The Baia Sprie epithermal system, a well-known deposit for its impressive mineralogical associations, shows the proper conditions for acid mine drainage and can be considered a general example for ...affected mining areas around the globe. Efflorescent samples from the abandoned open pit Minei Hill have been analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman and near-infrared (NIR) spectrometry. The identified phases represent mostly iron sulfates with different hydration degrees (szomolnokite, rozenite, melanterite, coquimbite, ferricopiapite), Zn and Al sulfates (gunningite, alunogen, halotrichite). The samples were heated at different temperatures in order to establish the phase transformations among the studied sulfates. The dehydration temperatures and intermediate phases upon decomposition were successfully identified for each of mineral phases. Gunningite was the single sulfate that showed no transformations during the heating experiment. All the other sulfates started to dehydrate within the 30–90°C temperature range. The acid mine drainage is the main cause for sulfates formation, triggered by pyrite oxidation as the major source for the abundant iron sulfates. Based on the dehydration temperatures, the climatological interpretation indicated that melanterite formation and long-term presence is related to continental and temperate climates. Coquimbite and rozenite are attributed also to the dry arid/semi-arid areas, in addition to the above mentioned ones. The more stable sulfates, alunogen, halotrichite, szomolnokite, ferricopiapite and gunningite, can form and persists in all climate regimes, from dry continental to even tropical humid.
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•Efflorescent salts from mining areas have a great impact on the environment.•Secondary minerals are influenced by geology, hydrology, biology and climate.•AMD-precipitates samples were analyzed by XRD, SEM, Raman and NIR spectrometry.•The dehydration temperatures and intermediate phases were identified.•A climatological model was obtained on the formation and long-term presence.
Abstract The wounding of the Hungarian king Matthias Corvinus in the battle of Baia with Stephen the Great, in 1467, is known and true. The issues that need to be clarified and that we proposed in ...this study, concern the weapon(s) that caused the king’s wound during the Battle of Baia; if there were arrows, how many arrows struck the king’s body; what parts of the body were pierced by the arrow(s); how did Matia Corvin’s wound heal: naturally or through the intervention of a surgeon? All this has given rise to some controversies, which we would like to analyze from the most important known sources.
Industrial pollution is a worldwide problem, especially near mining/smelter sites where toxic metals tend to accumulate in soils, sediments, and water. These elements pose a risk both for humans and ...other organisms' health. In Eastern Europe, assessment of toxic elements such as Pb, Cu, Zn, and others remain challenging because traditional methods are costly and time consuming due to sample collection, chemical digestion, and quantification in laboratories. To reduce these limitations, new assessment methods are needed for deployment in impacted areas. The study conducted herein is the first of its kind to combine portable X-ray fluorescence (PXRF) spectrometry with non-parametric indicator kriging for rapid soil pollution hotspot mapping in Eastern Europe. PXRF was used to assess As, Cu, Cr, Mn, Pb, Zn, and V at 131 georeferenced points (121 impacted; 10 control) in and around the city of Baia Mare, Romania. For spatial variability analysis, ordinary kriging interpolation was used to predict elemental levels in unsampled locations. Pb exceeded the action limit in 91.09% of the area, followed by As (81.20%), Cu (41.52%), Zn (26.69%), and Cr (5.58%). Indicator kriging was then used to estimate the probabilities of data exceeding certain threshold levels. As a result, the pollution hotspots were quickly identified. The highest estimated probabilities of surpassing the Romanian action limits were found around the smelting plant and dispersal stack. Results indicated a likelihood of exceeding action limits of 75% for Cu and between 50 and 75% for Zn. A major portion of the study area showed high probabilities for As and Pb surpassing the Romanian action limits by 75%. Summarily, the PXRF/indicator kriging approach proved effective at rapidly assessing the potential of metal-laden soils to exceed government mandated limits. Using this approach, other cities impacted by similar operations can quickly and cost effectively map areas of concern.
•PXRF and indicator kriging were used to map soil metal hotspots.•Government action limits were exceeded in many locations.•Highest probability of impacted soils were near smelting plants.
After the cessation of mining activities, concerns for mining cadastre research are only sporadic. The present study aims at bringing up to date the evolution of the mining cadastre in the Romanian ...provinces with a mining book regime, territories that were until 1918 within the structure of the former Habsburg Empire. (Austro-Hungary since 1867). Several stages can be distinguished in the evolution of the mining cadastre in the areas shown. From the 16
century until 1854 the principles and methods of the mining cadastre were set up. Between 1854 and 1924 the provisions of the Austrian General Mining Law of 1854 were followed. From 1924 to 1948, the mining cadastre provisions provided for in the mining law of 1924 and other specific regulations are applicable. After 1948, under the conditions of a statist regime, the mining record did not respect the principles of the mining cadastre previously assessed. After 1990, the new mining cadastre only partially takes over the classical principles and methods of the mining cadastre. The way of applying the mining cadastre was focused upon in the town of Borșa, a mountainous place where farmers had not formed cooperatives and where intensive mining was carried out until 2007. With the cessation of mining in Baia Borșa, the mining cadastre was reduced to inventories of some mining assets and sporadic cadastre registrations of some premises and settling ponds. The study analyzes the current situation and proposes some integrated solutions, mediated by GIS technology, aiming the introduction of the mining cadastre in correlation with the introduction of the general cadastre. In this context, GIS technology offers modeling tools that, for example, can assess the degree of suitability of the land for construction.
