Lecture 3: Rocks Classification
3 main categories of rocks are:
1.
-Formed from the ______________and ______________________ of molten rock
(_____________)
When magma comes to surface & contacts ___________or ____________ it becomes
_____________
-Cooling and solidification is called __________________________- formation of
crystals
-igneous rock formed from magma cooling in the crust (below ground) is called
_________________ rock
-igneous rock formed by lava cooling on earth’s surface is called
___________________rock
-rock that cools ____________ makes ____________ crystals (example granite) and rock
that cools ____________ makes ______________ crystals (example obsidian or basalt).
Some rock cools so rapidly that ___________is trapped inside (like pumice)
-_______________ colored igneous rocks tend to contain feldspar and silicate minerals
which are not very ____________________ (ex. Granite and pumice)
-_______________ colored igneous rocks are rich in iron and magnesium and are much
__________________(example basalt and gabbro)
*the only rocks that form from _________________ ______________are igneous rocks*
2.
-formed from the ____________________of sediments (tiny rock particles that are
broken off/weathered from preexisting rock or organic material)
-many sedimentary rocks form at the bottom of
_________________________________________________(where the sediments have collected)
-usually contain strata (___________________________)
-this is the only type of rock that contains ________________
-the process by which accumulating sediment turns into a solid mass is called
____________________
-there are 4 main processes that cause sediments to lithify
1.
______________________= binding the sediments together with a
substance such as iron oxide, silicates, or CaCO3 (sandstone and
conglomerate made this way)
2.
______________________________________________= as sediments
collect on top, they push down harder (increased pressure) eventually
the pressure is great enough to form a solid mass (shale is made this
way-70% of all sedimentary rocks on Earth are shale!)
3.
______________________________________________= solids made
from dissolved particles in water (precipitation example- stalagmites
and stalactites. Evaporation- rock salt deposits)
4.
Involving some type of ____________________________= collected
dead bodies of animals are compressed and compacted (at the bottom
of the ocean –fossil limestone. At the bottom of a swamp with dead
plants collected- bituminous coal)
3.
-formed when ___________________________ rocks undergo a change as a result of
exposure to intense ___________and ____________________.
-these preexisting rocks are often either _________________ or ______________ rocks
(called _____________ rocks)
-Metamorphic rocks are often associated with ________________because when
mountains form, there is usually lots of heat and pressure
-involves recrystallization (new arrangement of the atoms and molecules in a rock and
this gives it new_____________) of the minerals inside parent rock
-metamorphic rocks become _______________ (having distinct layers) the more intense
the heat and pressure the __________________the bands of foliation
-metamorphic rocks often have folding or curving and typically higher
_________________ than parent rock
-metamorphic rocks are often found inside igneous or sedimentary rock
*If magma intrudes into an ________________rock layer, the heat can cause
metamorphic rock to form as the magma cools it turns into igneous rock, but
the existing rock’s contact area has been turned into metamorphic rock.
*__________________ is a metamorphic rock whose parent rock was the
sedimentary rock limestone
-Metamorphic rocks are classified mainly by their______________________________,
___________________, and ________________.