Formation of Dacite and Rhyodacite

Dacite

Rhyodacite

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1 Formation

1.1 Formation

Dacitic magma is formed by the subduction of young oceanic crust under a thick felsic continental plate. Further, the Oceanic crust is hydrothermally altered as quartz and sodium are added.

Rhyodacite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.

1.2 Composition

1.2.1 Mineral Content

Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon

1.2.2 Compound Content

Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide

Ca, Fe, Potassium Oxide, NA, Potassium, Silicon Dioxide

1.3 Transformation

1.3.1 Metamorphism

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1.3.2 Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism

1.3.3 Weathering

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1.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

1.3.5 Erosion

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1.3.6 Types of Erosion

Chemical Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Dacite and Rhyodacite Formation

Formation of rocks is a long process and hence, Dacite and Rhyodacite formation sounds very interesting. According to the formation, all rocks are divided into :Igneous Rocks, Fossil Rocks and Metamorphic Rocks. Igneous rocks form by crystallization of magma or lava. The magma is made up of various components of pre-existing rocks which have been subjected to melting either at subduction zones or within the Earth's mantle. Igneous rocks are generally seen at mid ocean ridges or in intra-plate hotspots. Sedimentary rocks are formed when sediments accumulate gradually. As the sediments are buried they get compacted as more and more material is deposited on top. Eventually the sediments become so dense that they form a rock. Metamorphic rocks are rocks which once existed as igneous or sedimentary rocks but have been subjected to varying degrees of pressure and heat within the Earth's crust. Get to know all about formation of Dacite and Rhyodacite, composition of Dacite and Rhyodacite and their transformation.