Valentinite forms through the alteration of stibnite in sulphide deposits. Colloform sphalerite is a widespread mineral in low-temperature deposits, particularly those of the Mississippi-Valley type. ...We identified valentinite and colloform sphalerite in hydrothermal deposits occurring in the Baia Mare area. The Baia Mare metallogenic district of Neogene age occurs in the northwestern part of the Neogene volcanic chain within the Eastern Carpathians. The Neogene volcanism from Baia Mare area is related to the subduction processes of the East European plate under two microplates, Alcapa and Tisza-Dacia/Tisia, in the post-collisional compressive phase. We have identified valentinite in the Dealul Crucii and Baia Sprie deposits, associated with other epithermal minerals, in the absence of the stibnite. Valentinite is deposited in the final phase of the epithermal process after calcite and manganese-bearing calcite. Micro-Raman and microprobe determinations indicate the presence of valentinite. The formula of valentinite is close to stoichiometric Me2O3 and contains small amounts of tin as an antimony substituent. Colloform sphalerite was identified in the Baia Sprie ore deposit associated with minerals formed in the final epithermal phase. It was deposited on idiomorphic crystals of stibnite, which it corrodes. Its structure and an alternate banding, exhibited on the nano-/microscale, were identified by optical microscopy, SEM (scanning electron microscopy), and BSE (backscattered electron microscopy) imaging. These structures are typical for colloform sphalerite and suggest a genesis due to episodic precipitation. The spherical nano/micro-particles (nodules) are characteristic of the colloform sphalerite from Baia Sprie. Raman analysis indicates the presence of a colloform sphalerite with low iron content. The typical diffraction lines for sphalerite were identified in X-ray diffraction: 3.118 Å (111), 1.907 Å (220), 1.627 Å (311). Microprobe analysis certifies the presence of sphalerite with the stoichiometric formula close to ZnS. Iron content is low (0%–0.0613%), but Sb (0.7726%–2.6813%), Pb (0.56%–1.1718%), Bi (0%–0.1227%) are also present. The negative correlation between Zn and Sb suggests the simultaneous deposition from the same epithermal fluids. Valentinite and colloform sphalerite were formed at low temperatures (100–150 °C) at the end of the epithermal process.
•Terme di Baia is one of the most important archaeological sites in Southern Italy.•Microstructural and compositional examination of coating mortars.•Long-lasting use of a valuable mix design created ...with local raw materials.•Secondary phases improved the technological properties of mortars.
Ancient pozzolanic mortars show the high technological quality achieved by Roman construction workers, due to their ‘excellent state’ of preservation in every environment. These workers well knew that thanks to the combination of lime with specific volcanic products (pozzolana), mortar and concrete become hydraulic, allowing underwater hardening and increasing mechanical strength. The use of pozzolana in a mortar provides the underwater curing (hydraulic limes) of whatever construction with higher speed compared to carbonation processes of slaked lime. Whenever pozzolana is not available, it is substituted by ceramic fragments, which possess similar hydraulic properties. This research focuses, for the first time, on the detailed characterization of mortars coming from the Thermal Complex of Baia, which represents one of the most important archaeological sites in the Campania region. Thanks to several thermal springs, the ancient city of Baiae (Campi Flegrei) was the holiday resort of the Roman aristocracy. The former Soprintendenza Archeologia della Campania, allowed us to perform non-invasive, but representative, sampling of mortars that were characterised by multianalytical methodologies (POM, XRPD, SEM-EDS, TGA, and MIP) providing useful information on possible future activities of restoration. Results confirmed the expertise of Roman workers, who skilfully combined volcanic tuff aggregate, hydrated lime, and ceramic fragments. In particular, the typical zeolitic mineral association of phillipsite>chabazite>analcime found in the tuff aggregate pointed out their provenance from the Neapolitan Yellow Tuff related to the volcanic activity of Campi Flegrei of ca. 15ka BP. The most relevant characteristic detected in all studied samples is the mortar hydraulicity testified by evidences such as reaction rims between pozzolana and binder, Hydraulicity Index (HI), and thermal analyses investigation. Also, composition of secondary mineralogical phases in the cementiceous matrix is particularly relevant. Distinctive is the contemporary presence of C-A-S-H gel, calcite and gypsum. C-A-S-H gel is derived from lime/ceramic fragments reaction; calcite is likely related to the partial reaction of underburned lime; and gypsum could be ascribable to the sulphation process of calcite. These secondary minerogenetic products fill pore space and enhance bonding in pumice fragments, thus contributing to long-term durability of mortars.
