The Sb-Au-district Brandholz/Goldkronach (Fichtelgebirge, Germany): mineralogical indications for the evolution of hydrothermal Sb-mineralization.

2021 ◽  
Author(s):  
Björn Fritzke ◽  
Thomas Seifert ◽  
Elmar Linhardt ◽  
Christin Kehrer
Keyword(s):  
Stage I ◽  
Geochemical Analysis ◽  
Precipitation Sequence ◽  
Bulk Rock ◽  
Southeastern Part ◽  
Precipitation Mechanism ◽  
Quartz Veins ◽  
Ore Mineralization ◽  
Hydrothermal Environment

<p>The Brandholz/Goldkronach district is situated in the southeastern part of Germany in the Bavarian Fichtelgebirge. Previous literature of the mineralogy of the district is rather descriptive and modern geochemical analysis are entirely missing. In this contribution, we combine petrography, bulk rock-geochemical analysis, SEM-MLA as well as EPMA to infer on precipitation mechanism and ore-forming processes. The quartz-polymetallic-sulfide veins are hosted in Ordovician shists, called “Phycodenschiefer”, which were intruded by upper Devonian meta-basalts. Antimony-sulfides are the main ore mineralization inside of the quartz-veins, accompanied by minor auriferous arsenopyrite and pyrite. Petrographic observations suggest a precipitation of an early stibnite phase (stage I). Sb-Pb-sulfides/sulfosalts (stage II) precipitated in fractures and fissures of stage I stibnite with a slightly change to Pb-rich Sb-phases. The antimony-mineralization event evolved from stibnite (Sb<sub>2</sub>S<sub>3</sub>), over fülöppite (Pb<sub>3</sub>Sb<sub>8</sub>S<sub>15</sub>), zinkenite (Pb<sub>9</sub>Sb<sub>22</sub>S<sub>42</sub>), plagionite (Pb<sub>5</sub>Sb<sub>8</sub>S<sub>17</sub>) to boulangerite (Pb<sub>5</sub>Sb<sub>4</sub>S<sub>11</sub>). Chemical analyses corroborate the petrographic observations and indicate a change in the hydrothermal environment from a Sb- to Sb-Pb dominated system with a distinct geochemical change from Pb-free to Pb-containing Sb-phases. A characterization of the precipitation sequence can be used to improve the understanding of the hydrothermal evolution of the whole Sb-Au-ore system in Goldkronach.</p>

scholarly journals Mineralogy, Geochemistry and Genesis of Zeolites in Cenozoic Pyroclastic Flows from the Asuni Area (Central Sardinia, Italy)

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 268
Author(s):  
Angela Mormone ◽  
Monica Piochi
Keyword(s):  
Natural Zeolite ◽  
Pyroclastic Flows ◽  
Bulk Rock ◽  
Pyroclastic Deposits ◽  
Geochemical Characterization ◽  
X Ray ◽  
Genetic Process ◽  
Dioctahedral Smectite ◽  
Hydrothermal Environment

Natural zeolite occurrences have been recognized in several Cenozoic pyroclastic deposits in central Sardinia. This study concerns the mineralogical and geochemical characterization of the zeolitized tuffites in the Asuni area (Oristano province) and aims to complement information regarding the zeolitization processes developed in the nearby Allai deposits. Optical and scanning electron microscopy, X-ray powder diffraction, qualitative vs. quantitative microanalyses and bulk-rock geochemistry were performed. Analytical results allow defining the mineral distribution, textural relationships and geochemical features of the zeolite-bearing rocks. The most abundant secondary minerals are Ca-Na mordenites. Contrarily to the most common worldwide clinoptilolite + mordenite paragenesis, mordenite is dominant and occurs in different morphologies, rarely coexisting with clinoptilolite in the studied volcanic tuffites. Glauconite and dioctahedral smectite complete the authigenic assemblages. The primary volcanic components mostly include plagioclase, quartz and glass shards, roughly retaining their original appearance. The tuffites range in composition from dacite to rhyolite. The collected dataset shows that zeolitization is most abundant in coarser-grained deposits and points to a genetic process that mainly involves an open hydrothermal environment governed by aqueous fluids with significant marine component, in post eruption conditions.

