Weathering of the continents has been much more widespread and intense in the past 10 million years than it was in earlier times. How might this observation be borne out in the sediments that now cover Earth’s surface?
If you drilled one oil well into the bottom of a sedimentary basin that is 1 km deep and another that is 5 km deep, which would have the higher pressures and temperatures? Oil turns into natural gas at high basin temperatures. In which well would you expect to find more natural gas?
A geologist is heard to say that a particular sandstone was derived from a granite. What information could she have gleaned from the sandstone to lead her to that conclusion?
You are looking at a cross section of a rippled sandstone. What sedimentary structure would tell you the direction of the current that deposited the sand?
You discover a bedding sequence that has a conglomerate at the base; grades upward to a sandstone and then to a shale; and finally, at the top, grades to a limestone of cemented carbonate sand. What changes in the sediment’s source area or in the sedimentary environment would have been responsible for this sequence?
From the base upward, a bedding sequence begins with a bioclastic limestone, passes upward into a dense carbonate rock made of carbonate-cementing organisms, and ends with beds of dolostone. Deduce the possible sedimentary environments represented by this sequence.
In what sedimentary environments would you expect to find carbonate muds?
How can you use the size and sorting of sediment particles to distinguish between sediments deposited in a glacial environment and those deposited in a desert?
Describe the beach sands that you would expect to be produced by the beating of waves on a coastal mountain range consisting largely of basalt.
What role do organisms play in the origin of some kinds of limestone? Compare the sediments formed in shallow environments with those formed in deep-sea environments.
Where are reefs likely to be found?
A bay is separated from the open ocean by a narrow, shallow inlet. What kind of sediment would you expect to find on the floor of the bay if the climate were warm and arid? What kind of sediment would you find if the climate were cool and humid?
How are chert and limestone similar in origin? Discuss the roles of biological versus chemical processes.