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The Petrology Workspace and Database (PWD; https://petro.wovodat.org) is a web‐based data repository and interface that allows researchers to access, share, store, and manage petrological, mineralogical, and whole rock data in a contextualized manner. The uniqueness of the PWD is that it links images to different types of images and to compositional data providing a powerful visualization and framework of information at a wide range of scales, from the meter‐sized outcrop to a few micrometers of a thin rock section. The PWD archives various data types and formats, and it includes multilevel data sets with an interactive online interface. The database is linked with other databases for volcanic eruptions (Smithsonian' Global Volcanism Program (GVP)) and for whole rock chemistry (EarthChem). The tool has four main features: (1) storage and management of spatial‐referenced data (e.g., from fieldwork notes to lab geochemical analysis); (2) a hierarchical relationship between different types of data using the Workspace interactive tool; (3) graph plots to visualize the data; and (4) the possibility of data sharing in a database structure that is managed by authorization levels. The PWD is a practical and efficient database management system that facilitates effective contextualized data preservation and sharing among scientists. It also can serve as a Data Management Plan and provide a framework for auditing research integrity both of which are becoming the new standards of most funding agencies and journals.©2019. The Authors. Plain Language Summary: The Petrology Workspace and Database is an online and standalone interactive data repository that allows management and visualization of a wide range of petrological and geochemical rock information. Users can organize many different data types at different scales into tree‐like structures. The system allows creation of links reflecting the spatial context between data that is critical for correct interpretation of the information. The Petrology Workspace and Database can serve as a Data Management Plan and provides a framework for auditing of research integrity. Key Points: The Petrology Workspace and Database (PWD) offers an online interactive data repository for the management and visualization of multilevel data setsThe Workspace tool allows to organize data into tree‐like structures, useful for the spatial context of data at different scales. Plotting tools are also availableThe PWD aims to provide an interactive data repository that facilitates data transparency, effective data communication, and sharing [ABSTRACT FROM AUTHOR]

Analyses of the zircon U—Pb age, mineralogical chemistry and whole-rock geochemistry of the Jiling pluton along the southern margin of the Alxa Block were conducted. The results of these analyses will provide crucial information for investigations of Paleozoic crust-mantle interactions in the North Qilian Orogenic Belt (NQOB) and explorations of the transition age from a compressional to extensional environment during the collision between the Alxa Block and the Qilian-Qaidam Block. The zircon dating results reveal that the Jiling pluton is composed of Early Silurian granitoids (435–442 Ma) with contemporaneous mafic microgranular enclaves (MMEs). Most granitoids contain amphibole and titanite and have A/CNK values <1, illustrating that they belong to amphibolite-rich calc-alkaline granitoids (ACGs) and K-rich and K-feldspar porphyritic calc-alkaline granitoids (KCGs). Both the granitoid and MME samples display variable initial Sr and Nd isotopic compositions. We suggest that the Jiling pluton was formed by crust-mantle-derived magma mixing. The high HFSE content of the MMEs indicates that the mantle-derived magmas were derived from melting of the mantle wedge metasomatized by adakitic magma, and the crustal-derived magmas were derived from melting of Paleoproterozoic meta-basaltic rocks in the Longshoushan Group. The discovery of the Jiling granitoids indicates that the NQOB was dominated by a compressional environment during Middle Ordovician-Early Silurian in response to the collision between the Qilian-Qaidam Block and the Alxa Block, and the initial extensional environment began before 442 Ma. • The Jiling granitoids and MMEs were emplaced at Early Silurian (442–435 Ma). • The Jiling granitoids were formed by crustal-mantle-derived magma mixing. • Transition from compression to extensional environment started before 442 Ma in the NQOB. [ABSTRACT FROM AUTHOR]

Zisha stoneware is a distinctive pottery tradition unique to China. This ceramic tradition was highly popularized during the Ming Dynasty (1368–1644 CE), and continues to be manufactured through the present day. Throughout history, Zisha stoneware vessels have been highly desirable objects used mainly by high status individuals, and by the early 17th century was exported to Europe as trade items. Soon thereafter, European imitations of Zisha stonewares were produced in the Netherlands at Delft, and in England and Germany. Today, authentic Zisha wares are difficult to discern from imitations using the naked eye alone, which poses problems for provenance, authenticity of antiquities, and reconstructing ancient ceramic technologies developed in China. The goal of this study was to determine the elemental and mineralogical properties of Zisha clays and to evaluate their suitability for archaeological provenance study. This study used petrographic thin-section analysis and neutron activation analysis to characterize multiple distinct types of Zisha clays, as well as other regional clays, from deposits around Huanglong Mountain (Yixing City, China). Representative samples of each clay type were sub-divided into untreated raw clays and processed and fired ceramics for comparison. The results show clays from each major collection area have unique compositional signatures based on their trace element chemistries and mineralogical properties. Additionally, those characteristics are stable and not significantly altered by preparation or firing processes. We propose that Zisha clays have high potential for archaeological provenance studies of Zisha stoneware antiquities. • Zisha stoneware is representative of cultural heritage in China • Clay samples measured using neutron activation analysis (NAA) • Geochemical characteristics examined by statistical analysis • Comparison between fired samples and raw clay materials provides reliable provenance information [ABSTRACT FROM AUTHOR]

The Paraná deposit, located at Southwestern Rio Grande do Norte state, in Brazil, is one of the few emerald deposits found at Borborema Province. The mineralization occurs in phlogopite schists and actinolite-phlogopite schists associated with pegmatites and albitites within the Portalegre Shear Zone. Unlike other well-known Brazilian emerald deposits, the mineralogy of Paraná emeralds has remained poorly investigated for the last 40 years. In this study, we conducted mineralogical characterization of theses emeralds through gemological testing, mineral chemistry, absorption and reflectance spectroscopy, and thermal analysis. The Paraná emeralds are bluish-green colored, characterized by high refractive index, several two-phase fluid inclusions and mica is the main mineral inclusion. Electron probe microanalysis and laser ablation-inductively coupled plasma-mass spectrometry analyses detected the presence of Fe2+ (0.43-1.94 wt.% FeO) and Cr3+ (0.04-0.14 wt.% Cr2O3) as the main chromophores replacing octahedral Al3+ in the crystal structure. In addition, substantial amounts of MgO (0.40-2.72 wt.%), Na2O (0.50-1.81 wt.%), and Cs2O (0.07-0.44 wt.%) were also identified. The main causes for its coloration were attributed to Cr3+ absorption features in visible spectral range, which were corroborated by absorption and reflectance spectra. The presence of types I and II H2O at channel-sites was recorded in Fourier-transform infrared spectra and demonstrated by dehydration processes observed in different thermal and thermogravimetric analyses. [ABSTRACT FROM AUTHOR]

