What is microlitic texture?Asked by: Sofia Marshall | Last update: 29 June 2021
Score: 4.3/5 (34 votes)
Hyalopilitic texture is a texture of volcanic rocks in which the groundmass consists of small microlites of feldspar (sub-parallel to each other) embedded in glass.View full answer
Also to know, What is meant by the texture of an igneous rock?
The texture of a rock refers to the details of its visible character. ... There are nine main types of igneous rock textures: Phaneritic, vesicular, aphanitic, porphyritic, poikilitic, glassy, pyroclastic, equigranular, and spinifex. Each kind of texture has a variety of different characteristics that make them unique.
Regarding this, What kind of texture do the igneous rocks have?. Plutonic Rocks
The texture of an igneous rock made up entirely of crystals big enough to be easily seen with the naked eye is phaneritic. Phaneritic texture is sometimes referred to as coarse-grained igneous texture. Granite, the most well known example of an intrusive igneous rock, has a phaneritic texture.
In this manner, How is Poikilitic texture formed?
Poikilitic texture refers to igneous rocks where large later-formed less perfect crystals ('oikocrysts') surround smaller early-formed idiomorphic crystals ('chadacrysts') of other minerals. A poikilitic texture is most easily observed in petrographic thin sections.
What is the texture of olivine?
An olivine crystal is normally a roundish lump 2 mm or less across. A mass of pure olivine crystals thus forms a distinctive granular texture. Olivine's color ranges from the deep green of peridot to the olive green of olives to the pale olive green of pale green olives.
Texture - phaneritic (coarse grained). Mineral content - generally olivine with lesser pyroxene ( augite) (dunite is dominantly olivine), always contains some metallic minerals, e.g. chromite, magnetite.
Olivine is one of the first minerals to be altered by weathering. Because it is so easily altered by weathering, olivine is not a common mineral in sedimentary rocks and is only an abundant constituent of sand or sediment when the deposit is very close to the source.
Trachytic is a texture of extrusive rocks in which the groundmass contains little volcanic glass and consists predominantly of minute tabular crystals, namely, sanidine microlites. The microlites are parallel, forming flow lines along the directions of lava flow and around inclusions.
From Wikipedia, the free encyclopedia. In petrology, micrographic texture is a fine-grained intergrowth of quartz and alkali feldspar, interpreted as the last product of crystallization in some igneous rocks which contain high or moderately high percentages of silica.
Glomeroporphyritic or glomerophyric is a term used to describe a porpyritic texture in which phenocrysts are clustered into aggregates called glomerocrysts or crystal clots. Glomeroporphyritic textures are common and often included plagioclase and pyroxenes in basic rocks.
Glassy or vitreous textures occur during some volcanic eruptions when the lava is quenched so rapidly that crystallization cannot occur. The result is a natural amorphous glass with few or no crystals. Examples include obsidian.
obsidian, igneous rock occurring as a natural glass formed by the rapid cooling of viscous lava from volcanoes. Obsidian is extremely rich in silica (about 65 to 80 percent), is low in water, and has a chemical composition similar to rhyolite.
That's why intrusive igneous rocks usually have a coarse to very coarse texture. As you can see from the chart, coarse texture = grain sizes of 1 to 10 mm and very coarse texture = grain sizes of 10mm and larger. Granite, Diorite, Gabbro, Peridotite and Dunite are the names of the coarse grained igneous rocks.
Explanation: The term texture is defined as the mutual relationship of different mineralogical constituents in a rock. It is determined by the size, shape and arrangement of these constituents within the body of the rock.
The most common extrusive igneous rock is basalt, a rock that is especially common below the oceans (Figure 4.6).
Hypidiomorphic refers to a texture, in which the grains of some mineral species are anhedral, those of. others subhedral, and those of some may even be anhedral. The texture is typical of granitic rocks in. many of which quartz and orthoclase tend to be anhedral, and plagioclase and biotite are subhedral to.
Myrmekite describes a vermicular, or wormy, intergrowth of quartz in plagioclase. The intergrowths are microscopic in scale, typically with maximum dimensions less than 1 millimeter. ... Myrmekite is formed under metasomatic conditions, usually in conjunction with tectonic deformations.
Vitrophyric texture is porphyric texture with phenocrysts isolated in glassy matrix. Glassy and vitrophyric texture occur in volcanic rocks. ... These are composed of disintegrated fragments of glass, rocks, minerals, or pumice cemented by volcanic ash. Presence of glass among pyroclasts defines the hyaloclastic texture.