Academic literature on the topic 'K-Fe metasomatism'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Contents
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'K-Fe metasomatism.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "K-Fe metasomatism"
1
Neumayr, P., J. R. Ridley, and D. I. Groves. "sPhysicochemical conditions of fluid–wall rock interaction at amphibolite-facies conditions in two Archean hydrothermal gold deposits in the Mt. York District, Pilbara Craton, Western Australia." Canadian Journal of Earth Sciences 32, no. 7 (July 1, 1995): 993–1016. http://dx.doi.org/10.1139/e95-083.
Full textAbstract:
Synamphibolite facies Archean gold mineralization in the Mt. York District, Pilbara Craton, Western Australia, is hosted in metamorphosed banded iron formation (Main Hill–Breccia Hill prospect), amphibolites, and ultramafic schists (Zakanaka prospect). Mineralization at Main Hill occurs in quartz breccias with sulfide matrices and in altered wall rock adjacent to quartz–biotite–amphibole ± clinopyroxene veins. Alteration associated with quartz veins is zoned, with biotite—pyrrhotite vein selvedges and a distal calcic-amphibole, arsenopyrite–lôllingite zone. Hydrothermal biotite and actinolite have highest Mg/(Mg + Fe) ratios where associated with abundant sulfarsenides in the distal alteratin zone. Whole-rock geochemical analyses and calculated metasomatic reactions indicate the addition of K, Al, S, As, Au, Ag, and Ni during hydrothermal alteration. Mineralization at Zakanaka is characterized by a broad wall rock alteration halo of biotite–amphibole, and zoned quartz–calc silicate veins proximal to ore. Wall rock adjacent to the veins contains pyrrhotite, pyrite, and gold. The alteration is explained by K-metasomatism distal to mineralization and K and Ca metasomatism proximal to mineralization. Balanced metasomatic reactions and mass-balance calculations indicate addition of K and depletion of Na, Ca, Mg, and Fe in distal alteration zones and addition of K, Ca, Mg, Fe, and Ti in proximal zones. Gold precipitation at both prospects occurred through loss of S, and possibly As, from the ore fluid during sulfidation reactions with Fe-rich amphiboles and biotites to form Mg-enriched equivalents and sulfarsenides. Changes in the oxidation state of the ore fluid may have enhanced gold precipitation, though pH changes are unlikely to have been important. The controls on mineralization are thus similar to those at many lower temperature, mesothermal deposits. The lack of consistently increasing Mg ratios of calc-silicate phases with increasing intensity of alteration and sulfidation at Main Hill may be the result of coupled substitutions in amphiboles and biotites during infiltration of a fluid with high-S, but low-As, activities.
2
Nixon, Peter H., and Eric Condliffe. "Yimengite of K–Ti metasomatic origin in kimberlitic rocks from Venezuela." Mineralogical Magazine 53, no. 371 (June 1989): 305–9. http://dx.doi.org/10.1180/minmag.1989.053.371.05.
Full textAbstract:
AbstractThis second recorded occurrence of yimengite, K(Cr, Ti, Fe, Mg, Al)12O19, is in a Precambrian kimberlitic sill in the Guaniamo District of Bolivar Province, Venezuela. The paragenesis is similar to that of the type area in Shandong Province, China, where the mineral is in kimberlite dykes. At both localities the yimengite is a K, Ti-bearing metasomatic product of chromium-rich spinel. In the Venezuela rocks the spinels are of the type occurring both as diamond inclusions and as a component of diamond-related Cr-rich garnet harzburgite mantle xenoliths. Yimengite contains significant amounts of barium (up to 3.4wt.% BaO) and is thus transitional to the recently described mineral hawthorneite, Ba(Cr, Ti, Fe, Mg)12O19. Both members are part of a suite of titanate minerals found in kimberlites and their inclusions which has been described by Haggerty and coworkers; they formed as a result of mantle metasomatism generated by K- and Ba-rich fluids. In Venezuela, metasomatism of this type would appear to be deeper than that usually recorded, namely in the basal lithosphere. The metasomatizing fluids are derived from the underlying, more oxygenated asthenosphere. The host kimberlitic rocks are not significantly enriched in K and Ba, but these elements are concentrated in later micaceous dykes which are conjectured to have been generated within similar metasomatized mantle.
3
Paoli, Dini, Petrelli, and Rocchi. "HFSE‐REE Transfer Mechanisms During Metasomatism of a Late Miocene Peraluminous Granite Intruding a Carbonate Host (Campiglia Marittima, Tuscany)." Minerals 9, no. 11 (November 4, 2019): 682. http://dx.doi.org/10.3390/min9110682.
Full textAbstract:
The different generations of calc‐silicate assemblages formed during sequential metasomatic events make the Campiglia Marittima magmatic–hydrothermal system a prominent case study to investigate the mobility of rare earth element (REE) and other trace elements. These mineralogical assemblages also provide information about the nature and source of metasomatizing fluids. Petrographic and geochemical investigations of granite, endoskarn, and exoskarn bodies provide evidence for the contribution of metasomatizing fluids from an external source. The granitic pluton underwent intense metasomatism during post‐magmatic fluid–rock interaction processes. The system was initially affected by a metasomatic event characterized by circulation of K‐rich and Ca(‐Mg)‐rich fluids. A potassic metasomatic event led to the complete replacement of magmatic biotite, plagioclase, and ilmenite, promoting major element mobilization and crystallization of K‐feldspar, phlogopite, chlorite, titanite, and rutile. The process resulted in significant gain of K, Rb, Ba, and Sr, accompanied by loss of Fe and Na, with metals such as Cu, Zn, Sn, W, and Tl showing significant mobility. Concurrently, the increasing fluid acidity, due to interaction with Ca‐rich fluids, resulted in a diffuse Ca‐metasomatism. During this stage, a wide variety of calc‐silicates formed (diopside, titanite, vesuvianite, garnet, and allanite), throughout the granite body, along granite joints, and at the carbonate–granite contact. In the following stage, Ca‐F‐rich fluids triggered the acidic metasomatism of accessory minerals and the mobilization of high-field-strength elements (HFSE) and REE. This stage is characterized by the exchange of major elements (Ti, Ca, Fe, Al) with HFSE and REE in the forming metasomatic minerals (i.e., titanite, vesuvianite) and the crystallization of HFSE‐REE minerals. Moreover, the observed textural disequilibrium of newly formed minerals (pseudomorphs, patchy zoning, dissolution/reprecipitation textures) suggests the evolution of metasomatizing fluids towards more acidic conditions at lower temperatures. In summary, the selective mobilization of chemical components was related to a shift in fluid composition, pH, and temperature. This study emphasizes the importance of relating field studies and petrographic observations to detailed mineral compositions, leading to the construction of litho‐geochemical models for element mobilization in crustal magmatic‐hydrothermal settings.
4
Galliski, Miguel A., Encarnación Roda-Robles, Frédéric Hatert, María Florencia Márquez-Zavalía, and Viviana A. Martínez. "The Phosphate mineral assemblages from La Viquita Pegmatite, San Luis, Argentina." Canadian Mineralogist 58, no. 6 (November 1, 2020): 733–46. http://dx.doi.org/10.3749/canmin.1900106.
Full textAbstract:
ABSTRACT La Viquita is a rare-element pegmatite of LCT signature, REL-Li subclass, spodumene subtype, that shows Fe > Mn mineral paragenesis instead of Mn > Fe, which is more common in the rare-element pegmatite population of the San Luis ranges. The phosphate mineral association of this pegmatite can be subdivided into (1) primary, with dendritic triphylite [(Fe/(Fe + Mn) = 0.72] and montebrasite–amblygonite as main phases; (2) metasomatic, with subsolidus replacement of triphylite by ferrisicklerite and heterosite; and (3) hydrothermal, with secondary growth of alluaudite at the expense of heterosite and wardite from montebrasite caused by Na-metasomatism. A Ca-rich influx under oxidizing conditions produced childrenite–eosphorite–ernstite, jahnsite-(CaMnFe), and kingsmountite. Apatite-group minerals are present throughout the processes. Very late-stage solutions formed millimetric crystals of hydroxylherderite associated with hydroxylapatite in cavities in K-feldspar.
