Do Cenozoic analogues support a plate tectonic origin for Earth's earliest continental crust?
Hastie, A.R.; Kerr, A.C.; McDonald, I.; Mitchell, S.F.; Pearce, J.A.; Wolstencroft, M.; Millar, I.L.. 2010 Do Cenozoic analogues support a plate tectonic origin for Earth's earliest continental crust? Geology, 38 (6). 495-498. 10.1130/G30778.1Full text not available from this repository. (Request a copy)
Archean continental crust largely comprises the trondhjemite, tonalite, and granodiorite/dacite (TTG/D) suite of igneous rocks. Formation of the earliest Archean (>3.5 Ga) TTG/Ds is controversial, being attributed to either subduction zone processes with active plate tectonics or thermochemical mantle convection with no plate tectonic processes. A suite of Cenozoic adakite-like lavas in Jamaica has geochemical compositions comparable to early Archean TTG/D. The data indicate that the adakites were generated by underthrusting (or subducting) and partial melting of oceanic plateau crust beneath Jamaica. This setting is analogous to proposed plate tectonic processes in the early Archean where hot, thick, and more buoyant Archean oceanic crust underthrusts adjacent plates. The new adakite data imply that earliest Archean TTG/D continental crust could have formed above primitive subduction zones.
|Programmes:||BGS Programmes 2010 > NERC Isotope Geoscience Laboratory|
|Date made live:||24 May 2010 09:06|
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