D) late Paleozoic syncline north of the Tibetan Plateau.
Calderas range in size from less than 1km to tens of kilometers across. What do they all
have in common?
A) They all form by subsidence of the caldera center due to withdrawal of magma from
below.
B) They all form in explosive eruptions.
C) They all are formed in rhyolitic volcanos and have associated eruptions of ash flow
tuff.
D) They all form from collapse of composite volcanos following explosive eruptions;
Crater lake is an example.
African dust from the Sahara desert is observed across the Atlantic as far west as the
Caribbean region where it produces a hazy sky condition during the annual dry season.
You are a climate scientist and make a prediction that the Sahara was not a desert
during glacial periods in the northern hemisphere. How could you test this hypothesis
by looking at deep sea sediments from the Atlantic off west Africa?
A) You would look at fossils to see if there were organisms that preferred dusty
conditions vs. clear water conditions.
B) You could look at the sediments to see if there were biogenic sediments interbedded
with sediments with terrigeneous input corresponding to the dry, interglacial intervals.