Here Is Everything to Know about Porphyritic Granite Rocks
2022年8月30日 · Granite porphyry describes a granite rock texture with large crystals (phenocrysts) embedded in a finer but coarse-grained groundmass.
Porphyritic Granite - Geology 1501 - ECU
Type Igneous Rock Texture Porphyritic Origin Intrusive/Plutonic Chemical Composition Felsic Color Predominately white Mineral Composition Potassium Feldspar, Quartz, Sodium Plagioclase, Biotite, Hornblende Miscellaneous Very large Potassium Feldspar Phenocrysts in a phaneritic (coarse-grained) groundmass Tectonic Environment Convergent Boundary – Intruded into …
Porphyry (geology) - Wikipedia
Porphyry (/ ˈpɔːrfəri / POR-fə-ree) is any of various granites or igneous rocks with coarse-grained crystals such as feldspar or quartz dispersed in a fine-grained silicate -rich, generally aphanitic matrix or groundmass.
4.1: Classification of Igneous Rocks - Geosciences LibreTexts
Some igneous rocks have a mix of coarse-grained minerals surrounded by a matrix of fine-grained material in a texture called porphyritic. The large crystals are called phenocrysts and the fine-grained matrix is called the groundmass or matrix.
Porphyritic - Wikipedia
Porphyritic intrusive rocks have a matrix with individual crystals easily distinguished with the eye, but one group of crystals appearing clearly much bigger than the rest, as in a porphyritic granite. The term comes from the Ancient Greek πορφύρα (porphyra), meaning "purple".
Igneous Rocks - Geology (U.S. National Park Service)
2023年11月8日 · Porphyritic granite contains a set of crystals that are distinctly larger than the rest of the crystals in the granite. The large crystals are referred to as phenocrysts and the rest of the smaller crystals are referred as the groundmass.
PORPHYRITIC GRANITE
Granites are coarsely crystalline igneous rocks, having a phaneritic texture. Porphyritic granites have a mix of large & small crystals, but all crystals are still fairly decent-sized. Large crystals in a porphyritic rock are called phenocrysts. The smaller crystals make up the groundmass.
Porphyritic – Geology is the Way
Porphyritic granites, on the other hand, are characterized by megacrystals that are several centimeters long and are set in a matrix which actually consist of medium- to coarse-grained crystals (1-5 mm or more) but that are significantly smaller than the phenocrysts.
A Geologist’s Definitive Guide to Granite Rock | Geology Base
2023年8月29日 · i. Porphyritic granite. Porphyritic granite will have large (sometimes over 10 cm), usually k-feldspar (white or reddish/pinkish) crystals in the coarse-grained matrix. The groundmass may be quartz, feldspar, and mafic minerals.
Meredith Porphyritic Granite - Most Beautiful Rock in ...
The Meredith Porphyritic Granite can be found in and around Meredith, New Hampshire. I happen to live directly on top of this massive pluton and my college degree is in geology. Some references to this geologic rock formation in the older literature refer to it as the Kinsman granite.