5
Coulson, Ian M. "Post-magmatic alteration in eudialyte from the North Qôroq centre, South Greenland." Mineralogical Magazine 61, no. 404 (February 1997): 99–109. http://dx.doi.org/10.1180/minmag.1997.061.404.10.
Full textAbstract:
AbstractThe North Qôroq centre comprises a series of nested nepheline syenite intrusions and forms part of the mid-late Proterozoic Gardar province of South Greenland. Within the centre fractionation has produced varied rock types ranging from augite-syenite to lujavrite, a eudialyte microsyenite. Samples of eudialyte from the lujavrites of unit SN1B of the centre show evidence for two-stage alteration. This alteration ranges from slight modification along crystal margins to complete breakdown and replacement by new pseudomorphing phases. Modification to crystal margins is accompanied by increasing Nb and Zr contents and is related to metasomatism produced by the intrusion of younger syenite units of the North Qôroq centre. More extensive alteration is as a result of metasomatism followed by lower-temperature supergene alteration. Simplified reactions for this breakdown include eudialyte + metasomatic fluid = allanite + nepheline; eudialyte + metasomatic fluid = titanite + aegirine + møsandrite + wöhlerite; eudialyte + fluid = zirfesite + fluid. Mass balance calculations for altered compared with unaltered samples of lujavrite show that alteration took place at approximately constant volume with an overall increase in Fe (+2.41 g/100g), Si and K (+0.65 and +0.61 g/100g), whilst Na (−2.67 g/100g) and all trace elements, particularly La, Y, Nb and Zr (−5.6 to −166 g/10000g) are lost from the system.
6
Roza Llera, Ana, Mercedes Fuertes-Fuente, Antonia Cepedal, and Agustín Martin-Izard. "Barren and Li–Sn–Ta Mineralized Pegmatites from NW Spain (Central Galicia): A Comparative Study of Their Mineralogy, Geochemistry, and Wallrock Metasomatism." Minerals 9, no. 12 (November 29, 2019): 739. http://dx.doi.org/10.3390/min9120739.
Full textAbstract:
In Central Galicia, there are occurrences of barren and Li–Sn–Ta-bearing pegmatites hosted by metasedimentary rocks. A number of common and contrasting features between Panceiros pegmatites (barren) and Li–Sn–Ta mineralized Presqueira pegmatite are established in this study. K-feldspar and muscovite have the same trace elements (Rb, Cs, P, Zn, and Ba), but the mineralized one has the highest Rb and Cs and the lowest P contents. The barren bodies show fluorapatite and eosphorite–childrenite replacing early silicates. The mineralized body has primary phosphates (fluorapatite and montebrasite), a metasomatic paragenesis (fluorapatite and goyazite) replacing early silicates, and a late hydrothermal assemblage (vivianite and messelite). Ta–Nb oxides from the Presqueira body show a trend from columbite-(Fe) to tantalite-(Fe) and tapiolite-(Fe). In this body, the Li-aluminosilicate textures support primary crystallization of petalite that was partially transformed into Spodumene + Quartz (SQI) during cooling, and into myrmekite during a Na-metasomatism stage. As a result of both processes, spodumene formed. The geochemical study supports magmatic differentiation increasing from the neighboring granites to the Li–Sn–Ta mineralized pegmatite. In both barren and mineralized bodies, the pegmatite-derived fluids that migrated into the wallrock were enriched in B, F, Li, Rb, and Cs and, moreover, in Sn, Zn, and As.
7
Kuleshevich, L. V., М. М. Filippov, N. А. Goltsin, R. Sh Krymsky, and K. I. Lokhov. "Мetasomatic rocks after shungite-bearing rocks of the Maksovo Deposit, Onega Structure, Karelia." Литология и полезные ископаемые, no. 2 (March 28, 2019): 149–64. http://dx.doi.org/10.31857/s0024-497x20192149-164.
