A study of oceanic geology shows that there are few oceanic crustal rocks found that are older than 80 million years. Why?
A) Oceanic crust was not formed until the beginning of the Precambrian, 80 my ago.
B) Current radiometric dating techniques cannot date rocks older than 50 million years.
C) Subduction remelts oceanic rock and most has been destroyed of that age
D) Oceanic crust is only found at the ridges, which are mostly unsampled.

Question

Quizplus · Accepted Answer

Subduction processes, part of plate tectonics, cause oceanic crust to be recycled back into the Earth's mantle. This process destroys older oceanic crust, making it rare to find pieces that are older than 80 million years.

A Study of Oceanic Geology Shows That There Are Few