Qualities that define minerals
natural
inorganic
solid
specific chemical composition
characteristic crystalline structure
Extrusive igneous rock groups
Rhyolite (quartz and feldspar phenocrysts)
Andesite (plagioclase and amphibole/pyroxene phenocrysts)
Basalt (plagioclase and pyroxene/olivine phenocrysts)
Intrusive igneous rock groups
Granite (feldspar and quartz)
Diorite
Gabbro
Rock Cycle
-igneous rock forms as magma cools
-igneous rock is weathered, becomes unconsolidated
-unconsolidated material becomes consolidated or sedimentary rock
-sedimentary rock is either uplifted and weathered or heated and pressurized to metamorpic
-metamorphic
Mineral Identification
streaking
cleavage planes
hardness
density
crystal form and growth
Mineral Groups
Silicate
Sulfides
Oxides
Halides
Carbonates
Sulfates
Phosphates
Native Elements (crystal structures of single element)
Silicate Minerals
Orthosilicates-single tetrahedra
Disilicates-2 tetrahedra
Inosilicates-chains of tetrahedra
Phyllosilicates-sheets of tetrahedra
Tectosilicates-3D tetrahedra network
Coarse grained igneous rock
Phanerite (G. "visible") >= 2mm at largest dimension
Fine grained igneous rock
Aphanite (G. "invisible") <2mm at largest dimension
Mostly course grained igneous rock
Porphyry
Isolated large grains in fine grained matrix
Phenocrysts
Pyroclastic rock groups (non-mineral)
bombs >64mm
lapilli 2mm-64mm
ash <2mm
Tephra rock groups (sedimentary pyroclasts)
Agglomerate-coarse grain
Tuff-fine grain
Welded tuff-glassy cemented ash particles
Plutons (intrusive igneous rock formations)
Minor
-Dikes (vertical)
-Sills (horizontal)
-Laccoliths (mushroom shaped because viscous)
-Volcanic pipe
Major
-Batholiths (large irregular shaped bodies intruding in other rock)
-Stoping-expanding magma fractures chamber walls and causes chunks to fall
-
Common mineral groups
Olivine (Mg,Fe)2SiO4, Garnet (orthosilicate)
Pyroxene (single chains),
Amphibole (double chains)
Micas (sheets)
Crust composition by weight
O (45.2%)
Si (27.2%)
Al (8%)
Fe (5.8%)
Ca (5.06%)
Mg (2.77%)
Na (2.32%)
K (1.68%)
Ti (0.86%)
(the rest are less than 2%)
Varves
Pair of layers in lake sediment defined by year