The stretching of the continents 56 million years ago may have caused one of the most extreme episodes of global warming in Earth’s history, new research shows.
During this time, the planet has seen an increase in temperature of 5-8 ° C (9-14 ° F), culminating in the Paleocene-Eocene thermal maximum (PETM), which lasts about 170,000 years.
It caused the extinction of many deep-sea organisms and changed the course of evolution of life on Earth.
Scientists have studied the effects of global tectonic forces and volcanic eruptions during a period of environmental change nearly 60 million years ago.
They believe that the great stretching of the continental plates in the northern hemisphere – more like pulling a toffee bar that thins and eventually separates – significantly reduces the pressure in the deep interior of the Earth.
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, which includes experts from the universities of Southampton, Edinburgh and Leeds, suggested that the resulting volcanic activity coincided and probably caused a massive release of carbon into the atmosphere associated with the warming of PETM.
The “stretching” of the continents 56 million years ago probably caused one of the most extreme episodes of global warming in Earth’s history, new research shows. The photo shows a fake color satellite image of the Faroe Islands – one of the places studied by scientists
The team studies volcanic ash and lava layers in the laboratories of the Integrated Ocean Drilling Program (IODP) core repository in Bremen, Germany
Scientists have found that intense episodes of volcanism are likely responsible for rapid warming during the Paleocene-Eocene thermal maximum warming. Pictured is a volcano in Montserrat, West Indies
WHAT WAS THE PALEOCENE-EOCENE THERMAL MAXIMUM?
The Paleocene-Eocene thermal maximum (PETM) is a global warming that occurred about 56 million years ago.
During this time, scientists have estimated about 3,000 to 7,000 gigatons of carbon accumulated over a period of 3,000 to 20,000 years.
This leads to a jump in global temperatures of 5 to 8 degrees Celsius (9 to 14 degrees Fahrenheit), with the average reaching 23 degrees Celsius (73 degrees Fahrenheit).
This leads to dramatic changes in the Earth’s climate, causing major organisms to become extinct and forcing others to migrate.
Dr Tom Gernon, an associate professor of Earth science 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 root cause is highly debated.
“It is generally accepted that the sudden and massive release of greenhouse gas, carbon, from the Earth’s interior must have caused this event, but the scale and rate of warming are very difficult to explain with conventional volcanic processes.”
Scientists have found evidence from a rock drilled from the seabed of widespread 200,000-year-old episodic volcanic activity that coincides with PETM.
Using archives of rocks drilled under the seabed near the edge of the Atlantic Ocean, the team found evidence of a sharp and widespread episode of volcanic activity in the North Atlantic, lasting just over 200,000 years, strikingly similar to the duration of PETM.
The discovery prompted researchers to explore a wider region of the North Atlantic, including Greenland and the Faroe Islands.
Here, they found that the miles of lava that began to erupt just before PETM showed unusual compositions that showed a significant increase in the amount of melting of the uppermost solid mantle below the continent.
Dr Gernan said that would lead to a rapid increase in carbon emissions, which would lead to global warming.
Fragments of lava from the Atlantic Ocean are depicted here under a microscope
Volcanism originated when the North Atlantic region was in the final stages of rifting or disintegration, in some way similar to the geological processes taking place today in the East African Rift Valley, pictured
Intense volcanic activity occurred just when the continental land that unites Greenland and Europe was most intensely stretched by plate tectonic forces.
Eventually, North America and Greenland finally separated from Europe, leading to the birth of the North Atlantic.
Scientists believe that it is this last phase of stretching that has led to significant melting in the Earth’s mantle, leading to massive carbon sequestration and in turn global warming.
Dr Thea Hinks, a senior fellow at the University of Southampton and co-author of the study, said: “Using physically realistic estimates of the key characteristics of these volcanic systems, we show that the amount of carbon needed for warming could be achieved by enhanced melting.
Dr Gernan added: “Such rapid events are causing a fundamental reorganization of the Earth’s surface environment, changing huge ecosystems.”
The study was published in the journal Nature Geoscience.
WHEN WAS THE PALEOCENE AND HOW DID IT INFLUENCE BRITAIN’S CLIMATE?
The Paleocene (“old recent”) is a geological period that stretches 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 extend further north and would be widespread in the United Kingdom.
At that time there was no ice age of 100 million years.
The distance between Europe and Greenland was one tenth of what it is today.
Between Baffin Island and northwestern Europe, there was a huge volcanic activity that stretched south to the Bristol Canal.
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 landlocked, and the Arctic Sea was almost completely surrounded by land
Britain, Ireland and Norway were landlocked, and the Arctic Sea was almost completely surrounded by land.
The shape of the continents is similar to that of today, except that they are arranged differently due to tectonic plates, according to a website dedicated to the Paleocene.
Most of the world’s most famous geological features would not be recognizable, including mountain ranges such as the Alps and the Himalayas, which formed during the Tertiary period.
Before the Paleocene-Eocene heat peak (PETM) – which occurred about 55 million years ago – non-bird dinosaurs became extinct in about ten million years.
Early mammals, amphibians, reptiles, insects and flowering plants were the dominant life forms.
Mammals are usually small, with short legs and five toes on each foot.
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