Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
65 Cards in this Set
- Front
- Back
|
Geoecosystem
|
Plants and animals depend on their ecology
|
|
|
Components of our Earth system
|
atmosphere, hydrosphere and cryosphere, biosphere, and geosphere
|
|
|
Atmosphere
|
thin blanket of "air" - mixture of gases with suspended solids and liquids
|
|
|
Atmosphere's composition
|
Changes over time
78% nitrogen and 21% oxygen |
|
|
Hydrosphere
|
surface waters and ground water
|
|
|
Cryosphere
|
ice sheets and snow cover
|
|
|
Condensation caused
|
a cooling Earth
|
|
|
Ocean covers
|
71% of the Earth's surface
|
|
|
Oceans account for
|
97% of our water budget on the planet
|
|
|
Biosphere
|
sum of all life on Earth
near the surface |
|
|
Range of the biosphere
|
a few kilometers into the earth and several kilometers into the atmosphere
|
|
|
largest component in the earth system
|
geosphere
|
|
|
topography
|
the ups and downs of eats surface measured to sea level
|
|
|
Highest and lowest point on Earth
|
Highest - Mount Everest 8850
Lowest - Challenger deep 11030 |
|
|
Typical elevation of land
|
0-1 km
|
|
|
Typical depth to the ocean floor
|
4-5 km
|
|
|
Earth's composition
|
35% Iron
30% Oxygen 15% Silicon 10% Magnesium 10% other elements |
|
|
Silicic
|
rich in Silicon and Oxygen
rocks like granite |
|
|
Mafic
|
rich in Iron and Magnesium
rocks like basalt |
|
|
Ultramafic
|
very rich in Iron and Magnesium poor in Silicon and Oxygen
rocks like peridoite |
|
|
we study the deepest parts of the earth by
|
seismic waves
|
|
|
seismic waves
|
travel better in dense rock, get stuck in liquids, change routes when hit boundaries
|
|
|
what layer is the crust
|
outermost layer
|
|
|
how thick is the crust
|
< 1% Earths radius
|
|
|
Crust's composition
|
46% Oxygen
28% Silicon 8% Aluminum 6% Iron 4% Magnesium 2.4% Calcium 5.6% Other |
|
|
Continental Crust
|
density 2.8 g/cm^3
underlies the continents average 35-40 km thick composition ranges from silicic to mafic |
|
|
Oceanic Crust
|
density 3.0 g/cm^3
underlies sea floor average 7-10 km thick composition limited to mafic |
|
|
Moho Discontinuity
|
the boundary layer between the crust and the mantle, the core-mantel boundary represents one of the most significant discontinuities within our earth
|
|
|
physical layers ...
|
might behave differently under varying temperature and pressure conditions
|
|
|
mantle
|
2885 km thick
composition ultramafic peridotite density changes from 3.5 to 5.5 g/m^3 from top to bottom |
|
|
mantles composition
|
44% Oxygen
21% Silicon 22.8% Magnesium |
|
|
core-mantle
|
earth's major discontinuity
gutenberg 1914 |
|
|
Outer core (chemical)
|
2890-5150 km thick
density 10-12 g/cm^3 |
|
|
outer core's composition
|
Iron Nickel Alloy
85% Iron 5% Nickel 5% Sulfur 5% Oxygen |
|
|
Inner Core (chemical)
|
5150-6370 km thick (Earth's center)
density 13g/cm^3 similar to iron meteorites |
|
|
Inner Core's composition
|
Iron Nickel Alloy
94% Iron 6% Nickel |
|
|
Lithosphere
|
sphere of rock
includes the crust and relatively cool upper most mantle 100-150 km thickness continental and oceanic lithosphere plate tectonics |
|
|
Astheeosphere
|
Weak sphere
below lithosphere upper mantle 300 km thick |
|
|
Outer Core (physical)
|
liquid
magnetic field self sustaining geodynamo generates earth's magnetic field |
|
|
Inner Core (physical)
|
solid iron alloy
|
|
|
what are the processes of the scientific method
|
1. observation and identify a problem
2. gather data and form a question 3. possible answers (hypothesis) 4. test your hypothesis (if it fails revise the hypothesis, if pass test again) 5. theory |
|
|
continental drift hypothesis
|
proposed by Alfred Wegener in 1915
said that the continents drifted to present positions after a supercontinent called Pangaea began breaking apart about 200 million years ago |
|
|
what are the five lines of evidence for Wegener's hypothesis?
|
1. the fit of the continents
2. locations of past glaciations 3. distribution of climatic belts recognized in sedimentary rocks 4. distribution of fossils 5. matching geological units |
|
|
why was Wegener's hypothesis rejected?
|
no plausible mechanism capable continents, no direct reliable observation of motion, and he didn't have multiple working hypotheses it died in 1930
|
|
|
continental margins
|
transitional zone between oceanic and continental crust
|
|
|
abyssal floor (plain)
|
deep, relatively flat ocean floor
|
|
|
trenches
|
lowest regions on Earth
|
|
|
seamounts and guyouts
|
submarine volcanoes
|
|
|
Mid-Ocean Ridges (MOR)
|
elongate submarine mountain ranges
|
|
|
positive marine magnetic anomalies
|
the magnetic files strength is stronger than expected
|
|
|
negative marine magnetic anomalies
|
the magnetic field is weaker than expected
|
|
|
magnetic fields
|
reverse periodically
|
|
|
normal polarity
|
the earths north magnetic pole is near the north geographic pole
|
|
|
reverse polarity
|
the earths north magnetic pole is near the south geographic pole
|
|
|
how and where is new oceanic crust created?
|
at mid-ocean ridges (MOR) from cooling magma recording the magnetic signature time
|
|
|
as the oceanic crust moves away from the MOR the age..
|
increases
|
|
|
oldest oceanic crust
|
200 million years old
|
|
|
what two hypothesis led to the plate tectonics theory?
|
continental drift and seafloor spreading
|
|
|
plates move..
|
relative to one another and over the asthenosphere (1-15 cm/year)
|
|
|
tectonic plates are fragments of..
|
the lithosphere
|
|
|
what are the three types of plate boundaries?
|
divergent, convergent, and transform
|
|
|
divergent
|
the diverge they move away
|
|
|
convergent
|
two opposed plates move towards one another
|
|
|
transform
|
tow opposed plates slide by one another
|
|
|
earthquakes occur at all three plate boundaries but the deepest is at the
|
subduction zones
|
