Mineral self-organization during the orthoclase-microcline transformation in a granite pegmatite

Sánchez-Muñoz, L.; García-Guinea, Javier; Bény, Jean-Michel; Rouer, Olivier; Campos, Rocío; Sanz, J.; Moura, Odulio J.M. de

doi:10.1127/0935-1221/2008/0020-1844

Cited by 11 publications

(8 citation statements)

References 21 publications

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“…This is not always the case. Sánchez-Muñoz et al (2008 provide light micrographs of the development of tartan microcline twins forming selvages adjacent to thick lenticular albite veins near (100) in otherwise featureless K-feldspar (orthoclase?) in pegmatitic feldspars.…”

Section: Perth: Crypto-and Micro-perthitic Microclinementioning

confidence: 99%

“…Sánchez-Muñoz et al (2006) used cathodoluminescence (CL) and SEM imaging to characterize twinning and exsolution features in a 'giant' microcline from the Golconda pegmatite, Minas Gerais, which has both macroperthitic veins and microperthitic film lamellae. Sánchez-Muñoz et al (2008) studied the orthoclase-microcline transformation in a K-feldspar from a granite pegmatite from Lavra do Fermín, Minas Gerais, using LM. The crystal has very coarse lenticular albite lamellae on scales of 100s of µm set in a predominantly orthoclase matrix, and long-range Balic-Zúnićet al (2013) studied two samples of mesoperthitic feldspars from pegmatites associated with the Larvik syenite, from the Oslo province, Norway.…”

Section: Previous Work On Alkali Feldspars From Pegmatitesmentioning

confidence: 99%

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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: Crypto-and Micro-perthitic Microclinementioning

confidence: 99%

Section: Previous Work On Alkali Feldspars From Pegmatitesmentioning

confidence: 99%

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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“…Twins are possible channels for decreasing the system's entropy [34]. This process could also be associated with yet another self-organization process that develops within the tribo-system at the micro-scale [33][34][35][36].…”

Section: Resultsmentioning

confidence: 99%

“…The crystal orientation map images indicate the absence of any plastic deformation and a clear grain orientation distribution function (ODF) of (0 0 1), (2 1 0) and (1 2 0) (see the pole figures in Figure8a). The pole figures indicate a (0 0 1) preferred orientation in the range of 0-20 degrees, predominantly perpendicular to the surface, which is typical for a CVD alpha-alumina orientation structure after deposition[33][34][35][36]. SEM images of the post-wear surface morphology (Figure8b) show that the alveoli disappear due to the intensive metal flow at the chip/tool interface.…”

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confidence: 86%

The Relationship between Cyclic Multi-Scale Self-Organized Processes and Wear-Induced Surface Phenomena under Severe Tribological Conditions Associated with Buildup Edge Formation

et al. 2021

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This paper presents experimental investigations of various interrelated multi-scale cyclic and temporal processes that occur on the frictional surface under severe tribological conditions during cutting with buildup edge formation. The results of the finite element modeling of the stress/temperature profiles on the friction surface are laid out. This study was performed on a multilayer coating with the top alumina ceramic layer deposited by CVD (chemical vapor deposition) on a WC/Co carbide substrate. A detailed analysis of the wear process was conducted by 3D wear evaluation, scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) and electron backscattered diffraction (EBSD), as well as X-ray photoelectron spectroscopy (XPS) methods. The following cyclic phenomena were observed on the surface of the tribo-system during the experiments: a repetitive formation and breakage of buildups (a self-organized critical process) and a periodical increase and decrease in the amount of thermal barrier tribo-films with a sapphire structure (which is a self-organization process). These two processes are interrelated with the accompanying progression of cratering, eventually resulting in the catastrophic failure of the entire tribo-system.

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“…The above explanations generally imply a transformation mechanism in which the process takes places by coarsening of the ill-defined (wave) domain into twin domains via independent and unrelated atomic adjustments. However, recent observations in Krich feldspars from granitic pegmatites [78,79] indicate that the tweed microstructure of orthoclase cannot be explained by a random nucleation-and-growth process, i.e., by an atom-by-atom diffusion process of independent atomic units from a monoclinic (sanidine) precursor. Actually, the development of modules as fine tweed domains or large twin lamellae occurs from avalanche-like orthogonal recrystallization units or long-distance transformation waves in the solid state.…”

Section: Heterogeneous Structures At the Mesoscalementioning

confidence: 99%

Order–Disorder Diversity of the Solid State by NMR: The Role of Electrical Charges

et al. 2022

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The physical explanations and understanding of the order-disorder phenomena in the solid state are commonly inferred from the experimental capabilities of the characterization techniques. Periodicity is recorded according to the averaging procedure of the conventional reciprocal-space techniques (RSTs) in many solids. This approach gives rise to a sharp trimodal view including non-crystalline or amorphous compounds, aperiodic crystals and periodic crystals. However, nuclear magnetic resonance (NMR) spectroscopy offers an alternative approach that is derived from the distinct character of the measurements involved at the local scale. Here, we present a sequence of progressive order-disorder states, from amorphous structures up to fully ordered mineral structures, showing the great diversity existing in the solid state using multinuclear NMR spectroscopy. Some examples in glasses and products of their crystallization are used, as well as several minerals (including beryl-group and feldspar-group minerals) at magnetic fields up to 35.2 T, and some examples from literature. This approach suggests that the solid state is a dynamic medium, whose behavior is due to atomic adjustments from local compensation of electrical charges between similar structural states, which explains Ostwald’s step rule of successive reactions. In fully ordered feldspar minerals, we propose that the electronic structure of the elements of the cavity site is involved in bonding, site morphology and feldspar topology. Furthermore, some implications are derived about what is a mineral structure from the point of view of the NMR experiments. They open the possibility for the development of the science of NMR Mineralogy.

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Mineral self-organization during the orthoclase-microcline transformation in a granite pegmatite

Cited by 11 publications

References 21 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

The Relationship between Cyclic Multi-Scale Self-Organized Processes and Wear-Induced Surface Phenomena under Severe Tribological Conditions Associated with Buildup Edge Formation

Order–Disorder Diversity of the Solid State by NMR: The Role of Electrical Charges

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