The history of life on Earth has been a rocky one, to say the least, moving in semingly unstoppable cycles of thriving and extinction. Not many species last longer than a few million years before being snuffed out, only to be replaced by new species.
The Circle of Life
Well, researchers from the Institute and Museum of Paleontology at the University of Zurich have added another spoke to this wheel of death – an ecological disaster from the Lower Triassic, unknown until now.
By comparing the prevalence of pollen grains and spores from 400-metre samples of Greenland’s sedimentary layers, the team discovered a massive shift in the kind of plant life that dominated the landscape, where seed ferns and conifer trees were replaced by more hardy spore plants.
This all seems to have happened over a period of a few thousand years which, although it may seem like a long time by human standards, is practically overnight on a geological scale.
This new cataclysm changes our Triassic timeline almost as much as it changed the Triassic plant life.
One of the worst extinction events in Earth’s history happened some 252 million years ago. Cheerily referred to as “The Great Dying”, it marked the end of the Permian and ushered in the Triassic. Scientists have assumed that the environment slowly recovered during the Lower Triassic period that followed.
Approximately 500,000 years after the major natural disaster at the boundary between the Permian and the Triassic another event altered the vegetation fundamentally and for longer © UZH
However, analysis of the carbon isotopes from the sediment samples suggests that this new ecological upheaval happened 500,0000 years later than previously thought.
It’s still a mystery as to what exactly caused it, but Hugo Bucher, Director of UZH’s Institute and Museum of Paleontology, suggests that there is “a link between this previously unknown global event and the enormous volcanic eruptions we know from the Lower Triassic in what’s now Siberia.”
Perhaps that mental image of prehistoric life that many of us had as kids – ash raining from the skies, lava blurting from volcanoes in the background – isn’t too far off after all…
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