHOR]

This article presents a letter to the editor in response to the article "Effectiveness of prenatal treatment for congenital toxoplasmosis: a meta-analysis of individual patients' data," by the SYROCOT study group, published in the January 13, 2007 issue.

The geochemistry of rutile (TiO 2 ) has recently found its use in mineral exploration with some studies reporting anomalous concentrations of Fe, W, V, Sn and Sb in rutile associated with mineralized ore systems. However, the use of rutile as a prospecting tool is likely to be complicated by the systematic changes in trace element composition with TiO 2 polymorph type (anatase, brookite and rutile). Here we present TiO 2 trace element and U–Pb geochronological data from the mineralized and barren portions of the Palaeoproterozoic Moorarie Supersuite and (Capricorn Orogen, Western Australia), with a focus on the Minnie Creek Molybdenum Prospect in the northern part of the Gascoyne Province. The barren samples contain all three TiO 2 polymorphs (anatase, brookite and rutile). Textures suggest anatase and brookite may have formed during low-T metamorphism, either through replacement of previous rutile grains or titaniferous minerals. Rutile grains from barren samples yield variable U–Pb ages (ca. 3.0–2.2 Ga) as well as variable textures and chemical compositions suggesting detrital origins, thus most likely representing metasedimentary units intruded by the Moorarie Supersuite. Rutile grains from the Minnie Creek prospect yield Palaeoproterozoic (ca. 1.77–1.75 Ga) U–Pb cooling ages and Nb + Ta concentrations of up to 17 wt% that along with inclusions of manganocolumbite, oscillatory and patchy zonation of Nb and Fe, suggest a magmatic origin. The commonly used pathfinder elements for gold and base-metal mineralisation (Fe, Cr, V, W, Sn and Sb) are shown to be systematically lower in anatase and brookite, thus yielding false negatives if polymorph type is not identified during reconnaissance studies. For this reason, a ternary diagram was constructed based on the systematic changes in chemistry of TiO 2 polymorphs to provide a relatively fast and easy chemical discrimination of polymorphs in large volumes of reconnaissance data. Furthermore, it is shown that high Al concentrations are characteristic of brookite and, to a lesser degree, anatase but not rutile. In addition, Sn, Nb, Ta and W concentrations in rutile may be more sensitive to igneous processes and may be used to track processes occurring in strongly fractionated granitic magmas such as pegmatites and associated deposits. [ABSTRACT FROM AUTHOR]

The metallogeny of gold in northeastern Mozambique is still debated, with the main point of contention being the timing of mineralization with respect to regional tectonism, metamorphism, and magmatism. In this study, we applied Re–Os sulfide geochronology to constrain the age of gold mineralization in the Nanlia and Makorongo prospects hosted by the Xixano Complex, in the southern part of the Mozambique Belt. In addition, chemical analyses of host rocks and sulfides complement the discussion on the genesis of mineralization. Single-mineral Re–Os model ages of pyrite and pyrrhotite in quartz veins constrain the occurrence of gold mineralization in the Nanlia and Makorongo prospects between ca. 580 and ca. 560 Ma. This mineralization age interval postdated the timing of peak metamorphism of the host rocks established at ca. 631–607 Ma and is contemporaneous with the metamorphism of basement rocks between ca. 607 and ca. 564 Ma, during the thrusting of tectonic nappes in the last stage of the Pan-African orogeny. In addition, the strike of the veins in the Nanlia and Makorongo prospects is parallel to the local orientation of the thrust fault that separated the overlying rocks from the basement rocks and the dominant S1 foliation of the host rocks. These geochronological and structural data indicate a close relationship between auriferous veins in the study area and the Pan-African thrust fault associated with the emplacement of the tectonic nappes. We propose a metamorphic model for the gold mineralization in the Nanlia and Makorongo prospects, in which the mineralizing fluids were sourced mainly from dehydration of basement rocks, as a result of prograde metamorphism triggered by the juxtaposition of the Neoproterozoic tectonic nappes, including the Xixano Complex, during the last stage of the Pan-African orogeny. The mineralizing fluids ascended through the Pan-African thrust faults and structures to the overlying rocks, where the gold was deposited along the S1 foliation. [Display omitted] • The gold mineralization occurred between 580 and 560 Ma. • The mineralization postdated the metamorphism of host rocks. • The mineralization was coeval to nappes emplacement during the Pan-African orogeny. • Fluid-rock interaction was insignificant in these prospects. [ABSTRACT FROM AUTHOR]

