12/1/2023 0 Comments Himalayas plate boundary![]() ![]() Wind and water scour away the surface, washing sediment into streams that race down the mountain’s flanks. This may have been the case during the 2015 Nepal earthquake, according to satellite data.Īt the same time, as the rocks continue to rise toward the skies, erosion works against their upward progression. Depending on exactly how and where the ground shifts, temblors can cause the mountain to either grow or shrink small amounts. Yet the mountain doesn’t necessarily get taller during earthquakes. The blocks of earth can then suddenly shift, rattling the ground in the jolt of an earthquake. When the land compresses, pressure builds until it hits a breaking point. As India rams underneath Eurasia, it doesn’t always slide smoothly by. The growth can happen in fits and starts, brought on by more violent shifts in the landscape. ( Learn why it's so difficult to measure Everest.) India creeps northward a couple inches each year, and scientists estimate that the ongoing impact with Eurasia might force the mountains to ever greater heights, with an estimated average uplift of roughly 10 millimeters a year in the northwestern sections of the range, and around a millimeter a year at Everest. No matter when it started, though, the collision that formed Everest still continues today. That would leave a mysterious yawning gap between the two continents.ĭid the Indian plate initially collide with a now long-gone landmass that sat between the two larger continental blocks? Could the Indian plate’s northern edge have extended much farther than previously thought? Why was the Indian plate moving so fast before impact? These are among the many questions scientists are still working out. Study of ancient magnetic patterns in the rock allows researchers to chart a continent’s position over time, and recent work using this method revealed that when the mountain-forming collision supposedly took place, some 55 million years ago, India would have been strikingly far south from Eurasia. Or, at least, that’s long been the accepted version of the story.īut as scientists continue to pore over every bend, crack, and rock in this system, many mysteries have arisen. So, as the continents compressed and India shoved its way under Asia, the surface buckled and the crust thickened to form what would eventually become the mighty Himalaya mountain range. Unlike an oceanic plate, which is cold and dense, the Indian continental plate is thick and buoyant. Further evidence from marine sediments suggests the final swath of the Tethys ocean closed between 50 and 60 million years ago. ( See the summit of Everest and its surrounding peaks in 360 degrees.)Īround 50 million years ago, India’s speed precipitously declined, a shift many scientists interpreted as the early stages of the plate’s collision with Eurasia. The slow slip of the oceanic slab into the mantle scraped a thick layer of seafloor sediments into a pile at the edge of the Eurasian plate-and this sandy layer would later be squeezed into rock and end up on the mountainous peaks. The plate under the water, made of dense oceanic crust, plunged beneath the southern edge of the more buoyant rocks that make up the Eurasian continental plate, creating a feature known as a subduction zone. The Indian plate zipped along at surprisingly fast speeds, geologically speaking, shifting nearly 30 feet or more each century.Īt the time, the vast Tethys ocean filled the gap between India and Eurasia, but as India moved northward, the ocean began to close. The Indian plate eventually broke free, trekking northward toward the landmass we now know as Asia. The story of the Himalaya begins some 200 million years ago, as the supercontinent of Pangea began to split into pieces. ( Find out results from the latest surveys for the height of Mount Everest.) While mysteries remain about the precise steps happening in this continental crash, the collision continues to this day, which is, in part, why Everest’s altitude is always changing. The collision crumpled the landscape, raising mountains along some 1,5000 miles, a range we know as the Himalaya. Rising at the border of Tibet and Nepal, Mount Everest formed from a tectonic smashup between the Indian and Eurasian tectonic plates tens of millions of years ago. In others, they collide, shoving mountains into the sky. In some places, the plates pull apart, creating valleys in the land. These plates continually jockey for position, shaping the array of features visible at the surface. ![]() The rocks arrived at this surprising spot, nearly 30,000 feet above sea level, due to the slow march of tectonic plates, slabs of solid rock that make up our planet’s fractured outer shell. Climbers who make it to the top of Mount Everest may not know it, but under the snowpack sits an expanse of mottled gray rocks that once lay on the ocean floor. ![]()
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