Massive Volcanic Eruption Ignites Coal Seams
About 250 million years ago, about 95 percent of life was wiped out in the sea and 70 percent on land.
Researchers at the University of Calgary believe they have discovered evidence to support massive volcanic
eruptions burnt significant volumes of coal, producing ash clouds that had broad impact on global oceans.
"This could literally be the smoking gun that explains the latest Permian extinction," says Dr. Steve
Grasby, adjunct professor in the U of C's geoscience department and research scientist at Natural Resources Canada.
Grasby and colleagues discovered layers of coal ash in rocks from the extinction boundary in Canada's High
Arctic that give the first direct proof to support this and have published their findings in Nature Geoscience.
Finally an Explanation for Permian Extinctions?
Unlike the end of the dinosaurs, 65 million years ago-where there is widespread belief that the impact of a
meteorite was at least the partial cause-it is unclear what caused the late Permian extinction. Previous
researchers have suggested massive volcanic eruptions through coal beds in Siberia would generate significant
greenhouse gases causing run away global warming.
Coal Fires on Pangea
"Our research is the first to show direct evidence that massive volcanic eruptions-the largest the world
has ever witnessed-caused massive coal combustion thus supporting models for significant generation of greenhouse
gases at this time," says Grasby.
At the time of the extinction, the Earth contained one big land mass, a supercontinent known as Pangaea. The
environment ranged from desert to lush forest. Four-limbed vertebrates were becoming more diverse and among
them were primitive amphibians, early reptiles and synapsids: the group that would, one day, include mammals.
Siberian Traps: 2 Million Square Kilometers
The location of volcanoes, known as the Siberian Traps, are now found in northern Russia, centred around the Siberian
city Tura and also encompass Yakutsk, Noril'sk and Irkutsk. They cover an area just under two-million-square
kilometers, a size greater than that of Europe. The ash plumes from the volcanoes travelled to regions now in
Canada's arctic where coal-ash layers where found.
Grasby studied the formations with Dr. Benoit Beauchamp, a fellow professor in the geosciences department. They
called upon Dr. Hamed Sanei adjunct professor at the U of C and a researcher at NRCan to look at some of peculiar
organic layers they had discovered.
Emissions Similar to Coal-Fired Power Plants
"We saw layers with abundant organic matter and Hamed immediately determined that they were layers of coal-ash,
exactly like that produced by modern coal burning power plants," says Beauchamp.
Sanei adds: "Our discovery provides the first direct confirmation for coal ash during this extinction as it may
not have been recognized before."
Emissions Fueled Already-Heating Oceans
The ash, the authors suggest, may have caused even more trouble for a planet that was already heating up with its
oceans starting to suffocate because of decreasing oxygen levels.
"It was a really bad time on Earth. In addition to these volcanoes causing fires through coal, the ash it spewed
was highly toxic and was released in the land and water, potentially contributing to the worst extinction event in
earth history," says Grasby.
Read the Nature Geoscience article "Catastrophic dispersion of coal fly ash into oceans during the latest Permian
extinction" at: http://www.nature.com/ngeo/index.html.
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| About 250 million years ago intense volcanic eruptions in the area that is now Axel Heiberg Island, Nunavut, Canada ignited subsurface coal deposits that burned intensely. The fires produced enormous amounts of greenhouse gases and ash clouds that had an impact upon global oceans. Image © by Geology.com. |
| The lowest rank of coal is "lignite". It is peat that has been compressed, dewatered and lithified into a rock. It often contains recognizable plant structures. Image © by Geology.com. |
| A highly magnified view of coal in transmitted light. The large yellow object in the center of this image is a spore - a reproductive cell of the coal-forming vegetation. It is about two millimeters long. The spore was probably round before it was compressed with the coal-forming plant debris. The thin red horizontal bands are shreds of well-preserved woody material. The tiny yellow and orange particles are smaller spores and algal debris. The black material is either charcoal or mineral matter. This coal does not contain a lot of well preserved wood. Instead it is mostly charcoal and mineral debris representative of coal that formed under conditions that were not idea for the preservation of plant material. Image © by Geology.com. |
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