What Are Spatter Cones and How Do They Form?
Spatter cones are small, steep-sided, nearly circular conical hills or mounds of welded magma blobs or fragments formed around a vent. These welded lava blobs
Mcnair, B.
What Are Cinder Cone Volcanoes, Examples, and How They Form
Cinder cone volcanoes or scoria cones are small, steep-sided, conical-shaped, nearly circular, or oval hills. These hills are made of highly vesiculated, mafic to intermediate
Lherzolite Rock Composition and Occurrence
Lherzolite is a coarse-grained ultramafic rock with 40-90% olivine. Ultramafic rocks have less than 45% silica (SiO2) and more than 90% mafic minerals. Mafic minerals
What Are Hyaloclastites and How Do They Form?
Hyaloclastites are an accumulation of angular basaltic glass fragments or their breccia. A breccia is a rock with volcanic fragments cemented in a fine-grained matrix.
What Is Palagonite Including Tuff
Palagonite is a yellow, yellow-orange, or brownish material formed from the alteration of basaltic or glass with a chemical composition like basalt. However, it may
What Is Tachylite Rock?
Tachylite rock is an opaque black or brown basaltic glass with a greasy look and a resinous luster. It is a natural volcanic glass that
What Is Sideromelane
Sideromelane is a transparent or clear brownish or yellow-brown colored basaltic glass. It forms from rapid quenching of basaltic magma mostly (but not exclusively) in
Intermediate Rock Composition and Examples
Intermediate igneous rocks are medium in silica (52-63 wt.%) and have nearly equal amounts of felsic and mafic minerals. Examples are andesite and diorite. Felsic
Ultramafic Rocks Examples and Composition
Ultramafic rocks are igneous or metamorphosized igneous rocks that are very low in silica (usually less than 45 wt.%) and with more than 18% magnesium