Dynamic Causes of the Relation Between Area and Age of the Ocean Floor

Abstract

Old Plates and the Sea Estimates for the area and age of the ocean floor are at odds with assumptions for mantle convection, which imply that an older sea floor—rather than a new one—would be preferentially subducted over time. Previous efforts to explain these relationships have been based on geologic evidence and simple models. Coltice et al. (p. 335 ) created numerical three-dimensional convection models representing more realistic physical boundaries, including a spherical Earth, the existence of continents and supercontinents over time, and realistic rheologies. A combination of continents and plate-like behavior of the ocean floor sufficed to produce the observed relationship between plate area and plate age, which explains why some old oceanic crust still remains.