Porphyry Cu ± Mo ± Au deposits are centered within a distinctive arrangement of alteration assemblages including sodic calcic potassic propylitic chlorite sericite with early and late sericitic and finally near surface advanced argillic alterations Here we discussed the linkage between feldspar destructive processes and hypogene
WhatsAppWe show that K feldspar can form from NaCl rich fluids small changes in fluid compositions can cause a change in fluid saturation from albite to K feldspar aqueous composition change around peritectic point from Fig 3B thereby K rich fluid sources are not necessarily required 41 and sodic alteration followed by potassic
WhatsAppMicroscopically the feldspar host is usually a perthite which is decomposed into irregular intergrowth of sodic and potassic feldspar 3 The majority of the quartz grains undergrown with host feldspar are in the form of sub parallel tabular long rods and unconnected dendritic crystals which only show a distinctive graphic texture in
WhatsAppFELDSPAR POTASSIUM FELDSPAR POTASSIUM Safety Data Sheet Date of issue 05/31/2017 Version Print date 05/31/2017 EN English US SDS ID Page 1 SECTION 1 Identification Product identifier Product name FELDSPAR POTASSIUM Product code Product form
WhatsAppThe XRD results for the proportions of K feldspar phlogopitic biotite and muscovite shown in Table 2 clearly distinguish these two alteration assemblages and highlight the higher copper grade of the potassium feldspar zone This higher grade potassic core contains wt% of combined anhydrite and gypsum and the phyllic zone contains
WhatsAppDuan G Ram R Xing Y et al Kinetically driven successive sodic and potassic alteration of feldspar[J] Nature Communications 2021 12 4435 ( ) Plümper O Botan A Los C et al Fluid driven metamorphism of the continental crust
WhatsAppPotassic alteration The characteristic minerals of the potassic alteration are K feldspar biotite and sericite This mineralogical assemblage develops with a pervasive character in the central part of the porphyry quartz micromonzodiorite stock The potassic alteration with adularia is specific for the epithermal system associated with
WhatsAppThe potassic alteration has been ob served in the core of the deposit Figs 3 4 5 and 6 and includes magnetite secondary biotite and secondary K feldspar orthoclase
WhatsAppThe study presented here explored the alteration of K feldspar from 600 to 750 °C to illuminate the composition of a high salinity brine in equilibrium with K feldspar replicating the brine induced potassic alteration zone that is often observed within and close to the causative igneous body and interpreted from geological evidence to have
WhatsAppAnorthoclase is the only alkali feldspar that is not K feldspar It is sodic in composition optically triclinic and characterized by a twinning similar to microcline but on a smaller scale The structural state which is the basis of the alkali feldspar classification is dependent on the temperature of crystallization and subsequent cooling
WhatsAppThe feldspar group is one of the most common types of minerals in the earth s crust Feldspar alteration including the whole processes of feldspar dissolution transfer of released solutes and secondary mineral precipitation is ubiquitous and important in fields including resources and environmental sciences
WhatsAppThe potassic altered samples show selective texturally non destructive alteration of augite biotite plagioclase/alkali feldspar by hydrothermal K feldspar amphibole biotite Potassic alteration is overprinted locally by weak propylitic and anhydrite alterations Figs 4 d and 5 c
Major and trace element analyses of plagioclase alkali feldspar Ti magnetite biotite and apatite from the same Campi Flegrei samples investigated by Fedele et al 2009 are here presented to complete the study on the trace element partitioning for the typical paragenesis of evolved potassic melts GeoLoGicaL backGround
WhatsAppThe feldspar water system is arguably one of the most important in the earth sciences in particular with respect to chemical weathering associated with water rock interactions This is primarily due to the preponderance of feldspar minerals in the upper continental crust and at earth s surface Klein and Philpotts 2017 Feldspars are
WhatsAppThe potassic rock deposits in Poços de Caldas for example display Fe 2 O 3 content ranging from 2 to 6% [18] The spectrum of feldspar is quite similar to that of or thoclase except that the 1000 cm −1 band is unresolved and the main peak head in this region shifts down to 980 cm −1 with slight shifting of other bands
LSR1 Potassic feldspar from a pegmatitic body Fig 1 a It is composed of % K 2 O and % Na 2 O The pink mineral shows well marked cleavage and development of perthites with irregular boundaries approximately 50 to 150 μm in width which together cover about 25% of the total surface area of the thin section analyzed Fig
WhatsAppFeldspar any of a group of aluminosilicate minerals that contain calcium sodium or potassium Feldspars make up more than half of Earth s crust and professional literature about them constitutes a large percentage of the literature of mineralogy Learn more about the properties and uses of feldspar in this article
WhatsAppOptical and X ray studies of 15 chemically analyzed feldspars show that the optical properties of potassic feldspars may vary because of 1 compositional differences such as degree of substitution of Fe 3 for Al and of Na Ca Ba Sr and Rb for K in the feldspar structure with corresponding substitution of Al for Si where necessary to balance
WhatsAppPartition coefficients Min/L D for a series of geochemically relevant elements have been calculated from combined EMP/LA ICP HRMS analyses of plagioclase alkali feldspar Ti magnetite biotite apatite and trachytic/trachyphonolitic melt pairs in selected Campi Flegrei rocks Pl/L D and Kfs/L D values are generally very low for most
WhatsAppThe potassic feldspar in orthogneisses paragneisses and mica schists from the western Tauernfenster Hohe Tauern Tyrol were studied by optical and X ray methods with regard to their structural state and in relation to grade of the peripheral region of the Tauernfenster in greenschist facies rocks highly triclinic microcline occurs with an
WhatsAppTrace element partitioning between plagioclase alkali feldspar Ti magnetite biotite apatite and evolved potassic liquids from Campi Flegrei Southern Italy L orenzo F edeLe 1 M icheLe L
WhatsAppOther articles where potassium feldspar is discussed feldspar Chemical composition Microcline and orthoclase are potassium feldspars KAlSi3O8 usually designated Or in discussions involving their end member composition Albite NaAlSi3O8—usually designated Ab and anorthite CaAl2Si2O8—An are end members of the plagioclase series
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