3. The Mid-Atlantic Ridge: An Underwater Mountain Range
The Mid-Atlantic Ridge is one of the most broad geological formations on Earth hidden under the Atlantic Ocean. Comprising more than 16,000 kilometres, this undersea mountain range snakes from the Arctic Ocean to the southern tip of Africa. The Mid-Atlantic Ridge, a divergent tectonic plate boundary, shows where the North American and Eurasian plates in the north and the South American and African plates in the south are progressively separating.
About 180 million years ago, as the supercontinent Pangaea started to split, the Mid-Atlantic Ridge started to form. Magma from the Earth’s mantle rose to cover the progressively separating tectonic plates, generating fresh oceanic crust. With fresh crust created at roughly 2.5 cm year, this process—known as seafloor spreading—is still under way today. The continual building of fresh crust at the ridge drives the current of the continents and forms the Atlantic Ocean basin by pushing the old crust outward.
Though primarily buried under the waters, the Mid-Atlantic Ridge does surface in a few areas, most famously Iceland. Here the volcanic activity of the ridge has produced a distinctive scene of geysers, hot springs, and spectacular lava fields. Basically a large volcano, the island is always expanding over the divergent barrier. The exposed sections of the ridge give researchers great chances to investigate plate tectonics and the mechanisms sculpting the surface of our planet, therefore providing a window into the strong forces operating far down within the Earth.
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.
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