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Can The Size Of K Feldspar Phenocrysts Be Used To

(PDF) Can the size of K-feldspar phenocrysts be used

Can the size of K-feldspar phenocrysts be used to map the occurrence of mylonitic shear zones? Results from the Wyangala Granite, Eastern Lachlan Fold Belt, New South Wales.

(PDF) Can the size of K-feldspar phenocrysts be used

We report the results of mapping the high-strain (shear) zones in the Wyangala Granite. The high-strain zones are part of the Wyangala Fault System and primarily occur along the eastern margin of the Wyangala Granite, Eastern Lachlan Fold Belt in New

Can the size of K-feldspar phenocrysts be used to

作者: Lloyd T White and P G Lennox

Can the size of K-feldspar phenocrysts be used to

White, L. T. & Lennox, P. G. (2010). Can the size of K-feldspar phenocrysts be used to map the occurrence of mylonitic shear zones? Results from the Wyangala Granite, Eastern Lachlan Fold Belt, New South Wales.

"Can the size of K-feldspar phenocrysts be used to

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K-feldspar megacrysts in granites — Phenocrysts, not ...

Cited by: 243

K-feldspar phenocrysts in microgranular magmatic

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K-feldspar megacrysts in granites — Phenocrysts, not ...

K-feldspar megacrysts in granitoid plutons have been interpreted as either phenocrysts or porphyroblasts. Most of the microstructural, mineralogical and chemical evidence (e.g., shape, alignment, concentration, Ba content, zoning, inclusions, and twinning) favours a phenocryst origin. The main features that have been used to support a porphyroblast origin are occurrence of megacrysts: (1 ...

Phenocryst & Porphyritic Textures | Science Trends

Author: Trevor Nace

Igneous phenocrystic origin of K-feldspar megacrysts

Cited by: 33

K-feldspar megacrysts in granites — Phenocrysts, not ...

K-feldspar megacrysts in granitoid plutons have been interpreted as either phenocrysts or porphyroblasts. Most of the microstructural, mineralogical and chemical evidence (e.g., shape, alignment, concentration, Ba content, zoning, inclusions, and twinning) favours a phenocryst origin. The main features that have been used to support a porphyroblast origin are occurrence of megacrysts: (1 ...

Igneous phenocrystic origin of K-feldspar megacrysts

Igneous phenocrystic origin of K-feldspar megacrysts in granitic rocks from the Sierra Nevada batholith James G. Moore. ... The smaller K-feldspar phenocrysts in older marginal plutons ... Significance of K-feldspar megacryst size and distribution in the Tuolumne Intrusive Suite, California [abs.]:

Feldspar | Minerals Education Coalition

Feldspar can be replaced by other minerals and mineral mixtures of similar physical properties. Minerals that could be used to replace feldspar include pyrophyllite, clays, talc, and feldspar-silica (quartz) mixtures. The abundance of feldspar will make these substitutions unnecessary for the

Origin of K-feldspar megacrysts in granitic rocks ...

2007-8-28 · of K-feldspar crystallization. In basic to intermediate rocks, where K-feldspar is a common residual phase, Ba in K-feldspar is relatively high (e.g., Trzcienski and Kulick, 1972). The same is true for pegmatites if sufficient Ba is available, even though K-feldspar is commonly a primary phase (e.g., Afonina and Shmakin, I 9 70; Schmakin, I 97 ).

Hand specimen descriptions of igneous rocks

2019-1-2 · Pink K-feldspar phenocrysts are up to 2.5 cm long in a medium-grained matrix of pink K-feldspar, quartz, white plagioclase, biotite, and muscovite. The point of hand sample descriptions is to give enough information so someone at a complex outcrop could easily find the rock described. In this case, the term K-feldspar is used in

What is a porphyritic igneous rock? - Quora

Thanks for the A2A. Igneous rock is formed through the cooling and solidification of magma or lava and is one of the three main rock groups, the two others being sedimentary and metamorphic. The word igneous comes from the Latin term ignis, which ...

Feldspar - sandatlas.org

Feldspars include three compositional end-members: K-feldspar (KAlSi 3 O 8), albite (NaAlSi 3 O 8), anorthite (CaAl 2 Si 2 O 8). Abbreviations commonly used are Or (K-feldspar), Ab (albite), An (anorthite). ‘Or’ is an abbreviation of a common K-feldspar orthoclase, but sometimes it is used

Orthoclase Feldspar - Geology

Orthoclase as a Feldspar Mineral. Orthoclase is a member of the alkali feldspar series. The alkali feldspars include albite (NaAlSi 3 O 8), anorthoclase ((Na,K)AlSi 3 O 8), sanidine ((K,Na)AlSi 3 O 8), orthoclase (KAlSi 3 O 8), and microcline (KAlSi 3 O 8).. These feldspar minerals form a solid solution series between NaAlSi 3 O 8 and KAlSi 3 O 8.The minerals in that series crystallize from ...

