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How do mantle rocks melt ?. Adding water to the system: flux melting Decompress the rocks- decompression melting Heating. Path 2. Path 3. Path 1. Magmatic activity and plate tectonic setting. Liquid line of descent. How do igneous rocks evolve?. Fractional crystallization.
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How do mantle rocks melt ? Adding water to the system: flux melting Decompress the rocks- decompression melting Heating Path 2 Path 3 Path 1
How do igneous rocks evolve? Fractional crystallization
How do igneous rocks evolve? Fractional crystallization
How do igneous rocks evolve? Fractional crystallization
Igneous Textures Phaneritic Aphanitic Porhpyritic Glassy Vesicular Pyroclastic
Phaneritic Phaneritic – individual grains in an igneous rock are large enough to be identified without the aid of a microscope
Aphanitic Aphanitic – individual minerals are present in the igneous rock but in particles so small that they cannot be identified without a microscope
Porhpyritic Porphyritic-igneous texture referring to relatively large isolated crystals in a mass of fine texture (aphanitic) groundmass
Glassy Glassy textured igneous rocks are non-crystalline. Generally indicate very rapid cooling.
Vesicular Vesicular –Texture characterized by Vesicles (holes, pores, or cavities) within the igneous rock. Vesicles are the result of gas expansion (bubbles). Bubbles can by filled by secondary minerals due to fluid infiltration (Amygdule).
Pyroclastic Pyroclastic – composed chiefly of (variable) rock fragments.
How to classify a igneous rock Estimate plutonic or volcanic based on texture modal abundance of mafic vs felsic minerals (dark vs light colored) If M (%mafic minerals) is <90% use Streckeisen diagram Determine modal abundances K-feldspar, Plagioclase , Quartz, renormalize to 100%, plot in QAPF diagram.