Question

First, samples of the deep ocean floor show that basaltic oceanic crust and overlying sediment become progressively younger as the mid-ocean ridge is approached, and the sediment cover is thinner near the ridge:

a) Isostasy principles
b) Plate tectonics
c) Sedimentary deposition
d) Seafloor spreading

Answer 1

The age progression and sediment cover patterns along the ocean floor near mid-ocean ridges align with the concepts of seafloor spreading and plate tectonics. New crust forms at the ridges and older crust is recycled at subduction zones.

Step-by-step explanation:

Examining the patterns in the age and composition of the deep ocean floor provides evidence for the dynamic processes of earth's crust. Near the mid-ocean ridge, basaltic crust and overlying sediment layers are not only thinner but also increase in age as one moves away from the ridge. This is consistent with the concept of seafloor spreading, a critical mechanism of plate tectonics that explains the creation of new oceanic crust. As new crust forms at a mid-ocean ridge, it gradually moves away from the ridge axis, becoming progressively older. Subduction zones play an essential role in recycling older crust back into the mantle, thus balancing the formation of new crust. The thinner sediment cover near the ridges is due to the proximity to the ridge where newly formed crust has had less time to accumulate sediment through sedimentary deposition.