Smamite, Ca2Sb(OH)4H(AsO4)2·6H2O, is a new mineral species from the Giftgrube mine, Rauenthal, Sainte-Marie-Aux-Mines ore-district, Haut-Rhin department, France. It is a supergene mineral found in ...quartz-carbonate gangue with disseminated to massive tennantite-tetrahedrite series minerals, native arsenic, Ni-Co arsenides, and supergene minerals picropharmacolite, fluckite, and pharmacolite. Smamite occurs as lenticular crystals growing in aggregates up to 0.5 mm across. The new mineral is whitish to colorless, transparent with vitreous luster and white streak; non-fluorescent under UV radiation. The Mohs hardness is 3 and 1/2; the tenacity is brittle, the fracture is curved, and there is no apparent cleavage. The measured density is 2.72(3) g/cm3; the calculated density is 2.709 g/cm3 for the ideal formula. The mineral is insoluble in H2O and quickly soluble in dilute (10%) HCl at room temperature. Optically, smamite is biaxial (-), α=1.556(1), β=1.581(1), γ=1.588(1) (white light). The 2V (meas)=54(1)°; 2V (calc)=55.1°. The dispersion is weak, r>ν. Smamite is non-pleochroic. Electron microprobe analyses provided the empirical formula Ca2.03Sb0.97(OH)4H1.10(As1.99Si0.01O4)2·6H2O. Smamite is triclinic, P1̄, a=5.8207(4), b=8.0959(6), c=8.21296(6) Å, α=95.8343(7)°, β=110.762(8)°, γ=104.012(7)°, V=402.57(5) Å3, and Z=1. The structure (Robs=0.027 for 1518 I>3σI reflections) is based upon {Ca2(H2O)6Sb(OH)4H(AsO4)2} infinite chains consisting of edge-sharing dimers of Ca(H2O)3O2(OH)2 polyhedra that share edges with Sb(OH)4O2 octahedra; adjacent chains are linked by H-bonds, including one strong, symmetrical H-bond with an O-H bond-length of ∼1.23 Å. The name "smamite" is based on the acronym of the Sainte-Marie-aux-Mines district.
In light of the recent ‘lithium boom’, a screening study for Sn-W and Li-Cs-Ta deposits was carried out and located an early 1980s Bureau de Recherches Géologiques et Minières (BRGM) geochemical ...survey with W anomalies of >50 ppm in the Sainte-Marie-aux-Mines area, NE France. These anomalous areas, along with historic mining of polymetallic veins in the area, led to the present investigation of the regional potential for Variscan vein-hosted Sn-W-Li-Cs-Ta and Mesozoic-Cenozoic Cu-Pb-Zn-As-Ag-Ni veins in the central Vosges Mountains.
A total of 144 stream sediment samples were collected in the central Vosges Mountains covering an area of >200 km2. Multi-element pXRF and ICP-MS assays revealed previously undescribed W-Li-Cs-Ta geochemical anomalies related to major ENE-WSW trending fault zones and splay faults in the I-type Central Vosges Mg-K (‘CVMg-K’) granite. Field mapping evidence, previously published age data along with strong geochemical fractionation trends obtained from K/Rb, Zr/Hf and Nb/Ta ratios, imply that the CVMg-K granites were intruded by younger crustal melts derived from crustal anatexis of metasedimentary and metaigneous source rocks, that potentially exploited pre-existing fault control, and subsequently fractionated and enriched incompatible elements of economic interest.
This study demonstrates that Sn-W-Li-Cs-Ta geochemical anomalies can occur in I-type granites, if later orogenic processes leading to crustal anatexis resulted in the production of peraluminous melts, strong magmatic fractionation and emplacement of mineralization along regional fault zones. Therefore, the presence of I-type granites in Variscan and other geological terrains should encourage regional Sn-W-Li-Cs-Ta exploration.
•Previously undescribed W-Li-Cs-Ta geochemical anomalies revealed in I-type granites, Vosges Mountains, France.•I-type granites intruded by younger peraluminous melts enriching incompatible elements.•The presence of I-type granites should encourage regional Sn-W and Li-Cs-Ta exploration.
