The TTG window and the formation of Earth’s earliest continental crust.
Richard White, School of Earth and Environmental Sciences, University of St AndrewsCambridge Fluids Network - fluids-related seminars27 February 2024 12:00pmDepartment of Earth Sciences, Tilley Lecture TheatreA large number of papers have been written on the processes responsible for the formation of the Earth's earliest continental crust. These range from plume-based processes, through modern style plate tectonics all the way through to formation from bombardment as the solar system passed through galactic regions with high impact potential. Simultaneously, numerous papers have Attempted to identify the melting sources for the magnetic suites that define early continental crust, The Trondjhemite- Tonalite-Granodiorite suite. Despite the progress in these studies there remains considerable disagreement on sources and processes for TTG generation – in part because of a tendency to try and identify a single process and a single source for all the earliest fragments of continental crust. In this talk I will discuss a number of these issues and, in particular, whether or not a single source and single process is a geologically sensible approach, arguing instead that a number of different processes may operate and may independently form crust that is sufficiently thick and buoyant as to be preservable in the geological record.