Emily Hughes brings us tales of adventure and discovery from the Australian Outback as she and her mother search for unbelievably ancient fossils. Her team digs up the creatures that form the evolutionary boundary between microorganism and animal—the Ediacaran biota.
Get ready to put on your 3D glasses for this one, because Ediacara fossils aren’t flat anymore.
What’s so important about “three-dimensional” fossils? Well, a number of things. As opposed to 3D, 2D fossils are preserved on the bottom of fossil beds. They were squashed by sand layered on top of them, and when we pull out the entire rock bed, they are flattened on top of it. We can only see dimensions of length and width, not height.This photo depicts Jim and me working on the 3D bed. (Photo by Mary Droser)
3D fossils, on the other hand, are preserved within the rock. These fossils were the victims of an avalanche of sand and water, that tumbled over and over, with the fossils caught up in the middle. When we excavate them, the fossils can be a bit torn up, but often are nicely preserved and fabulous to look at. They also have a bit of depth, and therefore provide more information about what they would have actually looked like.
Today, we started (and finished) the long and arduous task of excavating the first 3D-fossil bed of the year. The bed had already been partly excavated, but as you might be able to imagine, it’s still very difficult. This is because, unlike a 2D bed, 3D beds have layers within the same bed of rock. The fossils are preserved within the rocks, so they have a top and a bottom, or a positive side and a negative side. Try to imagine it as a puzzle that you not only need to fit together horizontally, but also vertically, as in finding what pieces fit on top of what pieces. Sounds complicated, right?
Today, we began by trying to fit pieces of float (our word for fossils laying around on the ground, versus in the bed) onto the bed. We fit on a few pieces, and then spent a large amount of time using chalk to outline the way rocks fit together, so that when we put it together again out of the ground, we will have some idea of where they go.
After they were all marked, we took the rocks off layer by layer, piece by piece, and put them into the back of our Polaris. We are out in the valley between mountains, and there’s only a rugged dirt road back to the homestead, so we were very nervous about the rocks flying out the back. However, we solved that problem by securing them with good-old-fashioned rope and canvas.
Lastly, one of our fantastic hosts, Ross Fargher, used his fork lift to move the fossils from the Polaris.
Overall, it’s been a successful and exciting day, and everyone here is looking forward to the new dimension of fossil excavation.