The stretching of the continents 56 million years ago is likely to have caused one of the most extreme episodes of global warming in Earth’s history, according to new research.
During this time, the planet experienced a temperature increase of 5–8°C (9–14°F), culminating in the Paleocene-Eocene Thermal Maximum (PETM), which lasted around 170,000 years.
It caused the extinction of many deep-sea organisms and reshaped the evolutionary course of life on Earth.
Scientists have studied the effects of global tectonic forces and volcanic eruptions during the period of environmental change nearly 60 million years ago.
They believe that the extensive stretching of continental plates in the northern hemisphere – much like pulling a toffee bar that thins and eventually separates – has massively reduced pressures in the Earth’s deep interior. .
This then led to intense but short-lived melting in the mantle – a layer of sticky molten rock just below the planet’s crust.
The team, including experts from the universities of Southampton, Edinburgh and Leeds, suggest that the resulting volcanic activity coincided with, and likely caused, a massive burst of atmospheric carbon releases linked to the heating of the PETM.
The “stretching” of the continents 56 million years ago is likely to have caused one of the most extreme episodes of global warming in Earth’s history, according to new research. Pictured is a false-colour satellite image of the Faroe Islands – one of the locations studied by scientists
The team studied volcanic ash layers and lavas in the laboratories of the Integrated Ocean Drilling Program (IODP) Bremen Core Repository, Germany.
Scientists have found that intense episodes of volcanism were likely responsible for rapid warming during the Paleocene-Eocene thermal maximum warming event. Pictured is a volcano in Montserrat, West Indies
WHAT WAS THE PALEOCENE-EOCENE THERMAL MAXIMUM?
The Paleocene-Eocene Thermal Maximum (PETM) was a global warming event that occurred approximately 56 million years ago.
During this time, scientists estimate that around 3,000 to 7,000 gigatons of carbon accumulated over a period of 3,000 to 20,000 years.
This caused global temperatures to rise by 5 to 8 degrees Celsius (9 to 14 degrees Fahrenheit), bringing the average to 23 degrees Celsius (73 degrees Fahrenheit).
This caused dramatic changes in the Earth’s climate, driving major organisms to extinction and forcing others to migrate.
Dr Tom Gernon, Associate Professor of Earth Sciences at the University of Southampton and lead author of the study, said: “Despite the importance and wider relevance of PETM for global change today, the underlying cause is much debated.
“It is generally accepted that a sudden and massive release of the greenhouse gas, carbon, from within the Earth must have been the cause of this event, but the magnitude and rate of warming are very difficult to explain by conventional volcanic processes.”
Scientists found evidence in drilled seafloor rock of a 200,000-year-old episode of widespread volcanic activity, which coincided with the PETM.
Using records of rocks drilled beneath the seafloor near the edge of the Atlantic Ocean, the team found evidence of an abrupt and widespread episode of volcanic activity in the North Atlantic Ocean that lasted just over of 200,000 years, surprisingly similar to the duration of the PETM.
This discovery prompted researchers to investigate a larger expanse of the North Atlantic region, including Greenland and the Faroe Islands.
Here they found that kilometer-thick clumps of lava that began erupting just before the PETM show unusual compositions that indicate a significant increase in the amount of melting of the uppermost solid part of the Earth’s mantle. under the continent.
Dr Gernon said this would have led to a rapid increase in carbon release, which would have led to global warming.
Atlantic lava fragments are photographed here under a microscope
The volcanism occurred when the North Atlantic region was in the final stages of rifting, or rifting, in some ways similar to the geological processes occurring today in the East African Rift Valley, illustrated
The intense volcanic activity occurred just as the landmass that united Greenland and Europe was most intensely stretched by plate tectonic forces.
Eventually, North America and Greenland eventually separated from Europe, which led to the birth of the North Atlantic Ocean.
Scientists believe it was this final phase of stretching that caused substantial melting of the Earth’s mantle, leading to a massive release of carbon and, in turn, global warming.
Dr Thea Hincks, lead researcher at the University of Southampton and co-author of the study, said: “Using physically realistic estimates of key features of these volcanic systems, we show that the amount of carbon needed to drive warming could have been achieved by enhanced fusion.
Dr Gernon added: “Such rapid events are causing a fundamental reorganization of the Earth’s surface environment, altering vast ecosystems.”
The study was published in the journal Nature Geoscience.
WHEN WAS THE PALEOCENE AND HOW DID IT AFFECT THE CLIMATE OF GREAT BRITAIN?
The paleoscene (“old recent”) is a geological period that extended from 66 to 56 million years ago.
During this period, the Earth’s climate was up to 15°C (27°F) warmer than it is today.
As a result, tropical and subtropical forests extended further north and would have been widespread in the UK.
Back then, there hadn’t been an ice age for 100 million years.
The distance between Europe and Greenland was one tenth of what it is today.
There was massive volcanic activity between Baffin Island and northwestern Europe that extended as far south as the Bristol Channel.
The shape of the continents was similar to that of today, except that they were arranged differently due to tectonic plates. Britain, Ireland and Norway were all landlocked and the Arctic Sea was almost entirely surrounded by land
Britain, Ireland and Norway were all landlocked, and the Arctic Sea was almost entirely surrounded by land.
The shape of the continents was similar to that of today, except that they were arranged differently due to tectonic plates, according to a website dedicated to the Paleocene.
Many of the world’s most famous geological features would not have been recognizable, including mountain ranges like the Alps and the Himalayas that formed during the Tertiary period.
Before the Paleocene-Eocene Thermal Maximum (PETM) – which occurred about 55 million years ago – non-avian dinosaurs had been extinct for about ten million years.
Early mammals, amphibians, reptiles, insects and flowering plants were the dominant life forms.
Mammals were generally small, had short legs and five toes on each foot.