Mining and smelting activities have contaminated the environment with trace metals (TMs) at a worldwide scale for at least two millennia. A combination of chemical approaches and active biomonitoring ...was performed to analyse the environmental availability and bioavailability of TM palaeo-pollution in a former PbAg mining district in the Vosges Mountains, France. Along a soil TM contamination gradient that covered eight stations, including two archaeological mining sites, the toxicokinetics of six TMs (Pb, Cd, As, Ag, Co, Sb) in the snail Cantareus aspersus revealed that palaeo-pollution from the studied sites remains bioavailable. This study provides the first data on the accumulation kinetics of Ag and Co for C. aspersus. The environmental availability of the TMs was estimated with three chemical extraction methods (aqua regia, EDTA 50 mM, CaCl2 10 mM). Univariate regression analyses showed that EDTA extraction is the best method for estimating the bioavailability of Pb, As, Ag, Co and Sb to snails. None of the three extractants was efficient for Cd. A multivariate analysis of bioaccumulation data revealed that TM bioavailability and transfer were modulated by exposure sources (soil, humus and vegetation) rather than by soil physico-chemical characteristics. Hence, although the deposition of mining wastes dates back several centuries, these wastes still represent a source of contamination that must be considered to develop relevant site management and environmental risk assessment.
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•Deposited several centuries ago, mine wastes still represent contamination sources.•Cantareus aspersus snails were used as bioindicators in a biomonitoring campaign.•Palaeo-pollution are still bioavailable to vegetation and snails.•Bioavailability of trace metals to snails depends on exposure source.•EDTA is the best extractant for evaluating trace metal bioavailability to snails.
Field exposure analysis of land snails highlights the bioavailability and transfer of TMs in soils contaminated by mining wastes deposited several centuries ago.
Underground ancient mine work ventilation modeling Ars, Christophe; Gauthier, Joseph; Florsch, Nicolas
Journal of archaeological science, reports,
June 2021, 2021-06-00, 2021-06, Letnik:
37
Journal Article
Recenzirano
Odprti dostop
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•Renaissance duct remains question the air quality of underground mining works.•Numerical simulation was used to calculate air flow, heat and CO2 rates.•Forced ventilation system was ...necessary to exploit some parts of underground.•Scaffolding can both facilitate circulation of miners and improve ventilation.
Excavations at the Giro mine located in the commune of Sainte-Marie-aux-Mines (France) have revealed a metallic and cylindrical artifact that resembles a connecting element for wooden duct sections. Early modern literature, and especially De Re Metallica, mention such technologies intended in particular to force the ventilation of underground mines in which air quality was harmful for miners. The connecting element was found in a gallery leading to a stope of which ventilation seems problematic. The numerical simulation of the air flow in the tunnel makes it possible to test the ventilation hypotheses formulated from archaeological data. These simulations are performed with OpenFOAM, a free and open source software for computational fluid dynamics (CFD). Simulating not only the air flow, but also the heat and CO2 production of five miners at work highlights the need to force ventilation in the underground with a ventilation system. It also appears that the construction of scaffolding in the stope can fulfill the double function of facilitating circulation and improving ventilation. This first quantitative approach to one of the main obstacles to mining offers a new method for testing the solutions implemented by miners of the past.
Coring was carried out in a soligenous marsh in the Vosges Mountains in the past mining district of Sainte-Marie-aux-Mines (eastern France). High-resolution palynological, non-pollen-palynomorph, and ...geochemical analyses were performed along the core. Correlations between the herbal composition of the landscape and trace metals in the core reveal a specific palynological pattern during mining activities. Two main periods of anthropogenic impacts on vegetation and trace metal contamination are shown: during the 16th–17th centuries, for mining and smelting activities, and the beginning of the 20th century, for smelting and the Industrial Revolution. No drastic deforestations occurred near the study site, contrary to historical descriptions and prints of the valley. Controlled forest practices were implemented from the beginning of the record, that is, since cal. AD 1000, so the impact of mining activities seems to be less significant than expected near mining sites. We demonstrate that the minerotrophic characteristics of the record closest to past mining sites allows for (1) the description of the landscape associated with anthropogenic activities and (2) the recording of past trace metal emissions without post-depositional mobility.
Zircon and monazite from granulite- to amphibolite-facies rocks of the Vosges mountains (central Variscan Belt, eastern France) were dated by ion-microprobe and conventional U-Pb techniques. ...Different granulites of igneous (so-called leptynites) and sedimentary origin (kinzigites) and their leucosomes were dated at 334.9 ± 3.6, 335.4 ± 3.6 and 336.7 ± 3.5 Ma (conventional age 335.4 ± 0.6 Ma). Subsequent growth stages of zircon were distinguished by secondary electron (SEM) and cathodoluminescence (CL) imaging: (1) subsolidus growth producing round anhedral morphologies and sector zoning; (2) appearance of an intergranular fluid or melt phase at incipient dehydration melting that first resulted in resorption of pre-existing zircons, followed by growth of acicular zircons or overgrowths on round zircons consisting of planar growth zoning; (3) advanced melting producing euhedral prismatic zircons with oscillatory zoning overgrowing the sector zones. Two further lithologies, the Kaysersberg granite and the Trois-Epis units, were both formerly considered as migmatites. The intrusion of the Kaysersberg granite was dated at 325.8 ± 4.8 Ma. The Trois-Epis unit was found to be the product of volume recrystallization of a former granulite, which occurred under amphibolite-facies conditions 327.9 ± 4.4 Ma ago. The amphibolite-facies overprint of the Trois-Epis zircons led to the complete rejuvenation of most of the zircon domains by annealing and replacement/recrystallization processes. Annealing is assumed to occur in strained lattice domains, which are possibly disturbed by high trace element contents and/or large differences in decay damage between adjacent growth zones. Investigation of cathodoluminescence structures reveals that the replacement occurs along curved chemical reaction fronts that proceed from the surface towards the interior of the zircon. The monazite U-Pb system still records the age of high-grade metamorphism at around 335 Ma. The chemical reagent responsible for the rejuvenation of zircon obviously left the monazite unaffected.
