glacier normally move , well , glacially . However , Greenland ’s Sermeq Kujalleq ( also experience as Jakobshavn Isbræ ) travels at a more rapid rate , make it the huge island ’s firm moving river of methamphetamine hydrochloride . It seems this mellow - speed flow is partially the consequence of a real river , one that in quick times carve out the valley through which Jakobshavn Isbrae now flow .
Some radiocommunication relative frequency pass through ice with simpleness , and NASA has been using this fact tosurvey the bedrockbeneath Greenland . In studying the revealed shapesMichael Cooper , a PhD scholarly person at the University of Bristol , close a huge washbowl debilitate 20 per centum of Greenland ’s sphere .
The discovery follows the “ mega - canyon”discoveredin Greenland ’s north in 2013 .
“ Subglacial topography exerts strong controls on glacier dynamics , tempt the orientation course and velocity of ice menstruum , ” note Cooper and colleagues in a paper print inGeophysical Research Letters .
The basinful drain by Sermeq Kujalleq covers most of southern Greenland . Cooper et al Geophysical Research Letters
" The drainage basin we discovered shows signs of being carved by ancient rivers , prior to the extensive glaciation of Greenland ( i.e. before the Greenland Ice Sheet existed ) , rather than being carve by the movement of ice itself , ” Cooper say in astatement . “ It has been outstandingly well preserved – and has not been erode away by successive glaciation . The transmission channel web has never been seen before by humans – it was last uncovered around 3.8 million years ago . "
The special effect the glacier has had on the preexisting basin is ascribe by the authors to circumstances where Earth’s surface meltwaterreaches the glacier ’s bedor where higher temperatures tolerate increased icing velocity .
The area drained by this single web is 450,000 straightforward kilometers , ( 175,000 straight miles ) , an country equivalent to the Ohio River drain basin , more than twice the size of it of Great Britain . Were they not lay to rest under mountains of meth , canyon 1,400 metre ( 4,590 foot ) deep and 12 kilometers ( 7.5 mile ) astray would be famous holidaymaker attractions .
“ Surface velocity increase by many orders of order of magnitude towards the outlet , ” the paper reports . This is driven in part by increase ice thickness and the convergence of many streams , but the author add , “ it is remarkable to believe that the ancient bed topography has such a marked influence on the location of open speed and methamphetamine moral force , where the flow rate of ice itself is normally get wind as an important command upon fundamentals topography from an erosional standpoint . ”
This rapid flow has mean that the Sermeq Kujalleq accounts for a verylarge proportionof the loss of ice masses from Greenland , defecate it amajor contributorto heighten ocean level .