Objective To assess the relationship between congenital heart disease (CHD) and Down syndrome (DS) in utero. Design Retrospective case series. Subjects Fifty-two fetuses with a cytogenetic diagnosis of DS managed at our Fetal Cardiology Unit in the study period. In particular, two populations of fetuses with DS were studied: a group of 41 DS fetuses referred to our unit for fetal echocardiography due to the chromosomal anomaly and a second group of 274 fetuses referred because of suspected CHD, 11 of which were found to have DS. Methods All fetuses were submitted to detailed ultrasound evaluation of fetal anatomy. Associated extra-cardiac anomalies, and presence and type of CHD, were recorded for all fetuses. Karyotyping was obtained by means of cordocentesis or amniocentesis. Necropsy or neonatal echocardiograms were sought for confirmation of the prenatal diagnosis. Results In the group of 41 fetuses with known DS, the incidence of CHD was 56% ([atrioventricular septal defect (AVSD) 44%, ventricular septal defect (VSD) 48%], the remainder having other heart defects). Conversely, considering the incidence of DS in fetuses with CHD, 43% of all AVSDs (53% of AVSD with normal visceral situs) were associated with DS, whereas none of the 39 cases of VSD was associated with trisomy 21. Ventricular septal defects were diagnosed only in fetuses referred to our center with a known diagnosis of aneuploidy. Conclusions We have confined that more than half of the fetuses with DS bear a CHD, which is an AVSD in 44% of cases. Conversely, 43% of fetuses with an AVSD have trisomy 21. For VSDS, the situation is controversial, due to the relatively low detection level of this heart defect at the routine mid-trimester obstetric scan. [ABSTRACT FROM AUTHOR]

• New geochronological data of the Mesoarchaean Dominion Group. • ~ 2.96 Ga old Dominion-Nsuze Igneous Province. • Oldest large igneous province of the Kaapvaal Craton. • ~2.96 Ga as start of the deposition of the Witwatersrand Supergroup. The Kaapvaal Craton records a long Archaean to Phanerozoic history of intracratonic magmatism that reflects contrasting regimes of melt generation. The correct interpretation of this rich geological record relies critically on field evidence and ever refined chronological and isotopic data. Here, we present new U – Pb zircon, apatite and titanite ages, and Lu-Hf isotope results for volcanic and sedimentary rocks of the Dominion Group, its granitoid basement, and overlying strata of the Witwatersrand Supergroup. The data indicate an emplacement age of ca. 2.96 Ga for the Dominion Group, approximately 0.11 Ga later than previous estimates. These new ages, combined with lithological and geochemical similarities, allow the comparison and correlation between the Dominion Group and the Nsuze Group of the Pongola Supergroup. Together, the two successions constitute a single igneous province, here termed the Dominion-Nsuze Igneous Province, which was emplaced shortly after craton consolidation, spanning approximately 500 km across the central and eastern Kaapvaal Craton. This province constitutes the first intracratonic igneous province of the Kaapvaal Craton and one of the oldest in the world. The new age determinations also place limits on the onset of sedimentation of the overlying Witwatersrand Supergroup, which can now be constrained at < 2960 Ma. [ABSTRACT FROM AUTHOR]

Background: Food allergy (FA) is a growing health problem worldwide. Effective strategies are advocated to limit the disease burden. Human milk (HM) could be considered as a protective factor against FA, but its mechanisms remain unclear. Butyrate is a gut microbiota‐derived metabolite able to exert several immunomodulatory functions. We aimed to define the butyrate concentration in HM, and to see whether the butyrate concentration detected in HM is able to modulate the mechanisms of immune tolerance. Methods: HM butyrate concentration from 109 healthy women was assessed by GS‐MS. The effect of HM butyrate on tolerogenic mechanisms was assessed in in vivo and in vitro models. Results: The median butyrate concentration in mature HM was 0.75 mM. This butyrate concentration was responsible for the maximum modulatory effects observed in all experimental models evaluated in this study. Data from mouse model show that in basal condition, butyrate up‐regulated the expression of several biomarkers of gut barrier integrity, and of tolerogenic cytokines. Pretreatment with butyrate significantly reduced allergic response in three animal models of FA, with a stimulation of tolerogenic cytokines, inhibition of Th2 cytokines production and a modulation of oxidative stress. Data from human cell models show that butyrate stimulated human beta defensin‐3, mucus components and tight junctions expression in human enterocytes, and IL‐10, IFN‐γ and FoxP3 expression through epigenetic mechanisms in PBMCs from FA children. Furthermore, it promoted the precursors of M2 macrophages, DCs and regulatory T cells. Conclusion: The study's findings suggest the importance of butyrate as a pivotal HM compound able to protect against FA. [ABSTRACT FROM AUTHOR]

