Figure 4
From: Evidence for frozen melts in the mid-lithosphere detected from active-source seismic data
Schematic model for formation of oceanic MLDs. (a) Formation and emplacement of a melt at the lithosphere–asthenosphere boundary (LAB) on the flank of a mid-ocean ridge. The black line (isotherm) indicates the position of the LAB. Ascending mantle flow causes shallow decompression and melting with extracted melts ponded at and immediately above the LAB. (b) Formation of frozen melts incorporated in the lithosphere. As the lithosphere thickens away from the ridge, the melts are aligned horizontally in response to shear deformation as the plate moves away from the ridge and the melts freeze within the cooling lithosphere. (c) Present-day lithosphere preserving frozen melts as oceanic MLDs within the mid-lithosphere reflective zone. The dashed line indicates the approximate depth of the G discontinuity inferred from the results of previous studies2,22,23,24,25. The black shadow on the isotherm indicates the reflection position of the DR2 (Supplementary Fig. S4), which we interpreted to represent a thermal structure at the present-day LAB.
