The Kerguelen oceanic plateau sheds light on the formation of continents

View of the Rallier du Baty peninsula in the vicinity of the Mont du Commandant, Kerguelen Islands. A pale-coloured rock, syenite, was injected into the basalts (which are darker), uplifting them. The king pengins give an idea of the scale. Michel de Saint Blanquat - How did the continents form? Although to a certain extent this remains an open question, the oceanic plateau of the Kerguelen Islands may well provide part of the answer, according to a French-Australian team led by the Géosciences Environnement Toulouse laboratory (CNRS/Université Toulouse III-Paul Sabatier/IRD/CNES) 1 . From a geological point of view, it is the Earth's outermost layer that distinguishes the continents from the oceans: oceanic crust, which is relatively thin, is mainly made up of basalts, resulting from the melting of the Earth's underlying mantle, whereas continental crust, which is thicker and of granitic composition, is derived from magmas that evolved at depth before solidifying. Such magmas form especially at subduction zones, where one tectonic plate dives beneath another. However, a study published on June 16, 2020 in the journal Terra Nova provides evidence in support of a second model: the formation of embryonic continents within oceanic plateaus such as the Kerguelen plateau.