Formation of the Sierra Madre del Sur

The Sierra Madre del Sur in southern Mexico formed from the subduction of the Cocos Plate beneath the North American Plate. As the Cocos Plate descends, it melts, generating magma that erupts through volcanoes, building the range.

Key Points

• Young, still-growing mountain range.
• Volcanoes remain active; last major eruption was El Chichón (1982), killing 2,000+ and destroying villages.
• Rich biodiversity; popular for hiking, camping, ecotourism.