Monday, October 26, 2009

Boundary Questions

1. The first three boundaries listed are Divergent boundaries, Convergent boundaries and Transform boundaries.

2. Divergent boundaries are new crusts generated as the plates pull away from each other, so divergent means to move pull away. The force that moves the plates apart is magma pushing up from the mantle.

3. A specific mid-ocean ridge is the Mid-Atlantic Ridge. The country that sits directly on top of the ridge is Iceland. The red triangles of the map are volcanoes.

4.Convergent means a very slow collision.

5.
a.Oceanic-continental


b.Oceanic-oceanic

c.Continental-continental

6.
a. What happens to the Earth's surface above the Oceanic-continental subduction zone is that large mountains are created strong and destructive earthquakes occur, rapid uplift of mountain ranges. Also creating volcanic arcs.
b. What happens to the Earth's surface above the Oceanic-oceanic convergence is that it forms volcanoes. Typically these volcanoes are strung out in chains of island arcs. Those island arcs create trenches.
c. What happens when an continental-continental convergence happens, is that high mountains are created.

7. A transform boundary is when two plates are sliding horizontally past one another. They created a large fault or fracture zone that connects two spreading centers (divergent plate boundaries). One example in North America would be the San Andreas fault zone in California.

8.
a.It is a divergent boundary. The plates that are interacting are the Eurasian Plate and the North American Plate in the north being separated. As well as the African Plate and South American Plate in the south being separated.

b.It is a convergence boundary that interacts with the Pacific plate converging with other plates from the west.

c.It is a convergent boundary of the Eurasian plate and the Sunda plate.

d. It is a divergence boundary of the African plate

e.It was a divergent boundary between the Arabia Plate and African Plate.

f.It is a convergent boundary between the Nazca Plate being subducted under the South American Plate

g. It is a convergent boundary between the Pacific and North American plates.

Thursday, October 15, 2009

Geologic Timeline

1. What things had to happen were, oceans had to form. Since those oceans were created, cyanobacteria showed up cyanobacteria which created oxygen and slowly filled the atmosphere. Then when the atmosphere was filled with oxygen, multicelluar life was able to live.

2.The Archaeon Eon because that's when the Earth was born. This is also when the Earth finished stratifying and the atmosphere started showing up. Other events during this Eon was, oceans forming and heavy bombardment ending.

3.Human presence was insignificant compared to the History of the Earth because the Earth has been around for 4.5 billion years and life has only been alive for 543 million years.