Porphyry - Igneous Rocks

Porphyritic texture is a very common texture in igneous rocks in which larger crystals (phenocrysts) are embedded in a fine-grained groundmass. Porphyry is an igneous rock that contains larger crystals (phenocrysts) in a fine-grained groundmass. K-feldspar phenocrysts in this sample. Width of view 7 cm. TUG 1608-2807.

Geology 1 Flashcards | Quizlet

Dolerite, also called diabase, is a dark igneous rock intermediate in grain size between basalt and gabbro. Consisting of plagioclase feldspar and pyroxene, it is a widespread intrusive rock that forms when basaltic magma cools moderately quickly under basalt volcanoes such as at mid-ocean ridges.

Porphyry - Igneous Rocks

Porphyritic texture is a very common texture in igneous rocks in which larger crystals (phenocrysts) are embedded in a fine-grained groundmass. Porphyry is an igneous rock that contains larger crystals (phenocrysts) in a fine-grained groundmass. K-feldspar phenocrysts in this sample. Width of view 7 cm. TUG 1608-2807.

Formation of K-feldspar megacrysts in granodioritic ...

2009-10-15 · sometimes used to refer to any crystals that are signifi-cantly larger than others in a rock. Although this size cutoff is arbitrary, it does correspond to the largest K-feldspar crystals found in volcanic rocks. We are aware of only one documented example of lava with K-feldspar crystals larger than 5 cm, a dacite from Volca´n Taapaca

Paul Lennox - Honorary Senior Lecturer - UNSW |

Honorary Senior Lecturer at

Noncoaxial K‐feldspar and AMS subfabrics in the

The large K‐feldspar crystals occupy ∼ 30% of the rock's volume and their shapes approximate triaxial polyhedra forming elongated and flattened tablets. Despite localized clustering of feldspar phenocrysts, the majority are isolated in a contiguous matrix . The biotite grains occur in two structural positions: attached to large euhedral ...

Crystal Size Distributions (CSD) in Three Dimensions ...

Position of sections can be seen from breaks in slope on the surfaces (left). KF phenocrysts with their best-fit ellipsoids constructed with a function incorporated in GOCAD (right). (e) consists of two closely spaced fragments and has a long axis of ∼2 mm, (f) of ∼1 mm. (g) 247 K-feldspar phenocrysts and their best-fit ellipsoids.

Local Geology of the Study Area - University of the ...

2012-2-14 · Local Geology of the Study Area 3.1. Geological Characteristics of the Lebowa Granite Suite in the Rooiberg ... commonly porphyritic with K-feldspar phenocrysts up to 10 mm in size and quartz phenocrysts up to 3 mm in size (Plate 3.1 (f)), which weather prominently. ... characterised by an increase in K-feldspar/perthite over plagioclase, and

Abstract: USING K-FELDSPAR ACRYSTS AS

2017-5-23 · The QMP contains sparse K-feldspar phenocrysts up to 4 cm similar to the ones in the TPP that increase in size and abundance toward the TPP contact. Geochemical modeling of major oxides and trace elements suggest that the QMP magma likely fractionated from an early TPP magma and the TPP rocks now represent crystal cumulates.

Potassium-Feldspar Phenocrysts in the Surface of

Potassium-Feldspar Phenocrysts in the Surface of Colomera, and Iron Meteorite Abstract. Silicate aggregates, including large single crystals ofpotassium feldspar as long as 11 centimeters andsodium feldspar, are embeded in the surface of the medium octahedrite Colomera. Silicate nodules in the interior appear to be much smaller (about 0.3 ...

MONOCLINIC K-FELDSPAR JULIAN GOLDSMITH

The phenocrysts are also altered in varying degrees from place to place, and rarely is anything approaching a fresh K-feldspar found. Less than half of any of the original feldspar substance is generally observed, and normal cleavage behavior is destroyed as a consequence.

Igneous Minerals Flashcards | Quizlet

Start studying Igneous Minerals. Learn vocabulary, terms, and more with flashcards, games, and other study tools. ... term used to describe more or less uniform grain size within a rock. ... resulting in alkali feldspar phenocrysts. Latite. Euhedral plagioclase phenocrysts, An40 - An45, alkali feldspar in groundmass, biotite and glass ...