Digital isochrons of the world's ocean floor

TLDR

The grid is intended for studies of lithospheric thermal and elastic structure, Earth heat loss, ridge‑push forces, spreading asymmetry, and constraints on seismic tomography and mantle convection models. Ages at each node were derived by linear interpolation between adjacent isochrons along spreading directions, with passive continental margins interpolated from geological data and published plate models. We produced a 6‑arc‑minute global ocean‑floor age grid with self‑consistent isochrons and plate reconstruction poles, including error estimates that increase with anomaly‑age uncertainty, distance to nearest anomaly, and age‑gradient discontinuities.

Abstract

We have created a digital age grid of the ocean floor with a grid node interval of 6 arc min using a self‐consistent set of global isochrons and associated plate reconstruction poles. The age at each grid node was determined by linear interpolation between adjacent isochrons in the direction of spreading. Ages for ocean floor between the oldest identified magnetic anomalies and continental crust were interpolated by estimating the ages of passive continental margin segments from geological data and published plate models. We have constructed an age grid with error estimates for each grid cell as a function of (1) the error of ocean floor ages identified from magnetic anomalies along ship tracks and the age of the corresponding grid cells in our age grid, (2) the distance of a given grid cell to the nearest magnetic anomaly identification, and (3) the gradient of the age grid: i.e., larger errors are associated with high age gradients at fracture zones or other age discontinuities. Future applications of this digital grid include studies of the thermal and elastic structure of the lithosphere, the heat loss of the Earth, ridge‐push forces through time, asymmetry of spreading, and providing constraints for seismic tomography and mantle convection models.