High-alumina hydrothermal systems in volcanic rocks and their significance to mineral prospecting in the Carolina slate belt

10.3133/b1562 ◽  
1985 ◽  
Keyword(s):  
Volcanic Rocks ◽  
Hydrothermal Systems ◽  
High Alumina ◽  
Carolina Slate Belt ◽  
Mineral Prospecting

Oxygen isotope evolution of volcanic rocks at the Sturgeon Lake volcanic complex, Ontario

2000 ◽  
Vol 37 (1) ◽  
pp. 39-50 ◽  
Author(s):  
E M King ◽  
J W Valley ◽  
D W Davis
Keyword(s):  
Oxygen Isotope ◽  
Volcanic Rocks ◽  
Isotope Ratios ◽  
Hydrothermal Systems ◽  
Superior Province ◽  
Volcanic Complex ◽  
Volcanic Stratigraphy ◽  
Oxygen Isotope Ratios ◽  
Ore Body ◽  
The Many

Igneous zircons from the Sturgeon Lake volcanic complex, host to several massive sulphide deposits in the Superior Province, Canada, have an average δ18O(zircon) of 5.4 ± 0.3‰ VSMOW (n = 9 rocks). These zircons are from units differing in age by 18 million years in the 2.7 Ga complex. There is no detectable interaction of high δ18O, supracrustal lithologies in the magma. Quartz from volcanic units beneath the largest ore body, the Mattabi deposit, has an average δ18O of 9.3 ± 0.6‰. Quartz phenocrysts from the Mattabi unit and overlying volcanics have elevated and heterogeneous δ18O values averaging 13.8 ± 0.9‰ and are not in magmatic equilibrium with zircons. The δ18O values of whole-rock powders range from 5.6‰ to 14.3‰ and follow the trend observed in the δ18O values of quartz. Healed microcracks are visible in cathodoluminescence images (but are not obvious optically) of quartz phenocrysts from units with high δ18O values and disequilibrium Δ(quartz-zircon) suggesting that recrystallization facilitates the elevation of δ18O. Quartz phenocrysts from volcanic units with Δ(quartz-zircon) values near equilibrium at magmatic temperatures do not display healed microcracks in cathodoluminescence. The elevated δ18O(quartz) values are not restricted to units hosting orebodies, but are seen in all rocks in the volcanic stratigraphy that postdate eruption of the Mattabi unit. Oxygen isotope ratios combined with physical volcanology studies suggest that impermeable volcanic layers control the size and location of the many hydrothermal systems that may have occurred in the Sturgeon Lake complex.

Special Ceramic Material Based On Basaltic-Andesite for Extreme Environments

2008 ◽  
Vol 59 ◽  
pp. 39-41 ◽  
Author(s):  
Etele Albert ◽  
Marcela Muntean ◽  
A. Ianculescu ◽  
Florin Miculescu ◽  
B. Albert
Keyword(s):  
Ceramic Material ◽  
Basaltic Andesite ◽  
Complex Structure ◽  
Thermo Gravimetric Analysis ◽  
Volcanic Rocks ◽  
Extreme Environments ◽  
Ceramic Materials ◽  
Raw Material ◽  
High Alumina ◽  
Gravimetric Analysis

A special ceramic material with specific performances for some extreme environments can be elaborated using basaltic-andesite as raw material. The volcanic rocks presents specific compositions, a complex structure and properties, so some of them, such as basaltic-andesite, may have multiple utilization. The elaborated basaltic-andesite compound ceramic material, in mixture with porcelain-clay and alumina was characterized with SEM (scanning electron microscopy), EDS (energy dispersive spectroscopy), X-ray diffraction and thermo-gravimetric analysis. Many of the properties of this sort of ceramic material surpass the electric insulator porcelain type KER 110 ceramic, and in some approximate the high alumina-content ceramic materials.

scholarly journals Petrogeochemical features of the Neogene collision volcanism of the Lesser Caucasus (Azerbaijan)

2020 ◽  
Vol 29 (2) ◽  
pp. 289-303
Author(s):  
Nazim A. Imamverdiyev ◽  
Minakhanym Y. Gasanguliyeva ◽  
Vagif M. Kerimov ◽  
Ulker I. Kerimli
Keyword(s):  
Fractional Crystallization ◽  
Water Pressure ◽  
Basaltic Magma ◽  
Volcanic Rocks ◽  
Fluid Pressure ◽  
Material Balance ◽  
Parental Magma ◽  
High Alumina ◽  
Fractionation Process ◽  
Lesser Caucasus

