Extreme chemical conditions of crystallisation of Umbrian Melilitolites and wealth of rare, late stage/hydrothermal minerals

2014 ◽  
Vol 6 (4) ◽  
Author(s):  
F. Stoppa ◽  
M. Schiazza
Keyword(s):  
Low Temperature ◽  
Kola Peninsula ◽  
Late Stage ◽  
Mineral Assemblage ◽  
Mineral Species ◽  
Residual Liquid ◽  
Mineral Phases ◽  
Mineral Associations ◽  
Chemical Conditions ◽  
Crystallisation Sequence

AbstractMelilitolites of the Umbria Latium Ultra-alkaline District display a complete crystallisation sequence of peculiar, late-stage mineral phases and hydrothermal/cement minerals, analogous to fractionated mineral associations from the Kola Peninsula. This paper summarises 20 years of research which has resulted in the identification of a large number of mineral species, some very rare or completely new and some not yet classified. The progressive increasing alkalinity of the residual liquid allowed the formation of Zr-Ti phases and further delhayelitemacdonaldite mineral crystallisation in the groundmass. The presence of leucite and kalsilite in the igneous assemblage is unusual and gives a kamafugitic nature to the rocks. Passage to non-igneous temperatures (T<600 °C) is marked by the metastable reaction and formation of a rare and complex zeolite association (T<300 °C). Circulation of low-temperature (T<100 °C) K-Ca-Ba-CO2-SO2-fluids led to the precipitation of sulphates and hydrated and/or hydroxylated silicate-sulphate-carbonates. As a whole, this mineral assemblage can be considered typical of ultra-alkaline carbonatitic rocks.

Coiraite, (Pb,Sn2+)12.5As3Fe2+Sn4+5 S28: a franckeite-type new mineral species from Jujuy Province, NW Argentina

2008 ◽  
Vol 72 (5) ◽  
pp. 1083-1101 ◽  
Author(s):  
W. H. Paar ◽  
Y. Moëlo ◽  
N. N. Mozgova ◽  
N. I. Organova ◽  
C. J. Stanley ◽  
...  
Keyword(s):  
Low Temperature ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Mineral Species ◽  
New Mineral ◽  
Hydrothermal Solutions ◽  
X Ray ◽  
New Mineral Species ◽  
Primary Mineral ◽  
The Ideal

AbstractCoiraite, ideally (Pb,Sn2+)12.5As3Fe2+Sn4+S28, occurs as an economically important tin ore in the large Ag-Sn-Zn polymetallic Pirquitas deposit, Jujuy Province, NW-Argentina. The new mineral species is the As derivative of franckeite and belongs to the cylindrite group of complex Pb sulphosalts with incommensurate composite-layered structures. It is a primary mineral, frequently found in colloform textures, and formed from hydrothermal solutions at low temperature. Associated minerals are franckeite, cylindrite, pyrite-marcasite, as well as minor amounts of hocartite, Ag-rich rhodostannite. arsenopyrite and galena. Laminae of coiraite consist of extremely thin bent platy crystals up to 50 urn long. Electron microprobe analysis (n = 31) gave an empirical formula Pb11.21As2.99Ag0.13Fe1.10Sn6.13S28.0 close to the ideal formula (Pb11.3Sn2+1.2)Σ=12.5As3Fe2+Sn4+S28. Coiraite has two monoclinic sub-cells, Q (pseudotetragonal) and H (pseudohexagonal). Q: a 5.84(1) Å, b 5.86(1) Å, c 17.32(1) Å, β 94.14(1)°, F 590.05(3) Å3, Z = 4, a:b:c = 0.997:1:2.955; H (orthogonal setting): a 6.28(1) Å, b 3.66(1) Å, c 17.33(1) Å, β 91.46(1)°, V398.01(6) Å3, Z = 2, a∶b∶c = 1.716∶1∶4.735. The strongest Debye-Scherrer camera X-ray powder-diffraction lines [d in Å, (I), (hkl)] are: 5.78, (20), (Q and H 003); 4.34, (40), (Q 004); 3.46, (30), (Q and H 005); 3.339, (20), (Q 104); 2.876, (100), (Q and H 006); 2.068, (60), (Q 220).

