46 terms

science rock study guide

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how do scientists classify rocks
composition - what it's made of
texture - size of grains or crystals
how does the cooling rate affect the texture of igneous rocks
slower cooling = large/coarse grained rock (when magma solidifies far below the surface)
faster cooling = small/non-existent crystals
describe 3 ways magma forms
heating - heat to melting point
change in pressure - reduce pressure allowed a change in state like a solid to a liquid
change in composition - the presence of water and other minerals can lower the melting point of a rock
describe the texture of these sedimentary rocks: conglomerate, sandstone, and siltstone
conglomerate: coarse grained
sandstone: medium grained
siltstone: fine grained
list the order of processes involved in sedimentary rock formation
weathering of pre-existing rock
erosion of sediments
deposition
sediments pile up
compaction and cementation of the sediments
what kind of rock may contain fossils
sedimentary
~ the process that forms igneous and metamorphic rocks would destroy the fossils
describe regional and contact metamorphism
regional - extreme pressure caused by plate movement
contact - heat from magma/igneous intrusions
what is the heat source in contact metamorphism
heat from magma/igneous intrusions
atoms
the smallest part of an element that has all the properties of that element
cementation
the binding together of particles
chemical sedimentary rock
forms when minerals crystallize out of a solution, such as seawater, to become a rock
clastic sedimentary rock
forms from compaction and cementation (conglomerate, sandstone, siltstone, shale)
compaction
layers of sediment buildup, pressure increases, layers are squeezed together and any water is forced out
composition
what a rock is made of, types of minerals
contact metamorphism
magma comes in direct contact with surrounding rock, occurs near igneous intrusion, extreme heat
course grained
conglomerate like breccia (sedimentary rock)
crystallization
when magma cools crystals form in igneous rock
deformation
the bending, tilting, and breaking of the earths crust: the change in the shape of the rock in response to stress
deposition
the process in which material is lay down: sediment is laid down to rest
erosion
the process by which wind, water, ice, or gravity transports soil and sediment from one location to another
extrusive igneous
rocks that form from cooling lava
felsic
light colored rocks
fine grained
forms when lava that erupts onto earth surface cools rapidly
foliated
metamorphic rock has its mineral grains arranged in planes or bands
fossilferous
animal remains that are cemented together
igneous rock
forms when magma and lava cools and crystallizes
index mineral
types of minerals that form only at certain temperatures and pressures
intrusive igneous
rock formed when magma intrudes into other rock and cools
lava
melted rock that reaches the surface
mafic
dark colored minerals
magma
hot, liquid rock below earths surface
metamorphic rock
rock is exposed to heat and pressure below earths surface
minerals
naturally formed, inorganic solid that has a definite crystalline structure
nonfoliated
describes the texture of metamorphic rock in which mineral grains are NOT arranged in planes or bands
organic sedimentary rock
forms from the remains of once living plants or animals
parent rock
the original rock in which another rock is formed from
recrystallization
crystals of nonfoliated rocks may change size or the mineral may change in composition
regional metamorphism
when pressure builds up in rock that is very deep below other rock formations or when large pieces of earths crust collide
rock
most rocks are a mixture of minerals
rock cycle
the series of processes in which a rock forms, changes from one type to another, is destroyed and forms again by geological processes
sedimentary rocks
three kinds: clastic, chemical, organic
solidification
compacting something until firm
strata
layers of rock
stratification
the process in which sedimentary rocks are arranged in layers
texture
the quality of a rock that is based on the sizes, shapes, and positions of the rock grains
weathering
water, wind, ice, and heat breaks down rock