Dr. Damian Nance
Does Earth have another supercontinent hidden in its geologic history—about 600 million years ago?
“It looks like all hell was breaking loose on Earth, and my guess is that Pannotia is at the center of all these weird and wonderful things that were happening at that time,” says Dr. R. Damian Nance, Distinguished Professor Emeritus of Geological Sciences at Ohio University.
Nance, who “first proposed the concept of a global supercontinent cycle” along with fellow OHIO researcher Tom Worsley, has a new study that “offers a panoply of evidence for an often-overlooked supercontinent thought to have formed after Rodinia and before Pangea, called Pannotia, whose existence has long been in question,” says an article headlined “Piecing together the puzzle of Pannotia” in Earth Magazine.
Earth’s landmasses have joined together into supercontinents and then split apart again as many as six times in the planet’s history. Pangea is the most famous supercontinent, but at least five pre-Pangean supercontinents — Rodinia, Columbia, Kenorland, Ur and Vaalbara — have been widely championed, mainly based on paleomagnetic data. Now, a new study offers a panoply of evidence for an often-overlooked supercontinent thought to have formed after Rodinia and before Pangea, called Pannotia, whose existence has long been in question.
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…“When you assemble a supercontinent and then break it up, you produce all sorts of amazing changes in Earth’s surface systems,” Nance says. The most obvious signs are global episodes of mountain building when continents collide, and large-scale rifting when they separate. Other changes run the gamut from fluctuating ocean chemistry to dramatic climatic changes, including ice ages, to widespread radiations and extinctions in the biosphere as habitats are created and destroyed.
“If we look at changes in sea level, climate and the biosphere during this period between 650 million and 550 million years ago, it’s very similar to what we see when Pangea was forming and splitting up,” Nance says. “It looks like all hell was breaking loose on Earth, and my guess is that Pannotia is at the center of all these weird and wonderful things that were happening at that time.”
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