Pyrite is the most abundant ore mineral in gold-bearing quartz pebble conglomerates (QPCs) of the Witwatersrand Basin and similar Archaean sedimentary units. Much of the pyrite in Archaean conglomerates is detrital in origin, implying that it survived weathering, transport, and reworking under anoxic conditions. Detrital pyrite is generally found together with authigenic pyrite formed in situ as a result of syn- to post-depositional processes. As pyrite is frequently associated with gold mineralization, many authors have developed different pyrite classification schemes in order to better understand the nature and origin of the mineralization, although the different classifications cannot always be easily compared as they are largely based on inferred pyrite genesis. We propose a revised, entirely descriptive classification scheme for detrital and authigenic pyrite in Archaean QPCs. The scheme was created in order to provide a consistent framework for the petrographic description of pyrite in clastic sedimentary rocks. Detrital pyrite is subdivided into massive, inclusion-bearing, and coarsely crystalline types. Authigenic pyrite includes euhedral, overgrowth, infill, aggregate, and pseudomorphic types. We evaluate the methods used in pyrite classification, propose formation pathways for detrital and authigenic pyrites, and apply the classification scheme to some well-known occurrences of detrital pyrite-bearing conglomerates. [ABSTRACT FROM AUTHOR]

Oculoauriculovertebral spectrum, or Goldenhar syndrome, is characterized by varying degrees of prevalently unilateral underdevelopment of craniofacial structures (orbit, ear, mandible) and spinal anomalies. We report the prenatal ultrasonographic diagnosis made at 24 weeks' gestation in a family with a negative history. The prenatal diagnosis was suspected due to the presence of marked hemifacial microsomia and moderate ipsilateral cerebellar hemisphere hypoplasia in the absence of facial clefting. [ABSTRACT FROM AUTHOR]

The geochemical analysis of trace elements in rutile (e.g., Pb, U, and Zr) is routinely used to extract information on the nature and timing of geological events. However, the mobility of trace elements can affect age and temperature determinations, with the controlling mechanisms for mobility still debated. To further this debate, we use laser-ablation--inductively coupled plasma--mass spectrometry and atom probe tomography to characterize the micro- to nanoscale distribution of trace elements in rutile sourced from the Capricorn orogen, Western Australia. At the >20 µm scale, there is no significant trace-element variation in single grains, and a concordant U-Pb crystallization age of 1872 ± 6 Ma (2σ) shows no evidence of isotopic disturbance. At the nanoscale, clusters as much as 20 nm in size and enriched in trace elements (Al, Cr, Pb, and V) are observed. The 207Pb/206Pb ratio of 0.176 ± 0.040 (2σ) obtained from clusters indicates that they formed after crystallization, potentially during regional metamorphism. We interpret the clusters to have formed by the entrapment of mobile trace elements in transient sites of radiation damage during upper amphibolite facies metamorphism. The entrapment would affect the activation energy for volume diffusion of elements present in the cluster. The low number and density of clusters provides constraints on the time over which clusters formed, indicating that peak metamorphic temperatures are shortlived, <10 m.y. events. Our results indicate that the use of trace elements to estimate volume diffusion in rutile is more complex than assuming a homogeneous medium. [ABSTRACT FROM AUTHOR]

Abstract The Pena–Shokeir phenotype represents an autosomal recessive syndrome characterized by neurogenic arthrogryposis, facial anomalies and pulmonary hypoplasia. Prenatal diagnosis of this disease has been reported prospectively and in cases with positive family history. We describe here a patient who has had three consecutive pregnancies affected by the Pena–Shokeir syndrome. In these pregnancies, the onset of the arthrogryposis varied between the 12th and the 18th week of gestation. Therefore, the possibility of a variable chronological development of the main diagnostic feature of the syndrome, arthrogryposis, has to be taken into proper consideration while counseling families with a positive history for the Pena–Shokeir phenotype. [ABSTRACT FROM AUTHOR]