Highlights • A new optical pathway was developed for images acquisition in the UV-band (365 nm). • Multispectral images analysis is proven to differentiate six various sulfides. • Six common sulfides were automatically identified and quantified by cluster analysis. • Procedures can be developed for sulfides quantification by optical microscopy. Abstract The mining industry needs effective techniques to meet the future challenges of resources extraction. As the deposits become more and more complex, a very good knowledge of an orebody is necessary. Mineralogical characterization is an essential contribution to improve the knowledge on the ore and wastes for a given mining project. It could bring major advances in ore extraction, mineral processing, and integrated waste management. However, mineralogical analyses can be very tedious, when done manually. Consequently, automated mineralogy was developed during the last three decades to improve the rapidity of mineralogical characterization, so that mineralogical information can be routinely obtained. Nowadays, the systems commonly used are based on expensive equipment including scanning electron microscopes (SEM) with energy dispersive X-ray analyzers (EDX). Optical Microscopy (OM) is neglected, although this route can provide reliable and quick results, yet cheaper. In this study, the possibility of using optical microscopy in reflected light mode to automatically characterize opaque minerals is explored. The identification and quantification of six common sulfides from polymetallic ores (arsenopyrite, chalcopyrite, galena, pyrite, pyrrhotite, and sphalerite) were automatically accomplished on a polished section by optical microscopy. Six spectral images were acquired for multispectral image analysis. Five of them were acquired under a white light source, equipped with four different excitation filters (436 nm, 480 nm, 605 nm, and 650 nm). The sixth image was acquired under an UV-light source at 365 nm, after modifying the optical pathway to detect the reflectance of the minerals in the UV-spectrum without changing the acquiring camera. Two image analysis software solutions were then tested to automatically classify and quantify the six sulfide minerals. The classification was systematically done on the acquired multispectral images by grey thresholding with the Clemex Vision PE® software. The GOCAD® software used principal component analysis (PCA) analysis and a supervised K-means clustering method to classify the minerals. Then, the obtained results were compared to the SEM-EDS quantification, considered here as the reference. The differences between the computed surface areas were mainly due to the artifacts of the polished sections preparation. The two software solutions present promising results and could be fully exploited to proceed to other mineralogical analyses, such as mineral liberation, mineral associations, textures identification, and particle size distribution. This study is an initial step towards differentiate and identify sulfides via an optical route arguably reliable and cheaper to characterize mine products. [ABSTRACT FROM AUTHOR]

