Figure6

(A) Global compilation of observations of S receiver function based mid-lithosphere discontinuities (MLD), color coded by provenance (see text for references) the shading indicates lithospheric thickness in two bands: light grey for lithosphere > 150 km in thickness, and dark grey for > 250 km thickness (litho1.0, Pasyanos et al., 2014). (B,C) are representations of the depths of two mid lithosphere discontinuities (MLD1 and MLD2) imaged by Calò et al. (2016). Gaps in the interior of this study indicate regions where the discontinuity surface is absent. (D) Frequency count for the thickness of the lithosphere taken at every point in the litho1.0 model (blue and left axis), and for those points where MLDs have been identified in (green and right axis). (E) Cumulative frequency diagram for the same information (global lithospheric thickness, blue, from thick to thin) and for the lithosphere at locations in (A) where an MLD observation has been made (green, cumulative from thinner to thicker). The litho1.0 model is an icosohedral triangulation of the sphere at approximately 1° separation. The MLD information was projected to the nodes through a weighted average and only those nodes with at least one observation within their local support were counted in the histogram. No additional weight was given to multiple observations near any point.