What is the protolith for Slate?
For example, the protolith of a slate is a shale or mudstone. Metamorphic rocks can be derived from any other kind of non-metamorphic rock and thus there is a wide variety of protoliths. The non-metamorphic rocks fall into two classes: sedimentary rocks, formed from sediment, and igneous rocks, formed from magma.
What type of rock is andalusite?
metamorphic mineral
Andalusite is a common metamorphic mineral which forms under low pressure and low to high temperatures. The minerals kyanite and sillimanite are polymorphs of andalusite, each occurring under different temperature-pressure regimes and are therefore rarely found together in the same rock.
What is the protolith of greenschist?
Greenschist is a fine- to medium-grained foliated metamorphic rock dominated by chlorite, actinolite and epidote, with or without albite, quartz and calcite. Carobonatic protolith: calcite ± dolomite ± quartz ± micas, scapolite, wollastonite.
What is the protolith of Granulite?
The petrochemical as well as zircon U-Pb and Lu-Hf isotopic studies of granulite facies metamorphic rock from the Taoxi Group in eastern Nanling Range, Central Cathaysia indicate that its protolith is the sedimentary rock with low maturation index.
How does slate rock form?
Slate was formed under low-grade metamorphic conditions—i.e., under relatively low temperature and pressure. The original material was a fine clay, sometimes with sand or volcanic dust, usually in the form of a sedimentary rock (e.g., a mudstone or shale).
What is andalusite mineral?
Andalusite is a naturally occurring alumino-silicate mineral commonly found in metamorphic rocks. It is a high-purity mineral composed of prismatic and anhydrous crystals. Containing up to 60% alumina, andalusite transforms into mullite at low temperatures of between 1,200°C and 1,550°C.
How do you identify andalusite?
Keys to identification are high relief, low birefringence and parallel extinction. Color – generally colorless, rarely reddish. Often cloudy due to inclusions. Twinning – Although rarely seen in thin section, some andalusite shows distinctive penetration twins, forming a cross, that helps identify andalusite.
What is the parent rock of greenschist?
Usually, the best you can do when finding a chlorite schistose rock is to find out what the parent is. If the parent is a shale the rock is a greenschist. If basalt the rock is greenstone….Chlorite. Epidonte. Actinolite.
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What is the protolith of Metaconglomerate?
Metaconglomerate is a rock type which originated from conglomerate after undergoing metamorphism. Foliated metaconglomerate is created under the same metamorphic conditions that produce slate or phyllite, but with the parent rock (protolith) being conglomerate, rather than clay.
What is the protolith of Orthogneiss?
Definition: A gneiss with mineralogy and texture indicating derivation from a phaneritic igneous rock protolith. Typically consists of abundant feldspar, with quartz, and variable hornblende, biotite, and muscovite, with a relatively homogeneous character.
What kind of rock is Andalusite slate made of?
Andalusite Slate (intermediate porphyroblastic slate zone) This sample is a fine-grained, poorly foliated, porphyroblastic metamorphic rock, dominated by porphyroblasts of chiastolite and cordierite in a fine-grained matrix rich in quartz and iron-oxides.
What is the protolith of the serpentinite rock?
What is the Protolith of serpentinite? Serpentinite is a metamorphic rock that is mostly composed of serpentine group minerals. Serpentine group minerals antigorite, lizardite, and chrysotile are produced by the hydrous alteration of ultramafic rocks. These are igneous rocks that are composed of olivine and pyroxene (peridotite, pyroxenite).
What was the protolith made of in the Skiddaw slate?
This sample represents thermal metamorphism of the skiddaw slate with the growth of andalusite and cordierite occurring at the expense of micas and chlorite. Iron-oxide rims surrounding andalusites formed during growth of these porphyroblasts and suggests the protolith was an iron-rich pelite.
How did the serpentine group get its name?
Serpentine was named in 1564 by Georgius Agrigola (Georg Bauer) from the Latin “serpens” = snake in allusion to the mottled green appearance of the mineral suggesting the resemblance to some snakes. The Serpentine group is composed of several related minerals. A generic formula that includes all members is: