What is the texture of anorthosite?
The anorthosites are typically coarsely crystalline with cumulate textures.
What does anorthosite look like?
Since they are primarily composed of plagioclase feldspar, most of Proterozoic anorthosites appear, in outcrop, to be grey or bluish. Individual plagioclase crystals may be black, white, blue, or grey, and may exhibit an iridescence known as labradorescence on fresh surfaces.
What type of rock is anorthosite?
anorthosite, type of intrusive igneous rock composed predominantly of calcium-rich plagioclase feldspar. All anorthosites found on Earth consist of coarse crystals, but some samples of the rock taken from the Moon are finely crystalline. Most anorthosites formed during Precambrian times.
How is anorthosite formed?
Anorthosite can form by floatation of low-density plagioclase in the magma due to the density difference between plagioclase and melt (Wood et al., 1970). The extensive occurrence of anorthosite on the Moon requires a global magma body, referred to as the lunar magma ocean (LMO) (Yamamoto et al., 2012).
What is the density of anorthosite?
2.71 g/cm3
Mean densities are as follows: anorthosite, 2.71 g/cm3; norite, 3.00 g/cm3; granitic rocks, 2.75 g/cm3; surrounding gneisses, 2.70 g/cm3.
What is anorthosite used for?
Anorthosite is an almost monomineralic, feldspathic rock with a great variety of industrial applications (Table 1). Anorthosite massifs are known to host important ore depos- its such as ilmenite and are, in many cases, excellent sources for high-quality rock aggregate and also for dimension- stone.
Is anorthosite a moon rock?
Anorthosites, rocks composed almost entirely of plagioclase feldspar, are the oldest rocks on the Moon. They appear to have formed when feldspar crystallized and floated to the top of a global magma ocean that surrounded the Moon soon after it formed.
Is anorthosite a volcanic?
The rocks, known as anorthosites, occur in a few areas as gigantic bodies (many kilometers across) called batholiths. Although they crystallized from huge volumes of molten magma deep within the Earth’s crust, they have no known volcanic (lava) equivalents on the Earth’s surface.
What is lunar anorthosite?
From Earth, lunar anorthosite is visible as the light-colored, highly reflective parts of the Moon’s surface known as the lunar highlands. These are the Moon’s oldest rocks—more than 4 billion years old—and covered the young Moon’s entire surface before its crust was pummeled and broken up by asteroids and comets.
Where is anorthosite found in Canada?
The Warren Township Anorthosite Project is an advanced specialty industrial minerals development opportunity located 100 km west of Timmins, Ontario in the Porcupine Mining Division.
Why was the anorthosite rock important?
Lunar anorthosites in particular have assumed a key role in our understanding of the early history of the Moon because lunar geochemists think that these rocks crystallized directly from the global magma ocean.
What is the color of anorthosite?
Since they are primarily composed of plagioclase feldspar, most of Proterozoic anorthosites appear, in outcrop, to be grey or bluish. Individual plagioclase crystals may be black, white, blue, or grey, and may exhibit an iridescence known as labradorescence on fresh surfaces.
Do anorthosites recrystallize?
However, most Proterozoic anorthosites are deformed, and such large plagioclase crystals have recrystallized to form smaller crystals, leaving only the outline of the larger crystals behind.
What are the characteristics of anorthosite plutons?
Physical characteristics. While many Proterozoic anorthosite plutons appear to have no large-scale relict igneous structures (having instead post-emplacement deformational structures), some do have igneous layering, which may be defined by crystal size, mafic content, or chemical characteristics.
Is anorthosite a mafic rock?
A mafic intrusive igneous rock composed predominantly of plagioclase. Anorthosite ( /ænˈɔːrθəsaɪt/) is a phaneritic, intrusive igneous rock characterized by its composition: mostly plagioclase feldspar (90–100%), with a minimal mafic component (0–10%).