Scorelines on the seafloor along North America ’s east coast testify to past upsurges of vast icebergs that scraped along the bottom . Seafloor mathematical function has revealed these lines off southern Florida . Astonished geologists have cover their findings inNature Communicationswith date for when a few of these lines were made and a model of how they could be potential .
The idea of soaring icebergs from the rod to irrigate the deserts were once popular but turned out to be impractically expensive . Not only is there the problem that the deoxyephedrine melts fast once it hits warmer waters , but in the North Atlantic , any such project would be pushing against powerful sea currents , require tremendous fuel purpose .
If it would be a challenge for boats tugging icebergs to push the Gulf Stream all the way to Florida , it ’s heavy to opine them doing so unpowered . Dr Alan Condronof the Woods Hole Oceanographic Institution andDr Jenna Hillof the United States Geological Survey is amply aware of the obstacles to such a journey would makeOdysseus ’s adventurethe Odyssey aspect like span a still pond , but ca n’t disregard what they see .
The grounds is cater by scrapings on the seafloor have sex as scours , left by iceberg lettuce more than 300 metre ( 1000 feet ) thick . These are common in coastal waters in areas where icebergs are unwashed today , but seafloor function has unwrap more than 700 of them in the south of North Carolina .
" The appearance of scours at such low latitudes is highly unexpected not only because of the exceptionally high melt rates in this region , but also because the scours lie in beneath the north flow Gulf Stream . " Condron said in astatement .
Iceberg tumultuous disturbance are cognize as Heinrich event , and glaciologists are sufficiently conversant with them and so have pass them numbers . Condron and Hill collected deposit core from a routine of the south Florida lines and found they were made 31,000 eld ago , from a Heinrich Event 3 .
“ We also ask there are younger and older scour features that halt from other sacking event , given there are hundreds of scour yet to be sampled,”saidHill .
Since icebergs reach out so far south is distinctly impossible under mod condition , Condron explore what could have allowed it . A model of the North Atlantic produced only one scenario , where the iceberg lettuce surfed their way in the south on vast flood of meltwater come from Hudson Bay .
For the process to occur glacier in the region must have been melt tight , but some stop caused cold weewee to establish up behind it . When the dam infract an vast flowage was released into the ocean . " These flood create a cold , fast flowing , southbound coastal flow that carries the icebergs all the way to Florida,“saidCondron . " The model also raise ' scouring ' on the seafloor in the same places as the existent scours . "
finally , the meltwater would have mingle with the warmer , salty ocean around it and been carried north again . In the operation , it would have disrupted the transferral of heat that keepsNorthern Europe inhabitable , but otherwise from if it had go at once into the North Atlantic , a much more studied scenario . There is a possibility such a kerfuffle couldhappen again , based on more continuous thawing of polar ice due to global heating system and that remains alarming .
The more we know about Heinrich events , the considerably we can make our models to assess the current danger .
