slide notes ch1-8 - P relude H yd rosphere surface water on...

Prelude:
Hydrosphere - surface water on the earth, along with ground water that fills
cracks and holes in rocks or sediment underground
Atmosphere - an envelope of gas consisting of 78% nitrogen, 21% oxygen and minor
elements.
Geosphere
Biosphere - the living organisms
Inside the earth:
Layers : Chemical:
Crust - (silicates) continental (mostly felsic & intermediate but
has mafic)oceanic (mafic: sediment layer, basalt layer, gabbro
layer) the most abundant element in crust is OXYGEN
Mantle : (iron and magnesium silicates) ultramafic peridotite,
upper mantle-transition zone-lower mantle
Core : composed of an iron alloy. Outer core (liquid magma),
inner core (solid)
Physical :
Lithosphere : rigid- crust and upper mantle (in motion over the
asthenosphere)
Asthenosphere: plastic- portion of the mantle where rock can
flow
Mesosphere: solid- the rest of the mantle
Scientific method:
Observe-> working hypotheses -> tests -> eliminate hypotheses -> test again -
> draw conclusions -> develop theory
Ch 2. Interlude D

Earth : sphere, rotates, has oceans and continents, is composed of solids liquids and
gases.
Scientific method used on earth:
Observations: Earth is a rotating sphere (+many more). There must be
something inside.
Hypothesis: There have been numerous. Inside the earth is layered. Earth is
homogeneous. Earth is hollow. Earth is made of molten magma. Earth is
made of gold.
Tests: drill- deepest well ~ 12 km, mine ~ 3.5 km
Gravity to test density: plumb bob (know angle & mass of bob, mass of mountain-
can calculate)
Density= Mass/Volume
The density of material inside the earth is greater than the density of
material at the surface.
DENSER MATERIAL IS LOCATED IN THE EARTH. EARTH IS LAYERED
ACCORDING TO DENSITY (EX. EGG AND ITS LAYERS=EARTH AND
IT’S LAYERS)
What is the earth made of?
Evidence from earthquakes: by detecting depths at which earth’s wave velocities
change, can pinpoint boundaries between layers.
AT BOUNDARIES BETWEEN LAYERS OF DIFFERENT
DENSITIES/VELOCITIES, LIGHT WAVES ARE BENT.
WHEN THE COMPOSITION OF THE LAYER CHANGES, THE WAVE IS
REFRACTED (faster material: colder/denser… slower material: warmer/less
dense)
REFRACTION OCCURS WITH SEISMIC WAVES TOO
Seismic waves: absence provides clues to composition of center of earth:
physical layers, depths of each transition

P-waves: compressional, faster, travel through liquid and solid
| | | | | | | | | | | | | (pushpull)
S-waves: shear (deform), slower, travel through only solids
~~~~~~
(shake)
Both are body waves - travel through the body of the earth rather
than the surface
Energy travels as rays along multiple ray paths-  earthquakes
Evidence from meteorites (chondrites): chondrites are thought to represent the
bulk composition of the earth at formation.
EARTH: oxygen, iron, silicon, magnesium, other.
3 rock types for the lithosphere:
Granite- continental crust
Basalt- oceanic crust
Peridotite - upper mantle
Ch 3 interlude A
PLATE TECTONICS
Topography - physical features of land Bathymetry - physical features of sea floor
-mid-ocean mountain ranges
-deep trenches at continental margins & wide shallow continental margins
-linear chains of seamounts
-volcanoes
-continental mountain ranges
plate tectonics theory: