Later prehistoric settlement in Cornwall and the Isles of Scillyreports on the excavation between 1996 and 2014 of five later prehistoric and Roman period settlements. All the sites were ...multi-phased, revealing similar and contrasting occupational patterns stretching from the Bronze Age into the Iron Age and beyond.
This article is centred around a detailed review of D.H. Frost’s new (2023) critical edition and translation of the Cornish and Latin text Sacrament an Alter, in both its theological/historical and ...its philological/linguistic aspects. First, Dr Frost’s exposition of his text’s remarkable background is placed against the constantly changing character of official Tudor ideology, and the ecclesiological lens through which he views his material discussed. Points from his linguistic analysis (including revivalist reconstructions) are then examined and, prompted by Frost’s portrayal of the state of Cornish-language literacy in the last quarter of the sixteenth century, similarities are adduced with the known situation of near-contemporary Manx Gaelic. Traditional Cornish went into ultimately terminal decline, but Manx went on to receive both the Prayer Book and the Bible in translation; Cornwall’s disadvantage in not constituting a diocese in its own right is suggested as a significant factor in the contrasting fates of the two small Celtic languages in question. Finally, attention is drawn to the potentially striking efficacy of small networks of dedicated scholars, whatever their time and place.
Microplastics (plastic particles, 0.1 μm–5 mm in size) are widespread marine pollutants, accumulating in benthic sediments and shorelines the world over. To gain a clearer understanding of ...microplastic availability to marine life, and the risks they pose to the health of benthic communities, ecological processes and food security, it is important to obtain accurate measures of microplastic abundance in marine sediments. To date, methods for extracting microplastics from marine sediments have been disadvantaged by complexity, expense, low extraction efficiencies and incompatibility with very fine sediments.
Here we present a new, portable method to separate microplastics from sediments of differing types, using the principle of density floatation. The Sediment-Microplastic Isolation (SMI) unit is a custom-built apparatus which consistently extracted microplastics from sediments in a single step, with a mean efficiency of 95.8% (±SE 1.6%; min 70%, max 100%). Zinc chloride, at a density of 1.5 g cm−3, was deemed an effective and relatively inexpensive floatation media, allowing fine sediment to settle whilst simultaneously enabling floatation of dense polymers. The method was validated by artificially spiking sediment with low and high density microplastics, and its environmental relevance was further tested by extracting plastics present in natural sediment samples from sites ranging in sediment type; fine silt/clay (mean size 10.25 ± SD 3.02 μm) to coarse sand (mean size 149.3 ± SD 49.9 μm). The method presented here is cheap, reproducible and is easily portable, lending itself for use in the laboratory and in the field, eg. on board research vessels. By employing this method, accurate estimates of microplastic type, distribution and abundance in natural sediments can be achieved, with the potential to further our understanding of the availability of microplastics to benthic organisms.
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•Cheap, effective method for microplastic extraction from sediments.•High, reproducible recovery rates - 95.8%.•Comparison of three commonly used floatation media.•Zinc chloride (1.5 g cm−3) deemed an effective floatation medium.•Method applied to environmental samples across a range of sediment types.
We present a simple, portable method to extract microplastics from natural sediments of different grain size using zinc chloride density floatation, yielding accurate and reproducible results.
About 85% of all historically mined tin of about 27 million tonnes Sn is from a few tin ore provinces within larger granite belts. These are, in decreasing importance, Southeast Asia (Indonesia, ...Malaysia, Thailand, Myanmar), South China, the Central Andes (Bolivia, southern Peru) and Cornwall, UK. Primary tin ore deposits are part of magmatic-hydrothermal systems invariably related to late granite phases (tin granites, pegmatites, tin porphyries), and may become dispersed by exogenic processes and then eventually form placer deposits within a few km from their primary source, due to the density of cassiterite, its hardness and chemical stability. Alluvial placer deposits were usually the starting point for tin mining, and have provided at least half of all tin mined. The small-volume and late granite phases in spatial, temporal and chemical relationship to tin ore deposits are highly fractionated. Systematic element distribution patterns in these granite phases and their associated much larger multiphase granite systems suggest fractional crystallization as the main petrogenetic process controlling magmatic evolution and magmatic tin enrichment. Oxidation state controls the bulk tin distribution coefficient, with low oxidation state favoring incompatible behavior of divalent tin. Low oxidation state is also mineralogically expressed by accessory ilmenite (FeO TiO2) as opposed to accessory magnetite (FeO Fe2O3) in more oxidized melt systems. This difference in the accessory mineralogy and hence metallogenic potential (tin-bearing ilmenite-series versus barren magnetite-series granites), can be easily detected in the field by a hand-held magnetic susceptibility meter. The hydrothermal system is a continuation of the magmatic evolution trend and necessary consequence of the crystallization of a hydrous melt. The exsolved highly saline aqueous fluid phase, enriched in boron and/or fluorine plus a wide metal spectrum, can be accomodated and stored by the intergranular space in crystallized melt portions, or accumulate in larger physical domains, accompanied by focused release of mechanical energy (brecciation, vein formation), dependent on emplacement depth (pressure). The hydrothermal mobility of tin is largely as Sn2+-chloride complexes; the precipitation of tin as cassiterite involves oxidation. Tin typically characterizes the inner high-temperature part of much larger km-sized zoned magmatic-hydrothermal systems with the chemical signature Sn-W-Cu-As-Bi in the inner part (greisen, vein/stockwork/breccia systems, skarn) and a broader halo with vein- or replacement-style Pb-Zn-Ag-Sb-Au-U mineralization of lower temperature. This zoning pattern may also occur telescoped on each other. Active continental margins are the favorable site for both copper (−gold) and tin (−tungsten) systems. However, the narrowly segmented metal endowment and the episodic nature of ore formation suggest additional controls. These are the build-up of a subduction-derived metal and fluid inventory in the lower continental crust by flat-slab subduction (very little magmatism) for copper‑gold in the main arc, followed by large-scale intracrustal melting during mantle upwelling in the back arc for tin (chemically reduced reservoir rocks) and/or tungsten mineralization (less sensitive to oxidation state).
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•Tin granites display advanced degree of fractionation•Tin granites are of ilmenite series (reduced), irrespective of S-, I-, or A-type affinity•Hydrothermal tin solubility is optimal under reducing and highly saline conditions•Hydrothermal tin ore formation requires oxidation, fluid mixing, cooling
Historical mining of uranium mineral veins within Cornwall, England, has resulted in a significant amount of legacy radiological contamination spread across numerous long disused mining sites. ...Factors including the poorly documented and aged condition of these sites as well as the highly localised nature of radioactivity limit the success of traditional survey methods. A newly developed terrain-independent unmanned aerial system UAS carrying an integrated gamma radiation mapping unit was used for the radiological characterisation of a single legacy mining site. Using this instrument to produce high-spatial-resolution maps, it was possible to determine the radiologically contaminated land areas and to rapidly identify and quantify the degree of contamination and its isotopic nature. The instrument was demonstrated to be a viable tool for the characterisation of similar sites worldwide.
•We provide a high spatial resolution radiation map of a legacy uranium mining site.•We use a terrain independent UAS to provide the mapping.•Data is favourably comparable with ground-based radiation mapping.•The improved spatial resolution will increase the quality of future aerial surveys.
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