Scientists discover ancient fossils on Bathurst Island
420-million-year-old plants left an imprint on the rock
Long, long ago — about 420 million years ago to be precise — Nunavut’s Bathurst Island lay at the equator.
Its climate was steamy hot, but the land was almost completely barren as it had only recently emerged from the surrounding water.
“This is the beginning,” said Jim Basinger of the University of Saskatchewan. “It was a planet like none you could imagine.”
The Earth was warm, wet, young and populated by primitive animal and plant life. In this period, which geologists call the Silurian Period, there were no forests. Only tiny plants grew here and there in the wet lowlands.
In these ancient times, some plants were encased in mud and covered with sediment. Over many millions of years, sediment turned to rock, and as the plant tissues trapped inside slowly disappeared, they left an imprint — or fossil memory — on the rock.
Following a tip from geologists with the Geological Survey of Canada, Basinger went to Bathurst Island in 1993 to see whether the island’s rocks contained fossils from that far-off period.
Only a handful of sites around the world have produced plants fossils as old. The poor fossil record leaves paleo-botanists like Basinger, who study ancient plants, with more questions than answers.
“There’s very little known about plants at that time,” Basinger said. “This [Bathurst Island] is such an important location — it didn’t show us the same thing that people have found in other places.”
The fossils from Bathurst Island seem to show a plant world in transformation. The plants are changing, becoming more complex, larger and varied.
The 10 fossil plants from Bathurst Island that Basinger and his colleagues studied are up to 10 centimeters tall, significantly larger than other early plants, which measured only one centimeter.
While it would be many more millions of years before there was anything resembling trees in the area, Basinger said the Bathurst fossils show plants were becoming more complicated by 420 million years ago.
Basinger would like to return to Bathurst Island to see whether more fossils have been exposed by erosion.
“We scoured a hillside about the length of a football field. You could put it all [the fossils] in a shoebox. That’s all there is.”
But Basinger, who has worked extensively at the 45-million-year-old fossil forest on neighbouring Axel Heiberg Island, won’t be returning to the High Arctic this summer: his request for logistical assistance from the Polar Continental Shelf Project was turned down.
However, an article on the study on Bathurst Island’s fossil plants — of which Basinger is one of four authors — was published this week in the American Journal of Botany.
(0) Comments