Around 250 million years ago, most life on Earth was wiped out in an extinction known as the “Great Dying.” A team led by University of Cincinnati geologist Thomas J. Algeo finds that the end came slowly from thousands of centuries of volcanic activity.
The deadliest mass extinction of all took a long time to kill 90 percent of Earth's marine life--and it killed in stages--according to a newly published report.
It shows that mass extinctions need not be sudden events.
Thomas Algeo, a geologist at the University of Cincinnati, and 13 colleagues have produced a high-resolution look at the geology of a Permian-Triassic boundary section on Ellesmere Island in the Canadian Arctic.
Their analysis, published today in the Geological Society of America Bulletin, provides strong evidence that Earth's biggest mass extinction phased in over hundreds of thousands of years.
The Permian–Triassic(P–Tr) extinction event, informally known as the Great Dying,was an extinction eventthat occurred 252.28 Ma (million years) ago, forming the boundary between thePermian and Triassic geologic periods, as well as the Paleozoic and Mesozoiceras. It was the Earth's most severe extinction event, with up to 96% of allmarine species and 70% of terrestrial vertebrate species becoming extinct.
Credit: Wikipedia
Itis the only known mass extinction of insects. Some 57% of all families and 83%of all genera were killed. Because so much biodiversity was lost, the recoveryof life on Earth took significantly longer than after any other extinctionevent. This event has been described as the "mother of all massextinctions.
Credit: C.M. Henderson
A painstakingly detailed investigation shows that mass extinctions need not be sudden events. The deadliest mass extinction of all took a long time to kill 90 percent of Earth’s marine life, and it killed in stages, according to a newly published report.
Credit: Thomas Algeo
Thomas J. Algeo, professor of geology at the University of Cincinnati, worked with 13 co-authors to produce a high-resolution look at the geology of a Permian-Triassic boundary section on Ellesmere Island in the Canadian Arctic. Their analysis, published Feb. 3 in the Geological Society of America Bulletin, provides strong evidence that Earth’s biggest mass extinction phased in over hundreds of thousands of years.
About 252 million years ago, at the end of the Permian period, Earth almost became a lifeless planet. Around 90 percent of all living species disappeared then, in what scientists have called “The Great Dying.” Algeo and colleagues have spent much of the past decade investigating the chemical evidence buried in rocks formed during this major extinction.
Credit: C.M. Henderson
The world revealed by their research is horrific and alien: a devastated landscape, barren of vegetation and scarred by erosion from showers of acid rain, huge “dead zones” in the oceans, and runaway greenhouse warming leading to sizzling temperatures.
The evidence that Algeo and his colleagues are looking at points to massive volcanism in Siberia. A large portion of western Siberia reveals volcanic deposits up to five kilometers (three miles) thick, covering an area equivalent to the continental United States. And the lava flowed where it could most endanger life, through a large coal deposit.
The world revealed by their research is a devastated landscape, barren of vegetation and scarred by erosion from showers of acid rain, huge "dead zones" in the oceans, and runaway greenhouse warming leading to sizzling temperatures.
The evidence that Algeo and his colleagues are looking at points to massive volcanism in Siberia as a factor.
"The scientists relate this extinction to Siberian Traps volcanic eruptions, which likely first affected boreal life through toxic gas and ashes," said H. Richard Lane, program director in the National Science Foundation's (NSF) Division of Earth Sciences, which funded the research.
The Siberian Traps form a large region of volcanic rock in Siberia. The massive eruptive event which formed the traps, one of the largest known volcanic events of the last 500 million years of Earth's geologic history, continued for a million years and spanned the Permian-Triassic boundary.
The term "traps" is derived from the Swedish word for stairs--trappa, or trapp--referring to the step-like hills that form the landscape of the region.
A large portion of western Siberia reveals volcanic deposits up to five kilometers (three miles) thick, covering an area equivalent to the continental United States. The lava flowed where life was most endangered, through a large coal deposit.
"The eruption released lots of methane when it burned through the coal," Algeo said. "Methane is 30 times more effective as a greenhouse gas than carbon dioxide.
"We're not sure how long the greenhouse effect lasted, but it seems to have been tens or hundreds of thousands of years."
