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Beneath East Antarctica ’s undulating methamphetamine sheet lie an ancient , river - carved landscape that provides a perfect snapshot of the area before glaciers covered the continent , a new subject area finds .
Although most of the kingdom buried under the methamphetamine shroud was eroded over the eons by moving mass of trash , planet data show that a plot adjacent to the Aurora and Schmidt subglacial basins has remained for the most part unscathed for up to 34 million years .
Ice sheets can hide landscapes that have been preserved for millions of years as if frozen in time.
" We could see that there was something like the ghost of the landscape under the icing , " study co - lead authorStewart Jamieson , a prof of geographics at the University of Durham in the U.K. , assure Live Science . " At some point in the past tense , there ’s been rivers flowing over it , which mechanically must mean that it ’s from before the shabu sheet grew . "
Jamieson and his confrere used preexist datum to map out bumps and trough on the ice open mirror changes in aggrandizement in the underlie landscape . These slim slope revealed a " little island of topography " buried 1.2 miles ( 2 kilometre ) below the surface and three " block " of land separated by U - shape valleys , Jamieson say .
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A figure “lifting the lid” of the Antarctic ice sheet and revealing the land beneath. The study location is indicated with the label “Highland A."
The blocks likely imprint a uninterrupted land mass , he said . But when the ancient supercontinent Gondwana , which includedAntarctica , break up during theCretaceousperiod ( 145 million to 66 million age ago ) , architectonic force play may have ripped them asunder . " As part of that pulling away of continents , it ’s plausibly adulterate our landscape and break it up into those three blocks , " Jamieson said .
When the climate cooled following the Cretaceous , ice jacket may have formed on top of each block and carved out valleys as the frosting melted and water trickled down from the peaks . " Those river were believably flowing towards the coast , which is a few hundred kilometers aside , at a time when that coast was open up , " Jamieson said .
The big ice tack that still covers Antarctica today rise around 34 million year ago and smothered the total continent , according to the study , published Tuesday ( Oct. 24 ) in the journalNature Communications .
" on the spur of the moment , that landscape is frozen in meter , " Jamieson pronounce .
But not all of East Antarctica was uphold beneath a gelid cover . In places where the crank grew thickest , the weight that piled onto the land induce melting at the base of the ice sheet , pay rising to a thin level of water . This allowed the deoxyephedrine to grind over the land and gnaw at it over millions of twelvemonth .
In the freshly discover fix , the crank did n’t grow thick enough to create a layer of H2O , Jamieson said . " When you look at the traffic pattern of ice stream in the neighborhood , it ’s sort of going quicker on either side of our landscape . But then on top of our landscape it ’s pass really tardily , and that ’s because it ’s basically frozen to its seam , " he said .
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Whether this landscape painting has stayed completely the same for 34 million years is somewhat unintelligible . point of warming that deglaciated part of East Antarctica until about 14 million year ago may have caused some of the ice above it to dethaw , Jamieson said .
" What would be really challenging is actually die to that location and practise through the ice to get a sample of the rock and sediment underneath , " he said . " That would be the only way we could corroborate the eld . "
at last , empathize what lies beneath the East Antarctic ice sheet will help oneself researchers predict its fluctuations in a warming globe . " We need to understand the form of the landscape so that we can understand why the ice is course the way it does now and how it might react in the future , " Jamieson say .
