Deep Seismic Exploration of East Gondwana: A Proposal (LEGENDS)

Systematic exploration of the continental lithosphere by deep seismic reflection profiling over the past 20 years has revolutionized our view of the deep crust and upper mantle. Major geological features have been traced to lower crustal depths. Certain deep crustal features have been traced into the underlying mantle (fossil subduction zones?). Some geotectonic boundaries, considered by generations of geologists to be major crustal sutures, have been shown to be merely splays off underlying lithospheric boundaries. Hitherto unsuspected boundaries to crustal blocks have been identified, and in some cases, virtually whole mountain belts formerly considered as rooted in the Earth’s mantle have been shown to be allochthons riding above intact extensions of continental blocks at lower crustal depth. Seismic “bright spots” have mapped magma chambers in the deep crust and laminated reflectors have been interpreted as relicts of lower crustal flow.