Abstract The Belessa kaolin deposit in the western margin of the Central Main Ethiopian Rift was studied using geological, mineralogical, chemical and physical methods to understand its genesis and evaluate its potential suitability for different industrial applications. X-ray diffraction and Scanning Electron Microscopy were used to establish the mineralogical composition. Bulk chemical compositions were determined using ICP-MS and ICP-AES. The geology of the kaolin district is comprised of Miocene to Quaternary age rhyolite and pyroclastic tuff. The kaolin occurrence is located in the central part of the study area and is associated with rhyolite. The host rock is composed of quartz and alkali feldspar phenocrsyts set in a groundmass of very fine grained quartz, alkali-feldspar and plagioclase. The rhyolite is partially to completely altered to kaolin. The kaolin deposit is composed predominantly of kaolinite and quartz. The kaolinite minerals of the deposit have high structural order. The geological, mineralogical and geochemical studies indicate that supergene alteration played a major role in the formation of the Belessa kaolin deposit. The absence of quartz veining and alteration zones containing high temperature minerals precludes significant hypogene alteration. The Chemical Index of Alteration (CIA) and Chemical Index of Weathering (CIW) also show that the host rock experienced strong alteration and weathering. Furthermore, high Ce+Y+La values correspond to supergene-type alteration. The low P and high Cr+Nb concentrations also support a supergene origin. The physical properties, chemistry, mineralogy and crystal morphology indicate that the Belessa kaolin has potential applications for paper coating, filler (in paper, rubber, plastic and paint), ceramics, pharmaceuticals and cosmetics. Highlights • We investigated the Belessa kaolin deposit of Central Main Ethiopian Rift. • Chemical Index of Alteration showed that the host rocks are intensively altered. • The kaolin deposit is formed through supergene alteration of acidic volcanic rocks. • The dominant clay mineral identified in the kaolin ore is kaolinite. • The kaolin is found to be appropriate for ceramics, paper coating and filler. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The Lower Carboniferous Jiujialu Fm at Zunyi, northern Guizhou, contains 110 m of Kazakhstan-subtype karst bauxite deposits. • Alternating bauxite ore and bauxitic claystone layers having different petrological, mineralogical and geochemical compositions. • A total of seven cycles developed in response to fluctuating groundwater table levels, controlled by LPIA glacio-eustasy. Abstract The Lower Carboniferous Jiujialu Formation bauxite deposits at Zunyi, northern Guizhou are distinguished by their great thickness (to 110 m) and cyclic alternation of bauxite ore and bauxitic claystone layers. These features are typical of the Kazakhstan subtype of karst bauxite deposits, although the genesis of this type of deposit is poorly understood. Here, we undertook a petrological, mineralogical, and geochemical study of the Zunyi deposit in drillcore ZK5600 to gain insights into its formation history. The Zunyi profile contains seven bauxite cycles, as recorded by petrological, mineralogical and geochemical features, indicating a multistage formation history. Each cycle is composed of a lower bauxitic claystone layer and an upper bauxite ore layer. The bauxite ore is characterized by high Al 2 O 3 , high Al-mineral (diaspore), and low SiO 2 content. Positive Ce anomalies, high CIA values (>90), and strong depletion of major elements indicate that the bauxite ore formed through intense chemical weathering and leaching in a well-drained soil environment. The bauxitic claystone is characterized by relatively lower Al 2 O 3 and higher SiO 2 and clay mineral (mostly illite) content. This lithology exhibits both negative and positive Ce anomalies, moderate CIA values (70–80), and enrichment of some elements (e.g., Fe, K), indicating formation through moderate chemical weathering in a poorly drained soil environment. Secular variations in chemical weathering intensity and soil drainage conditions were linked to regional hydrologic changes. During the early Carboniferous, the Zunyi area was located in a karstified coastal upland setting, and its hydrologic system was affected by glacio-eustatic fluctuations. High groundwater table elevations during eustatic highstands led to formation of bauxitic claystone layers, whereas low groundwater table elevations during eustatic lowstands led to formation of bauxite ore layers. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ca-enriched silicates and carbonates in the endo and exocontact of granites. • Carbonate and calcsilicate minerals are very much responsive. • Physical-chemical regime of Ca-enriched mineral assemblages. • Marker mineral assemblages for crustal and subcrustal impact. • Ca-enriched silicates and carbonates and the geodynamic setting. Abstract Metacarbonate rocks (marble, calcsilicate rock, skarn) hosting strata- and structurebound Fe-, As-Sb, Bi-, Ni-Co, Cu-Pb-Zn, U-, W- ore minerals as well as talc, clay minerals, barite and fluorite are widespread in the country rocks south of the collisional calc-alkaline felsic to intermediate intrusive rocks of the Fichtelgebirge Pluton, Germany. At its western rim, thrustbound and vein-type mineral assemblages with Au-As-Sb and F-Ba minerals associated with carbonate gangue minerals developed. Only recently, a calcite-hosted Sb mineralization was encountered in a deep-seated lineamentary fault zone cutting through metaultrabasic rocks along the northern edge of the granites. The same structure zone forms the loci of calcite-bearing U episyenite situated within this pluton. A composite geological, mineralogical and chemical (major and trace elements, REE, C- and O isotopes) study has been conducted to distinguish the heat and element source in subcrustal or deep-seated crustal areas and in the largely exposed granite complex. Only Sn-W skarn deposits are genetically related to the highly fractionated granitic members of the Variscan pluton. Pegmatite skarn has a strong subcrustal component as to the heat source and the provenance of rare elements and a moderate crustal one as far as the silicates are concerned. Deep-seated fault zones were active over a rather long period of time and acted as conduits venting magmas and hydrothermal fluids from the waning stages of the Variscan deformation through the Neogene. Calcsilicate and carbonate mineral assemblages are an efficacious tool to constrain the physico-chemical regime in this mineral province, covering the temperature range from 745 °C down to 53 °C in a medium to low pressure regime at strongly varying redox conditions. The major and trace elements, the REE variation, the Ce and Eu anomalies as well as carbon and oxygen isotopes of the various mineral assemblages enable us to identify the fluid sources and depict the element concentration processes, e.g., mixing of fluids, connate fluid and meteoric fluid interaction. From the economic point of view, the mineralizing system is most prospective for rare element deposits, talc, kaolinite-group minerals, iron, and uranium. Accumulations of fluorite and barite are subeconomic in mineral assemblages inside as well as outside the granites, while base metals and precious metals are only of mineralogical interest. [ABSTRACT FROM AUTHOR]

Abstract Eastern United States loess mapped by the U.S. Department of Agriculture, National Resources Conservation Service (USDA-NRCS) mostly occurs near major river systems like the Delaware and Susquehanna Rivers. The proximity of loess along major river valleys suggests late-Quaternary glacial meltwater sediments were dominant sediment sources for loess. Based on differing lithologies of meltwater deposits in these systems, we hypothesize that loess in each river system has a unique geochemical and mineralogical signature. To test this hypothesis, we examined pedons developed in loess parent materials, and adjacent to either the Delaware or West-Branch of the Susquehanna River, both of which carried large amounts of Wisconsinan outwash. Soils were analyzed for particle size distribution, clay mineralogy, and coarse and fine silt particle density, mineralogy, and geochemistry. Results show that while the pedons are similar in morphology, substantial differences exist in the pedons' textures, mineralogies, and geochemical compositions. We attribute the differences to parent material differences that stem from lithologically distinct sediment sources for loess from the two river systems. Susquehanna River loess has a higher particle density, and lower abundance of minerals such as Zr, base oxides (such as CaO), and rare earth elements. Discriminant analysis results suggest that developing a "loess fingerprint" for each river system based on major, minor and rare earth elements is possible, and likely to be useful in differentiating sources; however coarse silts may be a more effective fraction (than fine silts) for sediment sourcing, especially if rare earth elements are used. Highlights • We examined pedons developed in loess parent materials. • Soils were analyzed for particle size, mineralogy, and geochemistry. • Results suggest major, minor and rare earth elements can differentiate loess sources. [ABSTRACT FROM AUTHOR]

Abstract The characterization of ceramic materials from archaeological sites is of great importance to learn about the human traditions and regional History. In this work, 12 pieces of ceramics of the Cuatrovitas Archaelogical Site (Bollullos de la Mitación, Seville, Spain) were studied to approach the provenance of the raw material and the firing temperature. In addition, raw materials, from possible sources areas used for the manufacture of those ceramics, were also studied. Mineralogical characterization by XRD and chemical analyses of major, trace and rare earth elements were performed on both raw and ceramic materials. Thin sections, SEM-EDS analyses and micro-XRF mapping were carried out to complete the mineralogical and chemical characterization. The results show that there are two types of ceramic materials, probably prepared by mixtures of different clays and sandy materials. A feasible source area for those raw materials could be the alluvial of the Guadiamar River. According to the mineralogy of the high-temperature phases found in the ceramic pieces, two firing temperatures can be approached: one at 800–850 °C owing to the presence of calcite, and another at 900–950 °C because of the presence of diopside and gehlenite. Highlights • Guadiamar River alluvial is a possible area for raw material in Cuatrovitas Site. • Diopside and gehlenite suggest firing temperatures above 900–950 °C. • Calcite and absence of high temperatures phases suggests firing below 800–850 °C. [ABSTRACT FROM AUTHOR]

