scholarly journals Diferenças Químicas e Texturais entre os Veios de Quartzo Férteis e Estéreis no Depósito Aurífero Pau-a-Pique (Grupo Aguapeí, Estado de Mato Grosso)

1999 ◽  
Vol 26 (2) ◽  
pp. 91
Author(s):  
CARLOS JOSÉ FERNANDES ◽  
GÊNOVA MARIA PULZ ◽  
ALESSANDRO SILVA OLIVEIRA ◽  
MARIA DO CARMO LIMA E CUNHA ◽  
ELZIO SILVA BARBOZA ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Quartz Vein ◽  
Mineral Assemblage ◽  
The Other ◽  
Chemical Characteristics ◽  
Mato Grosso ◽  
Vein System ◽  
Quartz Veins ◽  
Ore Minerals ◽  
Ph Fluctuations

The quartz veins in the Pau-a-Pique gold deposit hosted in Aguapeí Group metassediments have textural, paragenetic and chemical characteristics that provide prospectives criteria for gold. Gold disseminations occur in the quartz vein system and in the hydrothermal halo. The highest gold grades are within quartz veins that have comb, saccaroidal and replacement textures. The barren veins show ribbon and buck textures. Both fertile and barren veins exhibit a lack of correlation between gold grades and of the other elements (As, Fe, Sc and Ta). This behavior indicates that gold grades might be adequate chemical criteria for distinction between barren and the fertile veins. Gold grains appear associated to martite and oxihydroxides pseudomorphs that replace the ore minerals in veins. The mineral assemblage and textures of the quartz veins, suggest a gold remobilization due to Eh-pH fluctuations related to interaction between the ore and the meteoric solutions.

Estimation of paleostress from pore fluid pressure of the quartz veins and its significance in the Cu-Pb-Zn mineralization (Ambaji, Aravalli-Delhi mobile belt, NW India)

2020 ◽  
Author(s):  
Neeraj Kumar Sharma ◽  
Tapas Kumar Biswal
Keyword(s):  
Fluid Inclusion ◽  
Quartz Vein ◽  
Hydrothermal Fluid ◽  
Stress Condition ◽  
Fluid Pressure ◽  
Tectonic Stress ◽  
Mobile Belt ◽  
Mohr Circle ◽  
Quartz Veins ◽  
Ore Minerals

<p>Quartz veins are produced from the crystallization of the last silica enriched hydrothermal phase from granitic magma circulating along the pre-existing fracture of rock. In many instances, these hydrothermal fluid act as a carrier for the ore minerals. The intrusion of quartz veins along fractures depends upon the tectonic stress conditions in the area. Fluid pressure (P<sub>f</sub>) of these ascending liquids should be higher than the normal compressive stress (σ<sub>n</sub>) to dilate the fractures. We are studying the quartz vein intrusion in the Cu‒Pb‒Zn mineralization belt of Ambaji, South Delhi terrane, Aravalli- Delhi mobile belt, NW India. The host rocks include mica schist, amphibolite, calc schist, talc tremolite schist, and four phases of granite intrusion (G<sub>0</sub>‒G<sub>3</sub>). The age of G<sub>0</sub>, G<sub>1</sub>, G<sub>2</sub> and G<sub>3</sub> granite are 960, 860, 800, and 750 Ma respectively. The rocks underwent three phases of folding (F<sub>1</sub>‒F<sub>3</sub>) and show greenschist to amphibolite facies metamorphism. The quartz vein intrusion is related to syn to post F<sub>3</sub> folding and G<sub>3</sub> granite magmatism. This final phase hydrothermal fluid extremely altered host rock and formed biotite-tourmaline-quartz and tremolite-actinolite-talc-chlorite greisen along the contact. The greisen host chalcopyrite-pyrite-galena-sphalerite mineralization suggesting the ore minerals were transported by the quartz vein. Vein orientation, stress condition, fluid pressure fluctuation, and fluid temperature can decide the fracture dilation and mineralization processes. Therefore, this work concentrates on the geometrical distribution of the vein orientation data. From this we deduced (i) girdle distribution pattern of vein data  (ii) σ<sub>1</sub> = 120º/75º, σ<sub>2</sub> = 052º/07º, σ<sub>3</sub> = 323º/07º indicate maximum extension was NW-SE and σ<sub>1</sub>σ<sub>2</sub> plane strikes was N52ºE, (iii) θ<sub>2</sub> =12º, θ<sub>3</sub> = 40º  and (iv) R'(driving pressure ratio) = 0.95, ϕ (tectonic stress ratio) = 0.90 indicates high value for R' leading to dilation of wide range of fractures. Further, the high ϕ value suggests uniaxial extension. Microscopic petrography of fluid inclusions shows three generations of inclusion like primary inclusion, secondary inclusion, and pseudosecondary inclusion. Most of the inclusion has aqueous and vapour phase and some inclusions show solid halite phase. We observed different types of trail bound of inclusion like intragranular inclusion, intergranular inclusion and transgranular inclusion, which suggest deformation and recrystallization in the rock. We are studying microthermometry analysis of fluid inclusion present in the quartz vein and trying to estimate the fluid pressure. With the help of fluid pressure, the 3D Mohr circle will be constructed and paleostress will be quantified. That will help in understanding the stress condition and mineralization in the rock.</p><p>Keywords: Veins, Fractures, Paleostress, 3D Mohr Circle, Mineralisation, Fluid Inclusion, Microthermometry</p>

scholarly journals Geological and Geochemical Characteristics of the Archean Basement-Hosted Gold Deposit in Pinglidian, Jiaodong Peninsula, Eastern China: Constraints on Auriferous Quartz-Vein Exploration