The Baia–Fondi di Baia eruption is one of the sporadic events that have occurred in the western sector of the Campi Flegrei caldera. It dates back to 9525–9696
bp
and opened Epoch 2 of the caldera ...activity after a 1000-year-long period of quiescence. Although relatively small in terms of erupted volume with respect to most of the events of the past 15 ka, the Baia–Fondi di Baia eruption was characterized by a complex series of events, which have led to different interpretations in the literature. We present a detailed stratigraphic study of 40 outcrops in a sector of about 90 km
2
, coupled with sedimentological (grain size, componentry), physical (density, vesicularity), textural, and compositional analyses of the erupted deposits. Based on these data, we interpret the stratigraphic succession as being related to two distinct eruptive episodes (Baia and Fondi di Baia). These were separated by a short time interval, and each was characterized by different eruptive phases. The Baia eruptive episode started in a shallow-water environment with an explosive vent-opening phase that formed a breccia deposit (Unit I), rapidly followed by alternating fallout activity and dense, pyroclastic density current deposits generation (Unit II). Sedimentological features and pumice textural analyses suggest that deposition of Unit II coincided with the intensity peak of the eruption, with the fallout deposit being characterized by a volume of 0.06 ± 0.008 km
3
(corresponding to a total erupted mass of 4.06 ± 0.5 × 10
10
kg), a column height of 17 km, and a corresponding mass flow rate of 1.8 × 10
7
kg s
−1
. The associated tephra also shows the highest vesicularity (up to 81 vol.%) the highest vesicle number density (1.01 × 10
8
cm
−3
) and decompression rate (0.69 MPa s
−1
). This peak phase waned to turbulent, surge-like activity possibly associated with Vulcanian explosions and characterized by progressively lower intensity, as shown by density/vesicularity and textural properties of the erupted juvenile material (Unit III). This first eruptive episode was followed by a short quiescence, interrupted by the onset of a second eruptive episode (Fondi di Baia) whose vent opening deposited a breccia bed (Unit IV) which at some key outcrops directly overlies the fallout deposit of Unit II. The final phase of the Fondi di Baia episode strongly resembles Unit II, although sedimentological (presence of obsidian clasts which are absent in the Baia deposits) and textural (lower vesicularity, vesicle number density, and decompression rate values) features, together with a more limited dispersal, suggest that this phase of the eruption had a lower intensity. The large range of groundmass glass compositions, associated with variable proportions of highly (phonolitic–trachytic) and mildly (tephriphonolitic–latitic) evolved end-members in the erupted products, also suggests that these eruptive episodes were fed by at least two different magma batches that interacted during the different phases, with an increase of tephriphonolitic–latitic magma occurring during the Fondi di Baia stage.
The Baia Sprie epithermal ore deposit is one of the best-known deposits in Romania and Europe. It consists mainly of a vein system with two major veins: (1) Principal Vein and (2) Southern Vein, ...along fractures that delimitate an andesitic block and a subvolcanic intrusion. The Principal Vein is one of the longest hydrothermal veins in Europe, with more than 5km in length, a thickness that varies between 0.5 and 22m and it extends vertically on more than 800m. Samples belonging to different levels of Principal Vein have been analyzed using electron microprobe. A new occurrence of bismuth minerals was identified within the deeper part of the deposit: bismuthinite, lillianite–gustavite, disordered intergrowths of lillianite homologues, heyrovskyite and cosalite. The presence of Bi-sulfosalts suggests temperature of ~350°C, while the As content in arsenopyrite indicates formation temperatures between 320 and 360°C. The oscillatory zoning bands of pyrite and tetrahedrite–tennantite members indicate an increased Sb and As concentration in hydrothermal solutions. The zoning textures suggest a high S and low As concentration in the early fluids followed by multiple pulses of As-rich solutions in the late fluids. The high content of As in pyrite and the presence of bismuth minerals at Baia Sprie deposit can represent indicators for significant Au concentrations within the lower level of the mineralization. From the type locality Baia Sprie new analytical data for semseyite were presented and for the first time a new occurrence of geocronite–jordanite series was identified in the intermediate and upper part of the deposit.
•Samples from the all three main levels of Baia Sprie deposit were analyzed using EPMA.•New occurrences of bismuth minerals and Pb sulfosalts are identified and described.•Bismuth minerals suggest temperatures of ~350°C and may represent indicators for Au.•Zoning textures of pyrite and fahlores indicates increased Sb–As activity in fluids.•Arsenopyrite geothermometer shows temperatures of 320–360°C for the lower level.
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