Mineral Associations of Veins with Quartz of the "Diamonds оf Donbass" Type in the Seleznevsky Coal-Bearing District (Folded Donbass)

2021 ◽  
pp. 66-72
Author(s):  
Oleg S. Krisak ◽  
Yuri V. Popov
Keyword(s):  
Low Temperature ◽  
Hydrothermal System ◽  
Third Order ◽  
Quartz Crystals ◽  
The Third ◽  
Hydrothermal Mineralization ◽  
Water Composition ◽  
Mineral Associations

The authors have established quartz and quartz-carbonate veins, the formation of which is associated with a low-temperature hydrothermal system of methane-water composition within the Seleznevsky coal-bearing region of the Folded Donbass. The article considers the features of localization of hydrothermal mineralization containing quartz with inclusions of hydrocarbons, and its potential ore content. It is established that the vein bodies are localized mainly in the near-hinge parts of the third-order brachianticlines in the central and marginal parts of the Seleznevskaya syncline. These veins form systems associated with the fracturing of the inter-layer stratification or intersecting the layers. Interplastic veins are subdivided into plate-like massive and vein-like bodies with a druze texture. The veins of the second type contain quartz crystals with hydrocarbon inclusions, referred to as &quot;diamonds of Donbass&quot;. They form a paragenetic association with dickite. In addition, calcite in the form of short-prismatic crystals is a typical associated mineral in the vein bodies among limestone strata. In the veins among the sandstone layers, the association with goethite, oxides and hydroxides of manganese is developed. Two morphological types of cinnabar were found in the vein bodies on the basis of HMS sampling, the largest number is confined to the brachianticlines of the marginal parts of the Seleznevskaya syncline. The analysis of the results indicates the prospects for identifying mercury mineralization with quartz-dickite-cinnabar type of mineralization.

A Raman spectroscopic study of the natural carbonophosphates Na3MCO3PO4 (M = Mn, Fe, and Mg)

2021 ◽  
Author(s):  
Ekaterina Fomina ◽  
Evgeniy Kozlov ◽  
Mikhail Sidorov ◽  
Vladimir Bocharov
Keyword(s):  
Natural Increase ◽  
Mineral Species ◽  
Raman Shift ◽  
Russian Science ◽  
Epma Data ◽  
Raman Spectroscopic ◽  
Raman Spectroscopic Study ◽  
Mineral Phases ◽  
Vibrational Bands ◽  
Global Carbon

&lt;p&gt;Along with some other Na-minerals, carbonophosphates indicate a high initial Na activity in carbonatite and kimberlite melts, which is beneficial for petrological reconstructions. Because carbonophosphates are capable of incorporating large-ion lithophile and rare earth elements (REEs) in their structure, they can participate in the transport of these elements. Moreover, due to the presence of both [PO&lt;sub&gt;4&lt;/sub&gt;]&lt;sup&gt;3&amp;#8722;&lt;/sup&gt; and [CO&lt;sub&gt;3&lt;/sub&gt;]&lt;sup&gt;2&amp;#8722; &lt;/sup&gt;groups in carbonophosphates, these mineral phases play an important role in the Earth's global carbon and phosphate cycles. With all these properties, carbonophosphates have long attracted the attention of geologists. Raman spectroscopy appears to be one of the most suitable tools for their diagnosis, since they commonly present in rocks as small inclusions in other mineral grains. Despite this profit, only a few publications contain Raman characteristics of either natural or synthetic carbonophosphates.&lt;/p&gt;&lt;p&gt;We studied and compared Raman spectra of three natural carbonophosphate phases (sidorenkite, bonshtedtite, and bradleyite) with the general formula Na&lt;sub&gt;3&lt;/sub&gt;MCO&lt;sub&gt;3&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt; (M = Mn, Fe, and Mg, correspondingly). These spectra showed from 21 to 24 vibrational bands, of which the two most intense (963&amp;#177;5 cm&lt;sup&gt;-1&lt;/sup&gt; &amp;#1080; 1074&amp;#177;3 cm&lt;sup&gt;-1&lt;/sup&gt;) correspond to the &amp;#957;1(P&amp;#8211;O) and &amp;#957;1(C&amp;#8211;O) modes. These two bands split due to the occurrence of isomorphic impurities. It was found that the crystallographic orientation of the sample influences the intensity of most bands. A natural increase in the Raman shift was observed for most bands assigned to the same vibrations (the smallest shift in the spectrum is characteristic of sidorenkite, an intermediate - of bonshtedtite, and the largest - of bradleyite).&lt;/p&gt;&lt;p&gt;We propose the following algorithm for the diagnosis of carbonophosphates:&lt;/p&gt;&lt;ul&gt;&lt;li&gt;Checking minerals for belonging to the group of carbonophosphates by the main bands and the characteristic profile of the spectrum;&lt;/li&gt; &lt;li&gt;Testing the hypothesis that the mineral of question is bradleyite based on the analysis of the estimated shift of the main bands;&lt;/li&gt; &lt;li&gt;Diagnosis of a mineral species by peaks located between the main bands;&lt;/li&gt; &lt;li&gt;Validation of the diagnostics by considering the position of the bands at 185&amp;#177;9 cm&lt;sup&gt;-1&lt;/sup&gt;, 208&amp;#177;7 cm&lt;sup&gt;-1&lt;/sup&gt;, 255&amp;#177;5 cm&lt;sup&gt;-1&lt;/sup&gt;, and 725&amp;#177;6 cm&lt;sup&gt;-1&lt;/sup&gt;.&lt;/li&gt; &lt;/ul&gt;&lt;p&gt;The proposed algorithm allows one to perform Raman diagnostics of carbonophosphates in inclusions even in the absence of EPMA data. In the study of carbonatites, kimberlites, and other rocks, the diagnostics of the mineral species of the carbonophosphate group can be important in the petrological aspect.&lt;/p&gt;&lt;p&gt;This research was funded by the Russian Science Foundation, grant number 19-77-10039.&lt;/p&gt;

