Microstructural evolution during experimental albitization of K-rich alkali feldspar

Norberg, Nicholas; Neusser, Gregor; Wirth, Richard; Harlov, Daniel E.

doi:10.1007/s00410-011-0610-y

Cited by 70 publications

(49 citation statements)

References 45 publications

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“…There is localized coherency strain and dislocation arrays along the immediate interface between albite films and microcline, which is clearly semicoherent. Similar sets of periodic dislocations were found by Norberg et al (2011) at interfaces between albite and orthoclase produced during laboratory albitization experiments, and were reported by Fig. 4) along natural replacive albite-orthoclase interfaces in feldspars from the Shap granite.…”

Section: Perth: Vein Macroperthitesupporting

confidence: 85%

Diffusion-controlled and replacement microtextures in alkali feldspars from two pegmatites: Perth, Ontario and Keystone, South Dakota

Lee

Parsons

2015

Mineral. mag.

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Macro-and micro-perthitic microclines from pegmatites from Perth, Ontario (Wards catalogue 46 E 0510) and Keystone, South Dakota (Wards 46 E 5125) have been studied using light and electron microscopy. A sample of the type perthite from Perth, Ontario (Hunterian Museum, Glasgow, M2361) was compared using light microscopy. It differs in bulk composition and microtexture from the Wards sample. The Perth sample from Wards is a mesoperthite, with sub-periodic ∼mm-thick albite veins near (100), with irregular surfaces. The microcline has regular tartan twins and formed from orthoclase by a continuous process. The Keystone sample is a microperthite, with non-periodic albite veins mainly in {110}. Irregular tartan twins, volumes of irregular microcline and subgrains suggest that the microcline formed by dissolutionreprecipitation. Microcline in both samples contains semicoherent cryptoperthitic albite films that formed after the development of tartan twins. The bulk compositions of these intergrowths imply exsolution below ∼400°C. Diffusion parameters imply sustained heating for between 0.11 My at 400°C, 1.5 GPa and 8.4 My at 300°C, 1 GPa. Unrealistic times are required at 200°C. Subsequently, the crystals reacted with a fluid leading to replacive growth of the vein perthites. Unusually, Albite twin composition planes in replacive subgrains have sub-periodic dislocations, formed by coalescence of advancing growth twins. Processes that might lead to periodic, replacive intergrowths are discussed. The Perth and Keystone feldspars have been used for experimental work on dissolution during weathering and on anomalous thermoluminescence fading. Their microtextures make them unsuitable for obtaining properties that can be extrapolated to feldspars in general.

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Section: Perth: Vein Macroperthitesupporting

confidence: 85%

Diffusion-controlled and replacement microtextures in alkali feldspars from two pegmatites: Perth, Ontario and Keystone, South Dakota

Lee

Parsons

2015

Mineral. mag.

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“…During albitisation, when more Ca-rich plagioclase is replaced by the almost pure end member albite, the interface between parent and product is very complex and the product phase is invariably porous on a submicrometre scale. This has been observed both for experimentally produced albite (Hövelmann et al, 2010;Norberg et al, 2011) and for natural samples (Engvik et al, 2008). Relatively large porosities (several percent) can arise during replacement (Fig.…”

Section: Silicatessupporting

confidence: 55%

Sculpting of Rocks by Reactive Fluids

Jamtveit¹,

Hammer²

2012

Geochem Persp

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“…This difference in the compositions between the C13 and C11 plagioclase suggests that the albitization in the C11 feldspars occurred hydrothermally furthermore after the main magmatic reactions. Albitization in granitic feldspars is a common phenomenon of their hydrothermal reactions Lee and Parsons, 1997;Hashimoto et al, 2005a;Putnis et al, 2007;Engvik et al, 2008;Parsons and Lee, 2009;Hovelmann et al, 2010;Norberg et al, 2011). Therefore, the formation process of the present microperthite discussed above probably occurred at the late magmatic or hydrothermal stage during the cooling.…”

Section: Microperthitic Texture In the C11 Alkali Feldsparmentioning

confidence: 87%

“…Thus, perthitic textures of alkali feldspars become a very important tool to clarify the cooling histo-ries of host plutons during magmatic to hydrothermal stages (Brown and Parsons, 1994;Parsons and Lee, 2009). Moreover, it has been pointed out that feldspar textures in granites should record metasomatic replacement reactions (Putnis, 2002;Putnis et al, 2007;Hovelmann et al, 2010;Norberg et al, 2011), and that the textures might be related to large-scale, crustal fluid flows of multiple-stage (Engvik et al, 2008;Plumper and Putnis, 2009;Słaby et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Microtexture and compositional variation of alkali feldspars from the Kakkonda granitic pluton, northeast Japan: Implications to the formation processes of granitic texture

Nakano

Sawaki

Sasaki

2014

Journal of Mineralogical and Petrological Sciences

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This paper describes textures and chemical compositions of alkali feldspars to get a clue of the cooling history of the Kakkonda granitic pluton. The Kakkonda pluton of tonalite-granodiorite contains two types of alkali feldspar: one is microperthitic alkali feldspar in the lower-temperature granodiorite of 370°C at the shallower depth (sample C11, 2936-2939 m) and the other is non-microperthitic alkali feldspar in the higher-temperature tonalite over 500°C at the deeper depth (sample C13, 3726-3729 m). The two types of alkali feldspars were examined using an electron microprobe analyzer with an attached cathodoluminescence spectrometer system. The former alkali feldspar is spotted due to microscopic pores and several types of inclusions with microperthitic texture, and the latter is clear and featureless under a microscope. Concentric and/or domain Ba zoning patterns with irregular veins were newly found in both the alkali feldspars. The microperthitic texture in the lower-temperature granodiorite contains two types of Ab-rich plagioclase: one is a bead type of smaller size with rather rounded shape, and the other is a flake type of larger size with irregular shape. The appearance of the microperthitic alkali feldspar is quite different from ordinary patch microperthites with turbidity in granitic rocks described to date. Based on the microperthitic textures and Ba-distribution patterns, resorption of primary plagioclase during the growth of interstitial alkali feldspar might contribute to the formation of the microperthitic alkali feldspar in the granodiorite of C11. Barium-zoning patterns are principally magmatic (C13 alkali feldspar), but they were modified during the formation of microperthite (C11 alkali feldspar) at cooling.

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Microstructural evolution during experimental albitization of K-rich alkali feldspar

Cited by 70 publications

References 45 publications

Diffusion-controlled and replacement microtextures in alkali feldspars from two pegmatites: Perth, Ontario and Keystone, South Dakota

Diffusion-controlled and replacement microtextures in alkali feldspars from two pegmatites: Perth, Ontario and Keystone, South Dakota

Sculpting of Rocks by Reactive Fluids

Microtexture and compositional variation of alkali feldspars from the Kakkonda granitic pluton, northeast Japan: Implications to the formation processes of granitic texture

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