Evolution of a Porphyry-Cu Mineralized Magma System at Santa Rita, New Mexico (USA)

The magmatic processes leading to porphyry-Cu mineralization at Santa Rita are reconstructed on the basis of petrographic studies, thermobarometry, and laser-ablation inductively-coupled-plasma mass-spectrometry analyses of silicate melt and sulfide inclusions from dikes ranging from basaltic andesite to rhyodacite. Combined results suggest that magma evolution at Santa Rita is similar to that of sulfur-rich volcanoes situated above subduction zones, being characterized by repeated injection of hot, mafic magma into an anhydrite-bearing magma chamber of rhyodacitic composition. The most mafic end-member identified at Santa Rita is a shoshonitic basaltic andesite that crystallized at 1000-1050°C, 1-3 kbar and log fO2 = NNO + 0·7 to NNO + 1·0, whereas the rhyodacite crystallized at 730-760°C and log fO2 = NNO + 1·3 to NNO + 1·9. Mixing between the two magmas caused precipitation of 0·1-0·2 wt % magmatic sulfides and an associated decrease in the Cu content of the silicate melt from 300-500 ppm to less than 20 ppm. Quantitative modeling suggests that temporal storage of ore-metals in magmatic sulfides does not significantly enhance the amount of copper ultimately available to ore-forming hydrothermal fluids. Magmatic sulfides are therefore not vital to the formation of porphyry-Cu deposits, unless a mechanism is required that holds back ore-forming metals until late in the evolution of the volcanic-plutonic syste

Simultaneous cathodoluminescence hyperspectral imaging and X-ray microanalysis

A facility has been developed to acquire hyperspectral cathodoluminescence (CL) images simultaneously with X-ray composition data. Based around an electron microprobe, the system uses a built-in Cassegrain microscope to efficiently couple emitted light directly into the entrance slit of an optical spectrograph. A cooled array detector allows the parallel acquisition of CL spectra, which are then built up into a multidimensional data-cube containing the full set of spectrally- and spatially-resolved information for later analysis. This setup has the advantage of allowing wavelength-dispersive X-ray (WDX) data to be recorded concurrently, providing a powerful technique for the direct comparison of luminescent and compositional properties of materials. The combination of beam and sample scanning thus allows the correlation of composition and luminescence inhomogeneities on length scales ranging from a few cm to sub-micron

Scrotal and Penile Erythrodysesthesia Associated with Neoadjuvant Capecitabine Chemoradiation.

Capecitabine, a prodrug of fluorouracil, is a component of many chemotherapy regimens used to treat a wide variety of malignancies. One of the most common adverse reactions experienced by those who have been exposed to capecitabine is palmar-plantar erythrodysesthesia (PPE). PPE is a cutaneous manifestation of chemotherapy-related drug toxicity that has signs and symptoms of erythema, edema, pain, ulceration, or desquamation of the palms of the hands and soles of the feet. The signs and symptoms occur with varying severity. There are few reports of the genitalia being similarly affected. The following case describes a patient with locally advanced rectal cancer who experienced erythrodysesthesia secondary to a capecitabine-containing neoadjuvant chemoradiation regimen that primarily and most significantly involved the genitalia

Highly Refractory Peridotites on Macquarie Island and the Case for Anciently Depleted Domains in the Earth's Mantle

Macquarie Island (Southern Ocean) is a fragment of Miocene ocean crust and upper mantle formed at a slow-spreading ridge system, uplifted and currently exposed above sea-level. The crustal rocks on the island have unusually enriched compositions and the strong signature of an enriched source requires low overall degrees of melt depletion in the underlying mantle. Peridotites on the island, however, are highly refractory harzburgites that can be modeled as residues of >20-25% of near-fractional melting from which all the free clinopyroxene was melted out. The peridotites have some of the highest spinel Cr-numbers (0·40-0·49) and lowest orthopyroxene-core Al2O3 concentrations (2·7-3·0 wt %) reported so far for oceanic peridotites. The peridotites were subsequently modified by melt-rock reactions underneath the Miocene ridge system. The refractory character of the peridotites is inconsistent with the slow-spreading ridge setting as well as with the enriched character of the overlying crust, and must indicate a previous depletion event; the peridotites are not the source residue of the overlying ocean crust on Macquarie Island. Osmium isotopic compositions of peridotite samples are very unradiogenic (187Os/188Os = 0·1194-0·1229) compared with normal abyssal peridotites and indicate a long-lived rhenium depletion. Proterozoic rhenium-depletion ages indicate that these rocks have preserved a memory of an old mantle melting event. We argue that the Macquarie Island harzburgites are samples from an anciently depleted refractory mantle reservoir that may be globally important, but that is generally overlooked because of its sterility; that is, its inability to produce basalts. This reservoir may preserve key information about the history of the Earth's mantle as a whol

Changes in trauma-related emergency medical services during the COVID-19 lockdown in the Western Cape, South Africa

Abstract Background To limit virus spread during the COVID pandemic, extensive measures were implemented around the world. In South Africa, these restrictions included alcohol and movement restrictions, factors previously linked to injury burden in the country. Consequently, reports from many countries, including South Africa, have shown a reduction in trauma presentations related to these restrictions. However, only few studies and none from Africa focus on the impact of the pandemic restrictions on the Emergency Medical System (EMS). Methods We present a retrospective, observational longitudinal study including data from all ambulance transports of physical trauma cases collected during the period 2019–01-01 and 2021–02-28 from the Western Cape Government EMS in the Western Cape Province, South Africa (87,167 cases). Within this timeframe, the 35-days strictest lockdown level period was compared to a 35-days period prior to the lockdown and to the same 35-days period in 2019. Injury characteristics (intent, mechanism, and severity) and time were studied in detail. Ambulance transport volumes as well as ambulance response and on-scene time before and during the pandemic were compared. Significance between indicated periods was determined using Chi-square test. Results During the strictest lockdown period, presentations of trauma cases declined by > 50%. Ambulance transport volumes decreased for all injury mechanisms and proportions changed. The share of assaults and traffic injuries decreased by 6% and 8%, respectively, while accidental injuries increased by 5%. The proportion of self-inflicted injuries increased by 5%. Studies of injury time showed an increased share of injuries during day shift and a reduction of total injury volume during the weekend during the lockdown. Median response- and on-scene time remained stable in the time-periods studied. Conclusion This is one of the first reports on the influence of COVID-19 related restrictions on EMS, and the first in South Africa. We report a decline in trauma related ambulance transport volumes in the Western Cape Province as well as changes in injury patterns, largely corresponding to previous findings from hospital settings in South Africa. The unchanged response and on-scene times indicate a well-functioning EMS despite pandemic challenges. More studies are needed, especially disaggregating the different restrictions

Anisotropy of magnetic susceptibility in alkali feldspar and plagioclase

Feldspars are the most abundant rock-forming minerals in the Earth’s crust, but their magnetic properties have not been rigorously studied. This work focuses on the intrinsic magnetic anisotropy of 31 feldspar samples with various chemical compositions. Because feldspar is often twinned or shows exsolution textures, measurements were performed on twinned and exsolved samples as well as single crystals. The anisotropy is controlled by the diamagnetic susceptibility and displays a consistent orientation of principal susceptibility axes; the most negative or minimum susceptibility is parallel to [010], and the maximum (least negative) is close to the crystallographic [001] axis. However, the magnetic anisotropy is weak when compared to other rock-forming minerals, 1.53 × 10−9 m3 kg−1 at maximum. Therefore, lower abundance minerals, such as augite, hornblende or biotite, often dominate the bulk paramagnetic anisotropy of a rock. Ferromagnetic anisotropy is not significant in most samples. In the few samples that do show ferromagnetic anisotropy, the principal susceptibility directions of the ferromagnetic subfabric do not display a systematic orientation with respect to the feldspar lattice. These results suggest that palaeointensity estimates of the geomagnetic field made on single crystals of feldspar will not be affected by a systematic orientation of the ferromagnetic inclusions within the feldspar lattice

Magnetite solubility and iron transport in magmatic-hydrothermal environments

Abstract-We have examined the effect of pressure on the apparent equilibrium constant, K=, for magnetite solubility (Fe 3 O 4 mt ϩ 6HCl fluid ϩ H 2 fluid ϭ 3FeCl 2 fluid ϩ 4H 2 O fluid ) and the relative iron-carrying capacities of magmatic vapor and brine by conducting experiments in a rhyolite melt-vapor-brine-magnetite system at 800°C, f O 2 ϭ NNO and pressures ranging from 100 to 145 MPa. Iron concentrations in synthetic vapor and brine fluid inclusions were quantified by using laser-ablation inductively-coupled-plasma-mass-spectrometry (LA-ICPMS). Hydrogen chloride (HCl) concentrations in magmatic vapor were inferred by potentiometric measurements of H ϩ in quenched run product fluids. These data yield calculated values for log K=, assuming a H 2 O ϭ X H 2 O , of 1.7, 4.9, 6.2, 6.8 and 9.1 at 100, 110, 130, 140 and 145 MPa, respectively. The concentration of iron in magmatic vapor increases by an order of magnitude, whereas the concentration of iron in magmatic brine remains constant (within 1) with increasing pressure as the 800°C critical pressure is approached along the vapor-brine solvus. The concentrations of iron in vapor and brine fluid inclusions yield calculated partition coefficients (D Fe v/b ) of 0.05, 0.14, 0.27 and 0.56 at 110, 130, 140 and 145 MPa, respectively. Our data reveal that pressure fluctuations may significantly affect the value of log K=. More importantly, the data demonstrate conclusively that a significant amount of iron can be transported by a low-density aqueous vapor in the magmatic-hydrothermal environment

Effect of starvation and temperature on gonad development of baby clam, Marcia opima (Gmelin)

For studying the influence of feed and temperature on gonad growth and maturity of the baby clam Marcia opima, experiments were conducted for 45 days at temperatures of 23°C and 28°C. The progress of gonadal recovery was followed by periodic determination of gonadosomatic index, condition index, digestive gland index and oocyte diameter. There was significant difference in the gonadosomatic index between fed and unfed clams at 23°C and 28°C. No significant difference in the gonadosomatic index was noted in the fed treatments at 23°C and 28°C, but the time of conditioning had significant influence on the gonadosomatic index. A significant relationship was found between the gonadosomatic index and condition index of the clams in all the treatment

Behavior and Impact of Zirconium in the Soil–Plant System: Plant Uptake and Phytotoxicity

Because of the large number of sites they pollute, toxic metals that contaminate terrestrial ecosystems are increasingly of environmental and sanitary concern (Uzu et al. 2010, 2011; Shahid et al. 2011a, b, 2012a). Among such metals is zirconium (Zr), which has the atomic number 40 and is a transition metal that resembles titanium in physical and chemical properties (Zaccone et al. 2008). Zr is widely used in many chemical industry processes and in nuclear reactors (Sandoval et al. 2011; Kamal et al. 2011), owing to its useful properties like hardness, corrosion-resistance and permeable to neutrons (Mushtaq 2012). Hence, the recent increased use of Zr by industry, and the occurrence of the Chernobyl and Fukashima catastrophe have enhanced environmental levels in soil and waters (Yirchenko and Agapkina 1993; Mosulishvili et al. 1994 ; Kruglov et al. 1996)