Quartz and feldspar microstructures in metamorphic rocks ...

(4) Simple twinning may occur in K-feldspar, which appears to be diagnostic of crystallization of K-feldspar in a melt, rather than in the solid state.", keywords = "Crystal faces, Feldspar, Inclusions, Leucosome, Metamorphism, Microstructures, Migmatites, Quar tz",

Quartz microstructures and deformation conditions in the ...

Quartz microstructures and deformation conditions in the Hatagawa shear zone, north‐eastern Japan. Norio Shigematsu. Corresponding Author ... but also the quartz LPO patterns and the presence of myrmekite around K‐feldspar porphyroclasts. Citing Literature. Number of times cited: 12.

Argon diffusion domains in K-feldspar I: microstructures ...

K-feldspar separates and samples heated in vacuum be- tween 750 and 1150 ~ in order to characterize the initial microstructure as well as any changes resulting from laboratory heating. The MH-10 rock shows almost no evidence of plastic deformation, and the K-feldspar does

Alkali Feldspar Microstructures as Provenance Indicator ...

If the bulk . the structurally disordered form of K-feldspar stable at high temperatures. feldspar bulk compositions or chemical zonation within crystals vary continuously from the plagioclase join along curved paths roughly parallel to the path 1–2–3–4 in Figure 2 (see Parsons and Brown 1988.

The influence of grain boundary fluids on the ... - DeepDyve

Read "The influence of grain boundary fluids on the microstructure of quartz-feldspar mylonites, Journal of Structural Geology" on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.

Correlations between microstructures, K-feldspar ...

Correlations between microstructures, K-feldspar triclinicity and trace element geochemistry in stanniferous and barren granites, northern Nigeria ... Abstract The biotite granites in the Nigerian Younger Granites are a major source of the economic metals Sn, Nb, Zn and W. ... coarsening and incoherent perthitic texture of the K-feldspar. The ...

Intracrystalline microstructures in alkali feldspars from ...

Intracrystalline microstructures in alkali feldspars from fluid-deficient felsic granulites: a mineral chemical and TEM study ... Alkali feldspar microstructures. ... Recrystallized K-feldspar contains up to 9–13 mol% of albite component, whereas the anorthite content is below the detection limit. ...

Charnockite microstructures: From magmatic to metamorphic ...

For both magmatic charnockites and dehydrated granites, subsequent fluid-mineral interaction at intergrain boundaries during retrogradation are documented by microstructures including K-feldspar microveins and myrmekites.

Microstructures in feldspars from a major crustal thrust ...

Samples collected across the NW Grenville Front in Ontario, Canada, have been used to document the change in feldspar microstructures produced during shearing under metamorphic conditions that range from upper amphibolite to lower greenschist grade.

Minerals and microstructures - Department of Earth Sciences

Mineral assemblages and microstructures of prograde and retrograde metamorphism in high-pressure complexes 1 Minerals: glaucophane Wadi Hulw, Oman. 2 Minerals: ... D840 Original myrmekite (Pl-Qz intergrowth replacing K-feldspar) in which plagioclase lamellae are replaced by jadeite. 34 Zermatt-Saas meta-ophiolite DWWA1 Eclogite-facies ...

Microstructures in Two Alkali Feldspar Megacrysts from the ...

The microstructures of alkali feldspars crystalli-sed at lower temperatures are relatively less known. TEM observations of twinning and exsolution texture in a hydrothermal and two pegmatitic microclines (TIBBALS & OLSEN, 1977) extended the study of K-feldspar microtextures below the temperature of the monoclinic–triclinic transformation.

Quartz and feldspar microstructures in metamorphic rocks ...

The shapes of quartz and feldspar grains in metamorphic rocks are among the most reliable criteria for determining parental rock-types. Rational faces and elongate crystals of feldspar, especially ...

PLANAR MICROSTRUCTURES (LAMELLAR SUBGRAINS) IN …

microstructures (such as PDFs) from those formed prior to impact such as exsolution lamellae, veins, cleavages, and twin planes [e.g. 2]. We investigated the microstructures of Or-rich alkali feldspar phenocrysts from granitoid rocks recovered from the peak ring of the Chicxulub impact structure during the recent IODP-ICDP Expedition 364 [3].

ALEX STREKEISEN-Feldspar structure-

Feldspar The name feldspar derives from the German words Feld, "field", and Spath, "a rock that does not contain ore." Feldspars are the most abundant mineral in the Earth's crust, making up more than 60% of both the continental crust and the oceanic crust.

Microstructures: Naturally deformed quartzofeldspathic rocks

Naturally deformed quartzofeldspathic rocks 68: Overview of a weakly deformed granodiorite. Quartz and biotite are deformed by intracrystalline plasticity processes, evident from the undulose extinction, subgrain formation, and dynamic recrystallization. ... Quartz grains form stretched ribbons wrapped around K-feldspar porphyroclats. Some ...

Biochemical evolution II: Origin of life in tubular ...

