New Insights Into the Cooling of the Oceanic Lithosphere From Surface-Wave Tomographic Inferences

Abstract

How oceanic plates cool and thicken with age remains a subject to debate, with several thermal models supported by apparently contradictory data. Combining a novel imaging technique that balances resolution and uncertainty with finite-frequency surface-wave measurements, we build tomographic model SS3DPacific to revisit the cooling style of the oceanic lithosphere beneath the Pacific ocean. Resolution analysis indicates a strong vertical smearing that biases estimates of the apparent lithospheric thickness, limiting the ability to discriminate between the half space and plate cooling models. Laterally, a pattern of anomalous bands in seismic velocity aligned with fracture zones points to additional lateral complexities in the lithosphere, complicating simple age-trend analyses.