Just because a bunch of German, French and British people invented geology some 200 or more years ago, all the "type locations" for the geological column have been defined in terms of Northern Hemisphere locations. Finally, though, we Australians have our own period, and it's a doozy - the earliest period in which multicellular life forms are recorded, before the Cambrian, from 542 to 635 million years ago.
For a while now, people have talked about the Vendian, but this wasn't an official name, and was based on a locale in Russia that could only be got to for a month or so a year, so the International Union of Geological Sciences has declared this the Ediacaran Period. A good article on the biota and geology is available from the AusGEO News.
Just recently, while I was travelling, Catalyst did a story on it, featuring my friend and Ediacaran specialist Chris Nedin, along with Jim Gehling of the South Australia Museum (which has one of the largest fossils of Dickensonia, a flat bilateral "worm" about the size of a kid's pool). And it was where Chris took a bunch of us Evotees to visit before the "gold spike" (not actually gold, which is a pity because I intended to go back there and steal it), or Global Stratotype Section and Point (GSSP), was installed.
One of the intriguing fossils from that site is a possible early chordate, though Chris thinks it's a frond animal. The molecular data have pushed the earliest dates for many metazoan "phyla" into the Ediacaran period, and these fossils, though hard on morphological grounds to assign to modern phyla, indicate that a lot of evolution was going on before hard parts that fossilise well evolved. See a discussion here (PDF, 256k). If it's a chordate, it may very well be part of the earliest group of which our ancestors were a species, undercutting the "uniqueness" of the so-called "Cambrian explosion" of which Gould wrote so well in Wonderful Life.
All hail this triumph of the South over the North!
Late note: Chris tells me he has now seen more than one of these protochordates and that he thinks it probably is just that.
Stumble It!
Comments
Cool. It's just a pity the "Light Switch" theory seems to be fucked.
Posted by: Alex | November 20, 2006 5:52 AM
Not fucked, exactly. Just deflated somewhat.
Posted by: John Wilkins | November 20, 2006 7:01 AM
But in your diagram, you have 'Edicaran', with one less 'a'. Worse, the larger diagram it links to has 'Vendian' .
Could you please fix?
JSW: fixed. The image I link to has the old terminology
Posted by: llewelly | November 20, 2006 11:36 AM
Does this mean the world was upsidedown during the Edicaran period?
Posted by: AndyS | November 20, 2006 6:53 PM
No, it means the world was right side up during the Ediacaran.
Posted by: John Wilkins | November 20, 2006 6:55 PM
Australians branded 'anti-intellectual'
Posted by: Mustafa Mond, FCD | November 20, 2006 7:24 PM
Nothing new. Trying growing up in the suburbs and having a lifelong love of learning...
But I doubt this differs much from the American experience. Or the British, for that matter.
Posted by: John Wilkins | November 20, 2006 9:13 PM
Shame on you! It's not like the Russians had geological periods to spare. Why not take one from the Brits instead? :)
Posted by: windy | November 21, 2006 6:38 PM