What is the Protolith of amphibolite?
Amphibolite is a metamorphosed mafic igneous rock (basalt, gabbro) although it is usually difficult to determine the protolith because original features are often obliterated. Basalt is composed of pyroxene + plagioclase. Schistose rocks with a similar composition are hornblende schists.
What are the properties of amphibole?
Long prismatic, acicular, or fibrous crystal habit, Mohs hardness between 5 and 6, and two directions of cleavage intersecting at approximately 56° and 124° generally suffice to identify amphiboles in hand specimens. The specific gravity values of amphiboles range from about 2.9 to 3.6.
How amphibolite is formed?
How Does Amphibolite Form? Amphibolite is a rock of convergent plate boundaries where heat and pressure cause regional metamorphism. It can be produced through the metamorphism of mafic igneous rocks such as basalt and gabbro, or from the metamorphism of clay-rich sedimentary rocks such as marl or graywacke.
What is amphibolite used for?
It is used as paving stones and as a veneer or facing on buildings (both for interior and exterior use). It is also used as crushed stone for the usual crushed stone applications such as road and railroad bed construction. In this application it is used locally, near the source of the amphibolite.
How old is the amphibolite?
Both the amphibolite and vein are crosscut by a brittle fracture. Two aliquots of amphibole were analyzed, with one yielding a weighted mean age of 303.4 ± 3.2 Ma.
Is amphibolite high grade or low grade?
metamorphic rock: Amphibolite facies The amphibolite facies is the common high-grade facies of regional metamorphism, and, like the greenschist……
What is the use of amphibolite?
Amphibolite is a common dimension stone used in construction, paving, facing of buildings, especially because of its attractive textures, dark color, hardness and polishability and its ready availability.
What is amphibolite rock?
amphibolite, a rock composed largely or dominantly of minerals of the amphibole group. The term has been applied to rocks of either igneous or metamorphic origin. In igneous rocks, the term hornblendite is more common and restrictive; hornblende is the most common amphibole and is typical of such rocks.
What does olivine mean?
Definition of olivine : a usually greenish mineral that is a complex silicate of magnesium and iron used especially in refractories — compare peridot.
What is the metamorphic grade of amphibolite?
amphibolite facies, one of the major divisions of the mineral-facies classification of metamorphic rocks, the rocks of which formed under conditions of moderate to high temperatures (500° C, or about 950° F, maximum) and pressures.
Which is the best definition of an amphibolite?
Definition of amphibolite. : a usually metamorphic rock consisting essentially of amphibole.
How big is an amphibolite rock in centimeters?
Amphibolite: Amphibolite is a coarse-grained metamorphic rock that has amphibole minerals such as the hornblende group as its primary ingredient. The specimen shown is about two inches (five centimeters) across.
Which is metamorphic and which is para amphibolite?
Metamorphosed basalt creates ortho-amphibolite and other chemically appropriate lithologies create para-amphibolite. Tremolite, while it is a metamorphic amphibole, is derived most usually from highly metamorphosed ultramafic rocks, and thus tremolite-talc schist is not generally considered as ‘amphibolite’.
What kind of minerals are found in amphiboles?
The amphiboles are usually members of the hornblende group. It can also contain minor amounts of other metamorphic minerals such as biotite, epidote, garnet, wollastonite, andalusite, staurolite, kyanite, and sillimanite. Quartz, magnetite, and calcite can also be present in small amounts.