21 November 2008

update, of the weekly variety

it's Photo Collage Madness 2008! Click through to our flickr.com page for highlights and more photos.

Gallivanting in Mexico aside, paleontology marches on here at Rancho La Brea. The grid that had been giving us so much trouble two weeks ago has met its match, and its demise:

l to r: Saber-toothed cat humerus, giant ground sloth vertebra, dire wolf skull.
The dire wolf skull had been upside-down in the grid; once we got it out and flipped it over, we discovered that it was heavily grooved and pitted as a result of pit wear. Or, in other words: there's a hole in his head! Observe:

On the left: a dire wolf skull with a gaping hole in his forehead. On the right, our fair leader Kristen (who will hopefully be joining this blog in the near future), forehead still intact. Click through to our flickr site for more close ups (of the dire wolf skull, not Kristen)...

In other news:
-we've measured out approximately 34 bones since Oct 31st.
-we just opened a new deposit: number 10A. Photos forthcoming.
-we've made a great deal of progress in our mapping -- the entire surface of deposit 1 has been sketched and stitched together. Again, photos forthcoming.

17 November 2008

Note from the Lone Male Excavator

Hi all. I'm still here, treading in a sea of tar and estrogen.
In an attempt to be more like Andie, I've decided to put up another post and to start reading occasional comic graphic novels instead of just paleomammalogy and Harry Potter books, as has become the habit. I found this graphic novel of the first 10 comics of "Y, The Last Man" about this guy who ends up being the last man on Earth after all the rest die from something (don't know yet what, but I think it must be something to do with an attack on some phenotype from the Y chromosome, eh?).

Anyway, this guy is left alone in a world full of women, so I thought the series highly appropriate for me. We'll see.
Anyway, pulled this juvenile Smilodon vertebra out the other day (see pic). It is a very confused vertebra; it does not know whether it's an individual vertebra or part of the sacrum. This is a sort of developmental disorder likely caused by genetic problems and not uncommon in Smilodon. You can see (compared to the adult normal vertebra in the pic) that one side of the bone thinks it is a normal vertebra and the other thinks it is part of the sacrum. Furthermore, the neural spine is both off-center and angled wierd. I thought this one was pretty neato, but Michelle is the excavator, excuse me, excavatrix, who is really into pathologies.

This is one of the sweet perks to having such a large collection/set of deposits like Rancho La Brea: not only do we get a clear picture of the complete skeletal morphology of members of our fauna, but we get a very good knowledge of the pathologies which affected them.

Also see below the complete leaf I uncovered yesterday!

14 November 2008

the-past-two-weeksly update: no news is good news

No weekly update last week because we were in beautiful El Golfo de Santa Clara in Sonora, Mexico collecting fossils! We camped in the desert for five days; collected numerous ice age (but older than RLB) fossils; watched many beautiful sunsets; and returned home to the rather sobering realization that excavating at the La Brea Tar Pits for one day leaves one even grimier than camping in the desert (without showering!) for five. Gross, right? Anyway...

This is El Golfo:

And this is us:

From left to right, standing: Laura Tewksbury, Trevor Valle, Robert Predmore, Melody Weaver, Chris Shaw, Michael Wilson, Andie Thomer. Kneeling: Fred Croxen, Aisling Farrell, Ryan Long

El Golfo de Santa Clara is a magical land, where cars glide along the ocean:

And boats wind up on the street:

And fossils are NOT in tar pits! Oh no! They are lying on the ground, for everyone to see! See all the little rocks in the picture below?

A good number of those are actually very small fossils. Geologist Fred Croxen (in the center, with the jaunty hat) is bagging up rocks and dirt from the surface, which will then be sifted through in mesh screens:

and eventually sorted through under a microscope for the same kinds of microfossils that we find here at Rancho La Brea. The fossils from El Golfo are considerably older than those here -- 1 to 1.5 million years old, compared to our measly 10 to 40 thousand -- but nevertheless contain many similar species as our tar pits.

More soon!

03 November 2008

view from the top

Over the weekend, I put together a faux-panorama of the top of Deposit 1. Standing in the northwestern corner of the deposit, I did my very best David Hockney impression and photographed everything I could see from there, and then overlaid the images in Photoshop. Though its not nearly as helpful as a wide-angle photograph would have been, I think this still gives a good idea of what the overall deposit looks like. The fossiliferous grids are (so far) all in the eastern portion of the box; most other grids are sterile (no fossils). If you click on the image above, you'll be taken to our page on flickr.com (where we store all the photos featured on this blog, as well as many others), where you can mouse-over different parts of the photo to read descriptive notes.