Geology 100 Spencer Kansas State University Chapter 9

D. 2 half lives

If a rock started with 1,000 atoms of a parent but now contains 250 atoms, how many half lives have passed? A. .25 half lives B. .5 half lives C. 1 half life D. 2 half lives E. there is no way to tell

D. all of the above

In this photograph, Paleozoic sandstone rests depositionally on Precambrian granite. What events must have occurred before deposition of the sandstone? A. uplift of granite to the surface B. solidification of granite at depth C. formation of an erosion surface D. all of the above E. none of the above

B. the scarp on the right

This figure shows two fault scarps, a lava flow, and erosion along one of the scarps. What is probably the oldest feature of those listed below? A. the scarp on the left B. the scarp on the right C. the lava flow D. erosion of the scarp on the right

D. the left section represents older rocks than the right section

This figure shows two sections that partially overlap in age. Dashed lines show how the two sections correlate. What can you conclude from these correlations? A. the oldest unit is unit 4 B. the youngest unit is unit 6 C. the rate at which unit 5 was deposited was constant across the area D. the left section represents older rocks than the right section E. none of the above

D. all of the above

What are the geologic features for which Siccar Point in Scotland is famous? A. a boundary between steep gray layers below and gently dipping red layer above B. an unconformity C. an ancient erosion surface D. all of the above E. none of the above

C. whether the creature had hard parts and how fast it was buried

What factors are the most critical in determining whether a fossil is preserved? A. the age of the fossil and the age of sediments in which it is preserved B. the temperature of the granite and how fast it cooled C. whether the creature had hard parts and how fast it was buried D. the color of the original organism compared to the color of the sediments in which it is found E. whether the creature was a predator or was prey

D. a surface with a well-developed soil is probably older than a surface with no soil

What is a principle we use to determine the age of a landscape surface? A. a landscape surface must be older than any rocks onto which it is carved B. a landscape surface is younger than any rock that is deposited on top of the surface C. the highest river terrace is probably the youngest in age D. a surface with a well-developed soil is probably older than a surface with no soil

D. a time when many different types of creatures appeared on Earth

What was the Cambrian explosion? A. a large volcano that went off in Wales, which the Romans called Cambria B. a meteorite impact that struck the north coast of the Yucatan Peninsula of Mexico C. a time when a meteorite collided with the center of a supercontinent, melting all the glaciers D. a time when many different types of creatures appeared on Earth

D. all of the above

What would fossil ages from the geologic timescale tell us about the age of this unconformity? A. the unconformity is younger than the fossil ages on the tilted bed B. the unconformity is older than the fossil ages in layers above the unconformity C. the amount of time represented by the unconformity can be approximately bracketed by the ages of the fossils above and below D. all of the above E. a and b only

E. all of the above

Which of the following is evidence that Earth's history is not short? A. millions of layers of light- and dark-colored sediment that record yearly cycles B. rates of seafloor spreading compared to the width of the Atlantic Ocean C. a 4-billion-year age on a rock in Canada D. thousands of isotopic ages measured by different methods E. all of the above