-
are the fundamental building blocks of rocks
Minerals
-
How do MINERALS form?
Crystallization
-
In order for a mineral to crystallize, ions from the nearby environment must be brought together.
- Precipitation-evaporation process
- Fractional crystallization- forming from magma
-
is molten rock that forms deep within the earth
magma
-
as magma cools
elements combine to form mineral
-
The first minerals to crystallize from magma are usually those rich in
iron, calcium and magnesium
-
as minerals continue to form, the composition of the magma changes, following with minerals rich in
sodium, potassium, aluminum
-
minerals naturally composed of only one element
native elements
-
native elements examples
diamonds, sulfur, gold
-
minerals containing SO4^-2 or S^-2 anions
sulfides and sulfates
-
sulfides and sulfates examples
galena, pyrite, gypusm
-
minerals containing O^-2 anions
oxides
-
oxides eamples
hematite, magnetite, rutile
-
huge family of minerals which all contains some variant of SiO2
Silicates
-
silicates examples
quartz, garnets, micas, feldspars, clay minerals
-
minerals containing the CO3 anion
carbonates
-
carbonates examples
calcite barite
-
including salts and several other groups
other
-
example of others
fluorite, halite
-
Common Ferromagnesian Silicates (mafic)
Olivine, Pyroxene, Biotite, Amphibole
-
Common Nonferromagnesian Silicates (felsic)
uartz, Orthoclase Feldspar, Muscovite, Plagioclase Feldspar.
-
Ferromagnesian Silicates (mafic) form at _______ temp and ______ to form
high, first
-
Nonferromagnesian Silicates (felsic) form at _______ temp and ______ to form
low, last
-
over 90% of the minerals in the earth' crust
silicates
-
compounds of oxygen silicon and a metal
silicates
-
formed via tetrahedrons
silicates
-
made of negatively charged carbonate ions bonds to positive metal ion
carbonates
-
contain significant amount iron combined with either oxygen or sulfur
oxides and sulfides
-
Calcite: CaCO3, Gypsum: CaSO4, Pyrite: FeS2, Galena: PbS, Graphite: C, Magnetite:Fe3O4
Non-silicate Minerals
-
fill outershell
Ionic Bonding
-
atoms share outer electrons with other atoms.
Covalent Bonding
-
metal atoms share outer electrons to such a degree that their outer shells tend to merge.
Metallic Bonding
-
relatively weak electrical attraction related to the asymmetry of certain atoms and ions.
Van der Waals
-
Ionic Bonding =
Electron Transfer
-
Covalent Bonding =
Electron Sharing
-
different between Diamond and Graphite
same components but different structure in the bonding
-
Heat flow across Core Mantle Boundary forces changes in
magnetic field
-
Why do most volcanoes occur at or near plate boundaries?
The conditions at the boundaries changes the normal pressure and temperature conditions enough to force the production of magma
-
Is the mantle made of “magma”?
no
-
Mantle “behavior” is broken into 3 zones:
- Just below crust as part of the “lithosphere”
- Asthenosphere- solid-elastic
- Mesosphere- more solid/rigid
-
How is Magma Generated?
Melting that occurs due to pressure and temperature changes during plate tectonic processes
-
The geothermal gradient reveals the ______ as the source of most magmas.
asthenosphere
-
a line that shows the change in temperature with depth within the earth.
Geothermal gradient
-
Magma temperatures range between
600° and 1200° C
-
When rock becomes molten, it becomes less dense and tends to rise toward the surface, which causes two things to happen:
–Cooling, which tends to solidify the magma.
–Pressure drop, which tends to allow it to remain molten.
-
Three factors influence melting point
0Temperature
0Pressure
0Volatiles
-
is the most important aspect of magma
chemical composition.
Silica content
-
generate mafic (basaltic) magmas with low volatile contents.
Divergent boundaries and hotspots
-
dry ultramafic asthenosphere.
Source material
-
Partial melting _______ silica content to mafic (basaltic) range.
increases
-
Eruptions are typically quiet because the basalt flows freely and does not have lots of volatiles (gases) that would tend to
escape quickly.
-
generate intermediate to felsic magmas with high volatile contents.
Subduction zones
-
dry asthenosphere + seawater saturated oceanic lithosphere (basaltic) and continental sediments and crust (granitic).
Source material
-
include all the products resulting from eruptions of lava
-
are those that have solidified below ground
-
How are Igneous Rocks Classified?
-
light cooler
Dominated by non-ferromagnesian minerals.
relatively low density (2.7 g/cm3)
feltic
-
dark cooler
Dominated by ferromagnesian minerals.
relatively high density (2.9 g/cm3)
mafic
-
mix of colors
intrusive/Plutonic/coarse
-
solid cooler of rocks
extrusive/volcanic rock/fine
-
a tabular body of igneous rock that cuts across layered or non-layered rocks.
Dike
-
a tabular body of igneous rock that lies parallel to the layers of a layered rock body.
sill
-
large, balloon-shaped pluton with a horizontal (map view) extent of >100 square km (36 square miles).
Batholith
-
similar to a batholith, but smaller (<100 km2).
Stock
-
Dominated by ferromagnesian minerals.
Dark color, relatively high density (2.9 g/cm3)
Intermediate
-
Divergent boundaries and hotspots Eruptions are typically quiet because the basalt flows freely and does not have lots of volatiles (gases) that would tend to __________.
escape quickly
-
Subduction zones Result is a viscous (sticky) magma that contain lots of volatiles that want to escape quickly – this tends to produce _______
violent eruptions
-
Subduction zones Partial melting and incorporation of crustal rocks increase silica content to ______________.
intermediate or felsic range
-
Divergent boundaries and hotspots Partial melting increases silica content to __________
mafic (basaltic) range.
-
an isolated area of volcanic activity that does not correspond to a plate boundary.
Hot Spot
|
|
