EAR 105 Lecture Notes - Lecture 15: Volcanic Arc, Clastic Rock, Metamorphic Rock
2 Nov 2016
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Document Summary
Igneous rocks are aggregates of minerals (crystals that are interlocking, rocks form from magma) Clastic (sedimentary) rocks are held together by cement composed of minerals precipitated between mineral grains. Rocks are basically chemicals, but not all rocks contain the same chemicals. Granite contains o, al, k, si, na, ca, fe, and mg. Uses a genetic scheme: based upon origin (genesis) of rocks. Form by freezing (lithification) of molten rock. The rate of cooling controls the crystal size. Lava (molten rock) freezes to form igneous rock. Here, the molten tip of brand-new flow still glows red. Form by the cementation of grains (clastic sedimentary) (ex. sandstone) Precipitation of minerals from a water solution (chemical) (ex. limestone) Sand , formed from grain eroded off the rock cliffs, collects on the beach. Physical characteristics of rocks tell the story of their formation. Proportions of chemicals that make up a rock.