Minerals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 62 ◽  
Author(s):  
Ruihong Li ◽  
Ntwali Albert ◽  
Menghe Yun ◽  
Yinsheng Meng ◽  
Hao Du
Keyword(s):  
Gold Deposit ◽  
Quartz Vein ◽  
Metamorphic Rock ◽  
Eastern China ◽  
Wall Rock ◽  
Gold Deposits ◽  
Ore Formation ◽  
Quartz Veins ◽  
Auriferous Quartz Vein ◽  
Archean Basement

The gold deposits that are hosted in the Archean metamorphic rock, have yet to be explored beyond Pinglidian gold deposit in the northwestern Jiaodong Peninsula, eastern China. This kind of gold deposit differs from those that are hosted in Mesozoic granitoids, showing good potential for the prospecting of auriferous quartz-vein gold deposits controlled by the structures in greenfield Archean metamorphic rock. Pinglidian gold deposit is located in the hanging wall of the Jiaojia fault and consists of eight separated orebodies that are enveloped by altered rock in Archean biotite plagiogneiss. These orebodies and wall-rock alterations are strongly controlled by local structures that formed during the Mesozoic rotation and kink folding of the foliated and fissile Archean basement host. The major wall-rock alterations comprise sericitization, silicification, pyritization, and carbonation, which is up to 18 m in width and progressively increases in intensity towards the auriferous quartz vein. The visible gold is present as discrete native gold and electrum grains, which have basically filled in all manner of fractures or are adjacent to galena. We recognize two types of gold bearing quartz veins that are associated with mineral paragenetic sequences during hydrothermal alteration in the Pinglidian gold deposit. The petrological features and geochemical compositions in the reaction fronts of the alteration zone suggest variations in the physicochemical conditions during ore formation. These minerals in the wall rock, such as plagioclase, biotite, zircon, titanite, and magnetite, have been broken down to hydrothermal albite, sericite, and quartz in a K–Na–Al–Si–O–H system, and sulfides in a Fe–S–O–H system. The major and trace elements were calculated by the mass-balance method, showing gains during early alteration and losses during late alteration. The contents of K2O, Na2O, CaO, and LOI varied within the K–Na–Al–Si–O–H system during alteration, while Fe2O3 and MgO were relatively stable. Rare-earth elements (REE) changed from gains to losses alongside the breakdown of accessory minerals, such as large ion lithophile elements (LILE). The Sr and Ba contents exhibited high mobility during sericite-quartz alteration. Most of the low-mobility high-field strength elements (HFSE) were moderately depleted, except for Pb, which was extremely high in anomalous samples. The behavior of trans-transition elements (TRTE) was related to complicated sulfides in the Fe–S–O–H system and was constrained by the parameters of the mineral assemblages and geochemical compositions, temperature, pressure, pH, and fO2. These factors during ore formation that were associated with the extents and intensity of sulfide alteration and gold precipitation can be utilized to evaluate the potential size and scale of an ore-forming hydrothermal system, and is an effective exploration tool for widespread auriferous quartz veins in Archean metamorphic basements.

Performance of two combine harvester header in soybean crops

2020 ◽  
Vol 13 (2) ◽  
pp. 1
Author(s):  
E. M. Samogim ◽  
T. C. Oliveira ◽  
Z. N. Figueiredo ◽  
J. M. B. Vanini
Keyword(s):  
Experimental Design ◽  
Crop Yield ◽  
Field Performance ◽  
Travel Speed ◽  
The Other ◽  
Combine Data ◽  
Mato Grosso ◽  
Tukey Test ◽  
Combine Harvester ◽  
And Performance

The combine harvest for soybean crops market are currently available two types of combine with header or platform, one of conventional with revolving reel with metal or plastic teeth to cause the cut crop to fall into the auger header and the other called "draper" headers that use a fabric or rubber apron instead of a cross auger, there are few test about performance of this combine header for soybean in Mato Grosso State. The aim of this work was to evaluate the soybean harvesting quantitative losses and performance using two types combine header in four travel speed. The experiment was conducted during soybean crops season 2014/15, the farm Tamboril in the municipality of Pontes e Lacerda, State of Mato Grosso. The was used the experimental design of randomized blocks, evaluating four forward harvesting speeds (4 km h-1, 5 km h-1, 6 km h-1 and 7 km h-1), the natural crops losses were analyzed, loss caused by the combine harvester (combine header, internal mechanisms and total losses) and was also estimated the  field performance of each combine. Data were submitted to analysis of variance by F test and compared of the average by Tukey test at 5% probability. The results show the draper header presents a smaller amount of total loss and in most crop yield when compared with the conventional cross auger.

