Titanium isotopes as a tracer for the plume or island arc affinity of felsic rocks

• DOI: 10.1073/pnas.1809164116
• Publication Date: 2019-01-04T03:25:14Z
• Authors: Zhengbin Deng; Marc Chaussidon; Paul Savage; François Robert; Raphaël Pik; Frédéric Moynier
• Keywords: Titanium isotopes; Plume; Magma differentiation; [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics; magma differentiation; GE; 550; plume; Plate tectonics; DAS; island arc; 01 natural sciences; 7. Clean energy; [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry; 13. Climate action; plate tectonics; Island arc; titanium isotopes; GE Environmental Sciences; 0105 earth and related environmental sciences

Significance

The debate on the onset of plate tectonics in the Earth’s history has partially originated from the controversial criteria of using felsic crust to trace plate tectonics in the past. Here, we demonstrate how Ti isotope ratios can be used as a proxy for the affinity of felsic rocks to plume or island arc settings. Our study shows that, contrary to what was previously assumed, Ti isotopes cannot serve as a direct evidence for plate tectonics from 3.5 billion years ago, and must be combined with other information on SiO 2 contents of crustal rocks to be reliable.