CHARACTERIZATION OF PALEOPROTEROZOIC STRUCTURES, AURIFEROUS QUARTZ VEINS, AND HOST ROCKS, FISHER PROPERTY, SEABEE GOLD OPERATION, SASKATCHEWAN, CANADA

2019 ◽  
Author(s):  
Courtney Carol Onstad ◽  
◽  
Kevin M. Ansdell ◽  
Camille A. Partin ◽  
Anders Carlson
Keyword(s):  
Quartz Veins ◽  
Host Rocks

scholarly journals PARAGUAY BELT LITHOSTRATIGRAPHIC AND TECTONIC CHARACTERIZATION: IMPLICATIONS IN THE EVOLUTION OF THE OROGEN (MATO GROSSO-BRAZIL) / CARACTERIZAÇÃO LITOESTRATIGRÁFICA E TECTÔNICA DO CINTURÃO PARAGUAY : IMPLICAÇÕES NA EVOLUÇÃO DO ORÓGENO (MATO GROSSO-BRASIL)

2018 ◽  
Vol 3 (2) ◽  
pp. 54-73
Author(s):  
Elzio Da Silva Barboza ◽  
Anderson Costa dos Santos ◽  
Carlos José Fernandes ◽  
Mauro César Geraldes
Keyword(s):  
Gold Content ◽  
Mato Grosso ◽  
Quartz Veins ◽  
Marine Sedimentation ◽  
Amazonian Craton ◽  
Gondwana Supercontinent ◽  
Surrounding Areas ◽  
Shelf Region ◽  
High Gold Content

The Paraguay Belt is composed by sediments deposited due to extensional events followed by inversion with deformation and magmatism and lastly collision of the Amazonian Craton and Paranapanema Block. The marine sedimentation, with Neoproterozoic ages, should have occurred in a continental shelf region, at about 800-550 Ma, when the closing of many oceans gave place to the amalgamation of the Gondwana supercontinent. Three areas were selected for this study which configuration define the perpendicular profile of the Paraguay Belt and allow the characterization of the main regional structures.The structural analysis in the sites here reported and surrounding areas allow suggesting that three deformational events are recorded in the rocks of this region. The sedimentary bedding S0, marked by alternations of dark gray and whitish coloration in the seritic phyllites is folded and the axial plane (Sn) is marked by a cleavage of ardosian. These surfaces are cut by two other deformations, Sn + 1 surface that plunges at high angles to SE as fracture cleavage and Sn + 2 that is orthogonal to the previous deformations and has NW-SE direction with vertical dips, where sometimes occurs quartz veins with high gold content. The Paraguay Belt fan geometry observed in the Sn foliation was developed during the closing of a Brazilian ocean that evolved between the Paranapanema Block and the Amazonian Craton. ResumoO Cinturão Paraguai é composto por sedimentos depositados durante eventos extencionais  seguidos de inversão com deformação e magmatismo e, por último, colisão do Craton Amazônico e do Bloco Paranapanema. A sedimentação marinha, com idades Neoproterozóicas, ocorreu  em uma região de plataforma continental, entre 800-550 Ma, quando o fechamento de muitos oceanos deu lugar à fusão do supercontinente Gondwana. Três áreas foram selecionadas para este estudo cuja configuração define um  perfil perpendicular do Cinturão do Paraguai e permite a caracterização das principais estruturas regionais.A análise estrutural nos locais aqui relatados e áreas adjacentes permite sugerir que as rochas do orógeno passou por três eventos deformacionais. O acamamento  sedimentar S0, marcado por alternâncias de coloração cinza-escura e esbranquiçada nos filitos e siltitos, é dobrado e o plano axial (Sn) é marcado por uma clivagem ardosiana. Estas superfícies são cortadas por outras duas deformações, Sn + 1 que mergulha em ângulos elevados para SE como clivagem de fratura e Sn + 2 que é ortogonal às deformações anteriores e tem direção NW-SE com mergulhos verticais, onde às vezes ocorrem veios de quartzo com alto teor de ouro. A geometria em leque  do Cinturão Paraguay observada na foliação de Sn foi desenvolvida durante o fechamento de um oceano brasileiro que evoluiu entre o Bloco Paranapanema e o Craton Amazônico.

scholarly journals HERMIONE, EVOLUTION OF ATe-BEARING EPITHERMAL MINERALIZATION, ARGOLIS, HELLAS

2007 ◽  
Vol 40 (2) ◽  
pp. 996 ◽  
Author(s):  
S. Tombros ◽  
K. St. Seymour
Keyword(s):  
Sedimentary Rocks ◽  
Ore Deposits ◽  
Stage I ◽  
Stage Ii ◽  
Quartz Veins ◽  
Minor Contribution ◽  
Epithermal Mineralization ◽  
Ore Bodies ◽  
Calcite Veins ◽  
Sandstone Formation

