Question

Which observation about the Mid-Atlantic Ridge region provides the best evidence that the seafloor has been spreading for millions of years?
A. The bedrock of the ridge and nearby seafloor is igneous rock.
B. The ridge is the location of irregular volcanic eruptions.
C. Several faults cut across the ridge and nearby seafloor.
D. Seafloor bedrock is younger near the ridge and older farther away.

Answer 1

Answer:

D. Seafloor bedrock is younger near the ridge and older farther away.

Explanation:

In a divergence boundary oceanic plates or continental plates move apart. The plates moves apart causing an uprising of molten magma to form a new crust. The divergent movement of plate is very prevalent in the oceanic plates.

The plates in the oceanic crust moves apart due to the up welling of aesthenosphere materials . These aesthenosphere materials(molten magma) are introduce to the ocean floor through the mid oceanic ridge . As this materials are introduced through cracks and fissures, the plates continue to drift apart. The molten magma later solidified to form a new crust closer to the oceanic ridge.  This is why sea floor bedrock closer to the ridge is younger as new rocks are formed here. But as one move farther away from the ridge the rocks become older. This phenomenon provide ample evidence that the seafloor is spreading. The older rocks found father away from the ridge proves the seafloor has been spreading given way for new rocks closer to the ridge.