GLY 1010L Lecture Notes - Lecture 5: Pegmatite, Komatiite, Porphyritic
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1(cid:895) melti(cid:374)g a(cid:374)d freezi(cid:374)g of ro(cid:272)k does(cid:374)"t happe(cid:374) at a single temperature, like water. This occurs over a wide range of temperatures. Grain size of igneous rocks is mainly related to cooling (crystallization) rate. Pyroclastic flow (welded) eruption of lava (glaasy vesicular) Felsic rocks- rigid composite, contain sodium calcium, potassium, rich in alkali lighter in color minerals associated (quarts biotite) *fun fact, new hampshire is the granite state. Andesite (from the andes mountains), more fine grain. Mafic rocks- typically darker, iron rich, magnesium rich, much less silicate tetrahedron minerals associated (pyroxene) Basalt (very common, fine grain) makes up virtually the entire ocean floor. Ultramafic rocks (very rare at the surface of the earth, make up the upper mantle minerals associated (olivine) Ultra(cid:373)afi(cid:272) lava (cid:894)super rare(cid:895) does(cid:374)"t (cid:374)or(cid:373)ally for(cid:373) o(cid:374) earth, has (cid:374)ot for (cid:271)illio(cid:374)s of years, o(cid:374)ly possible in the early history of the earth when earth was hotter.