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.

The Mineral Characteristics and Occurrence of Gold in Nali Gold Deposit, Guangxi

2014 ◽  
Vol 936 ◽  
pp. 2383-2388
Author(s):  
Zhi Wen Li ◽  
Cheng Dong Liu ◽  
Xuan Qing Zhao ◽  
Jian Hui Lu ◽  
Guo Lin Guo
Keyword(s):  
Gold Deposit ◽  
Mineral Composition ◽  
Electron Probe ◽  
Mining Area ◽  
Optical Microscope ◽  
Analysis Techniques ◽  
Mineral Characteristics ◽  
Ore Minerals

Using the analysis techniques of polarizing optical microscope and electron probe, mineral composition, ore texture and structure and the occurrence of Au in the primary ore are studied. The research shows that the main ore minerals in the ore include realgar, pyrite and arsenopyrite etc. Sulfur-stibarsen is the main carrier of Au, and is the major associated mineral of realgar, surrounded mainly by realgar, and partly is the associated mineral of arsenopyrite. The existence of visible gold and microscopic gold in the ore of this mining area can be excluded, and the gold might exist mainly in the form of inclusion gold, which is the so-called “nanoAu”.

scholarly journals Natural infection of phlebotomines (Diptera: Psychodidae) in a visceral-leishmaniasis focus in Mato Grosso do Sul, Brazil

2007 ◽  
Vol 49 (2) ◽  
pp. 119-122 ◽  
Author(s):  
João Cezar do Nascimento ◽  
Byanca Regina de Paiva ◽  
Rosely dos Santos Malafronte ◽  
Wedson Desidério Fernandes ◽  
Eunice Aparecida Bianchi Galati
Keyword(s):  
Visceral Leishmaniasis ◽  
Natural Infection ◽  
Leishmania Species ◽  
Common Species ◽  
The Other ◽  
Lutzomyia Longipalpis ◽  
Leishmania Chagasi ◽  
Mato Grosso ◽  
Negative Results ◽  
Mato Grosso Do Sul

The main purpose of this study was to investigate natural infection by Leishmania in phlebotomine females in a visceral-leishmaniasis focus in Antonio João county in Mato Grosso do Sul State, Brazil. Between June and October 2003, the digestive tracts of 81 females captured in Aldeia Campestre, Aldeia Marangatu and Povoado Campestre were dissected. The females were separated by species, location, area and date of capture into 13 groups and kept in ethanol 70%. To identify the Leishmania species using the PCR technique, amplifications of the ribosomal-DNA (rDNA) and mini-exon genes were analyzed. Of the 81 specimens, 77 (95%) were Lutzomyia longipalpis, making this the most common species; only one specimen of each of the species Brumptomyia avellari, Evandromyia cortelezzii, Evandromyia lenti and Nyssomyia whitmani was found. Trypanosomatids were identified in eight of the nine groups of Lutzomyia longipalpis (10.39%) one group from Aldeia Campestre, one from Aldeia Marangatu and six from Povoado Campestre; of the eight groups, one from Aldeia Marangatu and another, with promastigotes forms also confirmed by dissection (1.23%) from Povoado Campestre, were identified by PCR as Leishmania chagasi (2.6%). The other groups gave negative results. These findings indicate that there is a high risk of leishmaniasis transmission in this area.

scholarly journals Nutrient accumulation and biomass production of alfafa after soil amendment with silicates

Revista CERES ◽  
2014 ◽  
Vol 61 (3) ◽  
pp. 406-413 ◽  
Author(s):  
Angélica Cristina Fernandes Deus ◽  
Leonardo Theodoro Bull ◽  
Juliano Corulli Corrêa ◽  
Roberto Lyra Villas Boas
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Soil Amendment ◽  
Soil Acidity ◽  
Steel Slag ◽  
The Other ◽  
Chemical Characteristics ◽  
Nutrient Accumulation ◽  
Particle Size Fractions ◽  
Soil Liming

Studies on the use of silicate correctives in agriculture show that they have great potential to improve soil chemical characteristics, however, little information is available on the reactivity rates of their particle-size fractions. This study investigated whether the reactivity rates obtained experimentally could be considered in the calculation of ECC (effective calcium carbonate) for soil liming, promoting adequate development of alfalfa plants. Six treatments were evaluated in the experiment, consisting of two slag types applied in two rates. The experimental ECC was used to calculate one of the rates and the ECC determined in the laboratory was used to calculate the other. Rates of limestone and wollastonite were based on the ECC determined in laboratory. The rates of each soil acidity corretive were calculated to increase the base saturation to 80%. The treatments were applied to a Rhodic Hapludox and an Alfisol Ferrudalfs. The methods for ECC determination established for lime can be applied to steel slag. The application of slag corrected soil acidity with consequent accumulation of Ca, P, and Si in alfalfa, favoring DM production.

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