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Bedded barite, Fe-Zn-Pb sulfides, carbonates, and cherts within Ediacaran (Dalradian Supergroup) graphitic metasediments near Aberfeldy in Scotland have previously been interpreted as chemical sediments precipitated from hydrothermal fluids episodically exhaled into marine basins filled with organic-rich mud, silt, and sand. Lithological variation and compositional diversity in pyrite and sphalerite reflect varied redox environments and proximity to hydrothermal discharges. Thick beds (>2 m) of barite have relatively uniform δ34S of +36 ± 1.5‰, considered to represent contemporaneous seawater sulfate, as negative Δ17O indicates incorporation of atmospheric oxygen during precipitation in the water column. However, certain features suggest that diagenetic processes involving microbial sulfate reduction modified the mineralogy and isotopic composition of the mineralization. Barite bed margins show decimeter-scale variation in δ34S (+32 to +41‰) and δ18O (+8 to +21‰), attributed to fluid-mediated transfer of dissolved barium and sulfate between originally porous barite and adjacent sediments, in which millimetric sulfate crystals grew across sedimentary lamination. Encapsulated micron-sized barium carbonates indicate early diagenetic barite dissolution with incorporation of sulfur into pyrite, elevating pyrite δ34S. Subsequently, sulfidation reactions produced volumetrically minor secondary barite with δ34S of +16 to +22‰. Overall, these processes affected small volumes of the mineralization, which originally formed on the seafloor as a classic SEDEX deposit. [ABSTRACT FROM AUTHOR]

To characterize the source and effects of bacterial communities on corrosion of intertidal structures, three different UK coastal sites were sampled for corrosion materials, sediment and seawater. Chemical analyses indicate the activity of sulfate‐reducing microbes (SRBs) at 2 sites (Shoreham and Newhaven), but not at the third (Southend‐on‐Sea). Microbial communities in the deep sediment and corrosion samples are similar. The phylum Proteobacteria is dominant (40.4% of the total ASV), followed by Campilobacterota (11.3%), Desulfobacterota and Firmicutes (4%–5%). At lower taxonomic levels, corrosion causing bacteria, such as Shewanella sp. (6%), Colwellia sp. (7%) and Mariprofundus sp. (1%), are present. At Southend‐on‐sea, the relative abundance of Campilobacterota is higher compared to the other two sites. The mechanism of action of microorganisms at Shoreham and Newhaven involves biogenic sulfuric acid corrosion of iron by the combined action of SRBs and sulfur‐oxidizing microbes. However, at Southend‐on‐sea, sulfur compounds are not implicated in corrosion, but SRBs and other electroactive microbes may play a role in which cathodic reactions (electrical MIC) and microbial enzymes (chemical MIC) are involved. To contribute to diagnosis of accelerated intertidal corrosion types, we developed a rapid identification method for SRBs using quantitative polymerase chain reaction high‐resolution melt curve analysis of the dsrB gene. [ABSTRACT FROM AUTHOR]

Aynak is the largest known copper deposit in Afghanistan, with indicated resources of 240 Mt grading 2.3% Cu placing it in the 'giant' category. Host rocks are Neoproterozoic metasediments comprising dolomitic marble, carbonaceous quartz schist and quartz-biotite-dolomite schist containing garnet, scapolite and apatite. Chalcopyrite and bornite dominate the hypogene ore with lesser pyrite, pyrrhotite, cobaltite and chalcocite, and rare sphalerite, molybdenite, uraninite and barite. Sulphides occur as bedding-parallel laminae, disseminations, metamorphic segregations and crosscutting veins. Sulphide δ34S ratios range –14.5 to +17.3‰ in bedded and disseminated sulphides (n = 34). This broad range favours biogenic reduction of seawater sulphate as a major source of sulphur, although thermochemical reduction processes are not precluded. The narrower δ34S range of –6 to +12.2‰ in vein and segregation sulphides (n = 21) suggests localized redistribution and partial homogenization during metamorphism. Geochemical associations suggest that Al, P, Ca, Ti and Fe were primary sedimentary constituents whereas Cu, Mg, S, Se, As, Co and Bi were introduced subsequently. We infer that Aynak originated as a shale- and carbonate-hosted stratabound replacement deposit, resembling orebodies of the Central African Copperbelt, although underlying red-beds are absent at Aynak and mafic volcanics were the probable copper source. These giant deposits formed worldwide in the Cryogenian probably due to marine enrichment in copper, magnesium and sulphate coincident with profuse basaltic volcanism and ocean oxidation. [ABSTRACT FROM AUTHOR]

Archaeological science and field investigations are making greater use of multi-element geochemical survey as a tool for site prospection and intra-excavation analysis. This increasing use of geochemical survey is allowing a new field of geoprospection to develop, a technique that has specific relevance to the investigation of sites containing archaeometallurgical evidence, due to the high geochemical loadings within archaeological contexts produced from past metalworking activities. Correspondingly, there have been relatively few published examples that compare the results of geochemical surveys against excavation data. This study reports the use of geochemical data to investigate a multi-period mining site-scape at Alderley Edge, Cheshire, UK. The geochemical data is analysed using principle component analysis, which facilitates the identification of a number of geochemical anomalies. The site taphonomy and stratigraphic evolution of this mining site-scape is complex, with naturally occurring areas of lead and copper mineralization and a history of exploitation since the early Bronze Age. The geochemical anomalies were compared to the results of excavation within the survey area and this combination of excavation and prospection data allowed the reasons for the different geochemical anomalies to be explained. The article highlights the potential of using multi-element geochemical survey to investigate sites containing archaeometallurgical remains and provides a discussion of why context specificity is essential to correctly interpret multi-element geochemical data. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

As Roy says in his Preface, the book is as much about Sir Arthur's collection as it is about his long life and family - he held the hereditary title of 6 SP th sp Baronet of Swallowfield in Berkshire. At this point the book seems to abruptly change tack as chapter 5 is about goniometry and crystal drawing, a long-lost skill in which Sir Arthur was accomplished. Short chapters outline Arthur's unpublished work including notes on Britain's antimony mines and gold occurrences, and catalogue the "Russell Archive" of paper-format documentation. [Extracted from the article]