Geochronology - Confirming the existence of an Ancient ‘lost continent’ (LG-SIMS)

SIMS U-Th-Pb dating of zircon grains from lost continent

The Mauritius island is of young volcanic origin with the oldest rocks believed to be around 9 Ma old. SIMS U-Th-Pb age determination of zircon grains extracted from a volcanic rock on Mauritius revealed that these zircons are around 3 Ga old‚ far too old to belong to the island of Mauritius. Scientists have confirmed the existence of a “lost continent” beneath modern-day Mauritius that was left-over by the break-up of the supercontinent, Gondwana, which started about 200 million years ago.

Zircon minerals contains a rich record of geological processes and are one of the most useful geochronometers. Zircon can be dated extremely accurately and at local scale using ultra-high sensitivity SIMS. In this study, the break-up process of the continents could be studied using SIMS in order to better understand the geological history of our planet.

The IMS 1300-HR³ large-geometry ion microprobe provides benchmark sensitivity for in-situ isotopic analysis at high spatial resolution. It covers a wide range of geochronological applications, from precise age determination of zircon to dating of other U-rich minerals. It also offers high analytical flexibility allowing the development of innovative analytical protocols for mineral dating (ion imaging, depth profiling, …).

Data collected on IMS 1280-HR in GFZ Potsdam (Germany).
From: L. D. Ashwal, M. Wiedenbeck & T. H. Torsvik, NATURE Communications 8:14086 (2017).