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Some of these questions must be answered by consulting your textbook which correlates with the video series.  Consult: "Physical Geology -Earth Revealed" by Carlson, Plummer and McGeary; published by McGraw Hill, New York City, NY




 





















Quiz #1 Review




You may want to review episodes #1 - 7 (and the relevant chapters in your text)

James Hutton developed the law of superposition.  In a stack of sedimentary rock layers, the lowest in the strata will be the oldest.  He was a uniformist who believes that "the present is the key to the past".  He is the "father of geology".

You should know the location of the following in relation to the ocean basin:
shelf, break, slope, rise and abyssal plain
ocean ridge and central rift
transform faults perpendicular to ridges

In association to the shelf break (at 200 m or 600 feet) and slope are submarine canyons
we do know that turbidity currents are associated with these canyons.  Near the continents the sea floor is covered with terrigenous sediment, further out is pelagic sediment composed of ooze, the tiny shells of microscopic plankton.

Know plate relationships:

convergent boundaries (ocean-ocean, continent-ocean and continent-continent)
o-o and c-o boundaries are in association with trenches and subduction zones (benioff eathquake zones), you graphed one of those benioff zones in the lab showing shallow, intermediate and deep focus eq generated as the ocean plate is subducted down the trench.  Trenches are the deepest features on Earth, some over 6 miles below the water's surface.

subduction results in dangerous, explosive volcanoes (island arc volcanoes at the edge of a continental shelf) or volcanoes at the edge of a continent as the Andes and Cascade Mts.  Hawaii and small cinder cones are by comparison, "safe volcanoes".

c-c boundaries that are convergent can result in orogeny (mountain building) like the Himalayan Mts., the Appalachian Mts. resulted from the plates converging to form Pangaea 200 million yrs. ago.  As the Appalachians eroded, the sediments were deposited at the edge of the modern Atlantic making a continentl shelf.  The granite roots of the Appalachians rise as more erodes in the process of isostacy or isostatic rebound.

Our continental shelf of which LI is a part of is a quiet passive shelf far away from a plate boundary.  Large parts of it were above water during the ice age when sea level was lower.

divergent boundaries (ocean-ocean, continent-continent)
o-o associated with ocean ridges and their central rift valleys such as the Atlantic, Red Sea
c-c divergent boundary is like the Africa Rift Valley, when the earth rifts there is basaltic (mafic) magma which flows out onto the surface as a molten lava, cooling with vesicules (gas pockets) in a dark basalt rock

Transform faults run perpendicular to ocean ridges, the famous San Andreas Fault in California is an example of this kind of slippage.

There are mantle plumes unrelated to convection which may be the cause of "hot spots", some of these are long lasting.  The Hawaiian islands and many underwater mountains (seamounts) result.  There may be a hot spot below the continent in the area of Yellowstone Park which has geothermal features resulting from magma close to the surface.  Yellowstone is the site of a Super Volcano in the past.

Alfred Wegener wrote the book on Continental Drift, he wrote of the super-continent of Pangaea which broke apart as a new Atlantic Ocean was formed.

For the scientific community to embrace the concept of Continental Drift it took a number of independent studies as well as some plausible mechanism:  we believe the mechanism is "convection" in the mantle still molten by the heat of radioactive decay.  This is the internal heat engine (the external heat engine is the sun). We live on a tectonically active Earth.  Volcanoes, Earthquakes and Mountain Building is evedence of this.

Glomar Challenger did the drilling of cores of the ocean floor- found to be youngest at the Ocean Ridges where sea-floor spreading takes place, oldest at the edges of a continent

Magnetic reversal patterns are symmetrical at the ridge, as new ocean crust (basalt lava) oozes out of the Earth the magnetism preserves the magnetic field at the time.  The magnetic field reverses on an average of once every 500,000 yrs.  We believe the magnetic field is created by the circulation of molten outer core liquid iron around a solid metallic inner core.  All of this may be powered by an internal nuclear reactor according to a recent theory.

When Pangaea split, along the new east coast of what is now the US there were cracks that filled with basalt magma or lava.  The Palisades (basaltic) were emplaced 200 million yrs ago.

The Earth itself is 4.6 Billion Yrs ago.  Dating Meteorites (apparently from the asteroid belt) gives us the date for the formation of the planets of the Solar System.  In craton or shield areas which are the most ancient parts of a continent the rocks can be 3.0 to nearly 4.0 billion yrs.  Oldest rocks do not exist because of erosion and the fact that the Earth is tectonically active so rocks can get pretty messed up as continents crash into continents and oceans subduct.  There are exotic terrains which might get pushed by sea floor spreading into a continent therefore adding to a continent at the edge.

The Earth and inner planets are terrestrial, with a solid lithosphere.  The outer planets are jovian and are mostly gas and liquid giants with may posess smaller rocky moons.  Pluto may be more "moon-like" in this respect.

Know the structure of the Earth derived from seismic waves.  There are p waves that travel fast and s waves that travel slower and do not travel through liquid.  Timing these waves, we know there is a MOHO region, the upper mantle is the asthenosphere which the solid lithosphere plates seem to be sliding on.  The crust can be oceanic (mafic), new, thin;  the continents (sialic) are old and thick.  70% of the Earth's crust is volcanic basalt covered by ocean.

We learned in lab about topographic maps, latitude and longitude; also, contour lines.  We know of magnetic declination which you must set your compass to if you're using the map to navigate in the field. 

The role of geologists, and the tasks that geologist must assume for society is major in this time of depletion and degredation of water resources, depletion of fossil fuels, uranium, metals and other resources.  Science and unbiased science research must be used when making decisions which balance our environment with our societies need for raw materials and to live safely in spite of geologic hazards such as mudslides.  As scientists, geologists use the scientific method which established observation, an inquisitive attitude and experimentation as a way of determining the truth.




                                                                                                                    
 



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