Global Sedimentary and Crustal Thickness Constraints: Implications for Lithosphere-Asthenosphere Dynamics.

Sedimentary and crustal thickness constraints are important for a wide range of geological and geophysical applications, including: a) measuring dynamic topography; b) calculating heat flow; c) generating seismic tomographic models; d) improving predictions of resource distribution; and e) accurately assessing seismic hazards. In this contribution, we present the methodology and preliminary results of an ongoing study to improve sedimentary and crustal thickness constraints in the continental realm. Active-source seismic experiments and well data provide high-accuracy constraints for total sedimentary thickness. Interpolation between sedimentary thickness measurements is undertaken using a minimum curvature gridding algorithm. We investigate the impact of varying the grid resolution across a range of sedimentary basins, and demonstrate that a high-resolution grid (e.g., ~ 0.03 degrees) is crucial in order to capture lateral heterogeneity. We define crustal thickness as the vertical distance between the base of the sediment (i.e. top basement) and the Moho. Our new sedimentary thickness estimates constrain the top basement while measurements from a new publication of active- and passive-source seismic data are used to constrain Moho depth. Resulting crustal thickness estimates show relatively thin crust beneath a number of continental sedimentary basins. We investigate whether our new estimates of sedimentary and crustal thickness can improve predictions of surface heat flow. Our results demonstrate that constraints of the outermost layers of the Earth are important for understanding the interaction between crust, lithosphere and asthenospheric mantle.