Abstract The Dongyang gold deposit is located in Fujian Province in southeastern China, mainly hosted by a NW–SE trending Late Jurassic porphyritic rhyolite, and classified as a low-sulfidation epithermal gold deposit. The units associated with the gold mineralization in this area are highly altered and have undergone sericitic and argillic alteration as well as silicification, with the latter two types of alteration especially associated with gold enrichment. The deposit contains pyrite, marcasite, and arsenopyrite, with lesser amounts of chalcopyrite, galena, sphalerite, and silver minerals. The sulfides and silver minerals within the deposit provide insight into the evolution of the ore-forming fluid and the processes that caused the gold enrichments to form in the study area. In addition, the geochemical similarity of gold and silver means these elements tend to migrate and precipitate simultaneously, in turn indicating that sulfides and silver minerals can provide insights into the processes that concentrate gold. Here, we present chemical compositional, and crystal structural data for sulfides and silver minerals within the Dongyang gold deposit by scanning electron microscopy (SEM), electron microprobe analyser (EMPA), X-ray diffraction (XRD) and laser Raman microprobe, and use these data to gain insights into the characteristics and evolution of the fluids that formed the deposit. We also outline key concepts for future gold deposit exploration in this region. Four types of pyrite in the deposit are recognized based on arsenic content and crystal morphology, evolving from early As-poor pyrite (Py1) to As-rich pyrite (Py2) and/or arsenopyrite, to non-cubic As-poor pyrite (Py3), and finally to cubic As-poor pyrite (Py4), with an inverse correlation between sulfur and arsenic concentrations. Pyrite crystal morphologies vary from earlier pentagonal dodecahedron forms to later cube forms, indicating a decrease in degree of supersaturation (as controlled by the activity of dissolved Fe and sulfide) and/or temperature conditions for pyrite growth. In addition, the presence of As-poor marcasite associated with early pyrite (Py1) suggests that the early ore-forming fluid was relatively acidic. Arsenopyrite is generally concentrated in the shallower parts of the deposit, indicating that later hydrothermal fluids were enriched in arsenic. This study also identified a number of key silver mineral phases that formed in a sequence from chalcopyrite, to a galena–fahlore–allargentum–dyscrasite–polybasite–electrum assemblage, to stephanite, and finally to chlorargyrite. Chalcopyrite replaced by fahlore suggests increased oxygen fugacity and decreased temperature. Fahlore Sb / (As + Sb) (>90%) and Ag / (Ag + Cu) ratios (6%–27%) are indicative of relatively high temperatures (>200 °C), and allargentum is thought to form in elevated pH conditions (pH > 7). Stephanite and chlorargyrite precipitated under relatively low temperature (<200 °C). Finally, the presence of chlorargyrite suggested that silver was transported as chloride complexes, indicating relatively high oxygen fugacity. The sequence of silver mineral precipitation suggests that the ore-forming fluids showed a temporal increase in pH and oxygen activity, and a decrease in temperature and sulfur fugacity. This indicates that the hydrothermal fluids that formed the deposit can be divided into early and late stage fluids, with the former being a relatively higher-temperature and higher‑sulfur fugacity fluid compared with the lower-temperature and higher‑oxygen-fugacity late-stage fluid. Finally, the presence of silver minerals with high gold contents (up to 2 wt%), as well as arsenian pyrite and arsenopyrite, may be useful indicators of prospective areas for gold exploration in this region. Highlights • Components and morphology of pyrite indicated decreased supersaturation and/or temperature. • Silver minerals indicated decreased temperature and sulfur fugacity, and increased pH and oxygen fugacity. • Ore-forming fluids are divided into early stage of reduced and high-temperature and late stage of oxidized and low-temperature. [ABSTRACT FROM AUTHOR]

Abstract Historical Cu-Slags located at former industrial sites in Poland are exposed to weathering that may trigger release of metallic contaminants to the surrounding soils. However, the extent to which different metals are leached depends on the mineral composition of the slags and the conditions of their deposition. Historical slags are often crystalline and composed of phases with a variable response to weathering. Also, weathering of crystalline slags (CS) is different from that of amorphous slags (AS). To understand how the slag phase composition triggers weathering and the ultimate release of metallic elements, we studied the leaching of historical crystalline and amorphous slag. A combined geochemical and mineralogical approach determined the weathering sequence(s) of slag components subjected to different conditions of specific slag disposal. In detail, experiments under: i) various pH conditions in the range of 2–13 in a batch mode simulated slag deposition within a deep soil profile, whereas ii) exposure to solutions of artificial root exudates (ARE) in a dynamic experimental system simulated slag deposition within topsoil. The results demonstrated that crystalline phases in the order Leucite > Plagioclase > Pyroxene are preferentially dissolved in inorganic conditions of a pH ≤ 7, in contrast to glass, which is preferentially dissolved in alkaline conditions (pH > 7). Also, inorganic conditions better promote the dissolution of metal-bearing phases (sulphides and metals) when compared to silicates. In contrast, artificial root exudates do not show preferential dissolution of any phase and cause the strongest leaching in all of the analyzed conditions. We show that reconstructing the susceptibility of complex crystalline slags to weathering requires a specific approach including analyses and interpretation of all major components such as Ca, Mg and K, not merely a focus on Si and metals. Highlights • Mg, Ca and Cu/Mg, Cu/Ca track preferential dissolution of slag phases. • Acidic artificial root exudates (ARE) promote severe dissolution of bulk slag. • Phase stability for inorganic acidic conditions: Cu phases > silicates > glass. • Phase stability for inorganic alkaline conditions: Cu phases > glass > silicates. • Cu release in ARE and inorganic conditions (pH 2–3) is environmentally relevant. [ABSTRACT FROM AUTHOR]

