scholarly journals Barytová mineralizace v granodioritovém porfyritu z Bělovsi u Náchoda (orlicko-sněžnické krystalinikum, Česká republika)

2020 ◽  
Vol 28 (1) ◽  
pp. 86-93
Author(s):  
Michal Kovář ◽  
Zdeněk Dolníček

A new occurrence of baryte mineralization at Běloves near Náchod is bound to a steep NNE-SSW trending fissure in a dyke of granodiorite porphyrite, which cut phyllites of the Nové Město Group (Orlica-Sněžník Crystalline Complex). The mineralization is composed of three generations of baryte differing in Sr contents (~0.10 apfu in the oldest generation, ~0.003 apfu in the youngest generation) and small amount of hematite. The primary fluid inclusions in baryte belong to type L and L+V; the variable phase proportions are probably caused by postdepositional damage of part of the present fluid inclusions. The wide range of temperatures of both initial melting (-40 to -1 °C) and final ice melting (-0.3 to -12.3 °C) suggests involvement of fluids with very variable salt systems and salinities. The δ34S values of baryte range between +5.5 and +7.1 ‰ CDT. The mineral composition, chemical composition of minerals and fluid inclusion data suggest that the studied mineralization is similar to Late Variscan vein baryte and mineralizations of the Bohemian Massif. The source of fluids is interpreted in evaporated fresh waters of Permian lakes, which occurred in the adjacent Krkonoše Piedmont Basin during the Permian.

1990 ◽  
Vol 54 (375) ◽  
pp. 305-309 ◽  
Author(s):  
A. Canals-Sabate ◽  
J. C. Touray ◽  
J. Fabre

AbstractLarge thenardite crystals have been sampled at New Agorgott, in the Taoudenni area of northern Mali. They are still in equilibrium with a pressurized NaCl saturated brine capped by a halite layer. Clays located about 1 m above the thenardite occurrence have been dated at 6760 y.BP. The crystals contain numerous, large, brine and solid inclusions. Microcryscopic studies show that the fluids can be explained by the addition of MgCl2 to the Na2SO4-NaCl-H2O system (eutectic temperature: −31 to −35°C; possible bloedite Na2Mg(SO4)2.4H2O formed after freezing). The homogenization temperatures of primary fluid inclusions are in the range 28 to 50°C. In order to understand the significance of the highest Th values, overheating experiments under 1 bar pressure were performed at different heating rates up to 170°C. The results are as follows:(i)When the temperature of stretching (TOh) is higher than about 10°C, overheating is recorded and fossilized (identical Th after some hours, several days or 8 months storage at 5°C).(ii)The lowest Th values (28°C) are probably near the formation temperature of thenardite; the highest ones reflect stretching under present desert conditions.(iii)With TOh lower than about 60°C, a fair correlation is observed between Th and TOh.Finally, taking into account recent natural overheating, the fluid inclusion data are compatible with the formation of thenardite from underground brines later than the beginning of desert conditions in the Taoudenni area (i.e. about 3000 y.BP).


Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 831
Author(s):  
Anatoliy R. Galamay ◽  
Krzysztof Bukowski ◽  
Igor M. Zinczuk ◽  
Fanwei Meng

Currently, fluid inclusions in halite have been frequently studied for the purpose of paleoclimate reconstruction. For example, to determine the air temperature in the Middle Miocene (Badenian), we examine single-phase primary fluid inclusions of the bottom halites (chevron and full-faceted) and near-surface (cumulate) halites collected from the salt-bearing deposits of the Carpathian region. Our analyses showed that the temperatures of near-bottom brines varied in ranges from 19.5 to 22.0 °C and 24.0 to 26.0 °C, while the temperatures of the surface brines ranged from 34.0 to 36.0 °C. Based on these data, such as an earlier study of lithology and sedimentary structures of the Badenian rock salts, the crystallization of bottom halite developed in the basin from concentrated and cooled near-surface brines of about 30 m depth. Our results comply with the data on the temperature distribution in the modern Dead Sea.


