North Patagonian Massif facts for kids

The North Patagonian Massif, also known as the Somún Cura Massif, is a huge landform in Argentina. It's located in the northern part of Patagonia, spreading across the Río Negro and Chubut provinces. A massif is like a very large, solid block of the Earth's crust.

This massif is mostly a high, flat area called a plateau. It is surrounded by lower areas known as sedimentary basins, where layers of rock have built up over time. The North Patagonian Massif covers a massive area of about 100,000 square kilometers (about 38,600 square miles). It stands tall, usually 500 to 700 meters (1,600 to 2,300 feet) higher than the land around it. Its highest point reaches about 1,200 meters (3,900 feet) above sea level. The Earth's crust under this massif is thicker compared to nearby regions.

Rock Layers and History

The North Patagonian Massif is made up of many different layers of rock, like a giant geological sandwich. The oldest rocks form the "basement" of the massif. These rocks are from the Cambrian and Ordovician periods, which were hundreds of millions of years ago!

Ancient Rocks

On top of these very old rocks, you can find the Sierra Grande Formation. These rocks formed during the Silurian period. Over time, other types of rocks were added. Some of these include metamorphic rocks (rocks changed by heat and pressure) and igneous rocks (rocks formed from cooled lava or magma).

Volcanic Activity

Later, during the Permian period, large groups of igneous rocks formed, like the Pailemán and Navarrete Plutonic Complexes. Even more recently, from the Early to Middle Jurassic periods, the Marifil Volcanic Complex formed. This shows that there was a lot of volcanic activity in this area long ago. There are also dikes (cracks filled with igneous rock) called the Enjambre Dikes, which are from the Late Triassic period.

Younger Layers

The top layers of the massif, which are much younger, formed during the Cenozoic Era. In the western part of the massif, you can find rocks from the Eocene to Oligocene periods, like the Ventana Formation and Ñirihuau Formation. In the south, there's the Ñorquincó Formation from the Miocene period. The eastern part of the massif also has Miocene-era rocks, including the Collón Cura Formation, La Pava Formation, and Chimehuín Formation. These layers tell us about the long and active geological history of the North Patagonian Massif.

See also

In Spanish: Macizo Norpatagónico para niños

• Golfo San Jorge Basin
• Neuquén Basin