Geology of Argentina

The geology of Argentina includes ancient Precambrian basement rock affected by the Grenville orogeny, sediment filled basins from the Mesozoic and Cenozoic as well as newly uplifted areas in the Andes.

[4] Extremely ancient trace fossils have been found in the Puncoviscana Formation in the northwest, which grades into gneiss, schist and migmatite, as well as conglomerates, pelagic clay and volcanic rocks.

As the breakup of Gondwana began, narrow half-grabens filled with volcaniclastic rocks and the Pampa de Agnia Basin formed along the Gastre fault system.

The Magallenes Basin experienced rifting and the Chon Aike province witnessed intraplate volcanism during the acceleration of the breakup around 180 to 165 million years ago, as the Weddell Sea opened.

Rifting and strike-slip faulting in weak Cretaceous magmatic arc rocks was reactivated with the subduction of the Nazca Plate under South America around nine million years ago.

[13] Uplift began around seven million years ago in the Sierra Pampeanas, a group of reverse fault-bounded Precambrian and Paleozoic rocks in the central Andes foreland basin.