2014 ◽  
Vol 6 (2) ◽  
Author(s):  
Oktay Canbaz ◽  
Ahmet Gökce

AbstractThe Çöpler gold deposit occurs within the stockwork of quartz hosted by the Çöpler granitoid (Eosen) and by surrounding metasediments of Keban metamorphic (Late Paleozoic - Early Mesozoic) and the Munzur limestones (Late Carboniferous - Early Cretaceous).Native gold accompanied by small amounts of chalcopyrite, pyrite, magnetite, maghemite, hematite, fahlerz, marcasite, bornite, galena, sphalerite, specular hematite, goethite, lepidochrosite and bravoitic pyrite within the stockwork ore veinlets. In addition, epidote (pistazite - zoisite), garnet, scapolite, chlorite, tremolite/actinolite, muscovite and opaque minerals were determined within the veinlets occurred in skarn zones.The study of fluid inclusions in quartz veinlets showed that the hydrothermal fluids contain CaCl2, MgCl2 and NaCl and the salinities of the two phases (L+V) inclusions range from 1.7 to 20.6% NaCl equivalent. Salinity values up to 44% were determined within the halite bearing three phases inclusions. Their homogenization temperature values have a wide range from 145.0 to 380.0°C, indicative of catathermal/hypothermal to epithermal conditions. The δ 18O and δD values of the fluid inclusion waters from the Çöpler granitoid correspond to those assigned to Primary Magmatic Water, those from the metasediments of Keban metamorphics fall outside of the Primary Magmatic and are within the Metamorphic Water field. A sample from a quartz vein within the skarn zone hosted by the Munzur limestones has a particularly low δD value.The results suggest that fluids derived from the granitoids were mixed with those derived from the metasediments of Keban metamorphics and the the Munzur limestones and resulting in quartz veinlets in these lithologies and the formation of stockwork ores. In view of the occurrence, the features described and processes envisaged for this study area may be applicable in similar settings.


2021 ◽  
pp. 104451
Author(s):  
Christian Schmidt ◽  
Matthias Gottschalk ◽  
Rongqing Zhang ◽  
Jianjun Lu

1993 ◽  
Vol 20 (8) ◽  
pp. 1139-1151 ◽  
Author(s):  
A. Canals ◽  
B. Carpenter ◽  
A.Y. Huc ◽  
N. Guilhaumou ◽  
M.H. Ramsey

2006 ◽  
Vol 70 (2) ◽  
pp. 141-158 ◽  
Author(s):  
Ye. Vapnik ◽  
I. Moroz ◽  
M. Roth ◽  
I. Eliezri

AbstractKianjavato emerald (Mananjary deposits, East coast of Madagascar) was formed during metasomatic processes at the contact between pegmatites and hornblendites. The metasomatic exchange was related to a Pan-African tectonometamorphic event.Fluid inclusions in the Kianjavato emerald and quartz were studied by means of microthermometry and Raman probe analysis. Three main types of inclusions were revealed: CO2-rich, CH4-rich and aqueous-rich, with a salinity of ∼2 wt.% NaCl equiv. The inclusions occurred along the same primary and pseudosecondary trails and were considered to be formed simultaneously. Based on fluid-inclusion data, the conditions of emerald growth were 250°C < T < 450°C and P = 1.5 kbar.The fluid inclusion data for Kianjavato emerald were compared to the data for another Madagascar emerald, Ianapera. The latter is of similar age, but its genesis was determined by a shearing event. Our fluid inclusion data suggested that shearing was also important as a mechanism of introducing CO2-rich fluid for the genesis of the Kianjavato emerald.


2013 ◽  
Vol 50 (6) ◽  
pp. 607-635 ◽  
Author(s):  
Yawooz A. Kettanah

Fluid inclusions hosted in rock salt from the Triassic Argo Formation in the Canadian Atlantic continental margin were studied to investigate the nature and origin of petroleum fluids in them. Inclusions were studied in two wells: Glooscap-C63 and Weymouth-A45. The pillow-shaped salt body intersected by the Glooscap-C63 well is autochthonous, and the salt is transparent and colorless compared with that in the allochthonous, canopy–diaper-shaped body cut by the Weymouth-A45 well which is translucent and buff-colored. Aqueous (AFI), petroleum (PFI), and heterogeneously trapped, mixed petroleum – aqueous (MFI) fluid inclusions were identified using transmitted and fluorescent microscopy, and representative samples were analyzed microthermometrically. Petroleum-bearing fluid inclusions (PFI and MFI) are more common and contain more concentrated petroleum phases in the allochthonous salts of Weymouth-A45 well. Based on microthermometric studies, the AFI and MFI in Glooscap-C63 salt mostly belong to NaCl–H2O and NaCl–H2O–petroleum systems, respectively; in contrast, those of Weymouth-A45 belong to NaCl–MgCl2–H2O and (or) NaCl–CaCl2–H2O and NaCl–MgCl2–H2O–petroleum and (or) NaCl–CaCl2–H2O–petroleum systems, respectively. Each of the AFI, PFI, and MFI types consists of different phases. The medians of Tf (freezing temperature), Tim (initial melting temperature), Te (Eutectic temperature), Tm (final melting (peritectic) temperature), and Th (homogenization temperature) in the AFI and MFI in the salts of Glooscap-C63 well are (−82, −75 °C), (−39, −38 °C), (−25, −24 °C), (−1.8, −3 °C), and (291, 287 °C), respectively. The corresponding medians for the Weymouth-A45 well are (−71, −78 °C), (−52, −52 °C), (−37, −38 °C), (−2.7, −3 °C), and (122, 20 °C), respectively. The median Th of PFI in Glooscap-C63 and Weymouth-A45 salts are 79 and 23 °C, respectively. The most probable source rocks for the petroleum are the shales of the Late Triassic – Early Jurassic Eurydice Formation which is widely distributed at depth underlying the Argo salt.


2021 ◽  
Author(s):  
Kata Molnár ◽  
Marjan Temovski ◽  
László Palcsu

&lt;p&gt;Late Miocene to Pleistocene volcanism within the Vardar zone (N. Macedonia) covers a large area, has a wide range in composition and it is largely connected to the tectonic evolution of the South Balkan extensional system, the northern part of the Aegean extensional regime. A recent study indicated an increasing rate of mantle metasomatism towards the younger centers in the region [1]. During the last stage of activity, ultrapotassic (UK) centers that formed between ca. 3.2 and 1.5 Ma originated from the lithospheric mantle beneath the region [2]. Although there are no reported mantle xenoliths from these centers, the erupted mafic rocks contain abundant olivine as phenocrysts [3]. Noble gas isotopic characteristics of fluid inclusions in olivine can reveal important information about the origin of the fluid and the metasomatic state of the lithospheric mantle. We analyzed for the first time the noble gas composition of fluid inclusions of olivine phenocrysts from the Mlado Nagori&amp;#269;ane volcanic center, the northernmost member of the UK centers with an eruption age of 1.8 &amp;#177; 0.1 Ma [2]. The R/R&lt;sub&gt;A&lt;/sub&gt; ratios give a range of 3.1-4.5 with &lt;sup&gt;4&lt;/sup&gt;He/&lt;sup&gt;20&lt;/sup&gt;Ne values of 11.7-14.6. These R/R&lt;sub&gt;A&lt;/sub&gt; values are lower than the MORB and the averaged subcontinental lithospheric values, and considering the negligible amount of atmospheric contribution, imply a more metasomatized character for the underlying lithospheric mantle beneath the region. Mantle-derived noble gases were detected in a recent geochemical study on the thermal springs and gas exhalations in the region, with up to 20% of mantle contribution calculated based on their noble gas composition using the MORB R/R&lt;sub&gt;A&lt;/sub&gt; value [4]. These new Mlado Nagori&amp;#269;ane fluid inclusion noble gas values indicate that the mantle contribution in the recent gas emissions in the region could be higher than what was thought.&lt;/p&gt;&lt;p&gt;This research was supported by the European Union and the State of Hungary, financed by the European Regional and Development Fund in the project of GINOP-2.3.2-15-2016-00009 &amp;#8216;ICER&amp;#8217; project&lt;/p&gt;&lt;p&gt;[1] Moln&amp;#225;r et al. 2020 &amp;#8211; EGU2020-13101.&lt;/p&gt;&lt;p&gt;[2] Yanev et al., 2008 &amp;#8211; Mineralogy and Petrology, 94(1-2), 45-60.&lt;/p&gt;&lt;p&gt;[3] Yanev et al., 2008 &amp;#8211; Geochemistry, Mineralogy and Petrology, Sofia, 46, 35-67.&lt;/p&gt;&lt;p&gt;[4] Temovski et al. 2020 &amp;#8211; EGU2020-2763.&lt;/p&gt;


Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 823 ◽  
Author(s):  
Anatoliy R. Galamay ◽  
Krzysztof Bukowski ◽  
Daria V. Sydor ◽  
Fanwei Meng

Fluid inclusions in halite are widely used in research to determine the conditions of sedimentation in salt basins and reconstruct the chemical composition of seawater during a specific geological period. However, previous preliminary studies of the genetic types of inclusions, considered in the present research project, have not received due attention. Consequently, we decided to take into account the main distinguishing features of fluid inclusions in halite, belonging to various genetic types. The ultramicrochemical analysis (UMCA) method is one of the several methods that are used for the quantitative determination of the chemical composition of the primary fluid inclusions in halite. We have upgraded that technique, and that allowed us to reduce the analytical error rates of each component determination. The error rates were calculated in the study of Ca-rich and SO4-rich types of natural sedimentary brines.


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