Week 5 Converging Plates

The convergent plate margin visits would be the Peru Chile Trench, where you have a subductive zone of Oceanic crust (Nazca Plate) against continental crust (South American Plate) and the formation of what is known today as the Andes Mountain range.

Here, the two plates are involved in a compressive type of stress where the plates move toward each other. When a collision occurs, the oceanic crust sinks under the light continental crust because it is denser. The molten rock rises to the earth’s surface, resulting in eruptions and the formation of mountain ranges.

Intrusive rocks like granite and granodiorite which are resistant to corrosion are normally deposited and form the core of the mountains (Andeansummits.com).

In the Andes Mountain regions we can see where folding is taking place and dominating the structural style. This is where the pressure of the converging plates cause the crust to fold, resulting in the creation of the mountain ranges.

Faults occurring along this region are normal faults.

Reference:

Andean Summits (nd). Geological history of the Andes. Retrieved from https://www.andeansummits.com/geological-history-andes#:~:text=Intrusive%20rocks%20such%20as%20granite,over%20the%20surrounding%20sedimentary%20rocks.

Week 5 - Aaron Gomez - Converging Plates

Today we visit the Southern Andes near Osorno, Chile.  This region of the demonstrates many of the developing and fully developed features of converging plates.  We have shallow subduction of the Nazca Plate under the South American Plate.  In this particular region, a forearc is beginning to develop as the large accretionary wedge to the West of the city is uplifted.

To the East, numerous stratovolcanoes like Tronador and Volcan Osorno dot the terrain.  They result from partial melting of the subducting oceanic plate.  The Liquine-Ofqui fault is a large strike-slip fault running through the region at approximately 1000 km in length.