The Charnwood Terrane Revisited – Tim Pharaoh

The Charnwood Terrane revisited: A new model for Ediacaran crustal evolution in southern Britain

A new model is presented for the Ediacaran (635-541 Ma) evolution of the crust of southern Britain. Charnian magmatic activity (at 570-560 Ma) occurred towards the end of this phase of crustal evolution when southern Britain lay south of the Equator, at the margin of the Gondwana supercontinent. The model is driven by a petrophysical model created by inversion of aeromagnetic potential-field data, which provides insights into the possible internal structure of the Charnian Domain. The latter is inferred to comprise a primitive mafic magmatic arc (Oxfordshire-Warwickshire), which fed volcaniclastic material into adjacent fore-arc (Charnwood-Nuneaton) and back-arc marginal (Worcester) basins. The domain was emplaced as a magmatic rift wedge into older (> 600 Ma) Gondwanan crust in the Welsh Borderland (now referred to as the Marches Terrane). Contemporaneous volcanic rift successions here and in Wales (Uriconian, Llangynog, Pebidian etc) developed in coeval ensialic rifts within less strongly extended Marches Terrane lithosphere. The new model emphasises the role of extensional tectonics, rather than accretionary processes, as in previously published models. Comparable diversity of subduction-related magmatism is found in the Neogene–Recent Hikurangi destructive margin of New Zealand, which provides a plausible analogue for Charnian magmatism and sedimentation.

This lecture will be offered in a hybrid format. Please join us in person if you can, or register to attend virtually via zoom using the link below.

Register in advance to attend virtually:
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Venue:
St Francis Of Assisi RC Church, 110 Warwick Rd, Kenilworth CV8 1HL
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