Chapter 5

Mapping Pangean lithosphere

Story

“We could see that the old parts of the continents were more extensive than the surface outcrop. That didn’t surprise me, that the old parts continued underneath flat-lying sediments. And then Mike DalyMike DalyMike Daly (1953-present) is a Professor at Oxford University with research interests in continental tectonics and stratigraphy; the evolution of rift and cratonic basins; and resource systems. He works mostly in Africa, Latin America and the UK. He also serves as a Board Director of Tullow Oil and Compagnie Générale de Géophysique (CGG). Mike started his working life as a structural geologist in the Geological Survey of Zambia. This was followed by a career with BP in various research, geoscience and exploration leadership roles. He retired from BP in 2014 after almost a decade as their Global Exploration Executive. asked “what does it look like if you reconstruct this to Pangea?” And I thought, well, I’ve never really tried to do that seriously, so I had a go. What we found was an arc of lithosphere which lay inboard from where the subduction went on. It was all one continent and both shapes were arcuate. The smooth shape of the lithosphere produced by reconstruction implied that the same thick lithosphere had been deformed as the plates moved together. “To get it all to fit, to make one continuous zone, you’ve clearly got to deform it,” stressed McKenzie. “And it may be of geological importance, but quite what the significance of it is, I’ve no idea. It was really a surprise.”