The article is devoted to the petrogeochemical features of Neogene collision volcanism in the central part of the Lesser Caucasus within Azerbaijan. The main goal of the study is to determine the thermodynamic conditions for the formation of Neogene volcanism in the central part of the Lesser Caucasus using the available petrogeochemical material. Using factor analysis, as well as the “IGPET”, “MINPET”, “Petrolog-3” programs, material balance calculations were performed that simulate the phenocryst fractionation process, the crystallization temperature, pressure, and figurative nature of the rock-forming minerals of the formation rocks were calculated. It was determined that at the early and middle stages of crystallization of the rocks of the andesite-dacite-rhyolite formation, the fractionation of amphibole played an important role in the formation of subsequent differentiates. Based on computer simulation, it was revealed that rocks of the andesite-dacite-rhyolite formation were formed by fractional crystallization of the initial high-alumina basaltic magma of high alkalinity in the intermediate magma foci. The calculations of the balance of the substance, simulating the process of fractionation of phenocrysts, as well as magnetite, confirmed the possibility of obtaining rock compositions from andesites to rhyolites as a result of this process. In this case, the process of crystallization differentiation was accompanied by processes of contamination, hybridism and mixing. Based on the geochemical features of rare and rare-earth elements, changes in their ratios, the nature of the mantle source and the type of fractionation process are determined. It was revealed that the enrichment of formation rocks by light rare earths, as well as by many incoherent elements, is associated with the evolution of enriched mantle material. Under high water pressure, as a result of the fractionation of olivine and pyroxene, high-alumina basalts are formed from primary high-magnesian magma, which can be considered parental magma. It was established that, in contrast to the elevated Transcaucasian zone in the more lowered East Caucasus, under conditions of increased fluid pressure and reduced temperature, the melt underwent fractional crystallization in the intermediate centers, being enriched with alkaline, large-ion lithophilic elements, light REEs, etc. This is evidenced by the presence of large crystals of feldspars, the contamination of these minerals by numerous crystals of biotite, magnetite, several generations of these minerals, zonality, as well as the presence of related “water” inclusions, such as hornblendites, hornblende gabbro, etc. The physicochemical conditions for the formation of Neogene volcanic rocks of the Lesser Caucasus are determined.

scholarly journals Application of B, Mg, Li, and Sr Isotopes in Acid‐Sulfate Vent Fluids and Volcanic Rocks as Tracers for Fluid‐Rock Interaction in Back‐Arc Hydrothermal Systems

2019 ◽  
Vol 20 (12) ◽  
pp. 5849-5866
Author(s):  
Frederike K. Wilckens ◽  
Eoghan P. Reeves ◽  
Wolfgang Bach ◽  
Jeffrey S. Seewald ◽  
Simone A. Kasemann
Keyword(s):  
Volcanic Rocks ◽  
Hydrothermal Systems ◽  
Sr Isotopes ◽  
Acid Sulfate ◽  
Rock Interaction ◽  
Back Arc

scholarly journals Tonalite-Dominated Magmatism in the Abitibi Subprovince, Canada, and Significance for Cu-Au Magmatic-Hydrothermal Systems

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 242 ◽  
Author(s):  
Lucie Mathieu ◽  
Alexandre Crépon ◽  
Daniel J. Kontak
Keyword(s):  
Volcanic Rocks ◽  
Significant Proportion ◽  
Hydrothermal Systems ◽  
Heavy Rare Earth ◽  
Geological Surveys ◽  
Abitibi Subprovince ◽  
Heavy Rare Earth Elements ◽  
Pressure Melting ◽  
Greenstone Belts ◽  
Archean Greenstone Belts

In Archean greenstone belts, magmatism is dominated by intrusive and volcanic rocks with tholeiitic affinities, as well as tonalite- and granodiorite-dominated large-volume batholiths, i.e., tonalite–trondhjemite–granodiorite (TTG) suites. These intrusions are associated with poorly documented mineralization (Cu-Au porphyries) that, in the Neoarchean Abitibi Subprovince (>2.79 to ~2.65 Ga), Superior Province, Canada, are associated with diorite bearing plutons, i.e., tonalite–trondhjemite–diorite (TTD) suites. The importance of TTG versus TTD suites in the evolution of greenstone belts and of their magmatic-hydrothermal systems and related mineralization is unconstrained. The aim of this study was to portray the chemistry and distribution of these suites in the Abitibi Subprovince. The study used data compiled by the geological surveys of Québec and Ontario to evaluate the chemistry of TTG and TTD suites and uncovered two coeval magmas that significantly differentiated (fractional crystallization mostly): 1) a heavy rare earth elements (HREE)-depleted tonalitic magma from high pressure melting of an hydrated basalt source; and 2) a hybrid HREE-undepleted magma that may be a mixture of mantle-derived (tholeiite) and tonalitic melts. The HREE-depleted rocks (mostly tonalite and granodiorite) display chemical characteristics of TTG suites (HREE, Ti, Nb, Ta, Y, and Sr depletion, lack of mafic unit, Na-rich), while the other rocks (tonalite and diorite) formed TTD suites. Tonalite-dominated magmatism, in the Abitibi Subprovince, comprises crustal melts as well as a significant proportion of mantle-derived magmas and this may be essential for Cu-Au magmatic-hydrothermal mineralizing systems.