The Barito, Pasir, and Tarakan Basins in Kalimantan Island is the most extensive coal-bearing sedimentary basin in Indonesia, mined since 1989. The coal is notable in having high sulfur coal content, exceeding >10% in some cases, contributed by the presence of pyrite. The latter issue contributed to interest in the coal, forming economic mineral deposits hosted by the sedimentary pyrite and organic matter. Novel findings of this research providing valuable information of trace element behavior during the diagenetic conditions. This paper documents the textural and compositional evolution of pyrite-organic matter of coals using coal petrographic, proximate, ultimate, total sulfur content, scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), electron probe micro analyser (EPMA), and Raman spectroscopy. Coals from Kalimantan are mainly characterized by medium-high sulfur content (>3%) and the maximum temperatures reached by organic matter during diagenesis are 166 ± 10 °C for the Pasir Basin, 136 ± 11 °C for the Barito Basin, and 132 ± 12 °C for the Tarakan Basin. Pyrite is mainly found as large size framboids (mostly >5 μm), indicating formation in the sedimentary layer with dysoxic bottom water conditions during early–late diagenetic stages. The framboidal pyrite was preferably formed in detrovitrinite and gelovitrinite under topogenous mire conditions, due to the degradation of macerals and biochemical gelification, which provided the organic templates. High concentrations of trace elements (TEs) of framboidal pyrite, such as 1) Cu, Ni, and Co in the Pasir Basin and 2) As in the Barito Basin, likely reflect the local sedimentary provenance and underlying basement rocks. Pyrite texture evolved with increasing diagenetic temperatures from 1) framboidal pyrite, 2) recrystallized framboidal pyrite rims, and 3) anhedral, anhedral-euhedral pyrite transition, and euhedral massive pyrite. This study shows a similar average TE concentrations of various pyrite textures, suggesting that the TEs are not remobilized during the evolution of pyrite at the diagenetic stages. • Medium-high sulfur coals from Indonesia. • Association of pyrite and organic matter. • Textural and compositional evolution of pyrite in coals. • Trace elements of pyrite in coals. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study was to evaluate the incidence of toxoplasmosis infection during pregnancy and to describe the characteristics of the serological status, management, follow-up and treatment.Material and Methods: This is a population-based cohort study of women referred for suspected toxoplasmosis during pregnancy from January, 2001 to December, 2012. Suspected toxoplasmosis was defined as positive IgM antibody during pregnancy. Women with suspected toxoplasmosis during pregnancy were classified into three groups: seroconversion, suspected infection, or no infection in pregnancy. Women in the first and second group were treated according to local protocol, and amniocentesis with toxoplasmosis PCR detection and serial detailed ultrasound scans were offered. Neonates were investigated for congenital toxoplasmosis at birth and were monitored for at least one year after birth.Results: During the study period, there were 738,588 deliveries in Campania. Of them 1159 (0.2%) were referred to our Institution for suspected toxoplasmosis during pregnancy: 183 (15.8%) women were classified as seroconversion, 381 (32.9%) were suspected infection, and 595 (51.3%) were not infected in pregnancy. Neonatal outcome was available for 476 pregnancies, including 479 neonates (3 twins, 473 singletons), out of the 564 pregnancies with seroconversion or suspected infection. 384 (80.2%) babies were not infected at birth and at follow-up, 67 (14.0%) had congenital toxoplasmosis, 10 (2.1%) were voluntary induced termination of pregnancy, 15 (3.1%) were spontaneous miscarriage, and 4 (0.8%) were stillbirth (of which one counted already in the infected cohort). Considering cases of congenital toxoplasmosis, the transmission rate in women with seroconversion was 32.9% (52/158), and in women with suspected infection was 4.7% (15/321).Conclusions: Toxoplasmosis is uncommon in pregnancy with overall incidence of seroconversion and suspected infection in pregnancy of 0.8 per 1000 live births and incidence of congenital toxoplasmosis 0.1 per 1000 live births when applying a strict protocol of screening, follow-up, and treatment. 51.3% (595/1159) of women referred to our center for suspected infection were actually considered not infected. [ABSTRACT FROM AUTHOR]

The Dallol volcano and its associated hydrothermal field are located in a remote area of the northern Danakil Depression in Ethiopia, a region only recently appraised after decades of inaccessibility due to severe political instability and the absence of infrastructure. The region is notable for hosting environments at the very edge of natural physical-chemical extremities. It is surrounded by a wide, hyperarid salt plain and is one of the hottest (average annual temperatureDallol: 36–38°C) and most acidic natural systems (pHDallol ≈0) on Earth. Spectacular geomorphologies and mineral deposits produced by supersaturated hydrothermal waters and brines are the result of complex interactions between active and inactive hydrothermal alteration of the bedrock, sulfuric hot springs and pools, fumaroles and geysers, and recrystallization processes driven by hydrothermal waters, degassing, and rapid evaporation. The study of planetary field analog environments plays a crucial role in characterizing the physical and chemical boundaries within which life can exist on Earth and other planets. It is essential for the definition and assessment of the conditions of habitability on other planets, including the possibility for biosignature preservation and in situ testing of technologies for life detection. The Dallol area represents an excellent Mars analog environment given that the active volcanic environment, the associated diffuse hydrothermalism and hydrothermal alteration, and the vast acidic sulfate deposits are reminiscent of past hydrothermal activity on Mars. The work presented in this paper is an overview of the Dallol volcanic area and its hydrothermal field that integrates previous literature with observations and results obtained from field surveys and monitoring coupled with sample characterization. In so doing, we highlight its exceptional potential as a planetary field analog as well as a site for future astrobiological and exploration programs. [ABSTRACT FROM AUTHOR]

