Pit Visit

I promised a report on last week’s College Commons trip to the Page Museum at the Tar Pits, here in Los Angeles. It was an excellent trip. The usual thing I do for blogging these things is, some time later, as time allows, I sit down and do a sort of brain-dump. I tried to do something different this time, and walk on the tour with my Palm Tungsten (yes, really really old technology, I know) and simply write a sort of narrative into it as I went along. Then I combined the uploaded file with the images I took as I went along, and supplemented with some extra sentences here and there. The overall effect should be a sketchier description of the event than I usually do, which may or may not be an improvement given that everybody seems to skim everything these days anyway. (Click on the photos for larger views.) So, here goes:

And so it begins. And it begins well – after a name tag is given out, upon check in for the bus, we are given a little brown paper bag of snacks. Hurrah!

3:39 and we’re off! (We run by the excavations for the Expo line and since it is an elevated bus, I get a nice view of what’s going on for quite a way. Wish I’d had the camera out to make a video for you.)

My colleague David Bottjer, a paleontologist, gives a little run down of the history of the region (both social and paleontological) as we go north on La Brea (appropriately – they are the La Brea Tar Pits… Or given that La Brea means The Tar, they are The Tar Tar Pits…)

4:05 We’re here! Somehow, the little bag of goodies is all empty already. Except for the nice bottle of water they supplied. That is soon gone too. (No I did not eat the Wet Ones…)

4:35 Begin touring – We spend some time wandering the grounds getting information on the overall layout of the region, history of Hancock (yes, form whence the name Hancock Park – the large area of the city familiar to many at least by name – originates) and the space itself. The grounds we are seeing is quite lovely to wander (it’s a little park), even if you don’t go into the museum. I’ve visited it on several occasions on visits to LACMA (also on the grounds here over West), and in evenings and weekends there are often public gatherings of people for festivals, music, fairs, or just hanging out. Some of of them are connected to LACMA events. Next time you come to LACMA, buy and ice-cream and wander outside and take in the scenery.

An interesting fact (one of so many I learned). The asphalt that trapped even the largest of animals can be only a few inches thick. It is not that animals fall into a giant vat of tar and then get swallowed up. Not at all. They just get stuck (see demo machine later).

“Entrapment event”: A mammoth or something gets stuck. It calls out to the rest of the herd. This attracts other animals – perhaps predators, like a sabretooth cat. The predators go in for what looks like an easy meal. Some of them get stuck too. They’re all stuck. They die. Birds that feed on carcasses come down for an easy meal. They get stuck. Flies and other small animals get stuck in their attraction to the site too. Before you know it, you have a perfect package/snapshot of the life that went by, which eventually gets preserved by the tar/asphalt and sits there for 30-40K years to be dug up and studied by scientists, and all because LACMA wants to build a parking lot (well, not really, but you get the point I hope). Excellent.

Large entrapment events maybe took place only once every 15-20 years – you can estimate that from the density of animals found trapped vs the time period over which these finds came from. How come the whole tar region is so tiny? Well, it isn’t really. Two miles or so in all directions you have much of this kind of geology going on.

Several pits all over…Little ones popping up here and there form time to time.

Then we went to see “Project 23”.

“Project 23” came about as a result of digging a new parking structure for LACMA’s extension, very recently. 16 deposits of new material found. Millions of new fossils!! Excavated in 23 landscaping crates. They have excavators (such as Ryan Long and Laura Tewkesbury here) going through with small tools to dig out lots of interesting finds, and put the dirt/tar into containers to be analyzed further.

Smaller animals and plants (the majority of fossils) tell a lot more about the ecology than the big animals. (They’re locals – the big boys and girls are just passing through) Hope to have contrasting periods with nearby Pit 91, the more well-known dig that has been here for decades. Already learned about our regional summer fog… temperatures…

Laura Tewkesbury, telling one of our tour members about something:

They have a blog! Go look and say hi.

Pit 91 entrance:

This “just” in: Jaw of a juvenile American horse!

They also found Zed. A nearly complete mammoth (just part of a leg missing)! 40 years (or so) old. A complete large mammal find is a rare at Rancho La Brea! More later. Zed was not trapped – he just died on a stream bed.

We go inside:

Inside we get to see lots of the assembled display cases. Lots of wonderful things to see:

Among the things to see was a demonstration that it is easy to get trapped by even a shallow pool of the asphalt. You get to pull on the various rods (which end in a flat part representing a foot of an animal – varying sizes) and see how remarkably difficult it is to pull up.

Next, the “fishbowl!” This is the Lab. With transparent walls so that visitors can see them at work.

We get to actually go inside and talk with the scientists. Our host is Trevor Valle. Everything comes here. Zed is here! Lots of him all around us.

…Very unusual in that he was not accompanied by many large others…many mysteries about Zed to be solved…They’ve got so much of him so they can study a real individual. Both tusks… Even a bit of occified cartilage was found. You can see his giant pelvis in the shots… and a huge lower jaw…. Even for a mammoth, Zed was huge. Maybe not as tall as their largest mammoth skeleton, but much sturdier in build this fellow was.

They think Zed was severely ill. Arthritic on left side. Broken ribs… 3 on RHS. All sorts of deformities and abnormalities probably affecting movement, etc… How did he live so long?!!

There is a volunteer program! You can sign up for 3 months in the initial instance. 16 years old minimum!! Go find out more. It would be fun to do!

We then had a lecture from John Harris, the chief curator of the museum that gave us a nice overview (again) and then lots of things we had not heard before. We had heard that for a long time people thought that the bones they were finding were just animals from farms, and so forth. The long tooth of the sabretooth cat seemed to be a bit of a puzzle though! William Denton (1875?) described first fossil in a published journal article. This was largely ignored until later. (Probably not unconnected to the crackpot elements of his work with mediums, related to the spirit world – the bones talked to them apparently.)

Other fragments I learned during the lecture and elsewhere on the tour:

…Bird bones preserved here better than many places. Such bones are hollow, and so often don’t preserve well, but the asphalt tends to coat both inside and out rather well.

…Carnivore trap!! Much larger proportion of them than non-carnivores. Why? Apparently easy pickings – the trapped prey – but then they get stuck themselves. See above on entrapment events.

…1915 Pit 91. 1969 (?) is when they began to look at small things too, and not just the big animals. Began to realize that you can learn so much more about the complete ecosystem from the small critters. Project 23 and related projects exciting for this reason. They think they may have several separate ecosystems (or eras of the same ecosystem, if you see what I mean) as a result of these different samples at different depths and so forth. So much great science of the period going on right under our noses.

…Why did the species extinction happen? 14000-11000 BP Pleistocene. Wood shows plants under carbon (?) stress … Reduce food supply…

We then had a reception, and mingled with each other (USC faculty, students, and staff) munching on tasty things while looking at the exhibits. This was civilized enough to include wine (unusual with events that include undergraduates, so I was grateful for this. This is why ID cards were invented after all.) This gathering, chatting and reflecting on all we saw (and several of the museum staff joined us too) is exactly what the College Commons is supposed to be about. We all owe so many thanks to my colleague (and the College Commons committee chair) Hilary Schor especially for enthusiastically suggesting this event, and Cynthia Gellis and her team for so much of the hands-on organization.

19:30 Exhausted, I head to the nearby corner of Fairfax and Wilshire to catch one of the many buses that can take me on my way. An excellent afternoon and evening, I’d say.

-cvj