My plan for the start of summer was originally to leave MT a week from today, and take a five day drive through the Pacific Northwest, and check out several fossil localities I'm currently investigating, and eventually meet my folks up in Tahoe before finally making it back to the SF area for summer (and master's thesis fieldwork).
To make a long story short, I got a phone call from my dept. head, and now I'm TA'ing our Geology Field Camp summer course. It's way awesome on several levels - 1), I finally have a job; 2) its an honor, knowing how much more qualified many of the other candidates are; 3) the same professors who taught the course when I took it are doing it again, which is great; and 4) It was a freaking blast when I took field camp, and had to turn in assignments. Instead, this time around I don't have any assignments to turn in, and have to help students toward the answer (which... I end up doing for free during the school year anyway). And I get to camp and drink beer around a fire and hike all day in the foothills of the Northern Rockies for a month (and in Yellowstone N.P.). Sounds like the perfect job for me!
In any event, now that I have a job 'till the end of June that entails being away from civilization for a week at a time (Awesome!), I won't have internet access. In any event... all of you should be out doing fieldwork by now (that is, if you truly deserve to be reading this!). Bottom line is, there probably won't be many posts in the next month, although if there are, they will probably be from field camp. I still have to post the rest of the pictures of the acid prep 'experiment'.
So get out there and measure some sections, and dig up something up!
perspectives on marine vertebrate paleontology
Saturday, May 16, 2009
Thursday, May 7, 2009
The Tragic Tale Of Nate Murphy, Or How Not To Do Field Paleontology
There is an excellent series of articles on Nate Murphy in the Billings Gazette. Here are the links:
Nate Murphy with the hadrosaur specimen "Roberta" (Brachylophosaurus canadensis)
Murphy's tale is tragic, his downfall fueled by ambition, greed, lies, and theft. He is waiting for sentencing, and faces 5 years in jail. He lied to nearly everyone involved except his own son; lied to landowners, volunteers, coworkers, paleontologists, and the authorities.
Tuesday, May 5, 2009
Acid preparation, Part 1
Over spring break a friend of mine (Ash Poust) found a nearly complete sea lion jaw in a concretion. This was over a spring break road trip, during some reconnaissance fieldwork in coastal Oregon. Below is a photo of the specimen as found.
Photo of the specimen before acid preparation.
Over the last couple years, I've been experimenting with acetic acid for acid preparation. In the case of nodules from the Purisima Formation (material I usually am preparing), acetic acid merely softens the concretion to ease mechanical preparation. Nodules in the Purisima Formation are typically sandstone with calcium carbonate cement (i.e. the nodule is more or less a zone of calcium carbonate cemented sandstone that preferentially weathers out). This specimen appeared to be in a carbonate nodule as well. I figured before I started mechanical preparation of this jaw, I should at least stick it in an acid bath for a couple days. So I left it in a tub over night, and was amazed at what I saw the next morning.
Photo of the specimen after 20 hours of acid preparation.
That may not seem like a lot at first, but if you look closely it is obvious that there is about a 1/2 centimeter of the nodule missing. Unlike specimens from the Purisima Formation, the sand from this nodule simply fell away as the cement dissolved. Purisima nodules tend to stay together during acid prep; a few grains will be shed, but the acid just seems to weaken the outer centimeter of the nodule.
Photo of the specimen before acid preparation.
Photo of the specimen after 20 hours of acid preparation.That may not seem like a lot at first, but if you look closely it is obvious that there is about a 1/2 centimeter of the nodule missing. Unlike specimens from the Purisima Formation, the sand from this nodule simply fell away as the cement dissolved. Purisima nodules tend to stay together during acid prep; a few grains will be shed, but the acid just seems to weaken the outer centimeter of the nodule.
Photo of the specimen after 45 hours of acid preparation.
As of right now, approximately 1/2 of the entire nodule has been dissolved away, and it has used up 2/3 of a gallon of acetic acid (i.e. regular vinegar; costs me about 3$ a gallon). Thus, it looks like I may not really have to lift a finger to get this completely prepared - all I have to do is switch out the vinegar each day (once it stops fizzing), spend another three bucks (I doubt it will require more than another gallon to finish the job) and wait. Which is a good thing, because I have a take-home final exam to finish.
As of right now, approximately 1/2 of the entire nodule has been dissolved away, and it has used up 2/3 of a gallon of acetic acid (i.e. regular vinegar; costs me about 3$ a gallon). Thus, it looks like I may not really have to lift a finger to get this completely prepared - all I have to do is switch out the vinegar each day (once it stops fizzing), spend another three bucks (I doubt it will require more than another gallon to finish the job) and wait. Which is a good thing, because I have a take-home final exam to finish.
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