types of rocks Flashcards
What are the 3 main types of rock?
metamorphic, sedimentary, igneous
How are intrusive igneous rocks formed
slow cooling of molten rock under Earths surface.
How are extrusive igneous rocks formed?
fast cooling of molten rock aboveground a volcanic eruption
What is the crust?
A layer of solid rock
What is the mantle?
Made of solid and partially melted rock, thickest of four layers.
What is the outer core?
A liquid mixture of liquid iron and nickel
What is the inner core?
A solid mixture of iron and nickel at an extreme temperature.
Where do fossils form?
sedimentary rocks
Relative Dating
the scientific way of finding out whether one rock layer is older than another.
How can you tell if earthquakes younger than sedimentary rock layers?
if the layers are damaged then the earthquake is younger than the sequence of rocks.
How are igneous rocks made?
when molten rock cools
how are metamorphic rocks made
when rocks are subjective to high heat and pressure
define erosion
process by which rocks and mineral break apart while moving elsewhere.
define weathering
breaks down rocks into smaller particles while straying in the same place.
what is physical weathering
wind, temperature change, water, ice and salt crystallization
what is chemical weathering
when chemicals from soil and air react with rocks breaking down
what is biological weathering
living things like plant roots that grow through the cracks of rocks and destructing them.
How can sediments be transported?
by wind, rivers and ocean currents.
What happens to the transported sediments?
over millions of years they are deposited into bodies of water and form thick sequences of sediment.
define minerals
a natural substance with crystal structure
what is the Mohs Hardness Scale used for?
it is used to test the hardness of different minerals.
define lustre
the way light interacts with the surface.
what is a streak?
the color of the powder trail left behind the mineral
where is a streak tested?
on a white ceramic plate
define cleavage
flat surfaces on minerals that broke due to the atomic structure
how does the temp. and pressure change as depth changed below Earths surface?
temperature increases. pressure decreases.
what is a parent rock?
any rock before it changes under heat and pressure
how do clastic sedimentary rocks form?
when sediments are laid down by wind, water, gravity and ice then compacted and cemented.
how do chemical sedimentary rocks form?
when minerals dissolved in groundwater crystallize within the sediments or when water evaporates leaving behind crystals.
how do biogenic sedimentary rocks form?
when dead plant matter or animal remains are cemented together.