Constraining the timing of eukaryogenesis and the divergence of eukaryotic clades is a major challenge in evolutionary biology. Here, we present trace metal concentration and zinc isotope data for c. 2.1 billion-year-old Francevillian Group pyritized structures, previously described as putative remnants of the first colonial multicellular organisms, and their host black shales. Relative to the host rocks, pyritized structures are strongly enriched in zinc, cobalt and nickel, by at least one order of magnitude, with markedly lighter zinc isotope compositions. A metabolic demand for high concentrations of aqueous zinc, cobalt, and nickel combined with preferential uptake of lighter zinc isotopes may indicate metalloenzyme utilization by eukaryotes in marine habitats c. 2.1 billion years ago. Once confirmed, this would provide a critical calibration point for eukaryogenesis, suggesting that this major evolutionary innovation may have happened contemporaneously with elevated atmospheric oxygen levels during the latter part of the Great Oxidation Event, some 400 million years earlier than is currently widely accepted. • Biogenic origin of the c. 2.1-billion-year-old Francevillian Group biota. • Enrichment of light zinc isotopes in the Francevillian biota is consistent with eukaryotic metabolism. • Utilization of metalloenzymes by possible eukaryotes in the Paleoproterozoic oceans. • Possible eukaryotic biota preserved in the Paleoproterozoic Francevillian Group. • Inferred eukaryogenesis during the Great Oxidation Event. [ABSTRACT FROM AUTHOR]

Auriferous quartz veins in the Namicupo gold prospect occur parallel to the foliation of metasedimentary host rocks of the Xixano Complex in northeastern Mozambique. The geochemistry and ore-forming mechanism of the Namicupo prospect have never been scientifically investigated. This study discusses the ore mineralogy, fluid inclusion, and stable isotope (S-O) characteristics of the prospect. The mineralization in the Namicupo prospect is divided into two stages. The Stage I, primary mineralization, is represented by electrum with Ag contents of 15–26 at.%, associated with pyrite and chalcopyrite. The Stage II is supergene mineralization, characterized by electrum with Ag contents of 39–46 at.%, intergrown with goethite, barite, and minium, which replaced primary sulfides. Quartz from the mineralized veins hosts three types of primary fluid inclusions coexisting in the same fluid inclusion assemblage. Type A inclusions are three-phase aqueous‑carbonic inclusions (aqueous liquid, CO 2 liquid and vapor), with final homogenization temperature and salinity varying from 140 to 241 °C, and 1.0 to 7.8 wt% NaCl eq., respectively. Type B inclusions occur either as mono-phase (vapor or liquid) or two-phase (vapor and liquid) CO 2 -rich, N 2 -H 2 O-bearing inclusions, with homogenization temperature varying from +12.9 to +29.3 °C. The Type C inclusions are two-phase (liquid and vapor) aqueous inclusions, which homogenize to liquid phase at temperatures between 209 and 337 °C. The salinity of the Type C inclusions varies from 4.0 to 10.8 wt% NaCl eq. The sulfur isotopic ratios (δ34S CDT) of sulfides associated with Stage I mineralization and the oxygen isotopic ratios (δ18O SMOW) of water calculated from those of quartz from the quartz veins vary from −3.5 to +0.9 ‰ and −1.0 to +2.5 ‰, respectively. The primary mineralization at the prospect is classified as an orogenic-type gold mineralization, formed by aqueous‑carbonic metamorphic fluids. The precipitation of primary gold mineralization in the Namicupo prospect resulted dominantly from fluid immiscibility. The considerable amount of S up to 0.1 wt% and the high Ag contents of electrum intergrown with goethite, minium and barite suggest that the supergene mineralization in the Stage II was caused by oxidation of primary gold-bearing sulfides and Au-rich electrum under moderately acidic and oxidizing conditions, which resulted in Au and Ag liberation, likely by thiosulfate. Dissolution of primary mineralization and supergene gold enrichment in the Namicupo prospect appear to have occurred largely in situ, with little evidence of distant mobilization. • The Namicupo prospect consists of primary and supergene gold mineralization. • The primary mineralization is classified as an orogenic-type gold. • The primary mineralization was formed by aqueous‑carbonic metamorphic fluids. • Supergene enrichment consisted of the mobilization of primary ores by thiosulfate. [ABSTRACT FROM AUTHOR]

