Earth's Scars: Exploring the World's Five Great Rift Systems

4. The Rio Grande Rift: A Desert Oasis in North America

Rising across the centre of New Mexico and into southern Colorado, the Rio Grande Rift is evidence of the geological forces sculpting the American Southwest. About 1,000 kilometres of this north-south trending rift system produce a sequence of basins that have significantly changed the topography, temperature, and ecology of the area. Unlike many other rift systems that develop at the margins between tectonic plates, the Rio Grande Rift is an intraplate riving system found inside the North American plate. About 35 million years ago, tectonic forces started to strain and thin the Earth's crust in this area, hence forming the Rio Grande Rift. This process produced a sequence of deep basins surrounded by steep mountain ranges, forming the spectacular settings that define the region now. Periods of great volcanic activity that have left their imprint as large lava fields, volcanic peaks, and mineral-rich hot springs define the evolution of the rift. The Rio Grande Rift's river from whence its name comes is among its most important characteristics. One of the longest rivers in North America, the Rio Grande runs across the rift valley and offers an essential water source in otherwise parched territory. For thousands of years, human habitation in the region has been dependent on the river; it has also made it possible for distinctive riparian ecosystems to flourish. From lower levels' desert-adapted species to alpine communities in the nearby mountains, the rift zone today supports a wide range of plant and animal life.