High precision sulphur isotope measurements with CAMECA Ultra High Sensitivity SIMS bring new evidence about the timing of the initiation of plate tectonics
Thứ hai, 27/05/2013

April 2013: By analyzing volcanic rock that erupted millions of years ago on an island in the South Pacific, an international team of researchers from Blaise Pascal University (France), Boston University (USA), and Swedish Museum of Natural History Stockholm (Sweden) found clues about when components of the rock first left Earth’s surface and began their long journey through its interior. In-situ S-isotope composition was characterized using a CAMECA IMS 1280; the three most abundant S-isotopes were measured at good spatial resolution (<10 µm) and excellent precision using simultaneous collection on FC detectors. Data provide the key to the authors’ discovery: because mass-independently fractionated (MIF) Sulphur isotope signatures were generated exclusively through atmospheric photochemical reactions until about 2.5 billion years ago, material containing such isotope signatures must have originated at the Earth’s surface in the Archean.
The study appears in the April 25 issue of Nature: Anomalous sulphur isotopes in plume lavas reveal deep mantle storage of Archaean crust. http://www.nature.com/nature/journal/v496/n7446/full/nature12020.html