mining porphyritic texture

mining porphyritic texture

Igneous Rock Textures - ThoughtCo

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Igneous Rocks and the Rock Cycle

Porphyritic textured rocks contain both a coarse and fine-grained texture. The coarse grains in a porphyritic rock begin to develop as the magma is cooling below the surface of the earth. Following eruption or exposure to lower temperatures, the remaining magma or lava cools very quickly and forms minerals with fine-grained textures.

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Phaneritic Texture - Mining Fundamentals

Phaneritic texture is one of the six main textures of rocks. Phaneritic rocks are intrusive igneous rocks with coarse crystals of equal size. Phaneritic rocks indicate slow cooling of magma deep beneath the Earth's surface.

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Porphyry | geological feature | Britannica

Porphyry. Rocks have many different textures. Layered sandstone produces a gritty texture, whereas coquina may be rough with cemented shells occasionally producing a sharp edge. Likewise, breccia, which contains pieces of other rocks that have been cemented together, and porphyry, which contains interlocking mineral crystals, tend to be rough.

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PDF Activity 23: Igneous Rock Identification Maine Geological

Porphyritic rocks have had at least TWO cooling phases and contain larger mineral grains, called phenocrysts, in a mass of finer grained material. The following samples display porphyritic texture: Part II: For each plutonic rock listed in Part I above, use the attached percentage estimation

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Origin of Mesozoic Porphyritic Rocks and Regional Magmatic

Abstract: Mesozoic porphyritic rocks from the Zijinshan area, southwestern Fujian Province, China, are andesitic to rhyolitic in composition. The whole-rock SiO 2 contents of these rocks are between 62.5% and 78.1%. Magmatic zircon from the Mesozoic porphyritic rocks was determined

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Porphyry - Igneous Rocks

It is often assumed that phenocrysts that form the porphyritic texture must be felsic (feldspars (preferably alkali feldspars) or quartz). The green mineral here is olivine . But it does meet the most important and universal characteristics of porphyritic rocks — it is …

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www.jsjgeology.net

PORPHYRITIC GRANITE . Porphyritic granite has the same chemistry & mineralogy as ordinary granite, but differs in the size range of its crystals. Granites are coarsely crystalline igneous rocks, having a phaneritic texture. Porphyritic granites have a mix of large …

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Types of Porphyritic Rocks - Mineral Processing & Metallurgy

Porphyry. — This name refers to the structure, which is formed of larger crystals set in a fine-grained or glassy ground-mass. The porphyritic structure may be plainly visible, the larger crystals being easily seen (phenocrysts), or it may require the microscope to bring it out. Porphyritic structure may appear in any igneous rock, but the true porphyries are rocks in which there is a marked ...

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Porphyritic Granite

Name: Porphyritic Granite: Texture: Porphyritic: Origin: Intrusive/Plutonic: Chemical Composition: Felsic: Color: Predominantly pink: Mineral Composition: Potassium ...

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PDF Distribution of Marginal Texture in the Quanah Granite

The porphyritic texture has 5mm phenocrysts with a sub-millimeter alkali feldspar and quartz matrix (Figure 5C).

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Rock Textures - Geology for Today - Dr. Tambra L. Eifert

Porphyritic texture is represented by igneous rocks which have minerals grains of different sizes. The larger minerals are called phenocrysts. The smaller ones are collectively known as groundmass, which is simply the grains between the phenocrysts. The groundmass can be aphanitic or phaneritic; therefore, the only requirement for this type of ...

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Porphyritic texture - ALEX STREKEISEN

Porphyritic texture Porphyritic texture is an igneous rock texture in which large crystals are set in a finer-grained or glassy groundmass. Porphyritic textures occur in coarse, medium and fine-grained igneous rocks. Usually the larger crystals, known as phenocrysts, …

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The Texture of Igneous Rocks - Geology In

Porphyritic textures develop when conditions during cooling of a magma change relatively quickly. The earlier formed minerals will have formed slowly and remain as large crystals, whereas, sudden cooling causes the rapid crystallization of the remainder of the melt into a fine grained (aphanitic) matrix.

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Igneous Rocks: Formation Texture and Composition | Geology

This texture showing large sized crystals within a matrix of small crystals is the porphyritic texture. The large crystals, because of their prominence in the rock are called phenocrysts. Phenocrysts may have sharp edges and well-formed crystal faces or they may be corroded and somewhat irregular. iv. Pegmatite Texture: This rock is an intrusive rock.

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Igneous Rocks: Texture and Classification | Geology

The Porphyritic Texture is characterised by the presence of a few conspicuously large sized crystals (the phenocrysts) which are embedded in a fine-grained ground mass or matrix. The texture is sometimes further distinguished into mega-porphyritic and microporphyritic depending upon the size of the phenocrysts. Porphyritic texture may be caused by any one or more of the following factors:

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Textures of Igneous Rocks - Tulane University

In a porphyritic texture, the larger grains are called phenocrysts and the material surrounding the the phenocrysts is called groundmass or matrix : In a rock with a phaneritic texture, where all grains are about the same size, we use the grain size ranges shown to the right to describe the texture…

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Porphyry may refer to: Porphyritic, the general igneous text

Porphyry may refer to: Porphyritic, the general igneous texture of a rock with two distinct crystal phenocryst sizes Porphyry geology, an igneous rock with large crystals in a fine-grained matrix and important Roman building material Porphyry Mountain in Alaska Porphyry, a system of astrological house division Porphyry copper deposit, a primary low grade ore deposit of copper, consisting of ...

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what is porphyritic texture? | Yahoo Answers

Porphyry now refers to a texture of igneous rocks. Its chief characteristic is a large difference between the size of the tiny matrix crystals and other much larger crystals, called phenocrysts.

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Granite (porphyritic) - University of Oxford

Granite (porphyritic); Shap, Cumbria In terms of its mineral content this is a typical granite, consisting of pink potassium feldspar, cream sodium feldspar (plagioclase), grey quartz and black biotite mica. The most striking feature of its texture is the large pink angular potassium feldspar crystals (one of which is indicated by the yellow ...

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