Full textAbstract:
The Maksovo metasapropelite deposit, which contains shungite matter and is called maksovite, is located in the eastern Onega structure. The deposit is a diapiric fold which formed ca. 2070±10 Ma ago. It is underlain by carbonate rocks and overlain by tuff siltstones and is cross-cut by 1956±5 Ma gabbro-dolerites. Unaltered maksovites are pelitomorphic rocks with a massive to mildly layered texture and moderate concentrations of all petrogenic components and Сorg of about 30%. Fe-Mg rich and alkaline metasomatic rocks evolve after maksovites and mafic and carbonate tuff siltstones in the northwestern part of the deposit within a multiple ridge-like fold after brecciation zones. They differ from unaltered sedimentary rocks in heterogeneous (brecciated, streaky) textures, mineral and chemical composition and are saturated with numerous sulphide, carbonate, quartz and albite veinlets. They are identified by intense biotitization, chloritization and the presence of calcite, microcline metacrystals, albite-carbonate metacrystals with apatite and carbonate-quartz metacrystals with sulphides and rutile, veinlets and disseminated mineralization. Na concentration rises to 5.67% and K concentration to 7.57%. P and Ti concentrations, accompanying alkaline metasomatism, as well as Mg-Fe and ore-bearing components (often incompatible), increase locally. Metasomatic rocks evolve heterogeneously and are represented by breccia zones. Their slightly elevated radioactivity disturbs the qualitative characteristics of primary maksovite as a useful mineral. Maksovites were dated at 1558±61 Ma by the Re-Os method from sulphides.
8
Sutton, S. J., and J. B. Maynard. "Multiple alteration events in the history of a sub-Huronian regolith at Lauzon Bay, Ontario." Canadian Journal of Earth Sciences 29, no. 3 (March 1, 1992): 432–45. http://dx.doi.org/10.1139/e92-038.
Full textAbstract:
Confusion exists over the usefulness of chemical data from Precambrian weathering profiles in constraining models of atmospheric evolution. One difficulty is in correctly identifying ancient weathering effects and isolating them from numerous other processes that are likely to have affected such ancient rocks. In this study of a middle Precambrian granitic weathering profile, we have used several analytical techniques to separate weathering-related chemical and mineralogical changes from those resulting from other processes. The profile is exposed beneath the Huronian at Lauzon Bay in the Blind River area of Ontario and has a complex history of alteration events, addition of allochthonous material, and low-grade metamorphism. Much of this history can be deciphered, and changes in mineralogy and bulk and mineral chemistry can be assigned to separate alteration events. Specifically, the granite has undergone preweathering albitization, resulting in Na enrichment, followed by chemical weathering that corroded K-feldspar and nearly destroyed plagioclase feldspar and mica in the regolith. Clay minerals replaced feldspars, resulting in enrichment in Al, Ti, and Zr and depletion in Na, Ca, Sr, and K. Fe has also been leached. After weathering, a fine-grained 0.5 m layer of strongly weathered allochthonous material was deposited on the regolith, followed by deposition of the Matinenda Formation. Sometime after Matinenda deposition, K- and Rb-metasomatim affected the regolith and overlying sediments, converting some clays to illite and depositing secondary K-feldspar. Greenschist-facies metamorphism probably postdated this metasomatism and converted clay minerals to white mica and chlorite.
9
Kontonikas-Charos, Alkis, Cristiana L. Ciobanu, Nigel J. Cook, Kathy Ehrig, Roniza Ismail, Sasha Krneta, and Animesh Basak. "Feldspar mineralogy and rare-earth element (re)mobilization in iron-oxide copper gold systems from South Australia: a nanoscale study." Mineralogical Magazine 82, S1 (February 28, 2018): S173—S197. http://dx.doi.org/10.1180/minmag.2017.081.040.