The Ruwai deposit is the largest polymetallic skarn deposit in Borneo and is located within the Schwaner Mountains Complex. The mineralization is hosted by metalimestone of the Jurassic Ketapang Complex and the causative intrusions belong to the Cretaceous Sukadana Granitoids. Despite its large resources, the geochemical characteristics of the Ruwai skarn are still not well known. Thus, this study provides the whole-rock geochemistry of the skarn, metalimestone and intrusions, as well as the chemical compositions of sulfides (i.e., pyrite, sphalerite, galena, and chalcopyrite). The occurrence of skarn mineralization can be divided into proximal (Gojo-Karim) and distal (Central Gossan-Southwest Gossan) zones. Furthermore, the mineralization stage can be divided into prograde, retrograde and supergene stages. The whole-rock geochemical analyses clearly show that the skarn is enriched in several metals such as Ag, Nb, Co, La, Cu, V, Zr and Ti, which are higher in intrusions compared to metalimestone, which implies that these metals are mostly derived from magma. On the other hand, the skarn is also enriched in As, Pb, and Se, elements that are higher in metalimestone than in the intrusions. Thus, it can be inferred that metalimestone provided significant amounts of these metals to the mineralizing fluid. The pyrite analyses show that Cu, Zn, Bi and Ag increase towards the distal zone, while Fe, Mn and Bi in sphalerite also increase towards the distal zones Copper and Sb in galena and Ag in chalcopyrite collected from the distal zone increase from Central Gossan to Southwest Gossan zones while Bi in both minerals decrease. These trends of trace metal contents in sulfides can be utilized as a vectoring tool to delineate the center of the hydrothermal system. • Ruwai is the largest polymetallic skarn deposit in Indonesia. • The deposit is divided into proximal Gojo-Karim and distal Central-SW Gossan zones. • Some trace metals in pyrite and sphalerite show a trending pattern from proximal to distal zones. • Several metals in galena and chalcopyrite vary from Central to SW Gossan zones. • The trend can be used to delineate the hydrothermal center and as a guide to ore. [ABSTRACT FROM AUTHOR]

The felsic-dominant Gawler Range Volcanics and cogenetic Hiltaba Suite granitoids constitute the ca. 1590 Ma Gawler silicic large igneous province in the Gawler Craton, South Australia. The province includes minor occurrences of olivine-phyric basalt at Kokatha and Mount Gunson. In this study, we describe additional olivine-phyric basalts and dykes intersected by drill holes at the Olympic Dam Iron Oxide Cu–U–Au–Ag deposit and the Wirrda Well Cu–Au prospect. Laser Ablation Inductively Coupled Plasma Mass Spectrometry U–Pb dating results (un-anchored) of apatite in the basalts and dykes at Mount Gunson (1576 ± 33 Ma), Wirrda Well (1596 ± 17 Ma), and Olympic Dam (1621 ± 20 Ma) confirm their effective temporal correlation with the ca. 1590 Ma Gawler silicic large igneous province. Compositions of Cr-spinel inclusions enclosed in former olivine phenocrysts (forsterite number >80) in basalts at Mount Gunson, Wirrda Well and Olympic Dam imply derivation from a heterogeneous mantle source that may have been modified by subduction. Least-altered olivine-phyric basalts at Mount Gunson and Kokatha are characterized by negative Nb and Ta anomalies, which are typical of arc basalts but are also common in back-arc basin basalts, in accordance with the result suggested by the Cr-spinel source indicator. The mafic components of the Gawler Range Volcanics generally have higher Zr contents and Zr/TiO 2 ratios than those of high-Mg basalts and picrites produced in variable tectonic settings worldwide, possibly reflecting continental crustal components involved in their mantle source. High abundances (typically ∼20 vol.%) of former olivine phenocrysts in the basalt at Olympic Dam imply high-Mg whole-rock compositions and a high temperature of the primary magma. This result is consistent with previous models in which the heat flux from mantle magmas caused large-scale partial melting of crustal rocks that subsequently gave rise to silicic magmas erupted and intruded to form the Gawler silicic large igneous province. [ABSTRACT FROM AUTHOR]

Presents the case of a mild form of cleidocranial dysostosis in a third trimester fetus. Use of ultrasound imaging to determine abnormality of the bone growth; Presence of the same clavicular abnormality in the mother; Diagnosis of autosomal dominant cleidocranial dysostosis in the neonate and her parent.

Highlights: [•] Hydrothermal formation of illite, chamosite and berthierine in the FA Formation. [•] Differentiation of clay alterations in the main sedimentary units of FA Formation. [•] FA clay minerals as a hygrometer, rather than exclusively a thermometer. [•] Hydrothermal clays synchronous with intense leaching of U ca. 2040–2010Ma ago. [•] U mobilization controlled by oxidized and high temperature hydrothermal fluids. [Copyright &y& Elsevier]

