In reasonably regular cycle , Earth enters an frappe age , and glaciers spread across the globe . This is normally drive by changes in Earth ’s ambit around the Sun , with predictable fluctuations and “ wobble ” stimulate major changes to how the major planet receives solar energy .
Every now and then , however , dental plate tectonics encounter a major persona in altering the global mood . As novel research published in theProceedings of the National Academy of Sciencesreveals , the creation and devastation of these massive continental and oceanic plate may have been responsible for two ice ages that pass off between 80 and 50 million years ago .
“ Everybody agrees that on geological timescales over hundreds of meg of years , plate tectonic theory assure the mood , but we did n’t know how to connect this , ” Oliver Jagoutz , an associate professor of Earth , Atmospheric and Planetary Sciences ( EAPS ) at the Massachusetts Institute of Technology ( MIT ) and direct author of the study , said in astatement . “ I recall we ’re the first unity to really link large - scale tectonic events to clime change . ”
Plate tectonicsare cerebrate to mold the climate in a diverseness of complex way . If more dry land is generated at higher latitudes , atmospheric and pelagic flow transporting warmth around the major planet are airt . Sunlight - mull glaciers will take form at high latitudes , which will cool the world .
John Rock let on to the airwave also provides asinkfor carbon dioxide . The two react in a process known as “ chemical weathering ; ” atomic number 6 dioxide is taken out of the standard pressure as a outcome , which lead to global cooling . However , an growth in volcanic activity , sire by certain shell tectonic movements , will counter this by unleash carbon dioxide back into the atm .
The two major ocean rock exposure events ( gray-haired shaded ) occur just before the region register as negatively contributing ( absorb more than emitting ) to the world ’s carbon paper dioxide budget . sea temperatures fall as a result . Jagoutz et al./PNAS
Taking all this into story , Jagoutz ’s team used a mannikin , one develop to embolden the move of dental plate for a different study , to simulate the effect of the destruction of the supercontinent ofGondwanaon the globe ’s climate . The simulation was based on ancient rocks excavated from beneath the Himalayas that have geologically preserved the tectonic history of the entire realm .
About 180 million years ago , Gondwana began to break up , and the continental plates we see today began to take frame . Then , 80 million years ago , as Africa continued to move northwards , an overlying pelagic plate was short squeeze upwards , exposing it to the atmosphere , while trim down off the magmatic supplying to a vast range of vent . 30 million age by and by , India clash with Eurasia and another part of this pelagic plate was pushed skywards .
huge quantity of carbon dioxide commence to endure aside at these exhumed oceanic rocks – chemically speaking , the beneficial kind to absorb this banality nursery gas – just as the C dioxide - producing volcano were smothered . Additionally , these exposure occurred in the wet , humid tropics , furnish optimal weathering experimental condition .
Overall , there was a net reduction in C dioxide in the atmosphere on both occasions , which cooled the climate – just enough , the researchers remember , to cause an internal-combustion engine age without the aid of Earth ’s axial wobbling .
Plate tectonics have been implicated in this way before : The break - up of the ancient supercontinent Rodinia around 800 million years ago kick - start the Cryogenian period , where temperature plummet to such a degree that the integral world was essentially a “ snowball . ”