Full textAbstract:
ABSTRACTNanoscale characterization (TEM on FIB-SEM-prepared foils) was undertaken on feldspars undergoing transformation from early post-magmatic (deuteric) to hydrothermal stages in granites hosting the Olympic Dam Cu-U-Au-Ag deposit, and from the Cu-Au skarn at Hillside within the same iron-oxide copper-gold (IOCG) province, South Australia. These include complex perthitic textures, anomalously Ba-, Fe-, or REE-rich compositions, and REE-flourocarbonate + molybdenite assemblages which pseudomorph pre-existing feldspars. Epitaxial orientations between cryptoperthite (magmatic), patch perthite (dueteric) and replacive albite (hydrothermal) within vein perthite support interface-mediated reactions between pre-existing alkali-feldspars and pervading fluid, irrespective of micro-scale crystal morphology. Such observations are consistent with a coupled dissolution-reprecipitation reaction mechanism, which assists in grain-scale element remobilization via the generation of transient interconnected microporosity. Micro-scale aggregates of hydrothermal hyalophane (Ba-rich K-feldspar), crystallizing within previously albitized areas of andesine, reveal a complex assemblage of calc-silicate, As-bearing fluorapatite and Fe oxides along reaction boundaries in the enclosing albite-sericite assemblage typical of deuteric alteration. Such inclusions are good REE repositories and their presence supports REE remobilization at the grain-scale during early hydrothermal alteration. Iron-metasomatism is recognized by nanoscale maghemite inclusions within ‘red-stained’ orthoclase, as well as by hematite in REE-fluorocarbonates, which reflect broader-scale zonation patterns typical for IOCG systems. Potassium-feldspar from the contact between alkali-granite and skarn at Hillside is characterized by 100–1000 ppm REE, attributable to pervasive nanoscale inclusions of calc-silicates, concentrated along microfractures, or pore-attached. Feldspar replacement by REE-fluorcarbonates at Olympic Dam and nanoscale calc-silicate inclusions in feldspar at Hillside are both strong evidence for the role of feldspars in concentrating REE during intense metasomatism. Differences in mineralogical expression are due to the availability of associated elements. Lattice-scale intergrowths of assemblages indicative of Fe-metasomatism, REE-enrichment and sulfide deposition at Olympic Dam are evidence for a spatial and temporal relationship between these processes.
10
Sokol, Ella V., Anna S. Deviatiiarova, Svetlana N. Kokh, Vadim N. Reutsky, Adam Abersteiner, Kseniya A. Philippova, and Dmitry A. Artemyev. "Sulfide Minerals as Potential Tracers of Isochemical Processes in Contact Metamorphism: Case Study of the Kochumdek Aureole, East Siberia." Minerals 11, no. 1 (December 25, 2020): 17. http://dx.doi.org/10.3390/min11010017.
Full textAbstract:
Marly limestones from the Lower Silurian sedimentary units of the Tunguska basin (East Siberia, Russia) underwent metamorphism along the contact with the Early Triassic Kochumdek trap intrusion. At ≤ 2.5 m from the contact, the limestones were converted into ultrahigh-temperature marbles composed of pure calcite and sulfide-bearing calcsilicate layers. The sulfide assemblages in the gabbro and marbles were studied as potential tracers of spurrite-merwinite facies alteration. The gabbro-hosted sulfides show Fe-Ni-Cu-Co speciation (pyrrhotite and lesser amounts of chalcopyrite, pentlandite, and cobaltite) and positive δ34S values (+2.7 to +13.1‰). Both matrix and inclusion sulfide assemblages of prograde melilite, spurrite, and merwinite marbles consist dominantly of pyrrhotite and minor amounts of troilite, sphalerite, wurtzite, alabandite, acanthite, and galena. In contrast to its magmatic counterpart, metamorphic pyrrhotite is depleted in Cu (3–2000 times), Ni (7–800 times), Se (20–40 times), Co (12 times), and is isotopically light (about –25‰ δ34S). Broad solid solution series of (Zn,Fe,Mn)Scub, (Zn,Mn,Fe)Shex, and (Mn,Fe)Scub indicate that the temperature of contact metamorphism exceeded 850–900 °C. No metasomatism or S isotope resetting signatures were detected in the prograde mineral assemblages, but small-scale penetration of magma-derived K- and Cl-rich fluids through more permeable calcsilicate layers was documented based on the distribution of crack-filling Fe-K sulfides (rasvumite, djerfisherite, and bartonite).
Dissertations / Theses on the topic "K-Fe metasomatism"
1
Owen, N. D. "Characteristics of K-Fe alteration in relation to IOCG(U) mineralisation in the northern Yorke Peninsula." Thesis, 2015. http://hdl.handle.net/2440/118209.