Abstract: Iron and sulfur isotope compositions recorded in ancient rocks and minerals such as pyrite (FeS2) have been widely used as a proxy for early microbial metabolisms and redox evolution of the oceans. However, most previous studies focused on only one of these isotopic systems. Herein, we illustrate the importance of in-situ and coupled study of Fe and S isotopes on two pyrite nodules in a c. 2.7 Ga shale from the Bubi Greenstone Belt (Zimbabwe). Fe and S isotope compositions were measured both by bulk-sample mass spectrometry techniques and by ion microprobe in-situ methods (Secondary Ion Mass Spectrometry, SIMS). Spatially-resolved analysis across the nodules shows a large range of variations at micrometer-scale for both Fe and S isotope compositions, with and values from −2.1 to and from −0.5 to , respectively, and values from −1.6 to . The Fe and S isotope variations in these nodules cannot be explained by tandem operation of Dissimilatory Iron Reduction (DIR) and Bacterial Sulfate Reduction (BSR) as was previously proposed, but rather they reflect the contributions of different Fe and S sources during a complex diagenetic history. Pyrite formed from two different mineral precursors: (1) mackinawite precipitated in the water column, and (2) greigite formed in the sediment during early diagenesis. The in-situ analytical approach reveals a complex history of the pyrite nodule growth and allows us to better constrain environmental conditions during the Archean. [Copyright &y& Elsevier]

[Display omitted] • Ilmenite occurs either as monomineralic aggregates or interstitial fillings. • Textural and structural data support a cumulate origin for the Mazua intrusion. • The Mazua intrusion was formed from evolved and Fe-Ti rich basaltic melts. • Settling and sorting are the main formation mechanisms of the Fe-Ti oxide ores. • The rocks were subjected to extensive subsolidus re-equilibration during cooling. The Mazua ultramafic intrusion is among the most promising intrusions hosting Fe-Ti oxide ores in Mozambique. Fe-Ti oxide ores are mainly composed of ilmenite occurring as lenses, veins and layers, either massive or disseminated in hornblende pyroxenite. This study discusses the nature and origin of the intrusion and related ilmenite ore body on the basis of whole-rock and mineral chemistry. Textural and structural evidences support a cumulate origin for these rocks, including the occurrence of relict cumulate textures, layering of alternating oxides and silicate-rich rocks, and size-grading of silicate-rich layers. Primary magmatic features have, however, largely been overprinted by subsolidus processes. The occurrence of the cumulate assemblage (Fe-Ti oxides and clinopyroxene), without plagioclase and olivine, suggests that the magma underwent differentiation before its emplacement. The evolved magmatic nature of the intrusion is consistent with the calculated Mg-number of approximately 50 for the melt in equilibrium with clinopyroxene crystals. The high TiO 2 concentrations (>4 wt%) of the evolved magma, by differentiation, are interpreted as the main factors controlling the crystallization of Fe-Ti oxides. We propose that the ores formed from crystallization and settling of Fe-Ti oxide minerals from an evolved basaltic magma. This model is consistent with (1) the occurrence of Fe-Ti oxides and clinopyroxene as cumulates in relation to the coexisting amphibole, (2) the layering structures of alternating oxides and silicate matrix, (3) the scarcity of apatite supported by the extremely low whole-rock P 2 O 5 concentrations and (4) the restricted occurrence of ore veins, excluding the formation from immiscible oxide melts. [ABSTRACT FROM AUTHOR]

Olympic Dam is a supergiant Fe oxide Cu-U-Au-Ag ore deposit (~9 x 109 t) that is also enriched in rare earth elements (REEs) and fluorine (F). The immediate host to the ore is hydrothermal breccia within granite and volcanic rocks of a Mesoproterozoic silicic large igneous province. Analyses of melt inclusions in quartz phenocrysts in rhyolite show that the silicic magmas of this province were unusually rich in F (up to 1.3 wt%). Fluorite and other F-rich minerals that crystallized from these magmas provided a gigantic reservoir of F. As a result, the Olympic Dam ore-forming fluid was F-rich and had exceptional capacity to transport diverse elements. Further, we infer that hydrofluoric acid, the most corrosive acid known, contributed to hydrothermal breccia formation by dissolution that in turn increased permeability and accelerated the rate of fluid-rock interaction. It is no accident that the world's largest hydrothermal ore deposit occurs in an F-rich silicic large igneous province. [ABSTRACT FROM AUTHOR]

