Intro to Landform

Question 1

Structure of Earth

Answer 1

1) crust
2) mantle
3) core

Question 2

Crust

Answer 2

1) ~4 miles thick w. 2 types - continental, oceanic
2) ocean = thinner BUT denser rocks
3) density of crust increases w. depth
4) significant change in mineral comp. at base of crust (mohorovicic discontinuity aka moho)

Question 3

Mantle

Answer 3

1) Upper mantle = thin + rigid, called lithosphere
2) Asthenosphere = beneath lithosphere = hot rocks that become plastic like
3) low mantle = very hot rocks BUT rigid bc of pressure

Question 4

Core

Answer 4

1) warmth = release of energy from decay of radioactive elements
2) outer core = liquid
3) inner core = dense solid

Question 5

Igneous Rocks

Answer 5

1) formed by cooling + solidification of molten rock (magma)
2) Examples = granite, diorite, gabbro

Question 6

Sedimentary Rock

Answer 6

1) sedimentary deposits build up –> compacted + consolidate into sedimentary rock
2) Distinct layers - strata

Question 7

Metamorphic Rocks

Answer 7

1) rock physically/chemically altered by heat, pressure, chemically active fluids
2) associated w. lithosphere
3) types of metamorphism: contact (contact w. magma), regional (deep within crust exposed to heat/pressure), hydrothermal (fluids circulate thru cracks in rock)

Question 8

Foliated vs Nonfoliated (metamorphic)

Answer 8

Foliated - layered/banded appearance bc minerals arranged in parallel layers
Non-foliated - plan, grainy texture, no layers

Question 9

Clastic, Chemical, Organic Sedimentary

Answer 9

1) Clastic - formed from layers of debris, moved by water/wind (shale, sandstone)
2) Chemical - formed from minerals preciping out of solution (limestone from CaCO3)
3) Organic = formed from remains of organisms (coal)

Question 10

Plutonic vs Volcanic (Igneous)

Answer 10

Plutonic/Intrusive = Form from magma cooling below surface (granite)
2) Volcanic/extrusive = form from cooling of lava ON surface (obsedian)

Question 11

Internal Process

Answer 11

1) Originates from WITHIN Earth
2) result in crustal movements via folding, faulting, volcanic activity
3) Building up –> Increase relief features on earth

Question 12

External Process

Answer 12

1) Operate at base of atmosphere + get energy from ABOVE lithosphere
2) Wearing down –> weathering, erosion

Question 13

Relationship btwn internal + external

Answer 13

1) Internal BUILDS UP
2) External BREAKS DOWN

Question 14

Uniformatirianism

Answer 14

1) present to key is past
2) Topography today shaped by same processes of the past + same in future

Question 15

Catastrophism

Answer 15

1) Older idea than uniformitarianism
2) Major features produced by sudden upheavals + catastrophes

Question 16

Continental Drift

Answer 16

1) Wegener postulated existence of Pangaea –> broke apart + moved to form present day continents

Question 17

Evidence for Continental drift

Answer 17

1) close affinities of geologic features on both sides of Atlantic
2) Rock records on both sides of Atlantic would be continuous if ocean didn’t separate it
3) Africa + South America fit like a jigsaw puzzle
4) Fossils of dinosaurs + reptiles (Mesosaurus) found on both sides of southern Atlantic BUT nowhere else

Question 18

Plate Tectonics Evidence

Answer 18

1) Using depth soundings –> created ocean floor topography
2) revealed chains of volcanoes (seamounts) + bands/ridges corresponded w. earthquakes
3) seafloor spreading + subduction

Question 19

Seafloor spreadin

Answer 19

Midocean ridges formed by magma rising up from mantles –> volcanic eruptions create new basaltic ocean floor –> spreads away from ridge
FORMS new seafloor

Question 20

Subduction

Answer 20

Ocean trenches –> ocean basin goes back into asthenosphere (into mantle)
seafloor DESTROYED

Question 21

relationship btwn seafloor spreading + subduction

Answer 21

amount of new seafloor created in midocean ridges = amount lost in trenches

Question 22

Paleomagnetism = proof of seafloor spreading

Answer 22

rock containing iron –> magnetized by magnetic field –> contains record of Earth’s polarity at time rock solidified
found bands of same polarity rocks on either side of midocean ridge

Question 23

Ocean Floor Cores

Answer 23

Showed sediment thickness + age of fossils increased as got further from ridges –> proof that sediments farthest from ridge oldest
like a conveyer belt

Question 24

Plate Tectonic Theory

Answer 24

1) Lithosphere has many rigid plates floating on plastic-like asthenosphere
2) Plates moved by convection in Earth’s mantle –> “pulled” by subduction of cold denser ocean lithosphere into asthenosphere

Question 25

Mafic vs Felsic Igneous

Answer 25

Mafic - darker, heavier (basalt)
Felsic - lighter in color + density

Question 26

Coarse vs fine igneous

Answer 26

Coase grain = to get large grains, you need time, pressure –> INSIDE magma chamber
fine grain = cools quickly outside so lava or volcanic eruption

Question 27

Types of Igneous

Answer 27

1) Mafic or Felsic
2) Fine or coarse
3) Plutonic vs volcanic

Question 28

Types of sedimentary

Answer 28

Clastic, Organic, Chemical

Question 29

Types of metamorphic

Answer 29

nonfoliated, foliated