What is a desert pavement? How do desert pavements probably form? What evidence supports this interpretation?
What will be an ideal response?
Desert pavement is a smooth surface of closely spaced pieces of gravel that covers some desert floors. Most or all pavements form when windblown particles are trapped between larger fragments at the surface. The dust settles and washes beneath the larger fragments. Over time, the accumulating dust lifts the surface clasts above a thickening layer of fine-grained sediment. This mechanism of desert pavement formation is supported by the observation of layers of silty dust beneath the pavement that do not contain gravel fragments. In addition, data revealing how long the gravel clasts have been at the surface indicates that all of them forming a particular age have been at the surface for about the same amount of time. This indicates that they were always exposed at the surface and are not a residual layer left behind as finer particles blew away.
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A student named a particular compound 2-propyl-1-butene. Assuming that the student's choice actually corresponded to the correct distribution of the double bond and the substituents, what is the correct IUPAC name for this compound?
A) 2-propyl-1-butene B) 2-ethyl-1-pentene C) 3-methyl-2-pentene D) none of these
The great majority of Superfund sites in the contiguous United States are located in the
A) Southwest. B) Northwest. C) Midwest. D) Northeast.
Cratons can be divided into what types of provinces?
a. Cratonic basement b. Cratonic roof c. Shields d. Cratonic platforms e. Both c and d
Surface winds tend to be ________ those at a higher level
A) faster than B) slower than C) clockwise to D) counterclockwise to E) at the same speed as