Abstract—Layer-by-layer chemical and mineralogical analysis was carried out to consider the evolution of the Fe-Mn crusts in different tectonic settings in the South Atlantic Ocean. The ferromanganese crust in the rift valley of the Mid-Atlantic Ridge was formed owing to the hydrothermal-hydrogenetic supply. The formation of crust in the Transform Fracture zones of the Angola Basin was related to the halmyrolysis of magmatic rocks and subsequent hydrogenetic supply, which affected the proportions of goethite and vernadite, the Mn/Fe ratio, and Ce anomaly, as well as the content of some elements (Co, Cu, Al, REE). It is revealed that the Fe-Mn crusts taken in the abyssal part and on the seamount top in the Cape Basin are hydrogenetic in origin and consist of vernadite significantly enriched in Co, Ce, Tl, and Pt. The relationship of trace elements with manganese minerals is estimated by leaching of crusts by reagents, which either completely dissolve manganese oxyhydroxides (1 M NH2OH · HCl + 25%CH3COOH) or no (3.5 N H2SO4). It was shown that 100% Co and only 28% Ce are incorporated in the manganese minerals, while REE, Y, Sr, and U form a sorption complex of oxhyhydroxides. To estimate the chemical peculiarities of the hydrogenetic Fe-Mn crusts of the Atlantic Ocean, they were compared with the crusts of the Pacific Ocean. It is shown that the crusts of the Pacific Ocean have higher manganese and cobalt contents. The additional manganese could be derived from a hydrothermal source. [ABSTRACT FROM AUTHOR]

This paper reports mineral and whole‐rock geochemical data (major and trace elements, Sr–Nd isotopes, and in situ plagioclase Sr‐isotope analysis) for Cenozoic volcanic rocks from Sabeto, NW Fiji, with the aim of constraining the origin of Cenozoic shoshonitic rocks found throughout Fiji. The most mafic shoshonitic lavas (absarokites) exhibit porphyritic textures and massive structure with phenocrysts of olivine (Fo = 76–78), clinopyroxene (Mg# = 73.9–80.0), and plagioclase (An = 71.9–92.1). Major element geochemical data include SiO2 = 47.31–48.46 wt%, MgO = 4.20–5.76 wt%, Mg# = 49–51, Al2O3 = 17.64–18.93 wt%, and (Na2O + K2O) = 5.12–7.01 wt%. The trace element geochemistry is typically arc like, with enrichment in the large ion lithophile elements (LILEs), the light rare earth elements (LREEs), and P, along with depletion in the heavy rare earth elements (HREEs) and high‐field‐strength elements (HFSEs; e.g., Nb, Ta, Zr, Hf, and Ti). Whole‐rock (87Sr/86Sr)i ratios and εNd(t) values vary from 0.7037 to 0.7039 and from +7.62 to +8.45, respectively. The former is near equal to the 87Sr/86Sr ratios of plagioclase phenocrysts (0.7034–07039). Based on these geochemical data and the results of previous studies, we propose that the Sabeto shoshonitic primary magma was derived from partial melting of the depleted lithospheric mantle, modified by subduction‐related fluids. The thermobarometric calculation indicates that the P–T conditions of Fiji shoshonitic magma chamber are ~1100 °C and ~2.8 GPa (~90 km depth), with an average H2O fraction of ~6 wt%. In addition, the shoshonitic melts experienced fractional crystallization of clinopyroxene, olivine, and plagioclase during magma evolution. These volcanic rocks formed in an extensional setting following collision of the Vitiaz arc and the Ontong Java Plateau during the Pliocene. [ABSTRACT FROM AUTHOR]

Abstract The role of secondary minerals in controlling the migration of arsenic and selected metals (Cu, Pb, Zn) has been investigated in voluminous mining waste dumps at Kaňk (northern part of the Kutná Hora ore district, Czech Republic). These wastes initially contained a large amount of Fe sulfides and arsenopyrite and have been exposed to atmosphere for approximately 500 years. The long-term weathering under acidic conditions caused dissolution of almost all sulfides and significant alteration of primary silicate minerals, producing deeply weathered As-, Fe-, and S-rich waste material (As: 13 g kg−1; Fe: 74 g kg−1; S: 44 g kg−1) with large proportion of clayey matrix filling the space between rock fragments. Detailed mineralogical investigation (powder X-ray diffraction, electron microprobe, Raman spectroscopy) and sequential extraction revealed that arsenic in these wastes is principally stored in reactive but not highly soluble minerals such as poorly-crystalline Fe (oxyhydr)oxides, bukovskýite, and X-ray amorphous hydrated ferric arsenate (HFA). Lesser fraction of As is contained in schwertmannite and less reactive scorodite, jarosite, and well-crystalline Fe (oxyhydr)oxides (especially goethite). Fe (oxyhydr)oxides also appear to be the main reservoirs of Cu and Zn; Pb is principally stored in jarosite. Acidic pore waters (pH ≈ 2.8) collected after rainfall events contain much Al (113 mg L−1), As (2.5 mg L−1), Ca (500 mg L−1), Cu (24 mg L−1), Fe (58 mg L−1), Si (44 mg L−1), SO 4 2− (2170 mg L−1) and Zn (16 mg L−1). Geochemical modeling revealed that most of these elements (Al, Ca, Cu, SO 4 2−, Zn) are controlled by ephemeral Al-Ca-Cu-Zn sulfates (e.g. gypsum, aluminite), which form at the surface of the waste dumps as a result of evaporation of pore solutions during dry seasons. Despite the fact that bukovskýite and other interesting Fe(III) (sulfo)arsenate minerals store a major part of As in the mining wastes, geochemical modeling supported the notion that mobility of As and Fe is controlled by the unspectacular poorly-crystalline As-bearing Fe (oxyhydr)oxides. The data show that the Fe(III) (oxyhydr)oxides, (sulfo)arsenates and hydroxysulfates in the 500-year-old mining waste dump retain arsenic efficiently but not completely. Monitoring wells installed at the site before our research recorded up to 1440 mg L−1 As in shallow groundwater. They argue, however, that this aquifer is disconnected from the larger groundwater bodies at the site and hence does not represent arsenic accumulation of environmental concern. Highlights • Speciation of As in medieval mining waste dumps was determined by combination of mineralogical and geochemical methods. • A multiple As-hosting phases (mainly bukovskýite, HFA, HFO) were identified. • As and Fe solubility is controlled by As-HFO. [ABSTRACT FROM AUTHOR]

