Thousands of mountains have been discovered under the - TopicsExpress



          

Thousands of mountains have been discovered under the sea; Scientists have generated a new map of the ocean floor using radar satellites, and the results have uncovered some of the ocean’s deepest mysteries. The findings from the new map are published in the journal Science, and provide the clearest picture to date of the plate tectonics that shape the ridges of the ocean floor. The groundbreaking map has revealed never-before-seen volcanoes, lakes, mountains, trenches and even canyons, refuelling scientific discussion over what lies at the bottom of the sea and how our continents formed. This map is twice as accurate as the last map of the ocean floor, which was created nearly 20 years ago, and will help scientists to explore some of the 80 percent of the oceans floor which, incredibly, has never been explored or mapped by humans. In fact, we know more about the topography of Mars than our own ocean. Already the new research has revealed an extinct ridge in the Gulf of Mexico, which was buried deep under layers of sediment about 150 million years ago, as well as the fracture zone where Africa and South America separated. There had been speculation for a long time that a spreading ridge existed in the Gulf of Mexico, but nobody knew where it was because it was buried under deep sediment, one of the studys authors, Dietmar Muller from the University of Sydney, told Stuart Gary over at ABC Science. The maps also show thousands of previously unseen mountains, called seamounts, rising from the ocean floor. These seamounts were once active volcanoes, and they stretch around one kilometer along the sea bed, and reach up to two kilometres high. These elevated seamounts are a hotspot for marine life, and knowing their location can help with conservation management. The kinds of things you can see very clearly are the abyssal hills, the most common landform on the planet,” said David Sandwell, lead author of the study, in a press release. In the past, the ocean floor was mapped by depth sounding using ships, which is very slow and expensive. In this new study, the scientists used data generated from the European Space Agency’s (ESA) CryoSat-2 satellite, which maps the Earths gravitational field, and NASA’s Jason-1 spacecraft, which monitors ocean currents. The two satellites are fitted with radar altimeters that can measure the topography of the ocean using gravity signals. The ocean surface mirrors the Earth’s gravity field - its pulled slightly higher above seamounts, and lower above trenches. After gathering the data, the team used a computer program to generate a marine gravity model that is twice as accurate as the previous map made in 1997. One of the most important uses will be to improve the estimates of seafloor depth in the 80 percent of the oceans that remain uncharted or [where the sea floor] is buried beneath thick sediment, said the researchers in a press release. The new data will greatly help in creating Google’s latest version of ocean maps, and will give scientists information in regards to previously unknown territory. The team hopes to refine the resolution of the model, and explore further with a satellite dedicated to this mission. “The team has developed and proved a powerful new tool for high-resolution exploration of regional seafloor structure and geophysical processes,” said Don Rice, program director of the USs National Science Foundation’s Division of Ocean Sciences, the organisation which funded the research. “This capability will allow us to revisit unsolved questions and to pinpoint where to focus future exploratory work.”
Posted on: Sat, 11 Oct 2014 13:18:04 +0000

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