Physical Geography

Front 1

What is "Circle of Illumination"?

Back 1

Divides darkness/daylight on a globe

Front 2

Subsolar Point?

Back 2

Point at which the Sun's rays hit directly at 90 degrees

Front 3

Declination?

Back 3

Latitude of subsolar point

Front 4

Approximate radius of the earth?

Back 4

6400 Km

Front 5

Seasons?

Back 5

cyclical changes in temperature that occur throughout the year. Caused by changes in the amount of solar energy receive.

Front 6

Aphelion

Back 6

Farthest position from the Sun (July 4th)

Front 7

Perihelion

Back 7

Closest position to the Sun (Jan 3rd)

Front 8

Remote sensing

Back 8

info acquired at a distance without physical contact with subject (e.g. radar)

Front 9

What is the thickness of the crust?

Back 9

8-40 km

Front 10

What is the thickness of the mantle?

Back 10

2900 km

Front 11

What is the thickness of the core?

Back 11

3500 km

Front 12

Mineral?

Back 12

Naturally occurring, inorganic crystalline solid with a definite chemical composition and characteristic physical properties

Front 13

Three most abundant elements in the Earth's crust?

Back 13

Oxygen, Silicon, Aluminum

Front 14

Chemical formula for quartz?

Back 14

SiO2

Front 15

What are the three ways that minerals are formed?

Back 15

Liquids (magma, lava) goes to a cooling state to a rock

Evaporation of a briny liquid

Precipitation from a fluid

Front 16

Igneous rocks?

Back 16

rock that solidified and crystallized from a molten state (e.g., granite, basalt, obsidian, pumice)

Front 17

What's the difference between extrusive and intrusive rocks?

Back 17

Extrusive rocks cools above the surface and have smaller crystals
Intrusive rocks cool beneath the earth's surface and have larger crystals

Front 18

Weathering?

Back 18

surface processes that physically disrupt and chemically change rocks

Front 19

Sediment?

Back 19

Igneous rock that has undergone weathering, transport and deposition. Fine grained mineral matter transported by air, water or ice.

Front 20

Sedimentary rock?

Back 20

formed through erosion, transportation, deposition, compaction, cementation and hardening of sediment.

Front 21

What are the three types of sedimentary rock and how do they form?

Back 21

Clastic—derived from weathered and fragmented rock

Chemical—dissolved minerals. Transported in solution and precipitated.

Organic—remains of dead organisms

Front 22

Metamorphic Rocks?

Back 22

rocks changed by heat and/or pressure

Front 23

What is the primary difference between metamorphic rocks and igneous rocks?

Back 23

Igneous rocks are cooled and solidified magma

Metamorphic rocks are heated and pressurized sedimentary rocks.

Front 24

What are the two types of geologic dating?

Back 24

Relative= sequential age
based on positions of rocks relative to each other
e.g., rock layer B is older than A and younger than C

Numerical = number age
based on radiometric age
e.g., rock layer B is 50 million years old

Front 25

Geologic contacts

Back 25

boundary between different rocks

Front 26

Deformation

Back 26

processes that fault and fold rocks

Front 27

Unconformity

Back 27

erosional contact

Front 28

Isotopes

Back 28

protons do not equal neutrons

Front 29

Half-life

Back 29

time required for half of the original parent atoms to decay to their daughter

Front 30

Decay Constant

Back 30

rate at which isotopes decay (yr ^-1)

Front 31

What assumptions are necessary for radioactive dating?

Back 31

Decay occurred at a constant rate over time
isotope system (in rock) has remained a closed system since the rock formed (I.e.--no gains or losses of isotopes)

Front 32

What is the formula used to calculate the age of a rock?

Back 32

T = 1/k ln(D/P + 1)

Front 33

What rocks are suitable/unsuitable for isotopic dating?

Back 33

Suitable—igneous rocks, (but why?)

Unsuitable—sedimentary rocks! They contain pieces of older material, thus dating the age of source materials not when deposition occurred

Front 34

How old are the oldest rocks?

Back 34

3.96 billion years old

Front 35

Plate Tectonics

Back 35

Process for continental drift

Front 36

What parts of the earth’s layers make up a tectonic (lthospheric) plate?

Back 36

Crust, mantle, asthenosphere and mesosphere

Front 37

What are the three major types of plate boundaries and what type of plate movement does each accommodate (i.e. plates colliding, pulling apart, etc).

Back 37

Spreading (plates pulling apart)
Convergent zones (plates colliding)
Transform (plates sliding...san andreas fault)

Front 38

How is oceanic crust made at spreading boundaries. Where is the most famous spreading zone in the world? In what two regions do spreading centers interrupt continental crust?

Back 38

Mid-Atlantic Ridge, Rift Valleys

Magma rises up from mantle, spreads and cools (occurs at spreading boundaries.

Front 39

What generally forms above the subducting plate?

Back 39

Volcanic Arc

Front 40

What is the most famous transform boundary in North America?

Back 40

San Andreas Fault

Front 41

What are three modern pieces of evidence that support the theory of plate tectonics? Explain each in detail. Don’t forget sediment thickness.

Back 41

Paleomagnetism
same pattern on both sides of ridge
alternating bands of normal and reversed polarity

Radiometric dating
the higher the distance from the ridge, the higher the age

Sediment thickens away from mid-ocean ridge

Front 42

Orogeny

Back 42

mountain-building episode. Can involve deformation, uplift, plate tectonics, intrusion of magma, or combo

Front 43

Limestone

Back 43

Sedimentary rock composed of calcite, commonly forms from the remains of marine organisms