- Convection movement in the uppermost layers of the mantle may pull on
- the lithospheric rocks, breaking them into huge plates that move slowly
- on the more plastic, lubricated surface of the asthenosphere
The uppermost layer of the mantle, located below the lithosphere
The outer part of the earth, consisting of the crust and upper mantle
What is plate tectonics?
Earth's outer layers , consisting of rigid plates, which encounter eachother, causing earth's dynamic events.
Plate Boundaries can interact in what three ways?
- Divergent: crust is stretched and thinned, like Baja from Mexico
- Covergent: two plates colliding creating, buckling, faulting, and folding, like the Gorda Plate subducting beneath the North American Plate
- Transform: Plates moving past eachother, without diverging or converging, like the Pacific Plate and the North American Plate with the San Andreas Fault
Massive Mountian Range?
Rates of Movement
- Could be any of these:
- rate of plate motions.
- rate of erosion.
- rate of deposition.
- rate of fault movement.
- rate of uplift.
- frequency of earthquake activity.
- frequency of volcanic eruptions.
- rate that sea level is increasing.
- rate of groundwater movement.
- frequency of flooding.
- rate of surface water movement.
- rate of natural gas production.
- rate of planktonic growth.
- many additional ones.
Equilibrium in the earth's crust such that the forces tending to elevate landmasses balance the forces tending to depress landmasses
Earth's Magnetic Field
- A magnetic field extends infinitely, though it weakens with distance from its source. The Earth's magnetic field, also called the geomagnetic field, which effectively extends several tens of thousands of kilometres into space, forms the Earth's magnetosphere.
- A paleomagnetic study of Australian red dacite and pillow basalt has estimated the magnetic field to be at least 3.5 billion years old
- Based upon the study of lava flows of basalt throughout the world, it has been proposed that the Earth's magnetic
- field reverses at intervals, ranging from tens of thousands to many millions of years, with an average interval of approximately 300,000 years
The migration over the surface of the Earth of the magnetic poles of the Earth through geological time
The movement of the Earth's continents relative to each other