Recent investigations found that hydrothermal activity and sulfide mineralization occurs along the Southwest Indian Ridge (SWIR). The Longqi and Duanqiao hydrothermal fields between 49° E and 53° E of the SWIR are two prospective mineralization areas discovered by Chinese scientists. With the aim to determine the mineralogical and chemical characteristics of sulfide minerals, we have conducted detailed studies for samples from the two areas using an optical microscope, X‐ray diffractometer, scanning electron microscope, and electron microprobe. The mineralization processes in the Longqi area are divided into three main stages: (1) the low‐medium‐temperature stage: colloform pyrite (Py I) + marcasite → euhedral pyrite (Py II), (2) the high‐temperature stage: isocubanite (±exsolved chalcopyrite) + pyrrhotite → coarse‐grained chalcopyrite (Ccp I), and (3) the medium–low‐temperature stage: sphalerite + fine‐grained chalcopyrite inclusions (Ccp II) → aggregates of anhedral pyrite (Py III) ± marcasite → Fe‐oxide (‐hydroxide) + amorphous silica. The mineralization processes in the Duanqiao area are divided into two main stages: (1) the medium–high‐temperature stage: subhedral and euhedral pyrite (Py I′) → coarse‐grained chalcopyrite (Ccp I′) and (2) the medium–low‐temperature stage: sphalerite → fine‐grained chalcopyrite (Ccp II′) + chalcopyrite inclusions (Ccp II′) → silica‐cemented pyrite (Py II′) + marcasite → Fe‐oxide + amorphous silica. We suggest that the fine‐grained chalcopyrite inclusions in sphalerite from Longqi and Duanqiao were formed by co‐precipitation and replacement mechanisms, respectively. Primary sphalerites from both fields are enriched in Fe (avg. 5.84 wt% for the Longqi field vs. avg. 3.69 wt% for the Duanqiao field), Co (avg. 185.56 ppm for the Longqi field vs. 160.53 ppm for the Duanqiao field), and Cd (avg. 1950 ppm for the Longqi field vs. avg. 525.26 ppm for the Duanqiao field). Cu contents in pyrite from the Duanqiao field (Py I′: avg. 849.23 ppm and Py II′: avg. 1191.11 ppm) tend to be higher than those from the Longqi field (Py I: avg. 26.67 ppm, Py II: avg. 445 ppm, and Py III: avg. 179.29 ppm). Chalcopyrite from both fields is enriched in Zn (Ccp I: avg. 3226.67 ppm, Ccp II: avg. 9280 ppm, Ccp I′: avg. 848 ppm, Ccp II′ (inclusions): avg. 1098 ppm, and Ccp II′ (fine‐grained): avg. 1795 ppm). The varying contents of Zn in the different pyrite and chalcopyrite generations may result from the zone refining process. An integrated study of the mineralogy and mineralogical chemistry suggests that the hydrothermal fluids of the Longqi area are likely conditioned with higher temperatures and relatively lower fO2 and fS2 than those of the Duanqiao area, but in contrast to the former, the latter is much affected by the compositions of the surrounding rocks. [ABSTRACT FROM AUTHOR]

Persistence and bioavailability of heavy metals in soils adjacent to ancient Cu mines continues to be a possible threat to human health. However, there have been very few studies to determine this risk. Asturias (Northwest of Spain) is a Cu metallogenic province with abundant epithermal-type deposits, whose paragenetic sequences also include As, Co, Ni, Sb and Hg minerals. Several Cu mines have been worked in this region since prehistoric times and the six most significant ones are studied in this work to provide new insights into the potential for both contemporary and past contamination due to Cu mining to impact human health. The main characteristics of each deposit were defined by means of optical and scanning-electron microscopy, X-ray diffraction and Electron Probe Micro Analysis. These characteristics were used to better interpret the environmental results, obtained from samples of mining wastes, soils and waters, which were analyzed by means of X-ray fluorescence and ICP-MS. Many of these mines are almost forgotten, but their negative effects will endure over time, since they were abandoned long before the introduction of environmental regulations to control metal release. An inheritance of derelict mine facilities and spoil heaps still remains in the sites of this district. The spoil heaps are the main pollution sources and concentrations of up to 2.1% Cu and 0.4% As, among others, were found in the surrounding soils. The potential adverse health effects of the exposure to these elements have been assessed, finding significant risks for potential receptors, such as farmers or local residents. [ABSTRACT FROM AUTHOR]

The ceramic properties of clay materials heated at high temperature are largely dependent on the mineral reactions, which usually are followed by XRD analysis on pressed pieces that are heated at different temperatures. Nevertheless, the use of “in-situ” high temperature X-ray diffraction (HTXRD) to follow the evolution of the crystalline phases under controlled temperature provides more precision. In this paper, the mineralogical changes produced during firing (RT-1000 °C) of two clay materials of very different mineralogical composition, frequently used in the manufacture of bricks in the SE Spain, have been studied by XRD classical procedure and with HTXRD, and the results obtained were compared. Although the phases identified by both X-ray analyses were the same, temperatures for the mineralogical reactions seem to be different, probably due to the experimental conditions. The patterns obtained by ex-situ XRD were at a higher speed than those by in-situ HTXRD, and probably the equilibrium was not achieved for the most reactions. Because of the expansion of the mineral structure parameters occurred during heating the mineral reflections do not match with those found in the database JPCDS, neither the position nor intensities of some stable phases at high temperature. For the optimization of the interpretation of the HTXRD patterns, and to facilitate the kinetics of the new phases, it is necessary to work at a high integration time per step and a slow heating rate. The in-situ HTXRD investigations of ceramic materials can save time respect to the classical XRD study of test-pieces heated at different temperatures, and lead immediate information of the transformation occurring on heating, which can be useful to improve the most suitable firing temperature in the industry. [ABSTRACT FROM AUTHOR]