scholarly journals Shannon Entropy as an Indicator for Sorting Processes in Hydrothermal Systems

Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 656
Author(s):  
Frank J. A. van Ruitenbeek ◽  
Jasper Goseling ◽  
Wim H. Bakker ◽  
Kim A. A. Hein
Keyword(s):  
Shannon Entropy ◽  
Chemical Elements ◽  
Volcanic Rocks ◽  
Mineralogical Composition ◽  
Short Wave ◽  
Hydrothermal Systems ◽  
Hydrothermal Processes ◽  
Primary Composition ◽  
Natural Mechanism ◽  
Measure Of Uncertainty

Hydrothermal processes modify the chemical and mineralogical composition of rock. We studied and quantified the effects of hydrothermal processes on the composition of volcanic rocks by a novel application of the Shannon entropy, which is a measure of uncertainty and commonly applied in information theory. We show here that the Shannon entropies calculated on major elemental chemical composition data and short-wave infrared (SWIR) reflectance spectra of hydrothermally altered rocks are lower than unaltered rocks with a comparable primary composition. The lowering of the Shannon entropy indicates chemical and spectral sorting during hydrothermal alteration of rocks. The hydrothermal processes described in this study present a natural mechanism for transforming energy from heat to increased order in rock. The increased order is manifest as the increased sorting of chemical elements and SWIR absorption features of the rock, and can be measured and quantified by the Shannon entropy. The results are useful for the study of hydrothermal mineral deposits, early life environments and the effects of hydrothermal processes on rocks.

scholarly journals Two Processes of Anglesite Formation and a Model of Secondary Supergene Enrichment of Bi and Ag in Seafloor Hydrothermal Sulfide Deposits

2021 ◽  
Vol 10 (1) ◽  
pp. 35
Author(s):  
Zhigang Zeng ◽  
Zuxing Chen ◽  
Haiyan Qi
Keyword(s):  
Okinawa Trough ◽  
Volcanic Rocks ◽  
Hydrothermal Systems ◽  
Sulfide Deposits ◽  
The Okinawa Trough ◽  
Supergene Enrichment ◽  
Seawater Environment ◽  
Back Arc ◽  
Enrichment Process

The in situ element concentrations and the sulfur (S), and lead (Pb) isotopic compositions in anglesite were investigated for samples from seafloor hydrothermal fields in the Okinawa Trough (OT), Western Pacific. The anglesite grains are of two kinds: (1) low Pb/high S primary hydrothermal anglesite (PHA), which is formed by mixing of fluid and seawater, and (2) high Pb/low S secondary supergene anglesite (SSA), which is the product of low-temperature (<100 °C) alteration of galena in the seawater environment. The Ag and Bi in the SSA go through a second enrichment process during the formation of high Pb/low S anglesite by galena alteration, indicating that the SSA and galena, which may be the major minerals host for considerable quantities of Ag and Bi, are potentially Ag-Bi-enriched in the back-arc hydrothermal field. Moreover, REEs, S and Pb in the OT anglesite are likely to have been leached by fluids from local sub-seafloor volcanic rocks and/or sediments. A knowledge of the anglesite is useful for understanding the influence of volcanic rocks, sediments and altered subducted oceanic plate in hydrothermal systems, showing how trace metals behave during the formation of secondary minerals.

scholarly journals Composition of Rift-Related Igneous and Sedimentary Rocks of the Keweenawan Supergroup in the Poersch No. 1, OZ-1, Finn, and Friederich Wells, Northeastern Kansas

1993 ◽  
pp. 55-72
Author(s):  
Robert L. Cullers ◽  
Pieter Berendsen
Keyword(s):  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Magnetic Polarity ◽  
Detrital Zircons ◽  
Primary Magma ◽  
High Alumina ◽  
Spinel Peridotite ◽  
Rift System ◽  
Reverse Fault ◽  
The North

