Rocks Flashcards
hard mass of material that comes from collection of common aggregate of grains of one or more minerals
Rock
formed from hot molten material within the earth’s crust that has undergone solidification, cooled, and hardened, due to high temperature
Igneous Rocks
igneous rocks are based on ___
crystallization before magma has reached the surface
formed inside volcanoes and has coarser texture due to big crystal formations
Intrusive rocks
formed outside volcanoes and has a glassy appearance due to fine crystals
Extrusive rocks
clastic rocks composed solely or primarily of volcanic materials
Pyroclastic rocks
___ appearance in rocks means the mineral crystals are large and a sign that the rock solidified deep in the earth’s crust after slow cooling
Coarse grained
___ appearance means the mineral crystals are small rock cooled so quickly
Fine grained
granite, gabbro, diorite, pumice, clay, basalt
Igneous rocks
formed from deposits of materials called sediments which are hardened, cemented, and packed together
Sedimentary Rocks
deposited on land by water, wind and glaciers; settle down to the bottom of lakes and oceans
sediments
formed mostly by weathering and erosion such as gravel, silt, shale and mud
Clastic sediments
formed from hardened minerals usually dissolved in water by evaporation or precipitation e.g. limestone, rock, gypsum, rock salt
Chemical sediments
frome remains of living organisms such as rocks
Organic sediments
why do igneous rocks enrich soil fertility?
they come from volcanic eruptions
valuable source of fuel and coal
Sedimentary rocks
from previous igneous or sedimentary rocks changes due to high pressure and temperature; changes may be in the shape of crystals
Metamorphic rocks
changing of rocks
Metamorphism
a rock is converted to metamorphic if it is in direct contact with the source of heat such as the formation of marble from limestone which is heated to high temperatures
Contact metamorphism
increased pressure and temperature si due to some processes known as plate tectonics and causes the formation of mountains
Regional metamorphism
minerals are flattened, drawn out, and arranged in bands and
parallel layers such as rocks
that contain mica or iron magnesium minerals
Foliated
fracture without definite pattern
unfoliated
- fine-grained textures
- rapid cooling
- small crystals
- extrusive rock
Aphanitic
- coarse-grained textures
- slow cooling
- large crystals
- intrusive rock
Phaneritic
- different minerals crystallize at
different temperatures and at
different rates. - large crystals (phenocryst)
embedded in a matrix of small
crystals (groundmass).
Porphyritic
Large crystals (__) embedded in a matrix of small crystals (__)
phenocryst
groundmass
during a volcanic eruption,
molten rock is ejected into the
atmosphere where it is
quenched quickly
Glassy
remains the major fuel used in power plants to generate electricity
Coal
commonly occur together in the pore spaces of sedimentary rocks and consist of hydrocarbon compounds mixed together.
Oil and natural gas
associated with sediment in ocean areas that are rich in plant and animal remains
petroleum formation
provides the energy to drive chemical reactions that result in recrystallization (Metamorphism Agents)
Heat
3 Metamorphism Agents
Heat
Pressure and Stress
Chemical Activities
at __ boundaries, rocks are slowly thrust downward to become metamorphosed at depth
convergent
buried rocks are subjected to stress or force exerted by the load above (metamorphism agent)
Pressure and stress
rocks are also subjected to directional tectonic forces during mountain building, these forces, which are unequal in different directions are called __
differential stress
the common fluid is water-containing ions in solution, some water is contained int eh pore spaces recrystallization of minerals (metamorphism agents)
Chemical activities
Metamorphic processes can cause changes like:
increased density
growth of large crystals
reorientation of mineral grains
low to high temp. minerals