Much of the evidence was washed into the ocean, and Algeo and his colleagues look for it among fossilized marine deposits.
“The eruption released lots of methane when it burned through the coal,” he said. “Methane is 30 times more effective as a greenhouse gas than carbon dioxide. We’re not sure how long the greenhouse effect lasted, but it seems to have been tens or hundreds of thousands of years.”
Putorana Plateau, a UNESCO World Heritage Area, contains 500 million years of history.
Credit: Thomas Algeo
A lot of the evidence ended up being washed into the ocean, and it is among fossilized marine deposits that Algeo and his colleagues look for it. Previous investigations have focused on deposits created by a now vanished ocean known as Tethys, a kind of precursor to the Indian Ocean. Those deposits, in South China particularly, record a sudden extinction at the end of the Permian.
“In shallow marine deposits, the latest Permian mass extinction was generally abrupt,” Algeo said. “Based on such observations, it has been widely inferred that the extinction was a globally synchronous event.”
Recent studies are starting to challenge that view.
Algeo and his co-authors focused on rock layers at West Blind Fiord on Ellesmere Island in the Canadian Arctic. That location, at the end of the Permian, would have been a lot closer to the Siberian volcanoes than sites in South China.
Marine biodiversity changed significantly in hundreds of millions of years of Earth history.
Credit: Thomas Algeo
The Canadian sedimentary rock layers are 24 meters (almost 80 feet) thick and cross the Permian-Triassic boundary, including the latest Permian mass extinction horizon. The investigators looked at how the type of rock changed from the bottom to the top of the section. They looked at the chemistry of the rocks. They looked at the fossils contained in the rocks.
They discovered a total die-off of siliceous sponges about 100,000 years earlier than the marinemass extinction event recorded at Tethyan sites. Chemical clues, Algeo said, confirm that life on land was in crisis. Dying plants and eroding soil were being flushed into the ocean where the over-abundant nutrients led to a microbial feeding frenzy and the removal of oxygen – and life – from the late Permian ocean.
Credit: C.M. Henderson
Previous investigations have focused on deposits created by a now vanished ocean known as Tethys, a precursor to the Indian Ocean. Those deposits, in South China particularly, record a sudden extinction at the end of the Permian.
"In shallow marine deposits, the latest Permian mass extinction was generally abrupt," Algeo said. "Based on such observations, it has been widely inferred that the extinction was a globally synchronous event."
Recent studies are starting to challenge that view.
Algeo and co-authors focused on rock layers at West Blind Fiord on Ellesmere Island in the Canadian Arctic.
That location, at the end of the Permian, would have been much closer to the Siberian volcanoes than sites in South China.
The Canadian sedimentary rock layers are 24 meters (almost 80 feet) thick and cross the Permian-Triassic boundary, including the latest Permian mass extinction horizon.
The investigators looked at how the type of rock changed from the bottom to the top. They looked at the chemistry of the rocks and at the fossils contained in the rocks.
They discovered a total die-off of siliceous sponges about 100,000 years earlier than the marine mass extinction event recorded at Tethyan sites.
What appears to have happened, according to Algeo and his colleagues, is that the effects of early Siberian volcanic activity, such as toxic gases and ash, were confined to the northern latitudes. Only after the eruptions were in full swing did the effects reach the tropical latitudes of the Tethys Ocean.
The research was also supported by the Canadian Natural Sciences and Engineering Research Council and the National Aeronautics and Space Administration Exobiology Program.
In addition to Algeo, co-authors of the paper are: Charles Henderson, University of Calgary; Brooks Ellwood, Louisiana State University; Harry Rowe, University of Texas at Arlington; Erika Elswick, Indiana University, Bloomington; Steven Bates and Timothy Lyons, University of California, Riverside; James Hower, University of Kentucky; Christina Smith and Barry Maynard, University of Cincinnati; Lindsay Hays and Roger Summons, Massachusetts Institute of Technology; James Fulton, Woods Hole Oceanographic Institution; and Katherine Freeman, Pennsylvania State University.
The research was supported by the National Science Foundation, Canadian Natural Sciences and Engineering Research Council and the National Aeronautics and Space Administration Exobiology Program.
Contacts and sources:
The deadliest mass extinction of all took a long time to kill 90 percent of Earth's marine life--and it killed in stages--according to a newly published report.
