Matches in SemOpenAlex for { <https://semopenalex.org/work/W2076124540> ?p ?o ?g. }
- W2076124540 endingPage "651" @default.
- W2076124540 startingPage "635" @default.
- W2076124540 abstract "K-feldspars in the system K[AlSi 3 O 8 ]–K[FeSi 3 O 8 ] were synthesized hydrothermally at P H 2 O = 1 kbar and T = 400 °C, 500 °C, and 600 °C to investigate their ordering behaviour, the extent of Al, Fe substitution, and the influence of oxygen fugacities on the run products (Ni–NiO compared to Cu–Cu 2 O buffer conditions). Starting materials were mixtures of Al 2 O 3 , Fe 2 O 3 and SiO 2 in non-stoichiometric ratios together with KOH solution as the transport medium. In the Ni–NiO buffered runs Fe 3+ was partly reduced to Fe 2+ . Abundant growth of mica with the approximate composition K 0.8 □ 0.2 (Ni 2.75 Fe 2+ 0.25 )[(Fe 3+ 0.3 Al 0.5 Si 3.2 )O 10 ](OH) 2 left the K-feldspar strongly depleted in Fe 3+ relative to the starting material. In the Cu–Cu 2 O runs with their larger oxygen fugacities, growth of delafossite (Cu 1+ Fe 3+ O 2 ) took up Fe 3+ so that the Fe 3+ content of the K-feldspars, varying between 20 at% and 100 at%, roughly correlated with the amount of delafossite present. Considering that the phase transition in both K-feldspar endmembers is first order, an approximate phase diagram has been calculated from known transition temperatures (480 °C and 704 °C, respectively) and known (7300 J/mol; Hovis, 1988) or derived transition enthalpies (11500 J/mol). The calculation results in a narrow two-phase field separating high-temperature (Al, Fe)-sanidine from low-temperature (Al, Fe)-microcline. In the Al-rich half of the diagram, metastable monoclinic K-feldspar occurred in the stability field of microcline, whereas Fe-rich compositions attained the triclinic ordered state. No indication of a miscibility gap has been detected. Fe-rich microcline that was found coexisting with less Fe-rich monoclinic K-feldspar in a few runs at 600 °C and 500 °C (not at 400 °C, however) is interpreted as the result of a conditional metastable phase separation, in the sense that the separation only occurs on the condition of triclinic ordering in the Fe-rich K-feldspars. b – c diagrams show that pure KAl-feldspars, even after long annealing at 600 °C to 400 °C, keep a high degree of disorder corresponding to reference high sanidine. This agrees with slow ordering kinetics predicted from the Mueller rate equation, when using an updated calibration of ln K D vs. 1/ T : − RT ln K D (J/mol) = 4047(668) − 1.80(47) T + 10955(929) Q . Structural incorporation of Fe 3+ leads to faster ordering kinetics. For example, substitution of 27 at.% Al by Fe enhances the ordering rate constant at 600 °C by a factor of ≈ 170. Further, the observed degrees of order increase at increasing Fe contents and decreasing temperatures ruling out ordering in the solid state subsequent to growth. One possibility would be initial growth with the observed degrees of order driven by atomic radii effects and the proton concentration in the structure (Graham & Elphick, 1991, 1994) having a larger effect on Fe, Si than Al, Si interchanges. A second possibility would be solution-reprecipitation becoming more effective at increasing Fe contents and increasing deviation of the metastable monoclinic crystals from their (Al, Fe)-sanidine stability fields, i.e. the lower the temperature." @default.
- W2076124540 created "2016-06-24" @default.
- W2076124540 creator A5005267128 @default.
- W2076124540 creator A5008275349 @default.
- W2076124540 creator A5023393421 @default.
- W2076124540 creator A5026876201 @default.
- W2076124540 creator A5036347183 @default.
- W2076124540 creator A5040354605 @default.
- W2076124540 creator A5054872326 @default.
- W2076124540 creator A5070832436 @default.
- W2076124540 creator A5015652475 @default.
- W2076124540 creator A5086369530 @default.
- W2076124540 date "2008-08-29" @default.
- W2076124540 modified "2023-10-16" @default.
- W2076124540 title "Synthesis and structural state of K-feldspars in the system K[AlSi3O8]K[FeSi3O8]" @default.
- W2076124540 cites W1579746625 @default.
- W2076124540 cites W1969800446 @default.
- W2076124540 cites W1985559227 @default.
- W2076124540 cites W2004746511 @default.
- W2076124540 cites W2008135826 @default.
