Lock tf in

Mineral requirements

Natural, solid, inorganic, and crystalline

3 ways minerals form

From a melt, from a solution/precipitation, and through recrystallization

Igneous rock

Rock formed when molten rock cools and solidifies

Sedimentary rock

Rock formed at or near Earth's surface from sediments or chemical/biochemical material

Metamorphic rock

Rock changed by heat, pressure, and/or fluids without completely melting

Igneous grain size

Controlled mainly by the rate of cooling

Fast cooling

Small/fine mineral grains

Slow cooling

Large/coarse mineral grains

Obsidian

Glassy igneous rock formed by extremely rapid cooling

Basalt

Fine-grained, dark-colored igneous rock

Granite

Coarse-grained igneous rock with visible mineral grains

Gabbro

Coarse-grained, dark-colored igneous rock

Rhyolite

Fine-grained igneous rock

Andesite

Fine-grained igneous rock

Pegmatite

Igneous rock with extremely large mineral grains

Granitic magma

High in silica, low in iron, and lower temperature

Basaltic magma

Lower in silica, high in iron, and higher temperature

Darker igneous rocks

Usually have more iron

3 types of sedimentary rock

Clastic, chemical, and biochemical

Weathering

Breakdown of existing rock into sediments, ions, or new minerals

3 agents of sediment transport

Water, wind, and ice

Clastic sedimentary rock sequence

Weathering → transport → deposition → burial/compaction/cementation

Chemical sedimentary rock

Forms when dissolved ions precipitate from water

Biochemical sedimentary rock

Forms from the activities or remains of organisms

Halite

Rock salt; NaCl; can form when water evaporates

Gypsum

An evaporite mineral used in drywall

Limestone

A common biochemical sedimentary rock made mainly of calcite

Limestone uses

Agricultural lime and cement/concrete

Chert

A silica-rich sedimentary rock

Diatomite

Forms from silica-shelled plankton; can be used in kitty litter

Chalk

Forms from accumulated calcite shells called coccoliths

Coal

Forms from accumulated, buried, and preserved plant remains

Metamorphism

Alteration of existing rock through heat, pressure, and fluids

Main process forming metamorphic rocks

Recrystallization

Shale → Slate

Low-grade metamorphism

Shale → Schist

Medium-grade metamorphism

Shale → Gneiss

High-grade metamorphism

Limestone → Marble

Limestone changes into marble through metamorphism

Foliation

A layered texture caused by minerals recrystallizing under directed pressure

Index minerals

Minerals that indicate the temperature and pressure conditions during metamorphism

3 index minerals

Kyanite, sillimanite, and andalusite

Regional metamorphism

Large-scale metamorphism caused by elevated pressure and temperature, commonly during continental collisions

Contact metamorphism

Local metamorphism caused mainly by heat from an igneous intrusion

Lithosphere

Rigid outer layer of Earth that includes the crust

Asthenosphere

Partially molten/soft layer immediately below the lithosphere

Continental crust

More granitic and less dense than oceanic crust

Oceanic crust

More basaltic and denser than continental crust

Bimodal topography

Earth has two major elevation levels because continental and oceanic crust have different densities

Divergent boundary

Two plates move apart

Convergent boundary

Two plates move toward each other

Transform boundary

Two plates slide past each other

Ocean-ocean divergent boundary

Plates move apart and new ocean crust forms

Seafloor spreading

Creation of new ocean crust at mid-ocean ridges

Mid-ocean ridge

Underwater mountain system where new ocean crust forms

Ocean-continent convergent boundary

Denser oceanic crust subducts beneath continental crust

Subduction

One plate moves beneath another plate

Trench

Deep depression formed where one plate subducts beneath another

Subduction zone features

Trench, shallow-to-deep earthquakes, and volcanoes

Ocean-ocean convergent boundary

One oceanic plate subducts beneath another, forming a trench and volcanic island chain

Continent-continent convergent boundary

Continents collide, causing folding, faulting, uplift, metamorphism, and possible melting

Himalayas

Classic example of continent-continent collision

Andes

Classic example of ocean-continent subduction

Transform boundary example

San Andreas Fault

Plate movement rate

About 2-10 cm per year

Triple junction

Where three plate boundaries meet

Active continental margin

A continental margin at or near a plate boundary

West Coast of the United States

Active continental margin

Passive continental margin

A continental margin without a plate boundary at the transition from continental to oceanic crust

East Coast of the United States

Passive continental margin

Evidence for plate tectonics

Matching continents, matching fossils/rocks, seafloor spreading, paleomagnetism, earthquakes, volcanoes, trenches, and ocean-crust age patterns

Ocean crust age pattern

Ocean crust is youngest near mid-ocean ridges and gets older away from the ridges

Why is ocean crust young?

New ocean crust is continually created at mid-ocean ridges and recycled at subduction zones

Jigsaw-fit evidence

Continents such as South America and Africa have shorelines that fit together

Fossil evidence

Same fossils are found on continents that are now separated

Glacial evidence

Matching ancient glacial features occur on continents that are now far apart

Hawaiian island evidence

Volcanoes get older away from the active end, showing movement of crust over a relatively stationary volcanic source