It shows that mass extinctions need not be sudden events.
Thomas Algeo, a geologist at the University of Cincinnati, and 13 colleagues have produced a high-resolution look at the geology of a Permian-Triassic boundary section on Ellesmere Island in the Canadian Arctic.
Their analysis, published today in the Geological Society of America Bulletin, provides strong evidence that Earth's biggest mass extinction phased in over hundreds of thousands of years.
The Permian–Triassic(P–Tr) extinction event, informally known as the Great Dying,was an extinction eventthat occurred 252.28 Ma (million years) ago, forming the boundary between thePermian and Triassic geologic periods, as well as the Paleozoic and Mesozoiceras. It was the Earth's most severe extinction event, with up to 96% of allmarine species and 70% of terrestrial vertebrate species becoming extinct.
The world around the time of the P–Tr extinction.
Credit: Wikipedia
Itis the only known mass extinction of insects. Some 57% of all families and 83%of all genera were killed. Because so much biodiversity was lost, the recoveryof life on Earth took significantly longer than after any other extinctionevent. This event has been described as the "mother of all massextinctions.
The geology of Griesbach Creek in the Arctic tells an ancient tale of slow extinction.
A painstakingly detailed investigation shows that mass extinctions need not be sudden events. The deadliest mass extinction of all took a long time to kill 90 percent of Earth’s marine life, and it killed in stages, according to a newly published report.
Paleogeography during the Permian-Triassic boundary extinction 252 million years ago.
Credit: Thomas Algeo
Thomas J. Algeo, professor of geology at the University of Cincinnati, worked with 13 co-authors to produce a high-resolution look at the geology of a Permian-Triassic boundary section on Ellesmere Island in the Canadian Arctic. Their analysis, published Feb. 3 in the Geological Society of America Bulletin, provides strong evidence that Earth’s biggest mass extinction phased in over hundreds of thousands of years.
Thomas J. Algeo
Credit: University of Cincinnati
About 252 million years ago, at the end of the Permian period, Earth almost became a lifeless planet. Around 90 percent of all living species disappeared then, in what scientists have called “The Great Dying.” Algeo and colleagues have spent much of the past decade investigating the chemical evidence buried in rocks formed during this major extinction.
The barren arctic landscape of Ellesmere Island was the site of the scientists' research.
Credit: C.M. Henderson
The world revealed by their research is horrific and alien: a devastated landscape, barren of vegetation and scarred by erosion from showers of acid rain, huge “dead zones” in the oceans, and runaway greenhouse warming leading to sizzling temperatures.
The evidence that Algeo and his colleagues are looking at points to massive volcanism in Siberia. A large portion of western Siberia reveals volcanic deposits up to five kilometers (three miles) thick, covering an area equivalent to the continental United States. And the lava flowed where it could most endanger life, through a large coal deposit.
The world revealed by their research is a devastated landscape, barren of vegetation and scarred by erosion from showers of acid rain, huge "dead zones" in the oceans, and runaway greenhouse warming leading to sizzling temperatures.
The evidence that Algeo and his colleagues are looking at points to massive volcanism in Siberia as a factor.
"The scientists relate this extinction to Siberian Traps volcanic eruptions, which likely first affected boreal life through toxic gas and ashes," said H. Richard Lane, program director in the National Science Foundation's (NSF) Division of Earth Sciences, which funded the research.
The Siberian Traps form a large region of volcanic rock in Siberia. The massive eruptive event which formed the traps, one of the largest known volcanic events of the last 500 million years of Earth's geologic history, continued for a million years and spanned the Permian-Triassic boundary.
The term "traps" is derived from the Swedish word for stairs--trappa, or trapp--referring to the step-like hills that form the landscape of the region.
A large portion of western Siberia reveals volcanic deposits up to five kilometers (three miles) thick, covering an area equivalent to the continental United States. The lava flowed where life was most endangered, through a large coal deposit.
"The eruption released lots of methane when it burned through the coal," Algeo said. "Methane is 30 times more effective as a greenhouse gas than carbon dioxide.
"We're not sure how long the greenhouse effect lasted, but it seems to have been tens or hundreds of thousands of years."