- W2076124540 cites W2020891191 @default.
- W2076124540 cites W2041103588 @default.
- W2076124540 cites W2060267768 @default.
- W2076124540 cites W2072275084 @default.
- W2076124540 cites W2087279957 @default.
- W2076124540 cites W2092067365 @default.
- W2076124540 cites W2095085027 @default.
- W2076124540 cites W2095365109 @default.
- W2076124540 cites W2119940511 @default.
- W2076124540 cites W2147798157 @default.
- W2076124540 cites W2182500888 @default.
- W2076124540 cites W2299563794 @default.
- W2076124540 cites W2324873584 @default.
- W2076124540 cites W2334661377 @default.
- W2076124540 cites W2339431658 @default.
- W2076124540 cites W2460946113 @default.
- W2076124540 cites W2465005086 @default.
- W2076124540 cites W2577425229 @default.
- W2076124540 cites W2581516404 @default.
- W2076124540 cites W2912772511 @default.
- W2076124540 cites W2916080746 @default.
- W2076124540 cites W3138018390 @default.
- W2076124540 cites W3143393405 @default.
- W2076124540 cites W3148808682 @default.
- W2076124540 cites W88505844 @default.
- W2076124540 cites W2587087993 @default.
- W2076124540 doi "https://doi.org/10.1127/0935-1221/2008/0020-1840" @default.
- W2076124540 hasPublicationYear "2008" @default.
- W2076124540 type Work @default.
- W2076124540 sameAs 2076124540 @default.
- W2076124540 citedByCount "11" @default.
- W2076124540 countsByYear W20761245402013 @default.
- W2076124540 countsByYear W20761245402015 @default.
- W2076124540 countsByYear W20761245402016 @default.
- W2076124540 countsByYear W20761245402019 @default.
- W2076124540 countsByYear W20761245402022 @default.
- W2076124540 crossrefType "journal-article" @default.
- W2076124540 hasAuthorship W2076124540A5005267128 @default.
- W2076124540 hasAuthorship W2076124540A5008275349 @default.
- W2076124540 hasAuthorship W2076124540A5015652475 @default.
- W2076124540 hasAuthorship W2076124540A5023393421 @default.
- W2076124540 hasAuthorship W2076124540A5026876201 @default.
- W2076124540 hasAuthorship W2076124540A5036347183 @default.
- W2076124540 hasAuthorship W2076124540A5040354605 @default.
- W2076124540 hasAuthorship W2076124540A5054872326 @default.
- W2076124540 hasAuthorship W2076124540A5070832436 @default.
- W2076124540 hasAuthorship W2076124540A5086369530 @default.
- W2076124540 hasConcept C11413529 @default.
- W2076124540 hasConcept C127313418 @default.
- W2076124540 hasConcept C17409809 @default.
- W2076124540 hasConcept C185592680 @default.
- W2076124540 hasConcept C199289684 @default.
- W2076124540 hasConcept C33923547 @default.
- W2076124540 hasConcept C48103436 @default.
- W2076124540 hasConcept C8010536 @default.
- W2076124540 hasConceptScore W2076124540C11413529 @default.
- W2076124540 hasConceptScore W2076124540C127313418 @default.
- W2076124540 hasConceptScore W2076124540C17409809 @default.
- W2076124540 hasConceptScore W2076124540C185592680 @default.
- W2076124540 hasConceptScore W2076124540C199289684 @default.
- W2076124540 hasConceptScore W2076124540C33923547 @default.
- W2076124540 hasConceptScore W2076124540C48103436 @default.
- W2076124540 hasConceptScore W2076124540C8010536 @default.
- W2076124540 hasIssue "4" @default.
- W2076124540 hasLocation W20761245401 @default.
- W2076124540 hasOpenAccess W2076124540 @default.
- W2076124540 hasPrimaryLocation W20761245401 @default.
- W2076124540 hasRelatedWork W1758497512 @default.
- W2076124540 hasRelatedWork W1987691177 @default.
- W2076124540 hasRelatedWork W2036099453 @default.
- W2076124540 hasRelatedWork W2040829098 @default.
- W2076124540 hasRelatedWork W2349947565 @default.
- W2076124540 hasRelatedWork W2361911732 @default.
- W2076124540 hasRelatedWork W2380934447 @default.
- W2076124540 hasRelatedWork W2538103680 @default.
- W2076124540 hasRelatedWork W2748952813 @default.
- W2076124540 hasRelatedWork W3008763070 @default.
- W2076124540 hasVolume "20" @default.