Friday, August 8, 2008

June 28 - July 4: Part IV

The other thing that points to why things preserve well out here is showcased in this graffiti carved into the sandstone wall behind our hosts’ home. Things don’t weather much here, and a love caught in sandstone almost a hundred years ago still remains.
Look at this! 1917!! Can you believe it?

We were walking out some beautiful views in an area that our hosts had not prospected, when JoAnne came upon bone fragments. When I went to look, it was not just ANY bone, but a large chunk of what appeared to be the limb bone of a small theropod, and even better, TEETH! And they were definitely meat-eating teeth.
Possible theropod bone, and DEFINITE theropod teeth!

Just as we were digesting this find, Tim and Liz hollered from around the corner “BONE! We found BONE, and lots of it!” and then Megan rounded the corner, and she said “I think I found some BONE!” It was pretty exciting, and when we all got to comparing notes, it appeared that we had found a new site, with evidence of at least two dinosaurs!
Look at the variety of different bones weathering out of this site!

There was more and more bone, everywhere we looked. It definitely met Jack’s criteria for a quarry-able site, and our hosts, who had been told that the best material was gone, were pretty excited.

In one area of the site, we found a lot of vertebrae coming down out of the hill. They were quite large, but it was impossible to tell from what we had what kind of dinosaur they were from. As I looked at them, I was surprised to see what appeared to be a small dinosaur, drawn on one of the vertebrae. I thought that someone had gotten to the site before us and that this was some kind of practical joke, but closer inspection showed that it was a secondary mineral deposit on the bone. It is sure suggestive of a fat long necked dinosaur!
Do you see the tiny dinosaur traced in mineral on this bone?

This was a very cool site. The more we looked around, the more we found. And when we dug just a little bit into the ground, we found enough to indicate that more bone was still in there. All in all, would have to say that it was a really great day! We surface-collected a lot of bone for the
landowners, because when this well preserved bone is exposed to weathering, it doesn’t last long. I am not sure what they plan for the rest of the material, but as this is on private land, it is their call.
Uncovering buried bone at the Madsen site, duly recorded by grad student Liz in her field notebook.

Thus ends our longest stint in the field for this year, but I have one more short trip back to our area before I head back to NC. In the meantime, there surely is a lot to get done. I have such a great life! And it is a real treat for me to share some of that with my students, out here on the high prairies of the place I will always love and call home….despite the less pleasant wildlife we sometimes see!

Baby diamondback says ‘see you later!”

Thursday, August 7, 2008

June 28 - July 4: Part III

One of the best things we got to do during this field week was to prospect for bone on land owned by one of the local ranch families. We rely so much on the good graces of the people who surround us, and they are, without fail, incredibly warm and generous. This family went out of their way, taking an entire day to show us where previous finds had been made, and allowed us to look around on our own.

Distant view of some of the land we prospected. Look how green the valley lands, in this dry, high prairie! These bluffs are amazingly productive for dinosaur bone.

It is an incredibly beautiful stretch of land, like a green oasis in the desert. And it is incredibly rich with dinosaur bone, all of which is extremely well preserved. In the company of our hosts, we saw a lot of dinosaur bone, still in the ground, that hinted at the possibility of more bone to come. Jack (Horner) has a minimum criterion of 3 or more bones, in association, of a single animal, before it is deemed a ‘quarry-able’ site. Many that we visited fit this category.

Need a hand to look closely at this bone—the cliff face is steep and slippery.

This one required a hand up from my grad student Tim (handily cropped out of this image to save him embarrassment), but the bone embedded in the hill also looks like it might belong to a theropod, big for this time period, and, if it is a meat eater, probably Albertosaurus. Its dense outer bone and hollow core look more like a theropod than anything else.

The bone is hollow, with a very dense outer layer—this might mean it is a meat eater,on the line of dinosaurs related to birds.

But, the cliff face is steep and slippery, and some of the sand is highly cemented, so quarrying would be difficult. In another area, it looks even more promising, with two bones that I think might be the blade of the ilium, one of the bones making up the hip, and the other possibly the femur of another large dinosaur. The bones are protected by a large, overhanging ledge, again making quarrying a bit risky, but this is pretty exciting, I think.
Under a sandstone overhang are hidden the remains of a dinosaur that may even be articulated! It would take some digging to know for sure.