CARYOCHROITE, A NEW HETEROPHYLLOSILICATE MINERAL SPECIES RELATED TO NAFERTISITE, FROM THE LOVOZERO MASSIF, KOLA PENINSULA, RUSSIA

2006 ◽  
Vol 44 (6) ◽  
pp. 1331-1339 ◽  
Author(s):  
P. M. Kartashov ◽  
G. Ferraris ◽  
S. V. Soboleva ◽  
N. V. Chukanov
Keyword(s):  
Kola Peninsula ◽  
Mineral Species ◽  
Lovozero Massif

Mineralogy of vesicles in an olivine leucitite at Cosgrove, Victoria, Australia

1980 ◽  
Vol 43 (329) ◽  
pp. 597-603 ◽  
Author(s):  
W. D. Birch
Keyword(s):  
Late Stage ◽  
Rock Type ◽  
Early Stage ◽  
Coarse Grained ◽  
Residual Liquid ◽  
Cooling History ◽  
History Of

SummaryAn olivine-titanomagnetite-apatite-clinopyroxene-mica-nepheline-feldspar assemblage occurs in late-stage vesicles in a small outcrop of olivine leucitite at Cosgrove, Victoria. The vesicles were formed by exsolution of volatiles at an early stage in the cooling history of the lava. Subsequently, a volatile-rich residual liquid filled cavities and fractures, giving rise to a coarse-grained pegmatoid rock type similar in over-all mineralogy to the vesicles. The volatiles facilitating crystallization in both the vesicles and the pegmatoid were probably enriched in F, CO2, and P. A number of geothermometers applied to the vesicle assemblage failed to agree on likely crystallization temperatures.

Skarn formation between metachalk and agglomerate in the Central Ring Complex, Isle of Arran, Scotland

1987 ◽  
Vol 51 (360) ◽  
pp. 231-246 ◽  
Author(s):  
G. Cressey
Keyword(s):  
Late Stage ◽  
Mineral Assemblage ◽  
Central Ring ◽  
Ring Complex ◽  
Metasomatic Fluid ◽  
Skarn Mineral