The Cu-Te-bearing pyrite deposits of Hermione, Argolis are hosted in Miocenic ophiolites. The ophiolites are overlain by a shale-sandstone formation with intercalations of limestones and manganiferous sedimentary rocks. The ore deposits form irregular lenticular or stratiform ore bodies, and veins. These ore bodies are related to volcanic activity in an arc-related rift at the margins of a palaeocontinent. Late N- to NNE-trending, sinistral, milky quartz-pyrite-calcite veins cut the host ophiolites. Alteration haloes of quartz-calcite, albite-sericitechlorite, and chalcedony-epidote-clay minerals are developed in the lavas as concentric shells, or as envelops that parallel the quartz veins. The telluriumbearing mineralization is developed in two successive stages, characterized by the assemblages: pyrite-(pyrrhotite)-magnetite-chalcopyrite-sphalerite (Stage I) and galena-sphalerite-freibergite-marcasite-chalcocite (Stage II), followed by a supergene stage. The cobaltiferous pyrite-chalcopyrite geothermometer defined two ranges of last-equilibration temperatures: 220° to 250°Cfor Stage I, and 120° to 195°Cfor Stage II. The calculated δ18 Ο and SD compositions of the mineralizing fluids, at 200° and 250°C, reflect the dominance of a magmatic component. The calculated δ SH2S fluid values reveal a magmatic source for the sulphur, with minor contribution from submarine sediments, whereas tellurium is proposed to be derived from a mafic-ultramafic source.

Evaluation of the level of natriuretic peptides in the diagnosis and characterization of chronic kidney disease and cardiorenal syndrome in children

2021 ◽  
Vol 25 (6) ◽  
pp. 87-92
Author(s):  
A. M. Mambetova ◽  
D. V. Bizheva ◽  
I. K. Thabisimova
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Natriuretic Peptides ◽  
Cardiorenal Syndrome ◽  
Stage I ◽  
Group Iii ◽  
Early Stages ◽  
Group I ◽  
Ckd Stage

BACKGROUND. Natriuretic peptides have cardio- and renoprotective effects, inhibiting inflammatory and proliferative processes. The role of natriuretic peptides in the early diagnosis and characterization of chronic kidney disease (CKD) and cardiovascular complications as the disease development and progresses has not been studied.TNEAIM: to study the level of natriuretic peptides in children depending on the stage of CKD development and to assess the significance of this indicator.PATIENTS AND METHODS. The study involved 93 children with congenital diseases of the urinary system at the age from 3 to 18 years. Three groups were identified: group I - 54 patients with CKD stage I , group II - 29 patients with CKD stage II; Group III - 10 children with CKD stages IV-V (patients with CKD stages IV and V were combined due to their small amount). Control group - 10 clinically healthy children of the corresponding age. The N-terminal propeptide of natriuretic hormone (NT-proBNP) was determined in the blood by the enzyme-linked immunosorbent assay.RESULTS. An increase in the level of NT-proBNP by 28.7% takes place already in the early stages of CKD. With the progression of CKD, an increase in the level of NT-proBNP was noted from 57.4 % in children in the group of patients with stage I CKD to 80 % in children in group III patients. The maximum concentrations of NT-proBNP, many times higher than those in CKD stages I and II, were observed in children with CKD stages IV-V. The degree of increase in the level of NT-proBNP correlated with the severity of CKD.CONCLUSION. In the diagnosis and characterization of CKD and cardiorenal syndrome in children, the determination of the level of natriuretic peptides is of great importance. A high level of natriuretic peptides characterizes the presence of cardiorenal relationships and can be used as an additional criterion for assessing the severity of CKD, including at the early stages of its development.

scholarly journals Structural characterization of the internal domain of Paraguai Belt, in the Cangas region, south central portion of Mato Grosso, Brazil

2015 ◽  
Vol 45 (1) ◽  
pp. 35-49 ◽  
Author(s):  
Bruno de Siqueira Costa ◽  
Carlos Humberto da Silva ◽  
Ana Cláudia Dantas da Costa
Keyword(s):  
Gold Mineralization ◽  
Axial Plane ◽  
Second Phase ◽  
Mato Grosso ◽  
Quartz Veins ◽  
South Central ◽  
Third Phase ◽  
Crenulation Cleavage ◽  
Internal Domain

The structural study of rocks in the district of Cangas showed the identification of three phases of deformation for the Cuiabá Group in this region. The main structure oriented 120/27 is related to the first phase of deformation defined by a slate cleavage, parallel to the bedding and to the axial plane of recumbent folds. In the early stages of this phase a family of quartz veins (V1) was generated, arranged parallel to the structures of this phase of deformation, being all almost deformed. The second phase of deformation formed a crenulation cleavage (Sn+1), axial plane of opened to gentle and asymmetric normal folds, with preferential orientation 110/68. The third phase of deformation is represented by a set of centimetric to decametric scale fractures and faults with metric slip that cut all previous structures, with orientations 35/82. Related to this phase of deformation occurs a second family of quartz veins (V2), which fills the fractures related to Dn+2 and may or may not be carrying gold mineralization.

