land evolution Flashcards
How does Earth affect biogeography?
North America Plate & Pacific Plate
What are the four TECO events?
Plate tectonic, Eustics, Climate Change, and orogeny.
How are mountains formed?
They are formed from hot spots. Subduction is oceanic plate subduction beneath the continent. Subduction occurs from volcanoes.
Origins of Mountains
An example of the mountain origin is Mt. Rainer, Cascades.
The origins of the mountains are converging boundaries: continent to continent. Yes to earthquakes and no to volcanoes
In Moutain geology, what are the 3 reasons of different ranges?
- Forarc: folded region seaward of subduction volcanism
- Accretionary wedges: scraped off subducting slab
- Exotic terranes: islands
Appalachians
A 300 mya continental collision formed. The Applalchians connected to the mountains of Russia, Norway, and Sweden.
How are mountains from the faults formed?
They formed by transform and extension pacific. Strike-slip and Dip - slip
What does transform do between the Pacific Ocean and the West Coast of North America?
Transform faults can produce localized extension and compression. This is also where the Farallon plate is. The Farallon plate lays between the converging Pacific and North American plates converged, where Farallon subducted underneath North America and eventually sank deep into the mantle.
what is the geology of the San Andreas Fault
The San Andreas Fault is a remnant of the oceanic crustal plate and a spreading ridge was subducted beneath the N. A plate as it moved west relative to the Pacific plate. Compression created by fault can create mountains
Explain the Sierra Nevada formation
Extension/fault block that occurs when plates are pulled apart, water to glaciers are cut down to create a valley to old batholith (granite underground) pushed up into denudation.
What is differential weathering
rocks erode at different rates and range is one tilted fault block
Columbia basalt
formed by dissection
Rocky Mountains
types of rocks are granite to metamorphic. Resistance to erosion form peaks
Igneous: formation?
formed by heat
What is the difference between intrusive and extrusive rocks?
Intrusive is formed in the earth like granite. Extrusive is formed by lava at the earth’s surface at the time of Pangea, the Ancestral Rocky Mountain uplift, where the collision of Famalon and North America plates.
What is Laramie orogeny ?
The Laramide orogeny is an orogenic event that gave rise to the Laramie block uplift in the U.S., the rocky mountain fold and thrust belt in Canada and the united states, and the sierra madre oriental Fold and thrust belt in east-central Mexico
What is the evidence for plate tectonics?
Seafloor, remnant Paleomagnetism, major line for plate tectonic b/c of age floor.
Age of the island increase with increasing distance from the mid oceanic ridge.
Paleoclimate evidence, glacial deposits in temperate regions, directions of striations
Difference between an old and a new island?
The older the island, the more developed the soil is. For example, the soil in a tropical rainforest may have more nutrient/development. Evolution in animals, the flightless bird where evolution and natural selection occur. Worse fliers stay on the island, adapt, and evolve than birds who leave the island and die. Sometimes younger island has better flier because it is still developing.
The current model (driving forces )
The lithosphere (the crust and upper portion of the mantle)’floats’ on the denser asthenosphere.
Ridge Push: addition of magma in oceanic ridges push the seafloor out.
Mantle Drag: the lithosphere is dragging on oceanic current
Slab Pull: the subduction plate is pulled into the mantle
Mountain from dissection
Columbia flood basalts. The age of the formation is from 20-17 mya fissure eruption, other is dissection by streams
What is the geology of the San Luis Valley?
The San Juans deposit of volcanic and the sangres are an extension faults
Explain 3 different ways (other than subduction, continental collision, and hot spots) that mountain ranges can be formed and give an example of each.
Divergent Plate Boundary: Volcanic eruptions and shallow earthquakes are commo where plates rip apart.
Age of Earth:
4.6 billion years
Radiometric methods are based on a halflife
uranium, lead, potassium, carbon, and dendrochronology (tree rings) , and optically stimulated luminescence
