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The discovery of entomb " clay waves " off the coast of western Africa reveals that the Atlantic Ocean was hold at least 4 million years earlier than scientists previously imagine .
These waves , each hundreds of feet high and over half a mi ( 1 kilometer ) long , were due to the mixing of extremely salty water from the southern cerebral hemisphere with less - piquant H2O from the northerly cerebral hemisphere as South America and Africa tore apart 117 million years ago , form the Atlantic , accord to new research release in the June event of the journalGlobal and Planetary Change .
The “mud waves” discovered off the coast of Africa, under the Atlantic Ocean, are hundreds of feet high and almost a mile long.
antecedently , the Atlantic was think to havefinished openingbetween 113 million and perhaps 72 million years ago .
The jumbo wave were determine in sediment cores drilled from 0.6 mile ( 1 km ) below the seabed about 250 miles ( 400 km ) west of Guinea - Bissau in 1975 , as part of theDeep Sea Drilling Project . The ocean - boring labor confirmed that Earth ’s control surface is broken into rafts of ever - moving tectonic plates .
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The mud waves formed when water from the north and south, with very different salinities, were mixed together following the final split of South America and Africa.
In further canvass these cores , Heriot - Watt University geologistsDébora DuarteandUisdean Nicholsonfound evidence of huge mud waves in this neighborhood , which would have been the last spot to pull out aside when Africa and South America split .
" guess one - kilometre - long Wave , a few hundred measure gamey : a whole field formed in one particular location to the Benjamin West of the Guinea Plateau , just at the last ' pinch - point ' of the separating continents of South America and Africa , " Nicholson said in astatement . " They formed because of dense , piquant water cascade out of the fresh formed gateway . "
Before the Atlantic split South America and Africa for honorable , the last link between the two continent would have been a series of deep basins , which were probably lake , Duarte said in the instruction .
Reconstruction of the final stages of the separation of Africa and South America, with a series of basins between the North and South Atlantic.
At that time , the South Atlantic was racy in salt sedimentation that made its water very saline , while the North Atlantic was less piquant . This difference in salinity caused huge currents when the northern and southerly Atlantic waters coalesce . The current , in turn , created the enormous clay waves along the seabed .
Over the eons , more sediment has buried the wafture , lock them below the Earth’s surface .
The being of these wave 117 million twelvemonth ago also suggests that the first step of the Atlantic stimulate Earth ’s climate to warm , Duarte said .
The mud waves were buried beneath sediment over 117 million years, the researchers found.
— Atlantic ocean currents are weakening — and it could make the mood in some region unrecognizable
— Do the Pacific and the Atlantic Oceans mixing ?
— Where do sea current issue forth from ?
The basins that deluge in the final rifting of South America and Africa were rich in carbon paper , and the birth of the ocean would have made the sequestering of carbon less efficient . This reduce efficiency go to a stop of warm up between 117 million and 110 million years ago , the researchers said . After that , the ocean currents that circulate throughout the Atlantic stabilized , leading to a period of time of cooling .
" This shows that the gateway played a really crucial role in global climate alteration , " Duarte said in the affirmation .
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