midterm 6 Flashcards
Who was Alfred Wegener and what did he do?
German Meteorologist laid out hypothesis that the continents were once together and then split apart.
What is unique about the magnetic field of the ocean floor?
That the Earth’s magnetic field was reversed when the basalts were created. Magnetic field reversed its polarity an average of every half million years. Magnetic strength to be in stripes
Where are the youngest and oldest sections of the oceanic crust?
young near the ridges and older closer to the continents. Trenches have the oldest and the ridges have the youngest.
What plate boundaries don’t have volcanoes?
continental-continental
What are the major faults in Utah and California?
Wasatch Fault and San Andreas fault line.
Where will you most likely find earthquakes and volcanoes here on Earth?
continental-oceanic zones.
fault lines and zones.
What are the most common rocks in the oceanic crust?
basalt
How old is the Earth?
4.6 billion years
What is an unconformity?
a break or gap in the geologic record.
noticing that certain fossils are missing, or by the worn off edges of rock layers. tell rocks age
What are all the principles of relative time?
determination of the sequence in which event occurred, relative to each other
- Original horizontality
- Superposition
- Inclusions
- Crosscutting relationships
- Faunal succession
What are all the geologic eras and what types of animals lived in them?
Precambrian- single-celled organisms
Paleozoic, ancient- marine invertebrates (trilobites, sponges, coral, mollusks) Fish, reptiles
Mesozoic, middle-dinosaurs, emergence of birds, small mammals, and flowering plants
Cenzoic, recent- mammals
Where is the oceanic crust formed?
Mid-ocean ridge
What type of convergent plate boundary doesn’t have Volcanoes?
Continental-continental
What are the 3 types of convergent plate boundaries?
continental-continental
continental-oceanic
oceanic-oceanic
What is all the evidence for continental drift and plate tectonics?
Plants and animals correlated, climate data, puzzle pieces, magnetic reversals, seductions zones, mid-ocean floor
Oceanic-Oceanic
when two oceanic plates collide, one dives under the other sinking, process called subduction.
They form Volcanic Island Arcs. (chain of volcanoes.
Ocean-Continent
in collisions, the oceanic plate always subducts.
collisions can create mountain belts and volcanoes. Material that comes from it will never subduct again so it makes the land grow.
continent-continent
collisions the material is welded together, nothing sinks because not dense enough.
