![]() She has shown that the Andes were already near their present elevation 14 million years ago. ![]() With collaborators at Scottish Universities Environmental Research Centre and partially funded by BHP Billiton, Dr Evenstar analysed large boulders from 2km high in the western margin of the Andes. ![]() Convergent boundaries are where the plates collide with each other. The abundance of cosmogenic He-3 depends on the altitude of the surface and thus can be used to understand the altitude history of a rock surface. There are three major types of plate boundaries, the places where large sheets of the Earths crust meet. The Andes Mountains were formed at a convergent boundary between an oceanic plate and a continental. As the plates move toward each other and intersect. To investigate the timing of Andean uplift, Dr Laura Evenstar from Bristol’s School of Earth Sciences used a new method based on cosmic rays that create a rare form of helium (cosmogenic He-3) in minerals at Earth’s surface. The Andes is a mountain range found in South America. The Andes mountains are an example of a CONVERGENT boundary between a continental and oceanic plate. The Nazca Plate is less dense than the South American Plate and subducts underneath. The timing of such uplift is important in helping scientists to understand how mountains form, how they erode and what impact this may have on global atmospheric circulation patterns and climate. Recently revised models on global tectonics describe the convergence of the North Andes, Nazca, Caribbean and South American Plates and their seismicity. The Andes mountains formed at the convergence of the Nazca Plate and the South American Plate. When this large portion of dense material was removed, the remaining portion of the crust underwent rapid uplift. In the south, the Andes share a long boundary with the former Patagonia Terrane. RM D99BBYThe Andes Mountains are part of the Southern Cordillera formed from subduction zone volcanism at the convergent boundary of the Nazca plate and. ![]() The prevailing view is that the Andes became a mountain range between ten to six million years ago when a huge volume of rock dropped off the base of Earth’s crust in response to over-thickening of the crust in this region. To the east, the Andes range is bounded by several sedimentary basins, such as Orinoco, Amazon Basin, Madre de Dios and Gran Chaco, that separate the Andes from the ancient cratons in eastern South America. ![]()
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