Biochemical evolution II: Origin of life in tubular microstructures on weathered feldspar surfaces. Ian Parsons *, Martin R. Lee *, and ... (K-feldspar) makes up 20–40% by vol of granites and is a major constituent of the Earth's crust.

Diagnostic microstructures for primary and deformational ...

Diagnostic microstructures for primary and deformational quartz rods in graphic granite Hantvr Srnr, ... of regularly spaced shear faults subparallel to crystal cleavages in feldspar. Diagnostic microstructures are parallel opposing surfaces of quartz rods, position of quartz-feldspar ... K: feldspar host. Reflected light micrograph. Scale bar ...

Argon diffusion domains in K-feldspar I: microstructures ...

Argon diffusion domains in K-feldspar I: microstructures in MH-10. Authors; Authors and affiliations ... Lovera OM, Heizler MT, Harrison TM (1993) Argon diffusion domains in K-feldspar II:Kinetic properties of MH-10. ... McLaren AC, O'Donnell RG (1987) Optical and electon microscope investigation of temperature-dependent microstructures in ...

Quartz and Feldspar Microstructures in Metamorphic Rocks

Quartz and Feldspar Microstructures in Metamorphic Rocks. Vernon, R.H. School of Earth Sciences, Macquarie University, Sydney NSW 2109, Australia ... Simple twinning in K-feldspar appears to be indicative of a magmatic orgin, and evidence of magmatic flow is provided by aligned feldspar crystals. Though deformation and recrystallization tend to ...

QUARTZ AND FELDSPAR MICROSTRUCTURES IN …

QUARTZ AND FELDSPAR MICROSTRUCTURES IN METAMORPHIC ROCKS Ftc. 6. Part of a K-feldspar porphyroblast in a high-grade metapelitic rock from Broken Hill, New South Wales, Australia, showing random inclusions of quartz, which are predominantly spherical, and biotite, which tend to be elongate with round terminations

High-temperature microstructures and rheology of deformed ...

Read "High-temperature microstructures and rheology of deformed granite, Erzgebirge, Bohemian Massif, Journal of Structural Geology" on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. ... K-feldspar deforms by fracturing and onset of dynamic ...

how is feldspar formed - talternatiefdehaan.be

quartz and feldspar microstructures in, quartz and feldspar microstructures in metamorphic rocks, of well-formed plagioclase crystals, quartz and feldspar microstructures in metamorphic rocks... 45 Myrmekite formed by Na- and Ca, 1 ISSN 1526-5757 45 Myrmekite formed by Na- and Ca-metasomatism of K-feldspar Jiashu RONG Beijing Research ...

Igneous microstructures in migmatites | Geology ...

Therefore, igneous microstructures can be preserved in leucosomes that have not undergone penetrative subsolidus deformation and recrystallization. The cores of many of the crystals of cordierite and K-feldspar have small, locally oriented inclusions similar to those in the same minerals in the mesosomes.

Microstructures and quartz lattice-preferred orientations ...

K-feldspar microstructures include fractures, undulose extinction, subgrains and myrmekite. Undeformed recrystallized feldspar grains, similar in size to subgrains, are occasionally recognizable adjacent to porphyroclasts, and we infer that these probably formed as a result of subgrain-rotation recrystallization (Figure 5 d).

40 Ar/39 Ar Ages In Deformed Potassium Feldspar: Evidence ...

The contact is decorated by several minor `domains' of the order of 300 ´ 300 lm. phases (white mica, chlorite, quartz and an opaque The K-feldspar has some microstructures that can phase) and separates the plagioclase from K-feldspar only be seen in the OC image (Figs. 3b, 5a and 6a).

ARTICLE IN PRESS - earth.usc.edu

ing K-feldspar grains, and aplites commonly show anhedral grain shapes (owing to simultaneous crystallization and consequent competition for space involving quartz, K-feldspar and plagioclase), granite/granodiorite microstructures do not resemble those of meta-morphic rocks. Instead, theyare characterized byelongate crystals of

Biochemical evolution II: Origin of life in tubular ...

Potassium-rich alkali feldspar (K-feldspar) makes up 20–40% by vol of granites and is a major constituent of the Earth's crust. Metamorphism has obscured the early geological record, but radioactive dating coupled with field geology and petrography is yielding valuable information on the earliest rocks.

Intracrystalline microstructures in alkali feldspars from ...

Perthite is a typical microstructure in alkali feldspar that is generated by exsolution of a more albite-rich phase from alkali feldspar or ternary feldspar of an intermediate composition producing at the same time a more orthoclase-rich host.

Tweed microstructures: Experimental observations and some ...

Abstract Experimental observations, mainly by transmission electron microscopy, of tweed microstructures in minerals (K-feldspar and cordierite), high-T c superconductors (Co-doped YBCO) and metals are reviewed. Structural models of the local structure within the tweed are compared and evaluated with respect to spectroscopic measurements in a number of systems.

K Feldspar: Mineral information, data and localities.

Adularia: A more ordered low-temperature variety of Orthoclase or partially disordered Microcline.Individual localities should be verified because the adularia structural state is nearly equally represented by microcline and orthoclase specimens.