What is pelitic in geology?
A pelite (Greek: pelos, “clay”) or metapelite is a metamorphosed fine-grained sedimentary rock, i.e. mudstone or siltstone.
What is meta sandstone?
General Lithology:Metasandstone. Description:A metamorphic rock formed by the action of tectonic forces on sedimentary rock ( sandstone). Representing:Sediment deposited during the Neoproterozoic Era, about 600 million years ago, and deformed during the building of the C.
How are Metapelites formed?
When shale is subjected to new pressure and temperature conditions during metamorphism, these chemical components will rearrange themselves to form a new assemblage of aluminous minerals depending upon the specific P-T conditions. Metamorphosed shales are referred to as metapelites.
How do you identify Hornfel?
Under a microscope the structure of hornfels is very distinctive, with small, generally equigranular, mineral grains fitting closely together like the fragments of a mosaic or a rough pavement. Texture – granular, platy or elongate crystals randomly oriented so no foliation evident.
Is gneiss a pelitic?
The gneisses are a very varied group, including both igneous rocks and metamorphosed sedimentary rocks , and may be categorized as quartzofeldspathic, pelitic, calcarous, or hornblende gneiss.
What minerals are in amphibolite?
The mineral composition of the amphibolites is simple and mostly contains hornblende and plagioclase, with variable amounts of anthophyllite, garnet, mica, quartz, and epidote. The rocks may originate from pelitic sediments, with amphibole (hornblende), plagioclase, and typically include green pyroxene.
What type of rock is meta?
metamorphic rock
In geology, metasedimentary rock is a type of metamorphic rock. Such a rock was first formed through the deposition and solidification of sediment. Then, the rock was buried underneath subsequent rock and was subjected to high pressures and temperatures, causing the rock to recrystallize.
What is Morphe means in metamorphism?
In geology, metamorphic describes a specific process that some rocks undergo when heat and pressure changes them. The Greek metamorphoun, “to transform,” is from meta, “change,” and morphe, “form.”
How do you identify sillimanite?
Sillimanite. Sillimanite is a metamorphic mineral found in high grade aluminous schists and gneisses. It is a polymorph of andalusite and kyanite, all having formula Al2SiO5. Keys to identification are high relief, needle-like, fibrous or bladed habit, characteristic square cross sections with one diagonal cleavage.
Where is Hornfel found?
In Africa, hornfels is found in Tanzania, Cameroon, East Africa, and Western Africa. The rock is found in Australia and New Zealand, as well.