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What is Pilotaxitic texture?

What is Pilotaxitic texture?

Said of the texture of the groundmass of a holocrystalline igneous rock in which lath-shaped microlites (typically plagioclase) are arranged in a glass-free mesostasis and are generally interwoven in irregular unoriented fashion.

What does granular texture mean?

A rock texture resulting from the aggregation of mineral grains of approx. equal size. used to describe an equigranular, holocrystalline igneous rock whose particles range in diameter from 0.05 to 10 mm. …

What is Trachytic texture?

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.

Is pumice a Subhedral?

The plagioclases of the T6 pumice, which are also subhedral to euhedral, are the dominant phenocrysts; some are larger (>1 mm) than those of the T3 pumice. Orthopyroxene is more common than clinopyroxene in the T6 pumice.

What’s the difference between aphanitic and phaneritic?

APHANITIC TEXTURE – Igneous rocks that form on the earth’s surface have very fine-grained texture because the crystals are too small to see without magnification. PHANERITIC TEXTURE – Igneous rocks with large, visible crystals because the rock formed slowly in an underground magma chamber.

What does Aphanitic texture look like?

Aphanitic texture consists of small crystals that cannot be seen by the eye with or hand lens. The entire rock is made up of small crystals, which are generally less than 1/2 mm in size. This texture results from rapid cooling in volcanic or hypabyssal (shallow subsurface) environments.

How is Trachytic texture formed?

Trachyte (/ˈtreɪkaɪt, ˈtrækaɪt/) is an extrusive igneous rock composed mostly of alkali feldspar. It is usually light-colored and aphanitic (fine-grained), with minor amounts of mafic minerals, and is formed by the rapid cooling of lava enriched with silica and alkali metals. It is the volcanic equivalent of syenite.