Sulfuric acid minerals are important clues to identify the speleogenetic phases of hypogene caves. Italy hosts ~25% of the known worldwide sulfuric acid speleogenetic (SAS) systems, including the famous well-studied Frasassi, Monte Cucco, and Acquasanta Terme caves. Nevertheless, other underground environments have been analyzed, and interesting mineralogical assemblages were found associated with peculiar geomorphological features such as cupolas, replacement pockets, feeders, sulfuric notches, and sub-horizontal levels. In this paper, we focused on 15 cave systems located along the Apennine Chain, in Apulia, in Sicily, and in Sardinia, where copious SAS minerals were observed. Some of the studied systems (e.g., Porretta Terme, Capo Palinuro, Cassano allo Ionio, Cerchiara di Calabria, Santa Cesarea Terme) are still active, and mainly used as spas for human treatments. The most interesting and diversified mineralogical associations have been documented in Monte Cucco (Umbria) and Cavallone-Bove (Abruzzo) caves, in which the common gypsum is associated with alunite-jarosite minerals, but also with baryte, celestine, fluorite, and authigenic rutile-ilmenite-titanite. In addition, the core of alunite and jarosite, from these two systems, results enriched in PO43-, clearly suggesting hypogene hydrothermal origin. Santa Cesarea Terme, Capo Palinuro, and Acqua Mintina caves show important native sulfur deposits, which abundantly cover walls, ceilings, and speleothems. Abundant copiapite, pickeringite, tamarugite, hexahydrate assemblages have been observed in the Calabrian systems; their association with pyrite and hematite would suggest they formed in very acidic conditions with pH ranging between 0 and 4. [ABSTRACT FROM AUTHOR]

Abstract Coastal dune (CD) and beach sand samples were mineralogically and chemically studied to assess the weathering rates in a coastal area surrounded by the Trans-Mexican Volcanic Belt (TMVB). The study area is a narrow coastal plain with sub-humid warm weather and vigorous coastal dynamics located in the Western Gulf of Mexico (WGM). Our results show that the grain size parameters remain homogeneous along nine CD and beach sites, probably due to the hydrodynamic mechanisms prevailing in the area, i.e. wind deflation, longshore currents, and waves. The minerals found in the CD and beach sands are enriched in recycled, highly corroded monocrystalline quartz (Qm), with loss of plagioclase (P) and olivine (ol), with ilmenite fractions (op) especially in the northern sites. The geochemical data show that the sands are controlled by the exhumation of the TMVB rocks composed of a high volcanic lithic content with lathwork, microlithic, and negligible vitric textures. These volcanic fractions are in agreement with the presence of lavas of calc alkaline, andesite, Na-alkaline lavas, and rhyolite tuffs derived from the TMVB. Significant Spearman Rank Correlations (SRCs) resulted from high silica, titanium, iron, magnesium, calcium, vanadium, chromium, cobalt, associated with the presence of Qm, ilmenite, clinopyroxene, shell fragments, and volcanic lithics. Monocrystalline quartz enrichments, compared to a quartz dilution effect (

Mineralogical studies indicate that two major phase transitions occur near the depth of 660 km in the Earth's pyrolitic mantle: the ringwoodite (Rw) to perovskite (Pv) + magnesiowüstite (Mw) and the majorite (Mj) to perovskite (Pv) phase transitions. Seismological results also show a complicated phase boundary structure at this depth in plume regions. However, previous geodynamical modeling has mainly focused on the effects of the Rw–Pv+Mw phase transition on plume dynamics and has largely neglected the effects of the Mj–Pv phase transition. Here, we develop a 3-D regional spherical geodynamic model to study the combined influence of these two phase transitions on plume dynamics. Our results show the following: (1) A double phase boundary occurs in the high-temperature center of the plume, corresponding to the double reflections in seismic observations. Other plume regions feature a single, flat uplifted phase boundary, causing a gap of high seismic velocity anomalies. (2) Large amounts of relatively low-temperature plume materials can be trapped in the transition zone due to the combined effects of phase transitions, forming a complex truncated cone shape. (3) The Mj–Pv phase transition greatly enhances the plume penetration capability through 660-km phase boundary, which has a significant influence on the plume dynamics. Our results provide new insights which can be used to better constrain the 660-km discontinuity variations, seismic wave velocity structure and plume dynamics in the mantle transition zone. The model can also help to estimate the mantle temperature and Clapeyron slopes at the 660 km phase boundary. [ABSTRACT FROM AUTHOR]

The central portion of the Canaã dos Carajás domain, located in the northern part of the Carajás province was originally marked by the occurrence of undifferentiated rocks belonging to the Xingu complex and Plaque suite, as well as greenstone belts, mafic rocks of the Pium diopside-norite and high K calc-alkaline leucogranites (Boa Sorte and Cruzadão granites). A semi-detailed geological mapping (1:100.000) was carried out in the Vila União area and allowed the identification of several deformed granite bodies intrusive in the Mesoarchean units. They correspond to the most expressive unit of the studied area and are composed predominantly of monzogranites with chemical and mineralogical affinity with the Neoarchean A-type granites of the Planalto and Vila Jussara suites. The variable felsic and ferromagnesian minerals contents, as well as the different proportions between them, allowed to distinguish four major groups of granitoids: (i) biotite-hornblende monzogranites (BtHblMzG); (ii) biotite granites and leucogranites (BtLG); (iii) biotite-hornblende tonalites (BtHblTn); and (iv) quartz diorites (QD). The tectonic foliation of these rocks follows the regional E-W trend and exhibits high angles (70–85°). Well-developed core and mantle structures in quartz and feldspar crystals, as well as the presence of serrated and irregular contacts between these crystals suggest that dynamic recrystallization occurred at relatively high temperatures (>500 °C). These rocks exhibit a wide variation in silica content (57.20–75.91 wt%), are metaluminous to slightly peraluminous and show affinity with A-type (high HFSE) and ferroan granites. Based on magnetic petrology studies it was possible to distinguish two groups of rocks: (1) granites containing only ilmenite with low magnetic susceptibility values (MS; <0.570 × 10 −3 SI), and (2) granites with magnetite as the main iron and titanium oxide mineral and higher MS values (>1.437 × 10 −3 SI). Textural and compositional evidences indicate that magnetite and ilmenite are early-crystallized phases and titanite has magmatic origin. Amphiboles are calcic and classified as hastingsite, whereas biotites are magnesian to ferroan. The relatively high Fe/(Fe + Mg) ratios found in the amphiboles of the BtHblMzG and BtHblTn varieties indicate that these granitoids were formed under low to moderate f O 2 conditions, whereas in the BtLG the lower values of this ratio suggest more oxidizing conditions. Geothermometers point to crystallization temperatures between 830 and 930 °C in the different facies. The high total Al content in the amphibole crystals suggests crystallization at pressures between 400 and 800 MPa, indicating that these granitoids were emplaced at different crustal depths. [ABSTRACT FROM AUTHOR]

