Shrimp dating zircon
However, by studying the rocks on the island, we have found zircons that are as old as 3 billion years.“The fact that we have found zircons of this age proves that there are much older crustal materials under Mauritius that could only have originated from a continent.”The lost continent of Mauritia began to form some 200 million years ago when Gondwana began to break up, and would have been a dangerous landmass peppered with volcanoes and susceptible to regular earthquakes.
Mr Ashwal continued: "According to the new results, this break-up did not involve a simple splitting of the ancient super-continent of Gondwana"But rather, a complex splintering took place with fragments of continental crust of variable sizes left adrift within the evolving Indian Ocean basin.”Previously, ancient zircons have been found on the island but it was argued these could have washed up or blown there.
Geochemically, the older granitoids are metaluminous and exhibit characteristics of I-type granites and most likely formed in a convergent margin (arc) tectonic environment.
On the other hand, the younger granites are peraluminous and exhibit the characteristics of A-type granites; these are post-collisional granites.
A fragment of the ancient continent, linking the 932 miles from India to Madagascar, was discovered by studying the mineral zircon, expelled during volcanic eruptions.This site stores nothing other than an automatically generated session ID in the cookie; no other information is captured.In general, only the information that you provide, or the choices you make while visiting a web site, can be stored in a cookie.Zircons from both samples show subrounded to rounded shapes and patchy CL patterns without inherited igneous cores, indicating that they are metamorphic zircons. SHRIMP U-Pb analyses of these zircons yielded apparent U-Pb ages of 214-280 Ma, with a weighted mean age of 237 ??
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of Geoscience, Madison, Wisconsin 53706, USA 2 Observatorio Volcanológico de los Andes del Sur (OVDAS) and SERNAGEOMIN, Chile, and Universidad de Concepción, Chile 3 Observatorio Volcanológico de los Andes del Sur (OVDAS) and SERNAGEOMIN, Chile 4 University of Alberta, Dept.