A volcanic crater off the west coast of Africa is considered potential to be from an asteroid impingement around the time of the much largerChicxulub Crater , responsible for the extinction of the non - avian dinosaurs . The scientist who made the discovery notice further ratification is postulate , but raise the opening of a two-fold - smasher , do by an asteroid that had previously separate .
Fewer than 10 percent of the shock crater we know of are on the ocean floor . More rapid recycling of pelagic freshness explains part of this , but the main understanding is we just have n’t looked that severely .
seismal reflection work of the Atlantic floor cull up a body structure at least 8.5 kilometers ( 5.3 mile ) wide buried beneath 300 - 400 meters ( 984 - 1,312 feet ) of sediment . In the journalScience Advances , the volcanic crater ’s discoverer make the case it is an impact crater that date to within a million days – and perchance within a few minutes – of the end of the Cretaceous .
The site of the Nadir crater off the coast of Guinea; Image CreditL Nicholson et al. Data courtesy of the Republic of Guinea and TGS.
The newly attain volcanic crater dwell on the Guinea Plateau , and has been named Nadir after a seamount 100 kilometer ( 62 miles ) to the south . Not all Crater are from encroachment from infinite . However , the generator show Nadir ’s location , cardinal peak and size - to - stature proportion are not consistent with alternative account such as volcanic flop or salt climb-down .
therefore , they argue the most probable explanation is an asteroid ( or perhapscomet ) around 400 meters ( 1,300 feet ) across landing in 800 - meter ( 2,625 - foot ) bass water .
We eff the Earth suffers impact of this sizing more than once every million years , but the timing is striking . aqueous deepness place its years very close to that of Chicxulub .
The discovery was made almost by chance . Dr Uisdean Nicholsonof Heriot - Watt University was doing a research undertaking on seafloor spreading when he noticed something odd . " I ’ve interpreted lots of seismal data point in my clock time , but had never seen anything like this . Instead of the flat sedimentary sequence I was wait on the plateau , I found an 8.5 - kilometer depression under the seabed , with very strange characteristic , " Nicholsonsaid .
Drilling at the internet site could settle the question of whether Nadir is an impact volcanic crater , and add precision to its dating . In the lag , the generator discuss the implications if their judgment is right .
The impact ; “ Would have generated a tsunami over 3,000 feet high , as well as an earthquake of more than order of magnitude 6.5 , " saidDr Veronica Brayof the University of Arizona in astatement . She added the impactor was believably similar in size of it toBennu , which could one dayhit the Earth .
The authors acknowledge it is potential the two impacts are sheer coincidence , unrelated objects striking close enough in time that we ca n’t tell them .
Alternatively , however , we might have been attain by a binary asteroid , perhaps form through a previous hit with a smaller object or when a cheeseparing encounter with a planet ’s somberness split it in two . Such asteroids are coarse in place , but the paper notes only 2 - 4 percent of know impact craters are binary body structure , although inquisitively the figure seems to be 14 percent on Venus .
A more complex scenario would be some major event in the asteroid belt affecting many space rock-and-roll so that many of them left unchanging orbits and entered the inner solar system . Most would have terminate their days crash into the Sun or an internal planet – if the numbers were sufficient , we might anticipate several to hit Earth over a million years or so . Perhaps some give the dinosaurs a admonition they were unable to heed or added an redundant blow to the main impact ’s few survivor . We sleep together something alike happened during theOrdovician earned run average .
“ If we have found one ' sibling ' to Chicxulub , it opens the question : Are there others ? ” Braywondered .
