Sunday, 29 May 2011
Thursday, 26 May 2011
Sunday, 22 May 2011
Thursday, 19 May 2011
Thursday, 12 May 2011
BEACHCOMBING PARADISE: FOSSILS OF SOOKE
Sunshine, salt air, the bark of seals and... fossils await for those lucky enough to beach comb the fossiliferous shores near the fishing community of Sooke on Vancouver Islands' southwestern edge. Sooke was originally inhabited by the T'sou-ke, a group related to the Salishan First Nations, who found the mild climate and sea access ideal. A fossil field trip brought me there last summer to explore the tidepools and well preserved marine fossils near the seaside exposures at Muir Creek.
Along the beachfront, you can find blocks of late Oligocene, 20-25 million year old, sandstone full of small gastropods, bivalves and barnacle bits of the Sooke Formation. By the late Oligocene ocean temperatures had cooled to near modern levels and the taxa preserved as fossils bear a strong resemblance to those found living beneath the Strait of Juan de Fuca today.
Mammal material, echinoids, coral, chitin and limpets are also found here but are rare. The largely intertidal assemblage of fossil species, many of which will look familiar as you've seen their modern relatives, tell us that the formation was layed down near shore.
The thickly strewn layers you'll see as big fossiliferous blocks and the lines of fossils you'll notice in the nearby cliffs suggest that they may have been deposited along a strand line. What you're sure to notice is the great ocean view and how easy it is to find something spectacular.
Whether you make a day of it or just a twenty minute luxurious beach stroll, your pockets will be filled with a healthy serving of ancient clam stew!
Wednesday, 11 May 2011
HAIDA GWAII: RING OF FIRE
Located as they are in Canada’s most active earthquake zone, the islands of Haida Gwaii have had their share of shake-ups and scourings. Many of the Islands’ hillsides are scarred by slides and these geologic tales have made their way into the stories of the Haida First Nations who call these islands home. But the rock beneath speaks of an even more violent past.
Very few people know that the rock here holds the key to a catastrophic event from eons ago.
We’ve heard tales and seen images of the cataclysmic damage caused by meteriorites smashing into the Earth’s surface.
Until recently, it was a meteorite impact that was blamed for the worldwide Triassic/Jurassic Mass Extinction. This wholesale dying out of species occurred some 200 million years ago.
New evidence challenges the meteorite theory. Experts now believe that tectonic forces may have caused hundreds of volcanoes around the world to erupt simultaneously. The subsequent showers of volcanic ash would have altered the composition of the atmosphere dramatically and plunged the world into near total darkness for years until it settled from the sky.
The picture painted of the sun flickering fitfully through inky clouds, paling against the torrents of glowing lava, while everywhere life is smothered, poisoned, or starved, rivals the most apocalyptic imaginings of Hollywood or religion. We know from worldwide evidence that the extinction was dramatic and affected upwards of 70% of the world’s biota.
Perhaps counterintuitively, for one might think of water as a refuge from fire, smoke, and lava, it was marine lifeforms that suffered the most.
This is particularly well documented in the rocks at Kennecott Point and Kunga Island.
Radiolarian microfossils, tiny, siliceous, single-celled microrganisms, tell the tale. In the Upper Triassic rocks, which predate the extinction by about 10 million years, radiolarians are preserved in hundreds of forms.
Just above them, in the early Jurassic rock layers laid down about the time of the great die-offs, only a fraction of the previous number of forms are represented. The more recent Jurassic rock shows a rebound of radiolarian diversity, though of course, in different forms, a diversity which continues to flourish and expand in today’s oceans.
