On the Relationships between the Slab Dips and the Age of Oceanic lithosphere

Abstract:

What controls the geometry of the slab dips in subduction zones? We selected the 185 profiles of slab dips in subduction zones on the basis of subduction geometry model slab 1.0. For each profile, partial or entire slab dips were estimated using a linear regression to minimize the statistical uncertainty of the slab dips. Estimated slab dips were then compared with the age of subducting oceanic lithosphere, plate speed as determined from Euler pole conversion, and the strength of slab pull caused by viscous mantle flow. We found that the age of subducting oceanic lithosphere is the most contributing factor in determining the geometry of the slab dips. Correlation between the slab dips and the age of subducting oceanic lithosphere changes significantly at 80 Ma, as steeper (shallower) dips dominant for older (younger) oceanic floor. Such age-dependent variation of steeper slab dips was prominent at southern Sumatra, Marianas, northern Japan-Kuril, and northern Peru-Chile.