Figure 23.1
-Assuming that the rate of seafloor spreading was constant during the 1-million-year period depicted in Figure 23.1,what should be the approximate age of marine fossils found in undisturbed sedimentary rock immediately overlying the igneous rock at the arrow labeled II?
A)10,000 years
B)250,000 years
C)500,000 years
D)1,000,000 years

Question

Figure 23.1
-Assuming that the rate of seafloor spreading was constant during the 1-million-year period depicted in Figure 23.1,what should be the approximate age of marine fossils found in undisturbed sedimentary rock immediately overlying the igneous rock at the arrow labeled II?
A)10,000 years 
B)250,000 years 
C)500,000 years 
D)1,000,000 years

Quizplus · Accepted Answer

The distance between the arrows labeled I and II is approximately 500 kilometers, and the rate of seafloor spreading is approximately 5 centimeters per year. Therefore, it would have taken approximately 10 million years for the seafloor to have spread and moved the location of the arrow labeled II. Therefore, the marine fossils found in undisturbed sedimentary rock immediately overlying the igneous rock at the arrow labeled II would be approximately 500,000 years old (halfway between the present-day location and 10 million years ago).

Figure 23.1 -Assuming That the Rate of Seafloor Spreading Was Constant During