On the relation between basal erosion of the lithosphere and surface
heat flux for continental plume tracks
Abstract
While hotspot tracks beneath thin oceanic lithosphere are visible as
volcanic island chains, the plume-lithosphere interaction for thick
continental or cratonic lithosphere often remains hidden due to the lack
of volcanism. To identify plume tracks with missing volcanism, we
characterize the amplitude and timing of surface heat flux anomalies
following a plume-lithosphere interaction using mantle convection
models. Our numerical results confirm an analytical relationship in
which surface heat flux increases with the extent of lithosphere
thinning, which is primarily controlled by on the viscosity structure of
the lower lithosphere and the asthenosphere. We find that lithosphere
thinning is greatest when the plate is above the plume conduit, while
the maximum heat flux anomaly occurs about 40-140\,Myr
later. Therefore, younger continental and cratonic plume tracks can be
identified by observed lithosphere thinning, and older tracks by an
increased surface heat flux, even if they lack extrusive magmatism.