Full textAbstract:
This item is only available electronically.The Moonta-Wallaroo area in the Northern Yorke Peninsula (NYP) is inferred to have been associated with the major deformation, metamorphic and magmatic event at ca. 1600-1575 Ma that affected much of eastern Proterozoic Australia. Widespread K-Fe (biotite-magnetite) alteration is genetically linked with the main pyrite ±chalcopyrite mineralising event within the Doora Member of the Wandearah Formation. Zones of high mineralisation were seen to correspond with coarsening grain size of biotite in petrological and hand samples and were supported by geochemical trends between Fe2O3, S and Cu. Later stage hematite bearing phases of alteration resulted in intense alteration and pyrite-chalcopyrite mineralisation locally within carbonate bearing zones. It is suggested that uranium enrichment is also associated with biotite-magnetite alteration but was later stripped from the highly mineralised zones by less pervasive hydrothermal fluids. U-Pb isotope analysis of zircon grains constrain the age of formation of the basement in which mineralisation occurs. The Moonta Porphyry revealed an age of 1752 ±6Ma. Based on its interdigitising relationship with the Moonta Porphyry a maximum age of sedimentation of the Doora Member is proposed at ca. 1752 Ma. The protolithic material of the Harlequin Stone was determined to be similar to that of the Doora Member and was sourced mainly from the ca. 1850 Ma Donington Suite Granitoids. A Pb207/Pb206 age of ca. 1708 Ma suggests a wider age of formation of the Wallaroo Group than previously reported in the literature. Alteration within the Oorlano Metasomatite metasediment samples showed a clear deviation in chemical characteristics from the Doora Member suggesting different styles of alteration in relation to their proximity to the Arthurton and Tickera Granites.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2015
Books on the topic "K-Fe metasomatism"
1
Bridges, John C. Evolution of the Martian Crust. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190647926.013.18.
Full textAbstract:
This is an advance summary of a forthcoming article in the Oxford Encyclopedia of Planetary Science. Please check back later for the full article.Mars, which has a tenth of the mass of Earth, has cooled as a single lithospheric plate. Current topography gravity maps and magnetic maps do not show signs of the plate tectonics processes that have shaped the Earth’s surface. Instead, Mars has been shaped by the effects of meteorite bombardment, igneous activity, and sedimentary—including aqueous—processes. Mars also contains enormous igneous centers—Tharsis and Elysium, with other shield volcanoes in the ancient highlands. In fact, the planet has been volcanically active for nearly all of its 4.5 Gyr history, and crater counts in the Northern Lowlands suggest that may have extended to within the last tens of millions of years. Our knowledge of the composition of the igneous rocks on Mars is informed by over 100 Martian meteorites and the results from landers and orbiters. These show dominantly tholeiitic basaltic compositions derived by melting of a relatively K, Fe-rich mantle compared to that of the Earth. However, recent meteorite and lander results reveal considerable diversity, including more silica-rich and alkaline igneous activity. These show the importance of a range of processes including crystal fractionation, partial melting, and possibly mantle metasomatism and crustal contamination of magmas. The figures and plots of compositional data from meteorites and landers show the range of compositions with comparisons to other planetary basalts (Earth, Moon, Venus). A notable feature of Martian igneous rocks is the apparent absence of amphibole. This is one of the clues that the Martian mantle had a very low water content when compared to that of Earth.The Martian crust, however, has undergone hydrothermal alteration, with impact as an important heat source. This is shown by SNC analyses of secondary minerals and Near Infra-Red analyses from orbit. The associated water may be endogenous.Our view of the Martian crust has changed since Viking landers touched down on the planet in 1976: from one almost entirely dominated by basaltic flows to one where much of the ancient highlands, particularly in ancient craters, is covered by km deep sedimentary deposits that record changing environmental conditions from ancient to recent Mars. The composition of these sediments—including, notably, the MSL Curiosity Rover results—reveal an ancient Mars where physical weathering of basaltic and fractionated igneous source material has dominated over extensive chemical weathering.