Exam 1 Flashcards
Scientific method
hypothesis testing
Hydrologic cycle
Evaporate, rain, run off
Water Facts
- Ocean covers about 71% of the surface
- > 97% in the ocean
- most fresh water is in glaciers
Big bang
about 13.8 years ago
Earth formation
- 4.54 billion years ago
- impacts, melting, stratification, oldest rocks and minerals
Matters on earth: Heavy Elements
Former stars like betelguese today
Matters on Earth: Silicates
Dominate crust
Origins of the ocean
Volcanic outgassing, impacts. cooling, condensation of
water
Early atmosphere
water vapor, CO2, N2, SO2) unlike today; photosynthesis later
Early explorers
Phoenicians, Greeks, Egyptians, Chinese, Polynesians
Eratosthenes
early maps,
Earth’s circumference; celestial navigation;
Hipparchus and Ptolemy
Longitude and latitude formalized by
Hipparchus and Ptolemy
Longitude and Latitude:
Sphere divided into degrees. 360°/24 hours = 15°
longitude/hour
Prime meridian
The line that all longitude os based off
Chronometer maker
John Harrison
Earth is layered. How we know?
Earthquakes and Seismology; P (primary) and S (secondary)
waves
Earth chemistry layers
crust (oceanic basaltic; continental granitic),
mantle more iron, magnesium in minerals),
core (more iron, magnesium in minerals)
Earth Mechanical layers
Lithosphere;
Asthenosphere (partly molten
upper mantle);
Core (liquid outer; solid inner).
Continental drift
the theory that Earth’s continents move over time. The continents were once joined together in a single landmass called Pangaea, and then split apart and drifted to their current positions
A. Wegner
Theory about Contiental drift and pangea;
Evidence: Fossils (Gondwana)
Divergent plates
two plates move apart from each other
Examples
African rift valley
Convergent plates
two plates move toward each other and interact
Plate Suturing: Mountain
Example
Ring of Fire (Aleutian Islands)
Transform plates
offsets; many along ridges; San Andreas; earthquakes); side to side;
No crust is created or destroyed
Convergent plate types
1) ocean-ocean (trench);
2) ocean-continent (trench);
3) continent-continent (mountains; Himalayas) (suture);
Terranes added to continents (Plateaus, continent fragments, volcanic islands
Bathymetry
mapping of the ocean floor
EX: Echo sounding, sonar, multibeam echo sounders, satellite altimetry (water
elevation vs. gravitational attraction by undersea hills, mountains, volcanos)
Continental Margin types
passive (rifting, divergent, quiet) and active (subduction,
convergent, volcanism);
continental margin parts
Shelf – shallow, low inclination; maximum depth typically < 150m
Slope – steeper, edge of continental crust (+sediment); submarine canyons
Rise – sediments piled against slope out into the ocean basin
Buoyancy
tendency of an object to float or to rise in a fluid when submerged.
Isostasy
The rising or settling of a portion of the Earth’s lithosphere that occurs when weight is removed or added in order to maintain equilibrium between buoyancy forces that push the lithosphere upward, and gravity forces that pull the lithosphere downward
Subduction Zone
Convergent) trenches;
where two tectonic plates meet and one slides beneath the other
Terrigenous Sediment
From the land;
weathering;
Sizes: clay, silt, sand, and gravel
Biogenic Sediment
Ocean life and skeletons;
Plankton and shell or other skeletal parts
Hydrogenous Sediment
Sediment that comes from the ocean itself;
Forms in the ocean by precipitation;
manganese and phosphate nodules
Cosmogenous Sediment
Sediment from space: meteorites and dust
Nertic Sediment
Near Land, Shallow water, most terrigenous
Pelagic sediment
Deep ocean sediment;
(can be on slope and rise
Ooze
deep see sediment contains at least 30% biogenous material
Turbidites
poorly sorted layers of sand to clay
Ocean Plateau
big area were lava forms layers and stick out from the abyssal plain
Seafloor spreading theory
By Hess and Dietz (~1960);
Seafloor develops at mid-Atlantic ridge and spreads outwards
Hotspot
a region of intense heat within the Earth’s mantle that causes volcanoes to form on the surface.
Terranes
a crust fragment formed on a tectonic plate and accreted or “sutured” to crust lying on another plate.
Passive Margins
no subduction zones
Face the edges of diverging plates
Active Margins
Yes tectonic
Faces edges of CONVERGING PLATES
Associated with ongoing earthquake and volcanic activity
