Carbonate alteration of ophiolitic rocks in the Arabian–Nubian Shield of Egypt: sources and compositions of the carbonating fluid and implications for the formation of Au deposits

Ultramafic portions of ophiolitic fragments in the Arabian–Nubian Shield (ANS) show pervasive carbonate alteration forming various degrees of carbonated serpentinites and listvenitic rocks. Notwithstanding the extent of the alteration, little is known about the processes that caused it, the source of the CO2 or the conditions of alteration. This study investigates the mineralogy, stable (O, C) and radiogenic (Sr) isotope composition, and geochemistry of suites of variably carbonate altered ultramafics from the Meatiq area of the Central Eastern Desert (CED) of Egypt. The samples investigated include least-altered lizardite (Lz) serpentinites, antigorite (Atg) serpentinites and listvenitic rocks with associated carbonate and quartz veins. The C, O and Sr isotopes of the vein samples cluster between −8.1‰ and −6.8‰ for δ13C, +6.4‰ and +10.5‰ for δ18O, and 87Sr/86Sr of 0.7028–0.70344, and plot within the depleted mantle compositional field. The serpentinites isotopic compositions plot on a mixing trend between the depleted-mantle and sedimentary carbonate fields. The carbonate veins contain abundant carbonic (CO2±CH4±N2) and aqueous-carbonic (H2O-NaCl-CO2±CH4±N2) low salinity fluid, with trapping conditions of 270–300°C and 0.7–1.1 kbar. The serpentinites are enriched in Au, As, S and other fluid-mobile elements relative to primitive and depleted mantle. The extensively carbonated Atg-serpentinites contain significantly lower concentrations of these elements than the Lz-serpentinites suggesting that they were depleted during carbonate alteration. Fluid inclusion and stable isotope compositions of Au deposits in the CED are similar to those from the carbonate veins investigated in the study and we suggest that carbonation of ANS ophiolitic rocks due to influx of mantle-derived CO2-bearing fluids caused break down of Au-bearing minerals such as pentlandite, releasing Au and S to the hydrothermal fluids that later formed the Au-deposits. This is the first time that gold has been observed to be remobilized from rocks during the lizardite–antigorite transition

Getting shot of elves: healing, witchcraft and fairies in the Scottish witchcraft trials

This paper re-examines the evidence of the Scottish witchcraft trials for beliefs associated by scholars with "elf-shot." Some supposed evidence for elf-shot is dismissed, but other material illuminates the interplay between illness, healing and fairy-lore in early modern Scotland, and the relationship of these beliefs to witchcraft itself

Franchises lost and gained: post-coloniality and the development of women’s rights in Canada

The Canadian constitution is to some extent characterised by its focus on equality, and in particular gender equality. This development of women’s rights in Canada and the greater engagement of women as political actors is often presented as a steady linear process, moving forwards from post-enlightenment modernity. This article seeks to disturb this ‘discourse of the continuous,’ by using an analysis of the pre-confederation history of suffrage in Canada to both refute a simplistic linear view of women’s rights development and to argue for recognition of the Indigenous contribution to the history of women’s rights in Canada. The gain of franchise and suffrage movements in Canada in the late nineteenth and early twentieth century are, rightly, the focus of considerable study (Pauker 2015), This article takes an alternative perspective. Instead, it examines the exercise of earlier franchises in pre-confederation Canada. In particular it analyses why franchise was exercised more widely in Lower Canada and relates this to the context of the removal of franchises from women prior to confederation

Addressing Criticisms of Large-Scale Marine Protected Areas

Designated large-scale marine protected areas (LSMPAs, 100,000 or more square kilometers) constitute over two-thirds of the approximately 6.6% of the ocean and approximately 14.5% of the exclusive economic zones within marine protected areas. Although LSMPAs have received support among scientists and conservation bodies for wilderness protection, regional ecological connectivity, and improving resilience to climate change, there are also concerns. We identified 10 common criticisms of LSMPAs along three themes: (1) placement, governance, and management; (2) political expediency; and (3) social–ecological value and cost. Through critical evaluation of scientific evidence, we discuss the value, achievements, challenges, and potential of LSMPAs in these arenas. We conclude that although some criticisms are valid and need addressing, none pertain exclusively to LSMPAs, and many involve challenges ubiquitous in management. We argue that LSMPAs are an important component of a diversified management portfolio that tempers potential losses, hedges against uncertainty, and enhances the probability of achieving sustainably managed oceans

The search for tensor interactions in the beta-decay of polarized ⁸⁰Rb

The spin polarized nuclear recoil asymmetry from β emission is nearly zero in the standard model. This observable is sensitive to tensor interactions which exist in certain standard model extensions. The nuclear recoil energy is very small (a few eV) and therefore requires a sensitively controlled environment for measurement, the TRINAT atom trap provides such an environment. Rudidium-80 is an unstable isotope which β-decays (positron emission or electron capture) with a half life of 30s. It is produced in large quantities at the ISAC facility located in TRIUMF. This isotope offers favorable nuclear and atomic properties for measurement in the TRINAT apparatus. Rubidium-80 is trapped in a vacuum by lasers combined with a magnetic field, and polarized with another laser. When the trapped Rubidium decays the sudden change of nuclear charge typically ejects a few low energy atomic electrons leaving a positive ion. An electric field accelerates the ions towards a position sensitive microchannel plate and the electrons to another microchannel plate. The direction of polarization is parallel to the plates surface, so an asymmetry manifests itself as a difference in the distribution of ion impacts when the polarization is inverted. The ion time of flight is used to discriminate between positron emission and electron capture events. This discrimination is required since electron capture has a large asymmetry in the standard model which would overwhelm the desired observable. There is a small polarization asymmetry expected to occur even within the standard model due to "recoil order" corrections to the V-A theory. Since these "recoil order" corrections have yet to be theoretically calculated, they are left as fit parameters. Unfortunately the data is statistically insufficient to fit both the "recoil order" corrections and the tensor couplings simultaneously. However, if the "recoil order" corrections are fixed to a crude theoretical estimate a fit for tensor couplings sets limits consistent with zero and complementary to other experimental results, namely nuclear recoils in He-6 and positron-polarization from C-10. Theoretical limits based on neutrino mass and naturalness arguments remain more restrictive at this time.Science, Faculty ofPhysics and Astronomy, Department ofGraduat

A lithological context for stratabound REE mineralisation at the birthplace of REE – Bastnäs, Riddarhyttan, Sweden

The Bastnäs ore field, in central Sweden, is the cradle of the rare earth elements (REE). It is the place of the discovery of several REE and important REE-minerals (e.g., Bastnäsite one of the primary REE-ore minerals). In recent years there has been an increased interest due to rising demand of REE for technological applications. Several recent studies have focused on the mineralogy and geochemistry but a lack of fresh in situ samples has meant that textural and stratigraphic relationships are not as well described. Recent exploration in the area has produced drill core traverses across the host stratigraphy of the Bastnäs deposit, allowing the collection of relatively fresh in situ samples which can be placed in lithological context. Here we present new mineralogical and textural information linked to the lithology indicating that the REE-mineralisation in Bastnäs is commonly associated with magnetite skarn and that it occurs over a wide range of stratigraphic levelsISBN for host publication: 978-2-8399-4046-7</p

A lithological context for stratabound REE mineralisation at the birthplace of REE – Bastnäs, Riddarhyttan, Sweden

The Bastnäs ore field, in central Sweden, is the cradle of the rare earth elements (REE). It is the place of the discovery of several REE and important REE-minerals (e.g., Bastnäsite one of the primary REE-ore minerals). In recent years there has been an increased interest due to rising demand of REE for technological applications. Several recent studies have focused on the mineralogy and geochemistry but a lack of fresh in situ samples has meant that textural and stratigraphic relationships are not as well described. Recent exploration in the area has produced drill core traverses across the host stratigraphy of the Bastnäs deposit, allowing the collection of relatively fresh in situ samples which can be placed in lithological context. Here we present new mineralogical and textural information linked to the lithology indicating that the REE-mineralisation in Bastnäs is commonly associated with magnetite skarn and that it occurs over a wide range of stratigraphic levelsISBN for host publication: 978-2-8399-4046-7</p