chapter 4 Igneous rocks Flashcards
what are igneous rocks mostly made of?
partially melted magma and silicate materials
this is molten rock, suspended crystals and dissolved gas
under the earth’s surface only
magma
the 3 materials of magma
memorization trick:
G
Li quid
S
name them and describe them
G as- volatiles/rock vapors
Li quid called melt
S olid- crystaline mush of silicates
this is molten rock on EARTH”S SURFACE ONLY
lava
___ reverses the events of melting and forms a solid
what is crystalization
describe how magma cools
silicon link together in tetrahedras
ignieous ricks with lots of silicates, quartz and feldspar is called___ which mosty solidifies into
felsic
granite
igneuous frocks with DARK silicates(Mg, Fe) is called___ which forms into magma having a _____ composition
mafic
basaltic
this composition is in between felsic and mafic
25% dark siicates
andesitic composition
rank these from high to low silica content
mafic, felsic, bafic
felsic
mafic
overall appearance of a rock based on the size, shape, and arrangement of its mineral grains is called ____
texture
rapid cooling creates ___ type of texture called
fine grained
aphantic
crystalization
- generation or percipitation of mineral grains
- as magma cools movements of ions slows
steps to name an igneous rock
1. extrusive or intrusice (small or big crystal)
2. chemistry
3. mineralology
4. texture
slowly cooling magma at a great depth has a ___ texture called P_____
hint: slow, big back
Coarse texture
phantraphenic
phaner= visable
Porphyritic texture is both ___
extrusive and intrusive texture
pegrmatitie texture
VERY LARGE course rocks, larger than 1 cm in diameter
holes in rocks are called ___ texture
swiss cheese is holy
Vesicular texture
(very quickly cooled) and becomes a solid. Rapid cooling of this type may generate rocks iswhat texture?
glassy
pyroclastic texture
condensition fo fragments od ash, mo.ten blobs ejected during exploive volcano
the most common pyroclastic rock
tuff
geothermal gradient (redline)
the gradual inc in temp in earth’s crust
what effects the way rocks melt?
pressure, introduction of water,
when a rock melts due to a DEC IN PRESSURE it is called
decompression melting
when i add water to rock melting what happens?
where does this happpen?
rock melts at a lower temperture
happens at subduction
factional crystaliation
body of magma is injected , darket line at the bottom is ultra mafic
assimulation
solid and liquid
magma coming up through earths crust, disloges other rocks and melts them thus changes maga body composition
magma body mixing
liquid magma a mixing with magma b
partial melting
source rock heats up, most idneous melts, but the mafi does not melt
columnar joints
rapid coolig of lava, felsic or madic resuktig i hexagonal pillars
due to the surface tension and rapid cooling causign shrinkage, hexagons have the least amt of surface evergy
layers of rock with lava traveling PARALLELP ALONG THE ROCK is a
sill
dike is
orcibly injected into fractures and cut across bedding surfaces and other structures in the host rock
SIDEWAYS LAYERS
