Tuesday, January 20th, 1999

Announcements: sign-up’s for extra credit will be available during the next class.

Lecture notes:
 

1. Death Valley

1. Lowest land level – 282 feet below sea level
2. Highest point – about 11,000 feet above sea level
3. There are 20 miles between the lowest point of land and the highest point of land

1. Erosion/deposition

1. Rain is sparse, but heavy
2. Alluvial fan – made of big pieces of rock, freshly broken rock; big angular pieces

1. Playa – evaporite minerals

1. Shallow, wide body of water
2. Water heats up then the chemicals within the water ferment; Bad Water

1. Summer’s are extremely hot; around 130˚ during the middle of the day
2. Extremely hot in the valley
3. Roughly 160˚ difference in temperature in the valley and in the mountains

• Death Valley is stuck underneath an oceanic spreading area; on both sides of the valley are two sets of mountains which are pulling away from each other at a diagonal; most motion along the faults is vertical

1. Accretion of meteorites

1. Pieces of rock that are very far away from each other have gravitational potential energy; it is b/c of this energy that the rock comes together
2. The pieces of rock collide due to the gravitational energy; the energy caused by the collision turns into heat (see figure 1)

1. Convection

1. When the earth gets rid of heat; driven by change in density (of rock) with temperature
2. Material moves from where it’s hot to where it’s cold
3. When rock reaches the top of earth’s surface, the material has to move laterally to get away from the heat coming from below
4. Rock material cools down and eventually sinks again to the original hot area and then repeats the entire process all over again