In this assignment, we will focus on the largest scale geomorphology of the Earth by working through problems that deal with big picture, “Whole Earth” geomorphology.
These problems aim to provide examples of back-of-the-envelope calculations that help develop your sense of scale on the Earth. In your calculations, be sure to work through each problem striving for clarity and organization.To earn full credit, you must show your work when solving this problem.In some cases, it may be useful to provide a definition sketch.
A&A Chp. 1 #4:Calculate the global average terrestrial erosion rate(in microns/yr)over the last 5 Ma based upon the 31x1018kg of sediment delivered to the oceans in the most recent 5 Ma bin (shown in Figure 1.5of the Anderson & Anderson textbook). You may assume that about 30% of the Earth’s surface is terrestrial (i. e. not underwater) and that the density of the terrestrial rock being eroded is 2700 kg/m3. Can you remember the Earth’s radius?
A&A Chp. 2#2:How fast is the Earth moving in its orbit?Report your answer in units of km/s.How does this compare withMars’s orbital velocity?Report this answer as a decimal or percentage. (Note that these speeds scale the speed at which a piece of debris collides with the planet.)
A&A Chp. 2#3: How much new water must be added to the ocean each year to sustain the measured 2 mm/yr rate of rise attributable to new water? Report your answer in both cubic km and gigat onnes. Hint: You’ll want to calculate the surface area of the Earth’s oceans first, to determine the volume represented by the 2 mm/yr sea level rise rate.
See Problem A&A Chp. 1 #4above to figure out what fraction of the Earth’s surface is covered by ocean water (or look this up on the hypsometric curve).