This paper presents the initial results of a common methodology for the evaluation of damage produced by a flood. A model has been developed for flood damage estimation based on a geographic information system (GIS). It could be used by land administration bodies and insurance companies to manage flood-related damage data. The model simulates flood scenarios and evaluates expected economic losses from the impact of floodwaters on exposed elements, through the application of a computational model elaborated by GIS. During the development of the model, the Boesio Stream, a small watercourse flowing into Lake Maggiore (Lombardy, northern Italy) which was recently affected by a flash flood, was used as case study to test and calibrate the methodology. The method could be used either as a forecasting tool to define event scenarios, utilizing data from events simulated with a hydraulic model, or for real-time damage assessment after a disaster. The approach is suitable to large-area damage assessment and could be appropriate for land use planning, civil protection and risk mitigation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Nanlia and Makorongo prospects are classified as orogenic-type gold deposits. • Gold mineralization is associated with quartz veins hosted by amphibolite rocks. • The results suggest metamorphic origin of the mineralizing fluids. • The mineralization post-dated the peak of metamorphism of the host rocks. • Gold precipitation was caused mainly by fluid phase separation. Northern Mozambique hosts numerous occurrences of gold mineralization in metamorphic terranes, which are little known because of the insufficient studies. In this work, we describe the main geological and geochemical characteristics of the Nanlia and Makorongo gold prospects located in the Namuno district, northeastern Mozambique. We report the mode of occurrence of gold, petrography and mineralogy of the host rocks and ores, fluid inclusion characteristics and stable isotope data, to understand the genesis of gold mineralization in the study area. The gold mineralization in the Nanlia and Makorongo prospects is hosted by the Neoproterozoic Xixano Metamorphic Complex in the Mozambique Belt, which is composed of mafic granulite, amphibolite, paragneiss and marble. The host rock amphibolite consists mainly of amphibole, plagioclase, biotite and minor quartz, titanite and sulfides. The gold mineralization is associated with E-W to ENE-WSW trending quartz veins, oriented parallel to low angle to the foliation of the host rock amphibolite. The ore mineralogy consists of pyrite, pyrrhotite, chalcopyrite, magnetite, galena and sphalerite, with minor tellurides, xilingolite, electrum and native gold. Mineralized quartz veins in the Nanlia and Makorongo prospects host two types of fluid inclusions which locally coexist in the same assemblage: type 1, one-phase CO 2 inclusions with final melting temperature between −58 and −52 °C; and type 2, two-phase H 2 O + NaCl (±CO 2 ± N 2 ± CH 4) inclusions with homogenization temperature ranging from 246 to 370 °C and 239 to 382 °C in the Nanlia and Makorongo prospects, respectively, and salinity of 12–21 wt% NaCl eq. Pressure and temperature (P-T) conditions of ore-formation were estimated from fluid inclusions and sphalerite geobarometry at 420–620 °C and 160–280 MPa, and 330–440 °C and 150–200 MPa in the Nanlia and Makorongo prospects, respectively. The Nanlia and Makorongo gold prospects are classified as orogenic-type gold deposits. We suggest that gold mineralization was caused by an aqueous-carbonic fluid with low-moderate salinity originated by devolatilization during prograde metamorphism of underlying rocks. The gold mineralization post-dates the peak of metamorphism of the host rocks, thus formed during the retrograde metamorphism of the host rocks. The precipitation of gold in the Nanlia and Makorongo prospects was caused by fluid phase separation induced by pressure drop as the mineralizing fluid migrated to shallower depths. [ABSTRACT FROM AUTHOR]

• Authigenic δ 238 U of 2.9-3.07 Ga marine and lacustrine shales were measured. • Range of δ 238 U variation was wider than the unfractionated bulk silicate Earth. • δ 238 U fractionation for marine shales was caused by iron oxide shuttling. • δ 238 U fractionation for lacustrine shales was caused by partial reduction. • Oxygenic photosynthesis evolved half a billion years before the Great Oxidation Event. Oxidative weathering of continental rocks is the major source of redox-sensitive elements to the ocean. The timing for the initiation of oxidative weathering remains strongly debated. Here we report new δ 238 U data for the authigenic component of well-preserved ca. 3.07–2.90 Ga marine and lacustrine shales from the Mozaan and Dominion groups of the Kaapvaal Craton, South Africa. The δ 238 U auth values in marine shales (−0.71‰ to −0.21‰ relative to CRM 112a) are lower than the bulk silicate Earth (BSE, −0.40‰ to −0.17‰), while those of lacustrine shales (−0.68‰ to 0.05‰) scatter above and below the BSE range. In addition, the δ 238 U auth values of marine shales deposited in shallow seawater are significantly lower than those of the shales deposited in deep seawater. We propose that U(VI) was adsorbed onto Fe-Mn oxides in oxic shallow water and then shuttled to the seafloor. The U isotope fractionations in lacustrine shales are best explained by reduction of U(VI) to U(IV) below the sediment-water interface. Together, these observations bolster the case that a mildly oxidative weathering regime had been established at the Earth's surface by ∼3.0 Ga, paving the way to the onset of aerobic metabolism in both continental and shallow marine environments. [ABSTRACT FROM AUTHOR]

In this article the authors respond to criticism of their report, titled "The fluorine link between a supergiant ore deposit and a silicic large igneous province," that appeared in a 2011 issue of "Geology." Topics discussed include dissolution of rock fragments by hydrofluoric acid (HF), which the authors claim contributed to the formation of the Olympic Dam mineral deposit in Australia, evidence of fluorine (F)-rich Olympic Dam hydrothermal fluid, and breccia formation.

An abstract of the research paper "Prenatal Diagnosis of Trisomy 18 in Fetus With Only Bilateral Choroids Plexus Cysts" by G.M. Maruotti and colleagues is presented.