Post on 23-Jan-2016
description
Minerals vs. RocksMinerals vs. Rocks
Common silicate minerals:Common silicate minerals:
OlivineOlivine- independent tetrahedra joined by Fe or - independent tetrahedra joined by Fe or MgMg
PyroxenePyroxene- single chains of linked tetrahedra- single chains of linked tetrahedraAmphiboleAmphibole- double chains of linked tetrahedra- double chains of linked tetrahedraMicasMicas and and ClaysClays- 2-D sheets of linked tetrahedra- 2-D sheets of linked tetrahedraQuartzQuartz- 3-D framework of fully polymerized - 3-D framework of fully polymerized
tetrahedratetrahedraFeldsparFeldspar- also a 3-D framework, but Al, Na, Ca, or - also a 3-D framework, but Al, Na, Ca, or
K can substitute K can substitute
Minerals vs. RocksMinerals vs. Rocks
Common non-silicate minerals:Common non-silicate minerals:
CalciteCalcite- CaCO- CaCO33 a carbonate a carbonate
DolomiteDolomite- CaMg(CO- CaMg(CO33))22
ApatiteApatite- Calcium phosphate (PO- Calcium phosphate (PO44))
HaliteHalite- NaCl- NaClGypsumGypsum- hydrated CaSO- hydrated CaSO44
Rock TypesRock Types IgneousIgneous
Volcanic
Plutonic
Mafic(hi Mg-Fe)
Silicic(hi Si-Al)
Intermediate
Basalt
Gabbro
Andesite
Diorite
Rhyolite
GranitePeridotite
Ultramafic(hi Mg-Fe)
Rock TypesRock Types IgneousIgneous
Polished slab of granitePolished slab of granite10 cm across10 cm across
Thin section of basaltThin section of basalt4 mm across4 mm across
Rock TypesRock Types SedimentarySedimentary
MetamorphicMetamorphic
Clastic
Chemical
> 2 mm0.6 -
0.004 mm0.6 - 2 mm
Conglomerate Sandstone
Silt
< 0.004 mm
Clay
Shale
SandCobbles, Pebbles
Limestone Dolostone
SiO2 NaCl, KCl, etc.
Evaporites
CaMg(CO3)2CaCO3
Chert
2) The Earth’s Interior2) The Earth’s Interior
General General Geological Geological Principles: Principles: 1) Geologic 1) Geologic
TimeTime
Geologic TimeGeologic Time RelativeRelative dating by superposition, cross-cutting dating by superposition, cross-cutting
relationships, fossils and evolutionrelationships, fossils and evolution
Geologic TimeGeologic Time RelativeRelative dating by superposition, cross-cutting dating by superposition, cross-cutting
relationships, fossils and evolutionrelationships, fossils and evolution AbsoluteAbsolute dating by radioactive decay (igneous) dating by radioactive decay (igneous)
# pa
rent
ato
ms
# pa
rent
ato
ms
time time
11
½½
¼¼
IsostasyIsostasy
Water density 1.0
Wood density 0.5
2 g 2 g3 g 3 g5 g 5 g
8 g
Water density 1.0
0.5 0.50.3 0.30.2 0.2
density= 0.1
Each block weighs 2 g
IsostasyIsostasy
IsostasyIsostasy
3) Plate Tectonics3) Plate Tectonics
Divergent and Transform Plate BoundariesDivergent and Transform Plate Boundaries
Continental Continental RiftingRifting
Continental Continental RiftingRifting
the East the East African Rift African Rift
Convergent Convergent Plate Plate
BoundariesBoundaries
““Andean-type” Andean-type” orogenesisorogenesis
Crust thickens by Crust thickens by addition of magma addition of magma
Compression due to Compression due to plate convergenceplate convergence
Convergent Plate BoundariesConvergent Plate Boundaries
The Origin of the HimalayasThe Origin of the Himalayas
““Himalayan-type” Himalayan-type” orogenesisorogenesis
Begins as Andean-typeBegins as Andean-type
““Himalayan-type” Himalayan-type” orogenesisorogenesis
How do you locate the “suture zone” today?How do you locate the “suture zone” today?How can you determine the “polarity” of subduction?How can you determine the “polarity” of subduction?
Slivers of oceanic crust and upper mantle (ophiolites) become incorporated into the “mélange” in the accretionary wedge of deformed sediments
The “suture zone” is marked by the mélange and particularly by the occurrence of ultramafic rocks composing the mantle portion of the ocean lithosphere
Chain of ultramafic bodies in Vermont indicating a suture zone of the Ordovician Taconic Orogeny. The ultramafics mark a closed oceanic basin between North American rocks and an accreted island arc terrane. From Chidester, (1968) in Zen et al., Studies in Appalachian Geology, Northern and Maritime. Wiley Interscience.
Appalachian Appalachian HistoryHistory
Can “accrete” Can “accrete” island arc island arc
terranes as well terranes as well as continentsas continents
Accreted Accreted Terranes of Terranes of the Western the Western CordilleraCordillera
Hot Spots Hot Spots
The Plate Tectonic The Plate Tectonic Regime of the Western Regime of the Western
USAUSA
Earthquakes and Plate TectonicsEarthquakes and Plate Tectonics
General General Geological Geological Principles: Principles: 4) The Rock 4) The Rock
CycleCycle
Plate Tectonics and the Rock CyclePlate Tectonics and the Rock Cycle
Examples of Other Examples of Other Cycles: the Cycles: the Hydrologic Hydrologic
CycleCycle
Examples of Other Cycles:Examples of Other Cycles: the the Carbon CycleCarbon Cycle
PopulationPopulation
PopulationPopulation
PopulationPopulation
Impacts:Impacts: ResourcesResources Waste DisposalWaste Disposal PollutionPollution Hazards/DisastersHazards/Disasters Farmland and Food/SoilFarmland and Food/Soil Disruption of Natural SystemsDisruption of Natural Systems