![]() Foliated texture can look like very thin horizontal layers in rock that appear like they can peel apart like leaves, like in this mica-schist formation. Rocks with foliated texture look like they have their minerals stacked together as though they were pages in a book hence the term “folia”, or leaflike. Some minerals, particularly micas, are usually thin and planar by default. ![]() Foliated Textureįoliation is a term that describes how minerals line up along a preferred direction. Metamorphic texture is broadly categorized as either Foliated or Non-Foliated. Therefore, the new metamorphic rock will have a different texture than the parent rock. ![]() As the original rock is subjected to higher temperatures and pressures, some of its minerals might stretch out in a single direction, recrystallize, or enlarge. Metamorphic texture describes the shape and orientation of mineral grains within a metamorphic rock. The metamorphic rocks that form at elevated temperatures and pressures are categorized by both metamorphic texture and the amount of change that the original rock appears to have undergone: metamorphic grade. Tectonic boundaries, in particular, cause different types of metamorphism at mountain-building cores, subduction zones, and spreading centers. Metamorphism usually happens at least a couple kilometers beneath the Earth’s surface. Metamorphism is a unique process that takes any type of preexisting rock (even old metamorphic units) and subjects it to heat and pressure over long periods of time until it has changed. ![]() They also involve the transformation of one rock type into another, but unlike sedimentary rocks, they do not reduce the original rock into fragments before reassembling. Metamorphic rocks can involve high temperatures, but unlike igneous rocks, they do not melt into magma. ![]() The result of this high temperature and pressure transformation is a Metamorphic Rock. These rocks are squeezed and warped like putty in a process called Metamorphism some of these rocks grow new minerals and textures and others lose minerals. When rock units are buried very deeply within Earth’s crust, they are subjected to high temperatures and pressures. The word “Metamorphic” is Greek: meta means change and morphos means form. Limestone and chert layers of rock that have been folded at high temperatures and pressures due to metamorphism. ![]()
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