Much of the evidence was washed into the ocean, and Algeo and his colleagues look for it among fossilized marine deposits.
“The eruption released lots of methane when it burned through the coal,” he said. “Methane is 30 times more effective as a greenhouse gas than carbon dioxide. We’re not sure how long the greenhouse effect lasted, but it seems to have been tens or hundreds of thousands of years.”
Putorana Plateau, a UNESCO World Heritage Area, contains 500 million years of history.
Credit: Thomas Algeo
A lot of the evidence ended up being washed into the ocean, and it is among fossilized marine deposits that Algeo and his colleagues look for it. Previous investigations have focused on deposits created by a now vanished ocean known as Tethys, a kind of precursor to the Indian Ocean. Those deposits, in South China particularly, record a sudden extinction at the end of the Permian.
“In shallow marine deposits, the latest Permian mass extinction was generally abrupt,” Algeo said. “Based on such observations, it has been widely inferred that the extinction was a globally synchronous event.”
Recent studies are starting to challenge that view.
Algeo and his co-authors focused on rock layers at West Blind Fiord on Ellesmere Island in the Canadian Arctic. That location, at the end of the Permian, would have been a lot closer to the Siberian volcanoes than sites in South China.
Marine biodiversity changed significantly in hundreds of millions of years of Earth history.
Credit: Thomas Algeo
The Canadian sedimentary rock layers are 24 meters (almost 80 feet) thick and cross the Permian-Triassic boundary, including the latest Permian mass extinction horizon. The investigators looked at how the type of rock changed from the bottom to the top of the section. They looked at the chemistry of the rocks. They looked at the fossils contained in the rocks.
They discovered a total die-off of siliceous sponges about 100,000 years earlier than the marinemass extinction event recorded at Tethyan sites. Chemical clues, Algeo said, confirm that life on land was in crisis. Dying plants and eroding soil were being flushed into the ocean where the over-abundant nutrients led to a microbial feeding frenzy and the removal of oxygen – and life – from the late Permian ocean.
Close-up of the geologists' West Blind Fiord, Ellesmere Island, Canada, study site.
Previous investigations have focused on deposits created by a now vanished ocean known as Tethys, a precursor to the Indian Ocean. Those deposits, in South China particularly, record a sudden extinction at the end of the Permian.
"In shallow marine deposits, the latest Permian mass extinction was generally abrupt," Algeo said. "Based on such observations, it has been widely inferred that the extinction was a globally synchronous event."
Recent studies are starting to challenge that view.
Algeo and co-authors focused on rock layers at West Blind Fiord on Ellesmere Island in the Canadian Arctic.
That location, at the end of the Permian, would have been much closer to the Siberian volcanoes than sites in South China.
The Canadian sedimentary rock layers are 24 meters (almost 80 feet) thick and cross the Permian-Triassic boundary, including the latest Permian mass extinction horizon.
The investigators looked at how the type of rock changed from the bottom to the top. They looked at the chemistry of the rocks and at the fossils contained in the rocks.
They discovered a total die-off of siliceous sponges about 100,000 years earlier than the marine mass extinction event recorded at Tethyan sites.
What appears to have happened, according to Algeo and his colleagues, is that the effects of early Siberian volcanic activity, such as toxic gases and ash, were confined to the northern latitudes. Only after the eruptions were in full swing did the effects reach the tropical latitudes of the Tethys Ocean.
The research was also supported by the Canadian Natural Sciences and Engineering Research Council and the National Aeronautics and Space Administration Exobiology Program.
In addition to Algeo, co-authors of the paper are: Charles Henderson, University of Calgary; Brooks Ellwood, Louisiana State University; Harry Rowe, University of Texas at Arlington; Erika Elswick, Indiana University, Bloomington; Steven Bates and Timothy Lyons, University of California, Riverside; James Hower, University of Kentucky; Christina Smith and Barry Maynard, University of Cincinnati; Lindsay Hays and Roger Summons, Massachusetts Institute of Technology; James Fulton, Woods Hole Oceanographic Institution; and Katherine Freeman, Pennsylvania State University.
The research was supported by the National Science Foundation, Canadian Natural Sciences and Engineering Research Council and the National Aeronautics and Space Administration Exobiology Program.
0 comments:
Post a Comment