Field, petrographical and geochemical characterization of a layered anorthosite sequence in the Upper Main Zone of the Bushveld Complex

2020 ◽  
Vol 123 (3) ◽  
pp. 277-296
Author(s):  
J.E. Bourdeau ◽  
S.E. Zhang ◽  
B. Hayes ◽  
A. Logue
Keyword(s):  
Bushveld Complex ◽  
Major Element ◽  
Parental Magma ◽  
Incompatible Trace Element ◽  
Limpopo Province ◽  
Main Zone ◽  
Bulk Rock ◽  
Magmatic Differentiation ◽  
Slurry Injection

Abstract A sequence of eight poikilitic anorthosite layers (labeled 1 to 8), within the Upper Main Zone in the eastern lobe of the Bushveld Complex, are exposed along a road-cut, 5.3 km northeast of the town of Apel, Limpopo Province. The anorthosite layers are meter-scale in thickness (0.4 to 10 m), have sharp contacts and are defined on the size and shape of pyroxene oikocrysts they contain. The anorthosite sequence is bounded by typical Main Zone gabbronorites. Euhedral, zoned primocrystic laths of plagioclase (An62.5-80.6; 0.2 to 4 mm long) are morphologically identical throughout the anorthosite sequence and define a moderate to strong foliation that is typically aligned parallel to the plane of layering. Interstitial clinopyroxene and orthopyroxene typically occur as large (0.8 to 80 cm) oikocrysts enclosing numerous partly rounded plagioclase chadacrysts. Rarely, orthopyroxene appears as subophitic crystals enclosing few and significantly smaller (0.08 to 0.4 mm), equant plagioclase inclusions. Detailed plagioclase and pyroxene mineral compositions for layers 2 to 5 show minimal variations within layers (0.1 to 2.3 mol% An and 0.7 mol% Mg#), whereas compositional breaks occur between layers (0.5 to 3.8 mol% An and 1.3 mol% Mg#). In layers 2 to 5, the An-content of plagioclase cores and the Mg# of both clinopyroxene and orthopyroxene crystals decrease by 2.5 mol%, 8.6 mol% and 13.0 mol% upwards, respectively. Bulk-rock incompatible trace element concentrations and patterns are similar for all analyzed anorthosite layers indicating that they are related to the same parental magma. However, bulk-rock major element oxides (e.g. Al2O3, TiO2, K2O) and atomic Mg# become more evolved upwards, consistent with magmatic differentiation. Based on the consistent plagioclase crystal morphologies and relatively constant chemistries within each anorthosite layer, we propose that each layer was formed by the intrusion of a plagioclase slurry. The upwards-evolving mineral chemistries, bulk-rock major element oxides and atomic Mg# suggests that each plagioclase slurry injection, that yielded an anorthosite layer, was derived from a slightly more fractionated parental magma prior to emplacement.

scholarly journals SYNTHESIS AND CHARACTERIZATION OF HEMATITE (Fe2O3) EXTRACTED FROM IRON ORE BY PRECIPITATION METHOD

2016 ◽  
Vol 16 (1) ◽  
pp. 15-17
Author(s):  
Andia Andia ◽  
Adi Rahwanto ◽  
Zulkarnanin Jalil
Keyword(s):  
Magnetic Separation ◽  
Steel Industry ◽  
Iron Ore ◽  
Precipitation Method ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Precipitation Mechanism ◽  
X Ray ◽  
Hematite Fe2o3

Indonesia has a lot of mining material of iron ore that could be used for various purposes in the steel industry or for other. This research, has synthesized and characterization of hematite from local iron ore from Lhoong area by precipitation mechanism. The iron ore powder was magnetic separation with magnet then mixed with HCl and NH4OH. Then, it was dried at temperature of 150 ºC and calcinated at 500º C for 2 hours. Characterizations were perfomed using X-ray Diffraction (XRD) and X-ray Fluorescence (XRF). As the results, it was found that the magnetic separation iron ore showed the composition of Fe2O3 (95.99%), SiO2 (2.10%). Then, by precipitation mechanism, the composition of Fe2O3 found around 96.58%. Next, the synthesis result are characterized with XRD show that the main phase is dominan in iron ore of Lhoong is hematit (Fe2O3). Scherrer calculations showed that precipitation mechanism to reducing grain size, the process of magnetic separation (58.009 µm) and the precipitation mechanism (20.950 µm.)

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