A protolith (from Ancient Greek πρωτο (prōto) 'first' and λίθος (líthos) 'stone') is the original, unmetamorphosed rock from which a given metamorphic...

new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than 150 to 200 °C (300 to 400 °F)...

Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place...

type of the original rock (the protolith) is discernible, the schist is usually given a name reflecting its protolith, such as schistose metasandstone...

metamorphism creates minerals entirely based upon the chemistry of the protolith, certain 'dirty marls' and volcanic sediments may also metamorphose to...

Skarns may form by metamorphic recrystallization of impure carbonate protoliths, bimetasomatic reaction of different lithologies, and infiltration metasomatism...

minerals present in each facies depends on the composition of the protolith. For a mafic protolith, the albite-epidote hornfels facies is characterized by albite...

meaning "leaf". The protolith (or parent rock) for phyllite is shale or pelite; or slate, which in turn came from a shale protolith. Its constituent platy...

metamorphic rock with a protolith of clay-rich (siltstone) sedimentary rock Metapsammite – A metamorphic rock with a protolith of quartz-rich (sandstone)...

Primary sedimentary textures and structures of the original carbonate rock (protolith) have typically been modified or destroyed. Pure white marble is the result...

layers. A common cause of nonhydrodynamic stress is the subjection of the protolith (the original rock material that undergoes metamorphism) to extreme shearing...

Chromitic serpentinite (7.9 cm (3.1 in) across), Styria Province, Austria. Protolith was a Proterozoic-Early Paleozoic upper mantle dunite peridotite that...

high pressure during regional metamorphism of a protolith which is rich in aluminium (a pelitic protolith). Kyanite is also occasionally found in granite...

Napier Orogeny in Antarctica, 4,000 ± 200 Ma. 4031 Hadean Formation of protolith of the oldest known rock (Acasta Gneiss) c. 4,031 to 3,580 Ma. Possible...

older, Cretaceous, pre-collisional granite. The granitic precursor (protolith) to the K2 Gneiss originated as the result of the production of large...

and found to be felsic but is metamorphic and has no definite volcanic protolith, it may be sufficient to simply call it a 'felsic schist'. There are examples...

metamorphic. In the context of metamorphic rocks, the parent rock (or protolith) is the original rock before metamorphism occurred. Bedrock Regolith v...

Craton including gneisses and other metamorphic rocks with volcanic rock protoliths and rapakivi granites. These rocks are much older than the rest (Paleoproterozoic...

properties and chemistry of the stone. The original rock, known as the protolith, transforms into other mineral types or other forms of the same minerals...

original composition of and the pressure and temperature experienced by the protolith (parent rock), chemical reactions between minerals in the solid state...

temperature, or both). The original rock, prior to change (called the protolith), may be of any sort. Experimental petrology employs high-pressure, high-temperature...

chlorite, from Maurienne Valley in the French Alps Composition Quartz Physical Characteristics Fabric Non-foliated Relationships Protoliths Quartz Sandstone...

undergone multiple deformations and multiple metamorphic episodes. The protolith age of the Narryer Gneiss Terrane is variable, but generally considered...

based on protolith, mineral composition, texture, or metamorphic facies. Naming based on texture and a pelite (e.g., shale, mudrock) protolith can be used...

banding within the metamorphic rock mass. Usually, this represents the protolith chemistry, which forms distinct mineral assemblages. However, compositional...

describe a metamorphosed sedimentary rock with a dominantly sandstone protolith. In Europe, this term was formerly used for a fine-grained, fissile, clayey...

Tumble polished unakite pebbles Composition Orthoclase feldspar, epidote, quartz Physical Characteristics Fabric Mottled Relationships Protoliths Granite...

unconsolidated sediment (protolith for future metamorphic rocks). As temperature and pressure increase with depth, a protolith passes through a diagenetic...

specific metamorphic rocks that, while being chemically similar to the protolith, differ significantly in appearance and in their resistance to weathering...

ultramafic rock (the protolith) is peridotite, which is rich in olivine, considerable magnetite and hydrogen are produced. When the protolith is pyroxenite,...