![]() ![]() ![]() The water probably got under the seabed in one of two different ways, say the researchers. They estimate that the region holds at least 670 cubic miles of fresh water. If future research shows the aquifer extends further north and south, it would rival the great Ogallala Aquifer, which supplies vital groundwater to eight Great Plains states, from South Dakota to Texas. The consistency of the data from both study areas allowed to the researchers to infer with a high degree of confidence that fresh water sediments continuously span not just New Jersey and much of Massachusetts, but the intervening coasts of Rhode Island, Connecticut and New York. Both methods work in a simple way: salt water is a better conductor of electromagnetic waves than fresh water, so the freshwater stood out as a band of low conductance. Analyses indicated that the deposits are not scattered they are more or less continuous, starting at the shoreline and extending far out within the shallow continental shelf - in some cases, as far as 75 miles. For the most part, they begin at around 600 feet below the ocean floor, and bottom out at about 1,200 feet. An apparatus towed behind the ship also emitted artificial electromagnetic pulses and recorded the same type of reactions from the subseafloor. They dropped receivers to the seafloor to measure electromagnetic fields below, and the degree to which natural disruptions such as solar winds and lightning strikes resonated through them. Langsethmaking measurements off southern New Jersey and the Massachusetts island of Martha’s Vineyard, where scattered drill holes had hit fresh-water-rich sediments.Īn electromagnetic receiver used in the study being deployed off the research vessel Marcus Langseth. Evans of Woods Hole Oceanographic Institution spent 10 days on the Lamont-Doherty research vessel Marcus G. More recently, Key decided to see if some form of the technology could also be used also to find fresh-water deposits. Starting about 20 years ago, study coauthor Kerry Key, now a Lamont-Doherty geophysicist, helped oil companies develop techniques to use electromagnetic imaging of the sub-seafloor to look for oil. The first hints of the aquifer came in the 1970s, when companies drilled off the coastline for oil, but sometimes instead hit fresh water. Drill holes are just pinpricks in the seafloor, and scientists debated whether the water deposits were just isolated pockets or something bigger. “It could turn out to be an important resource in other parts of the world.” The study appears this week in the journal Scientific Reports. candidate at Columbia University’s Lamont-Doherty Earth Observatory. “We knew there was fresh water down there in isolated places, but we did not know the extent or geometry,” said lead author Chloe Gustafson, a PhD. The researchers employed innovative measurements of electromagnetic waves to map the water, which remained invisible to other technologies. The study suggests that such aquifers probably lie off many other coasts worldwide, and could provide desperately needed water for arid areas that are now in danger of running out. If found on the surface, it would create a lake covering some 15,000 square miles. The aquifer stretches from the shore at least from Massachusetts to New Jersey, extending more or less continuously out about 50 miles to the edge of the continental shelf. It appears to be the largest such formation yet found in the world. Northeast coast, scientists have made a surprising discovery: a gigantic aquifer of relatively fresh water trapped in porous sediments lying below the salty ocean. ![]() In a new survey of the sub-seafloor off the U.S. Further out, dark blue, the continental shelf drops off into the Atlantic abyss. Dotted white line near shore shows edge of the glacial ice sheet that melted about 15,000 years ago. Solid yellow or white lines with triangles show ship tracks. Scientists have identified signs of a huge aquifer off the U.S. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |