Wednesday, 20 January 2010

CHUCKANUT FOSSIL TRACKWAYS

Chuckanut Drive is much younger than other parts of Washington. The fossils found there lived and died some 40-55 million years ago, very close to where they are now, but in a much warmer, swampy setting. The exposures of the Chuckanut Formation were once part of a vast river delta. Imagine, if you will, the bayou country of the Lower Mississippi. The siltstones, sandstones, mudstones and conglomerates of the Chuckanut Formation were laid down about 40-54 million years ago during the Eocene epoch, a time of luxuriant plant growth in the subtropical flood plain that covered much of the Pacific Northwest.

This ancient wetland provided ideal conditions to preserve the many trees, shrubs & plants that thrived here. Plants are important in the fossil record because they are more abundant and can give us a lot of information about climate, temperature, the water cycle and humidity of the region. The Chuckanut flora is made up predominantly of plants whose modern relatives live in tropical areas such as Mexico and Central America. If you are interesting in viewing a tropical paradise in your own backyard, look no further than the Chuckanut. Images and tag lines: Glyptostrobus, the Chinese swamp cypress, is perhaps the most common plant found here. Also abundant are fossilized remains of the North American bald cypress, Taxodium; Metasequoia (dawn redwood), Lygodium (climbing fern), large Sabal (palm) and leaves from a variety of broad leaf angiosperm plants such as (witch hazel), Laurus (laurel), Ficus (fig) and Platanus (sycamore), and several other forms.

While less abundant, evidence of the animals that called this ancient swamp home are also found here. Rare bird, reptile, and mammal tracks have been immortalized in the outcrops of the Chuckanut Formation including tracks of Diatryma, a massive flightless bird that reached up to 9 feet in height and made a living in the grasslands and swamps of the Eocene.

Tracks of a type of archaic mammal of the Orders Pantodonta or Dinocerata (blunt foot herbivores), footprints from a small shorebird, and tracks from an early equid or webbed bird track give evidence to the vertebrates that inhabited the swamps, lakes and river ways of the Pacific Northwest 50 million years ago.

WANNERIA DUNNAE

Wanneria dunnaeis an impressive trilobite from British Columbia's Eager Formation, and one of the more striking specimens found at the original research site of the lovely Lisa Bohach, a paleontologist now working out of Alberta.

The site has changed over the years, both physically and politically, but the one constant is the exquisite detail of the specimens. Both Wanneria dunnae and Ollenelus ricei are commonly found here. I had a eureka moment there a few years ago when ambling up the path to the main pit. The sun hit a wily would-be hiking track on a bit of shale at just the right angle. Closer inspection showed it to be a Tuzoia, one of the rare arthropods to come from the area.

Tuesday, 19 January 2010

Tuesday, 12 January 2010

MOONLIT PADDLE

CROCODILIAN UPSTARTS: THE CRUROTARSANS

Dinosaurs, long hailed as the rulers of the Triassic almost lost the title belt to a group of crocodilian upstarts, the crurotarsans. In a short lived battle for survival, geologically speaking, the two groups ran head-to-head for about thirty million years with the Crurotarsi butting their massive skulls and narrow snouts against their evolutionary opponent and ultimate successors, the dinosaurs.

The Crurotarsi or "cross-ankles" as they are affectionately known, are a group of archosaurs - formerly known as Pseudosuchians when paleontologist Paul Serono, the darling of National Geographic, renamed them for their node-based clade in 1991.

LIMESTONE AND SALT AIR: GORDES

Thursday, 7 January 2010

CETACEA: HUMPBACK WHALE

Look at this lovely maternal bond between an adult Humpback whale female, Megaptera novaeangliae, and her young. Humpbacks are a species of baleen whale for whom I hold a special place in my heart. 

Baleens are whales who feed on plankton and other wee oceanic tasties that they consume through their baleens, a specialised filter of keratin that frames their mouths.

There are fifteen species of baleen whales. They inhabit all major oceans, in a wide band running from the Antarctic ice edge to 81°N latitude.

In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest, whales are known as g̱wa̱'ya̱m. Both the California grey and the Humpback whale live on the coast. Only a small number of individuals in First Nation society had the right to harpoon a whale. It was generally only the Chief who was bestowed this great honour. Humpback whales like to feed close to shore and enter the local inlets. Around Vancouver Island and along the coast of British Columbia, this made them a welcome food source as the long days of winter passed into Spring.

Humpback whales are rorquals, members of the Balaenopteridae family that includes the blue, fin, Bryde's, sei and minke whales. The rorquals are believed to have diverged from the other families of the suborder Mysticeti during the middle Miocene. 

While cetaceans were historically thought to have descended from mesonychids— which would place them outside the order Artiodactyla— molecular evidence supports them as a clade of even-toed ungulates — our dear Artiodactyla. Baleen whales split from toothed whales, the Odontoceti, around 34 million years ago.

Tuesday, 5 January 2010

Saturday, 2 January 2010