It is impossible to tell how much of the animal remains in the cliff. But this setting is tailor-made for the kind of work I do, as our work indicates deep burial in sandstone is the best environment for preservation. The views are spectacular. It is fun to be able to share the love that I have for this land with my students and technician. I think they have caught the bug! One of the best things about being a paleontologist is right here—away from office, desk, computer and phones, and out where one can imagine that the land hasn’t really changed all THAT much since these magnificent beasts walked here…

Megan, Liz, Tim and me. Is this a great job or what?

Wednesday, August 6, 2008

June 28 - July 4: Part II

So we had our fun prospecting, and now it is back to the hard work of quarrying. The crew have exposed the bone in the upper quarry and gotten it to the point where we can begin to jacket it. The quarry seems to be running out of bone, and when we get the big jackets out, we will be ready to clean up and focus all the efforts on the lower quarry that is producing some really great stuff. The crew has done a great job of exposing the bones, and they pedestal the blocks so that we can form the jackets around them. As you can see from NCSU student Alex McCall, it is sometimes necessary to be a contortionist to do this job. It’s a good thing we have skinny students.
NCSU student Alex, clearly head over heels enjoying his work!

They finally got it pedestaled, which means that they necked the bottom sediments to make it funnelshaped. Then, because it was such a big block, they made tunnels in the sediment supporting it, so that they could pass 2x4s and plaster strips through them for support. Finally we are ready to add the plaster, which can sometimes be a real mess. If I am involved, I usually wear as much as ends up on the bones…
Jacketing a pelvis is a lot like being in kindergarten!
More plaster on me than the jacket, maybe! Look at all those white hands!!
Like Mickey Mouse with plaster gloves.
At last the bones are top-jacketed and ready to flip. Bob will come and collect all these jackets with Big Red, because it is probably asking too much of grad students to carry them up a 75 degree incline….I don’t know though, maybe we should try?

Tuesday, August 5, 2008

June 28 - Jul 4: Part I

Well, town day was great….I know that after a few days in the field, I will never ever take a shower, or the presence of water in more than bottle-sized containers for granted. But, the sun comes up, and camp stirs and once again it is time to get going. So after a quick breakfast of cold cereal, or maybe a granola bar, we fill water bottles and camelbacks, pack sandwiches for lunch, shoulder into our packs, and cram into the pick up trucks. This morning, the teams split up, because I wanted to prospect to see if I could find a site I’d seen earlier, in a previous summer.

We park the truck and walk across a grass field, crawling up the face of a weathered bluff. A small bird flew out directly from under my feet as I passed a clump of sharp prairie grass, and there, laying on the ground, was a small nest with unhatched eggs. I probably would have stepped on them if the little momma hadn’t given away their presence with her flight. Birds here have a precarious existence. Many are ground birds, meaning that they nest on the bare ground rather than trees. That makes sense, as trees are few and far between in this dry, harsh land, but it sure puts the babies at risk from snakes, foxes, coyotes, and all the other critters equally desperate to eke out a living here.

Hidden nest of the shy prairie ground birds. There are no trees, and their eggs are vulnerable to predators.

I took the high path up the bluff, Megan was walking low, and Ben, recovering from heat exhaustion in the quarry, took off by himself to walk out other outcrops. I came around the corner, and there it was, the quarry I remembered. It had been worked illegally, and bones with commercial value taken while others were left. There were fragments everywhere, indicating the possibility of many bones. There were also still big bones, half exposed to weathering, remaining in the wall.

Possible theropod femur remaining in the wall of an abandoned, and illegal quarry.

It’s a shame, really, this femur is broken and pretty useless at this point, though if they had been recovered correctly, could have contributed significant information about this ecosystem, underprinted beneath our own recent traces of human culture, familiar yet so exotic. Trapped in the gravel beneath this bone there was another femur (thigh bone), larger still, but in much worse shape.

This one might be a hadrosaur, but it is much, much greater in diameter than the above, and resting squarely in a high energy gravel layer.

The above has the hallmarks of a big theropod, probably Albertosaur, the ‘Trex’ of this period of time, but the larger one is probably a duckbill---a BIG duck. Theropods are fairly rare from the Judith River, and the find would have been important if it had been properly taken. But the real find from this abandoned quarry is this small gracile bone that I think is the metatarsal (foot bone) of a smaller meat eater—one that is on the lineage to birds.

Small, gracile bone, probably metatarsal, of a small meateater, maybe an ornithomimid?

It is a beautiful bone, almost complete. This one might be a first, but there is no other evidence at this point for any more of the animal…and this one is not so diagnostic without some additional material. Still, the importance of finds like this is that it documents, at least at some level, the presence of these guys, living together…the first step in understanding the ecosystem and dynamics of this not-well-studied time.