ROCKS Flashcards
(88 cards)
Define Rock
naturally occurring solid mixture of one or more minerals or organic matter
how are rocks classified?
- how they are formed
- composition (what they are made of)
- texture
Rocks change over time via what?
Rock Cycle
what are the three types of rocks
igneous, sedimentary, metamorphic
igneous rocks form from what
cooled liquid magma
Any rock can become an igneous rock if
it’s melted into magma
when magma reaches earth’s surface, it is called
lava
We identify igneous rocks by…
texture and color
how many types of texture?
four
how is texture determined?
how quickly a rock cools
the cooling rate determines what
the size of the minerals within the rock
texture describes what two things..
crystal size and appearance
What are the 4 types of texture (by speed of cooling)
pyroclastic (fastest)
froth
fine-grained
intrusive (slowest)
What does pyroclastic mean?
Formed by explosion
what is another word for pyroclastic
fragmental texture
pyroclastic are the _______ and _______ that are blown into atomosphere
ash and cinders
because pyroclastic cools so quickly…
no crystals form and ashes and cinders are cemented together
Froth is magma that is cooled by
water or forced far from the source of heat
Do crystals form with pyroclastic or froth?
NO
the texture of froth is called
glassy or vitrous
Name another name for volcanic glass
Obsidian
Pumice, which is not smooth is formed from…
froth
obsidian is formed from..
froth
fine-grained is magma that cools..
above the Earth surface