AbstractA skarn mineral assemblage occurs at the junction between vent pyroclastics and a xenolithic Cretaceous chalk block which subsided into the collapsed caldera of the Central Ring Complex, Isle of Arran, Scotland. Adjacent to the metachalk marble an andradite garnet exoskarn zone has developed at the expense of the carbonate. An andradite grossular/diopsidic clinopyroxene endoskarn zone has formed in the surrounding agglomerate, and a magnetite exoskarn is present in places between the andradite and garnet/pyroxene zones. The andraditic exoskarn garnets have fluor-hydrogarnet components, indicating that fluorine was present in the metasomatic fluid. From petrographic evidence, three distinct episodes of exoskarn garnet crystallization can be recognized, in which the fluor-hydrogarnet component steadily increased as a function of time, which probably reflects falling temperature. The REE compositions of the exoskarn minerals are regarded as having been largely inherited from the carbonate, and the exoskarn garnets increasingly fractionated HREE with time. The endoskarn and agglomerate have also been epidotized. The REE signatures of epidotes appear to be inherited partially from precursor clinopyroxenes or feldspars, which have been replaced by epidote. Late-stage vein minerals include prehnite, laumontite and K-rich laumontite, and their REE compositions appear to have been derived from the marble, probably via REE fluoro-complexes in the fluid.

Low-Temperature Aluminosilicate Nanostructured Binder - Characteristics and Applicability

2019 ◽  
Vol 945 ◽  
pp. 193-198 ◽  
Author(s):  
Igor V. Zhernovsky ◽  
Alla V. Cherevatova ◽  
Natalia Ivanovna Kozhukhova ◽  
Maya Sergeevna Osadchaya ◽  
D.A. Ksenofontov
Keyword(s):  
Low Temperature ◽  
Building Materials ◽  
Construction Material ◽  
Thermal Exposure ◽  
Green Technology ◽  
Unit Cell ◽  
Current Trends ◽  
Mineral Phases ◽  
Wide Range ◽  
Cell Volumes

Current trends in the field of construction material is focused on enhancement of sustainability of building materials and constructions urging on development of new types of inorganic binders and composites in order to meet the modern requirements of service performance and special properties. This research studied and demonstrated the opportunity to develop zero-cement heat-resisting granite-based nanostructured binder (GNB) using «green» technology production. XRD and DTA analyses demonstrated that the thermal exposure of GNB to wide range of temperatures of 20–1000 °C leads to such phase transformations in the binder as α-quartz to β-quartz transformation; amorphous alkali-aluminosilicate (gel) to crystal phase of Са-albite. The calculation of cell volumes characteristics for low-temperature (before thermal exposure) and high-temperature (after thermal exposure) phases was performed using following equation: where is concentration (by wt. %) of mineral phases;Viis unit cell volume of mineral phases, Å. The calculated ratios of unit cell volumes were close to 1 which ensures a structural stability of the GNB under thermal exposure and confirms its heat-resistant performance.

scholarly journals Lead and zinc in the structure of organic and mineral soil components

2013 ◽  
Vol 37 (2) ◽  
pp. 438-449 ◽  
Author(s):  
Larissa Kummer ◽  
Vander de Freitas Melo ◽  
Yara Jurema Barros
Keyword(s):  
Heavy Metals ◽  
Organic Matter ◽  
Mineral Soil ◽  
Complete Removal ◽  
Extraction Methods ◽  
Chemical Fractionation ◽  
Isomorphic Substitution ◽  
Fe Oxides ◽  
Mineral Phases ◽  
Mineral Associations

In addition to the more reactive forms, metals can occur in the structure of minerals, and the sum of all these forms defines their total contents in different soil fractions. The isomorphic substitution of heavy metals for example alters the dimensions of the unit cell and mineral size. This study proposed a method of chemical fractionation of heavy metals, using more powerful extraction methods, to remove the organic and different mineral phases completely. Soil samples were taken from eight soil profiles (0-10, 10-20 and 20-40 cm) in a Pb mining and metallurgy area in Adrianópolis, Paraná, Brazil. The Pb and Zn concentrations were determined in the following fractions (complete phase removal in each sequential extraction): exchangeable; carbonates; organic matter; amorphous and crystalline Fe oxides; Al oxide, amorphous aluminosilicates and kaolinite; and residual fractions. The complete removal of organic matter and mineral phases in sequential extractions resulted in low participation of residual forms of Pb and Zn in the total concentrations of these metals in the soils: there was lower association of metals with primary and 2:1 minerals and refractory oxides. The powerful methods used here allow an identification of the complete metal-mineral associations, such as the occurrence of Pb and Zn in the structure of the minerals. The higher incidence of Zn than Pb in the structure of Fe oxides, due to isomorphic substitution, was attributed to a smaller difference between the ionic radius of Zn2+ and Fe3+.

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