GEOL 1340 Lecture Notes - Lecture 24: Plagioclase, Feldspar, Pyroxene
26 Oct 2016
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Document Summary
Intrusive ign rocks cool slowly at depth large crystals (phaneritic) Extrusive rocks cool quickly minerals in rocks are small to non-existent. Comp reflects silica content (sio2: classification of ign rocks. Ca rich plagioclase feldspar, pyroxene and olivine. Large density cause iron: mafic ign rocks. Coarse: diorite: felsic ign (>65% sio2) Coarse: granite: intrusive ign, viscosity and volcanic eruptions. Plutons (batholiths) large, crystallized deep within crust. Dikes: tabular intrusions cut across layering in country rock. Low silica magma has low viscosity so lose gases easily. High have high viscosity and retain gases. Test 3 page 1: classification of pyroclastics. Blocks (>64 mm): large chunks around conduit. Most resistant minerals to w likely to end as sediment: susceptibility to w, weathering. Vulnerable to w destroyed are relatively rare in detrital sediment. Organic: chem and biochem sed rocks, sed environment. Dissolved ions from w precipitated from water to form. Influence nature of sed (size, shape, etc. )