A series of wells have been drilled up to a depth of 3,444 m (113,000 ft) into the midcontinent rift system (MRS) in northeastern Kansas. The age of a gabbro sill in the upper portion of the Precambrian rocks was determined to be 1,097.5 ± 3 Ma, and the magnetic polarity of the gabbro correlated to the lower Keweenawan rocks in the northern MRS (Van Schmus et al., 1990). The rocks below 2,259 m (7,411 ft) in the deepest well [Poersch no. 1, total depth 3,435 m (11,270 ft)] consist mostly of arkoses with subordinate amounts of shale, siltstone, and basalt. The rocks above 2,265 m (7,431 ft) in the Poersch well consist of basalt with minor siltstone, arkose, gabbro, and felsite. A proposed high-angle reverse fault could have juxtaposed the upper igneous rocks over the lower sedimentary rocks to produce a reversed stratigraphy. This would make the development of the southern MRS similar to that of the northern MRS. Thus, in the initial extensional phase of the MRS, broad subsidence coincided with abundant volcanism and little sediment production. Grabens formed in the later stages of rift development and were filled with abundant sedimentary rocks along with lesser volcanic rocks. The chemical characteristics of the basalts in the southern MRS are similar to those in the north. The southern basalts are subalkalic to alkalic and follow tholeiitic trends; a number of them are high-alumina basalts. Although there is a lot of scatter, Al2O3, Ni, and Cr concentrations decrease and Fe2O3, TiO2, K2O, rare earth elements, Ba, Hf, and Sc concentrations increase with decreasing Mg number. These trends are consistent with plagioclase, olivine, pyroxene, or spinel fractionation from primary basalts. One basalt could represent a primary magma because it has a high Mg number (0.68), high Ni (638 mg/kg) and Cr (233 mg/kg) concentrations, low incompatible element concentrations (e.g., La = 4.2 mg/kg), and a slight positive Eu anomaly. This possible primary magma could have formed by partial melting (20-25%) of an undepleted spinel peridotite at 30-40 km depth. Most basalts have not been contaminated by crustal rocks or silicic magmas. The mineralogy, chemical composition, and U-Pb geochronology of detrital zircons of the arkoses, siltstones, and shales are consistent with their derivation from the surrounding granitoid highlands with little or no input from the basalts. Even siltstones and arkoses within the mostly basaltic sequences are derived mostly from the granitoids, although the siltstones may have some input from the basalts (e.g., higher Ni concentration than the sandstones).

scholarly journals Sample Collection and Return from Mars: Optimising Sample Collection Based on the Microbial Ecology of Terrestrial Volcanic Environments

2019 ◽  
Vol 215 (7) ◽  
Author(s):  
Charles S. Cockell ◽  
Sean McMahon ◽  
Darlene S. S. Lim ◽  
John Rummel ◽  
Adam Stevens ◽  
...  
Keyword(s):  
Microbial Ecology ◽  
Large Scale ◽  
Spatial Scales ◽  
A Priori ◽  
Volcanic Rocks ◽  
Hydrothermal Systems ◽  
Sample Collection ◽  
Heterogeneous Distribution ◽  
Microbial Distribution ◽  
The Earth

Abstract With no large-scale granitic continental crust, all environments on Mars are fundamentally derived from basaltic sources or, in the case of environments such as ices, evaporitic, and sedimentary deposits, influenced by the composition of the volcanic crust. Therefore, the selection of samples on Mars by robots and humans for investigating habitability or testing for the presence of life should be guided by our understanding of the microbial ecology of volcanic terrains on the Earth. In this paper, we discuss the microbial ecology of volcanic rocks and hydrothermal systems on the Earth. We draw on microbiological investigations of volcanic environments accomplished both by microbiology-focused studies and Mars analog studies such as the NASA BASALT project. A synthesis of these data emphasises a number of common patterns that include: (1) the heterogeneous distribution of biomass and diversity in all studied materials, (2) physical, chemical, and biological factors that can cause heterogeneous microbial biomass and diversity from sub-millimetre scales to kilometre scales, (3) the difficulty of a priori prediction of which organisms will colonise given materials, and (4) the potential for samples that are habitable, but contain no evidence of a biota. From these observations, we suggest an idealised strategy for sample collection. It includes: (1) collection of multiple samples in any given material type (∼9 or more samples), (2) collection of a coherent sample of sufficient size (${\sim}10~\mbox{cm}^{3}$ ∼ 10 cm 3 ) that takes into account observed heterogeneities in microbial distribution in these materials on Earth, and (3) collection of multiple sample suites in the same material across large spatial scales. We suggest that a microbial ecology-driven strategy for investigating the habitability and presence of life on Mars is likely to yield the most promising sample set of the greatest use to the largest number of astrobiologists and planetary scientists.

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