Abstract: Intrusion of quartz‐monzodioritic igneous bodies of Oligocene age into Eocene lithic crystal tuffs and trachy‐basalts resulted in the occurrence of a widespread argillic alteration zone in the Jizvan district (northern Iran). Mineralogically, the argillic alteration zone includes minerals such as kaolinite, quartz, smectite, pyrophyllite, muscovite‐illite, alunite, rutile, calcite, feldspar, chlorite, hematite and goethite. Therefore, the non‐CHARAC behaviour for trace elements in the argillic samples is reflected in the non‐chondritic Y/Ho and Zr/Hf ratios and the irregular REE patterns, which appear related to the tetrad effect phenomenon. The chondrite‐normalized REE distribution patterns indicate both concave (W‐shaped) and convex (M‐shaped) tetrad effects in the argillic samples. Based on the field evidence and the results from geochemical studies, it can be concluded that the samples from the argillic alteration zone having high fourth tetrad effect values (>0.30) were developed in the fault and breccia zones. The results indicate that factors such as preferential scavenging by Mn‐oxides, crystallization of clay minerals, fluid‐rock interaction, overprint of hypogene mineral assemblage by supergene ones, and the structural control, have all played an important role in the occurrence of tetrad effects in samples of the argillic zone in the Jizvan district. [ABSTRACT FROM AUTHOR]

The Bukit Botol volcanic-hosted massive sulphide (VHMS) deposit is located in the Central Belt of Peninsular Malaysia. The deposit occurs in a package of Permian-aged coherent felsic volcanic and volcaniclastic rocks which have a geochemical signature indicative of a volcanic arc tectonic setting. Mineralisation shows distinct ore zonation, forming a stringer to massive sulphide zone at the footwall followed by barite lenses and exhalite layers (Fe-Mn ore) at the top. Mineralogy is characterised by pyrite as the major sulphide mineral, with minor chalcopyrite, sphalerite, and rare galena; traces of gold, silver- and tin-bearing minerals also occur in the massive sulphide and barite ores. Laser ablation inductively coupled plasma mass spectrometry (LA−ICP−MS) analysis combined with the textural characteristics of pyrite provides evidence for significant variations of trace elements in different pyrite types at Bukit Botol, having three types of pyrite in the paragenetic sequence. The concentrations of As, Se, Te, Cu, Zn and Pb decrease from the early pyrite 1 to the late stage pyrite 3, and the Co/Ni ratios vary for the three pyrite types. The combined textural and compositional data of pyrite suggest that the hydrothermal fluid responsible for mineralisation evolved from an early, high temperature, reduced, low pH and desulphurized fluid to more S-rich, oxidized, high pH and cooler fluid. Available sulphur isotope data from the Bukit Botol deposit point to reduced seawater, along with a possible magmatic contribution, as the most probable sources for the ore-forming fluids. [ABSTRACT FROM AUTHOR]

Abstract: Soils in mountainous areas are often polygenetic, developed in slope covers that relate to glacial and periglacial activities of the Pleistocene and Holocene and reflect climatic variations. Landscape development during the Holocene may have been influenced by erosion/solifluction that often started after the Holocene climatic optimum. To trace back soil evolution and its timing, we applied a multi‐methodological approach. This approach helped us to outline scenario of soil transformation. According to our results, some aeolian input must have occurred in the late Pleistocene. During that time and the early Holocene, the soils most likely had features of Cryosols or Leptosols. Physico‐chemical and mineralogical analyses have indicated that the material was denudated (between late Boreal to the Atlantic) from the ridge and upper‐slope positions forming a colluvium at mid‐slope positions. Later, during the Sub‐Boreal, mass wasting of the remains of silt material deposited at the end of the Pleistocene age on the ridge top seems to have occurred. In addition, the cool and moist conditions caused the deposition of a colluvium at the lower‐slope positions. The next phase was characterized by the transformation of Leptosols/Cambisols into Podzols at upper‐slope or shoulder positions and to Albic Cambisols at mid‐slope positions. During the Sub‐Boreal period, Stagnosols started to form at the lower part of the slope catena. Overall, the highest erosion rates were calculated at the upper‐slope position and the lowest rates at mid‐slope sites. Berylium‐10 (10Be) data showed that the Bs, BC/C were covered during the Holocene by a colluvium with a different geological composition which complicated the calculation of erosion or accumulation rates. The interpretation of erosion and accumulation rates in such multi‐layered materials may, therefore, be hampered. However, the multi‐methodological reconstruction we applied shed light on the soil and landscape evolution of the eastern Karkonosze Mountains. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The influence of different rock mineralogical compositions on element leaching and bio-weathering processes is poorly understood. Here, the role of basalt composition on nutrient leaching (calcium, iron, phosphorus or magnesium) and subsequent support of Cupriavidus metallidurans CH34 growth was evaluated. Seven different basalts were examined. In iron-limiting media, growth could be restored for all basalts tested, while only two basalts could restore growth in magnesium-limiting medium. Only for magnesium growth complementation was correlated with the composition of the basalts tested. Our results showed that basalt composition can affect leaching and availability of different elements, in turn, affecting bacterial growth. [ABSTRACT FROM AUTHOR]