As an environmental science major with a minor in geology and wetlands management, traveling into the field to look at outcrops is something that I look forward to for classes. I’ve hiked on glaciers to see moraines, trudged through 70 mph winds to see sandstone arches and deep canyon valleys, but going to a landfill to see an outcrop was not on my geological outcrop sightseeing to-do list.
The outcrop at the DongYong landfill is a part of the Jinhua Formation and was a previous site for a dinosaur excavation for the local museum a few years prior. Several pterosaur and theropod tracks have been found there too. So with high expectations of enthusiasm for finding something dino-licious-ly cool and stepping on something less than pleasing to the nasal and visual senses I prepare myself for the new discoveries of the day. The bus parks along side the landfill and we students exchange a look and quickly grab our gear which includes cameras, notebooks, pens and rock hammers and queue up to exit the vehicle. While navigating through piles of trash, rocks and the occasional random rusted piece of metal, I think to myself that “it’s a good thing I got my tetanus shot.”
After exploring for a while and getting my bearings I started to examine the more manageable and larger exposed boulders and to my delight saw exposed sedimentary structures of mudcracks, asymmetrical ripples and worm burrows. Looking through more and more rocks I observed a pattern worm burrows on surfaces with mudcracking. This lead me to hypothesize that the paleoenvironment could have included a period of low-energy water-deposited sediment followed by period of drying where worms found it a suitable habitat and then the cracks and burrows filled in with wind-deposited sediment. Overall the amount of preservation of these sedimentary structures indicates a low-energy depositional environment.
Continuing my exploration toward the eroding cliff made up of red alternating layers of mudstone, siltstone, and sandy mudstone with large chunks of rocks ranging from large boulders to small pebbles trailing down into the landfill. I hear in the distance that a dinosaur footprint has been found!
I tediously make my way toward the center of the landfill with my curiosity piqued, but not willing to let my excitement lead to an untimely injury. When I get close I ask Josette who found the track. She replies with a laugh, “Frankie did. A couple of us walked right by this pile of rocks with Frankie following behind and flipping over some of the rocks, getting her hands dirty and she found it!” As it turns out the dinosaur track is a theropod track. Theropods had three toes, were bipedal like birds and along with the sauropods make up the saurischian dinosuars.
I found some tracks too, although they are slightly more of the modern variety and not quite fossilized. -Christi