In what tectonic settings do mountains occur?

Mountains occur mostly on convergent boundaries but are also found in Subduction zones and continent-continent collisions.

Why are tectonic settings usually found in mountain belts rather than isolated?

They are found in belts according to plate lines and continent edge collisions.

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What happens to a mountain range after the compressional stresses that formed the mountain range stop?

Young are high, middle-aged are in a balance between erosion and uplift, and old are deeply eroded, eventually buried, and all uplift has ceased.

Why are crustal roots beneath mountain ranges so deep?

As you get compression, the crust thickens and forms a deep root. (Think convergent pieces smashing together and creating mountains both up and down.)

What evidence do we have in the rock record of old, eroded mountain belts?

Eroded mountain belt evidence: Canadian Shield.

What key rocks do we find that indicate a mountain range used to be there?

metamorphic rocks

What is the difference between stress and strain? (Stress causes strain)

Stress applied over time leads to strain. Strain is the change in shape (deformation) that occurs in a rock due to stress.

What are the major kinds of stress?

Compression (shortening/thickening crust)
tension (pulling apart thinning of crust)
shear (sliding differential stress)
pressure (stress on all sides at once)

What kinds of deformation do they cause? (types of faults, folds, & joints)

Compression leads to mountain ranges
Tension leads to basins
Shear leads to
Pressure leads to

What is the relationship between force and stress?

Force applied to an area is stress (stress = F/A).

What is an unconformity? What does it tell us about the environment during the missing time period?

a surface of contact between two groups of unconformable strata.; An erosional surface that marks a gap in time( angular, disconformity, noncomformity)

Uniformitarianism

the present is the key to the past

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superposition

(oldest strata is on the bottom, younger strata is on the top)

original horizontality

(sediments generally form in continuous sheets),

cross cutting relationships

younger features cut across older features. faults, dikes, and erosions must be younger that the material the it is faulting)

inclusions

(a rock fragments within another. the inclusions are older than the material enclosing it),

baked contacts

the baked rock was there first. Hornfels

fossil succession

fossil assemblage (a group of species) is unique to a given time period. species evolve, last for a while, then go extinct

Disconformity

Rocks are being formed, there was no faulting or tilting, but theres still a big gap in time

Angular Conformity

Layers of rock fault, fold or tilt and the layers on top of those were straight

Nonconformity

Sedimentary rocks on top of metamorphic or igneous rocks

the basics of the geologic timescale

Eon- The largest subdivision of time
Eras- Subdivisions of Eon
Periods- Subdivisions of a ERA
Epochs- Subdivision of a Period

4 eons

Hadean, Archean, Proterozic, Phanerozoic

the periods of the Phanerozoic

(Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Tertiary, Quaternary)

the epochs of the Cenozoic

(Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene, Holocene)

which eon, era, period, and epoch we are currently living in

- (Phanerozoic, Cenozoic, quaternary, Holcene)

Hadean Eon

Molten earth, heavy elements were sinking to the middle and lighter, element were floating to the top, no continents yet, atmosphere= gasses but no oxygen

Archean Eon

Archean Eon

Proterzoic Eon

...

Phanerozic Eon

Visible life, Supercontinent continues, life increased in size and complexity, development of major mountain belts today

How did banded iron formation form? What happened at the end of BIF formation?

BIF (Banded Iron Formation), Layers of iron oxide (magnetite/hematite) and red chert (jasper), combined the iron from the ocean and the oxygen in the air to make sediments until all the iron was gone and oxygen could start to build up, creating the atmostphere we have today

The different eras of the Phanerozoic are separated by mass extinction events (Permian-Triassic and Cretaceous-Tertiary). What is the current theory explaining the K/T boundary mass extinction event?

(K stands for Creaceous, T for tertiary) the cretaceous period ended by a 10 km wide meteorite, causing debris into the sky, tsunamis, fires, winter/night like atmosphere, acid rain)

What does snowball Earth refer to? What is some of the evidence found in the
rock record that supports this theory?

glaciers covered the land, and the entire ocean froze. Evidence- glacial deposits by equator. Warmed up by CO2 build up in atmosphere from volcanoes

stromatolites

A widely distributed sedimentary structure consisting of laminated carbonate or silicate rocks, produced over geologic time by the trapping, binding, or precipitating of sediment by groups of microorganisms, primarily cyanobacteria.

Has Minnesota always been in roughly the same geographic location?

no, it started moreby the equator and then ended up in the upper hemisphere.

What controls global sea level? What was sea level like in the Cretaceous? How about in the Pleistocene?

- The weather, hotter it is, higher the sea level. Colder it is, lower the sea level
- Cretaceous: very high sea level
- Pleistocene: very low sea level

How does coal form?

the remains of plants and organisms settle in swamp beds. sediments cover the remains. layers of the sediment compresses the organics. heat and pressure within the earth's crust form coal.

How does oil form? How is oil trapped?

It forms from tiny plants and animals that lived in the ocean. The remains turn into rock. Some of the remains don't turn into rock, instead into oil or natural gas.

What is the relationship between oil and natural gas?

They are both carbonates. They both start out as plankton and algae, and form as those deposits are buried and heat up. Oil forms at a lower temp than natural gas. If you take a deposit and bury it you will first form oil, in the "oil window." If it's buried even deeper, it will turn into natural gas. Same origin, different temps.

Understand where select mineral resources come from and which way they are concentrated (ex. aluminum, gold, iron, lead/nickel/copper (massive sulfides)).

- Iron is concentrated as a sedimentary deposit. It forms as a precipitate in the ocean when oxygen oxides reduced iron.
- Lead/nickel/copper are all massive sulfide deposits, concentrates at the bottom of the magma chamber
- Gold is very heavy. It often accumulates as a placer deposit, occupying places like pools in rivers
- Aluminum is concentrated through leaching in tropical soils

What is an "ore mineral"?

any mineral that has economic value and can be extracted from the ground at a reasonable profit