Based on single-crystal structure refinements, miguelromeroite, Mn5(H2O)4(AsO3OH)2(AsO4)2, from the Ojuela mine, Mapimi, Durango, Mexico, is described as a new species corresponding to the ...Mn-dominant member of a series with sainfeldite, Ca5(H2O)4(AsO3OH)2(AsO4)2, and type villyaellenite, (Mn,Ca)Mn2Ca2(H2O)4(AsO3OH)2(AsO4)2, from Sainte-Marie aux Mines, Alsace, France, is redefined as an ordered intermediate species in the series. Miguelromeroite is monoclinic, C2/c, a=18.030(1), b=9.2715(5), c=9.7756(5) Å, β = 96.266(2)°, V=1624.4(2) Å3, Z=4. At the Ojuela mine, miguelromeroite occurs as a compact spray of orange-pink, prismatic crystals up to 4 cm in length. Crystals are elongate on 001 with forms {100}, {110} and {101̄}. Physical properties: pale pink streak, transparent, vitreous luster, brittle, good {100} cleavage, conchoidal fracture, Mohs hardness approximately 4, measured density 3.69(3) g/cm3, and calculated density 3.714 g/cm3. Optical properties: biaxial (-), nα 1.713(2), nβ 1.723(2), nγ 1.729(2), 2Vmeas 70(5)°, 2Vcalc 75°, orientation X=b, Zc= 40° in obtuse β, pleochroic pale pink, Z>>X>Y. Miguelromeroite is named for Miguel Romero Sanchez (1926-1997) in recognition for his dedication to documenting and preserving Mexico's rich mineral heritage. Miguelromeroite also occurs at the Veta Negra mine, Tierra Amarilla, Copiapo Province, Chile, at Sterling Hill, Ogdensburg, Sussex County, New Jersey, and at the Gozaisho mine, Iwaki, Fukushima Prefecture, Honshu Island, Japan. Some material from the Gozaisho mine may correspond to another ordered species in the series with the formula (Ca,Mn)Mn2Ca2(H2O)4(AsO3OH)2(AsO4)2.
Two peat sequences were sampled in the vicinity of the main mining districts of the Vosges Mountains: Sainte-Marie-aux-Mines and Plancher-les-Mines. Lead isotopic compositions and excess lead fluxes ...were calculated for each of these radiocarbon-dated sequences. Geochemical records are in very good agreement with the mining history of the area, well known over the last millennium. Except for an anomaly corresponding to the Middle Bronze Age which has not yet been resolved, there is no clear geochemical evidence of local metal production in the Vosges before the 10th century as excess lead deposition archived between 500
BC and 500
AD is attributed to long-range transport of polluted particulate matter. The approach described here can be applied to other mining districts where archaeological evidence is scarce or even lacking, but where past exploitation is suspected.
This study presents a model of successive emplacement of three granite plutons in transtensional deformation regime controlled by the preextensional synconvergent history of the lower and middle ...crust in the central Vosges Mountains (France). The complex compressional orogenic structure recorded a vertical exhumation‐related fabric in midcrustal levels which was overprinted by the regional extension. Three successively emplaced granite sheets exploited the inherited vertical anisotropy obliquely oriented with respect to the applied tensile stress. This progressive opening of original steep fabric leads to the sequential generation of free spaces toward the south, and emplacement and deformation of granite sheets. Repeated granite intrusions are responsible for reheating of southern margins of the already partially solidified granites, which became reactivated under lower ambient thermal conditions related to overall ∼6 Ma cooling of rapidly exhumed crust. The results of anisotropy of magnetic susceptibility (AMS) fabric modeling suggest a highly partitioned oblique extension divided into pure shear‐dominated deformation close to the central and northern margins of intrusions and wrench‐dominated shear along the southern margins. The AMS modeling suggests the importance of overprinting of the intrusive fabrics by the transtensional deformation.
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