Orogenic development of the Argentinian/Chilean Andes during the Palaeozoic

The geological development of the basement of the Argentinian/Chilean Andes during the Palaeozoic is characterized by an almost continuous structural, metamorphic and plutonic mobility. Ultrabasic magmatism occurred only in a few regions; terrigenic psammopelitic sequences are widespread at all times. Metamorphism is mostly of low to intermediate pressure, but of variable temperature; late Palaeozoic high pressure metamorphism only took place near the present Pacific coast. There are about four culminations of orogenic activity, varying in space and time: from the mid-Cambrian to the mid-Ordovician, from the Silurian to the mid-Devonian, during the early Carboniferous, and at the Permian/Triassic boundary. Fold structures strike in variable directions at different times. On the whole, the Pacific margin of Gondwana consolidated continuously from the shield region in the E towards the Pacific during the Palaeozoic.