Farewell to Deposit 5b

Box 5b is done. We started in early November, and after 8 months there is now an empty spot in front of box 14. The "June gloom" weather during the last days of 5b matched the sadness we felt in knowing that the excitement of 5b would soon be gone. We had a good time discovering its intriguing asphalt infused stratigraphy and cool fossils including:

• Clyde, the partially articulated camel
• Alphie, the juvenile mammoth
• Little Timmy the juvenile coyote
• Pepe the weasle
• and a yet to be named rattlesnake.

The last noticeable fossils in 5b were freshwater snails and plant in asphaltic sediment and the bottom layer consisted of virtually sterile partially asphalt infused greenish gray clay.



Here Laura works with volunteers Cheyenne Robinson and Pat and Mary Simun to extract the last remains of fossils at this level


Michelle joined them for a time out to capture the adoration for our special safety glasses





Volunteer Herb Schiff hammers through the final remains




And then there was none.





Depending on who you ask one highlight of finishing a box is discovering who has been living underneath it. As the final bottom boards were lifted there was an unveiling of slugs, crickets, brown widows, black widows, and some other unidentifiable by me spiders and insects.

Well hello!




Box 14, the large box situated behind 5b and next to box 1 is the next to be opened. It is a partially slumped deposit which means complete measurement of fossils will be limited to what we know is for sure in situ. The idea is to quickly work through the thousands of fossils we will find slumped in the easier to excavate asphaltic "sugar sands" and the area it sits will then be used for bucket storage.

We also look forward to meeting the other half of 5 on the other side of the compound someday hopefully soon to learn more about deposit 5 geology and see if we can find more of Clyde and Alphie.

camelops!

When we last left our heroes:



They were digging away at deposit 5B. And the still are! The deposit has shrunk considerably from its original size, but excavators are still looking for more elements of Clyde, our partially articulated, partially complete Camelops hesternus.

As you may remember from two posts ago, we had most recently exposed his almost perfectly articulated 7th cervical and first thoracic vertebrae, and were pleased to find that his 6th cervical vertebra wasn't too far off:

Here's a closer look; volunteer Henry is holding a clean Camelops hesternus 6th cervical vertebra from our collection for comparison.

1) neural spine -- 2) postzygapophyses -- 3) prezygopophyses -- 4) henry

We have no idea why the 7th cervical and 1st thoracic verts stayed articulated over 10-40k years, while the 6th cervical wandered off a foot and a half to the north. However, we do know that this brings our tally of camel bones from deposit 5b to:

-1 skull

-1 jaw

- 8 thoracic vertebrae

-2 cervical vertebrae

- 1 right humerus

- assorted rib fragments

- 1 camel toe

- and maybe a femur, but we're not sure on that yet

project 23 on 'best of la'

Hey, we're on tv! Again! Video below features Dr. John Harris & Trevor Valle speaking, and Carrie Howard, Meena Madan, and Tara Thara excavating (and Aisling Farrell and myself for approx 2 seconds a piece, which is perfectly a-ok, because being on tv is scary). "Best of LA," check it out (email subscribers -- I think you'll have to click through to actual blog to view, sorry):

EDIT: UGH embed does not seem to be working. Here is link: http://bestoflatv.com/view/1185

why working in a public park is fun.

Little kid questions of the week (both addressed to Carrie):

Small child: "Do you guys ever find anything besides bones in there?"
Carrie: "Like what?"
Small child: "Like weapons??"

I'm sure the kid meant spearheads, but my mind went instantly to a giant ground sloth holding a rifle.

Small child: "Why do they save all the dirt?"
Carrie: "We will look through it for microfossils."
Small child: "Microfossils... ohhhh like ancient germs??"

Now that one, I suppose, depends on what you consider a germ... We do get asphalt-eating bacteria, after all...

One of the most frequent questions we get from park visitors is, "what do you do when it rains?"

clearly, you SMILE ADORABLY like laura

Well, as we've had to do more than once recently, we.... go inside. Despite our dirt-covered faces and tar-stained jeans, we are CIVILIZED after all (although to be fair, if it's only raining a little, and we've got a decent tarp rigged up, at least half the staff will opt to stay outdoors: "it smells nice!").

But this is California: we don't really have weather.

this photo was taken in february; they're smiling because it's 80 degrees out. sorry, everywhere else.

People also ask which is better: digging in the cold, or digging in the heat. After several years of excavatrix-ing, I've become quite the connoisseur of digging conditions. Colder days have their advantages -- the asphalt "freezes" to the point that it chips off in these nice ovoid fragments -- conchoidal fractures, as in flint -- and you can get rid of big chunks of sterile dirt at one time.

And sometimes you find neat stuff in between the fractured pieces:

imprint of an insect wing, photo by the awesome carrie howard

SO MANY MILLIPEDES........

However, cold days mean no detail work -- no dental picking! Which means no working on awesome stuff like these two articulated camel vertebrae (still from Clyde, our camel in 5B):

Cold days, for me, also mean I'm at least 83% more likely to hit my left thumb with my own hammer before 9:30am. But I'm weird.

Warmer days, like I said, mean detail work:

i'm not sure what insect or which part this is, but it's neat

more amazing photos by Carrie

Termite gnaw marks from the Pleistocene -- very cool. The keen-eyed excavator that got them out intact -- possibly cooler (I bet it was Carrie -- apparently this is We Love Carrie week).

So, warm days = melty asphalt and pretty fossils. However, warm days eventually turn into hot days, which eventually turn into oh-my-god-i'm-dying-get-me-an-iced-tea. We've got another 2 months until then, though.

Another keen-eyed excavator (your truly, to tell the truth) spotted a new instance of the family Suidae at Rancho La Brea....

yes, it's a pot-bellied pig. no, it's not george clooney's. damn.

but, alas, not exactly Pleistocene in age...

Monarchs at Pit 91

Volunteer Anna Lopez planted milkweed adjacent to the Pit 91 viewing station to entice monarch butterflies. It has been fascinating and refreshing for us to observe the life cycle of animals that are not dead:

we're back!

Friends, I am torn, because on the one hand, I feel extremely bad for not posting for two months, but on the other hand, it is because we have been busy being amazingly productive paleontologists who do not have time for this new-fangled computer contraption -- we simply have too much dirt, too many bones, too much science. Am I to apologize for progress? I think not. But am I to apologize for poor journalism? Absolutely.

As penance, I humbly offer you easily enough material for three separate posts. Photo heavy, be warned.

From New Year, New Dirt

This, as you may or may not remember (it has been a long time, after all) is a rough map of the Project 23 compound (Pit 91 is the square to the south). We've finished 3 boxes (10A, 10B, and 7B, all x'd out), got half-way through another (7A, put on hold until we can better figure out what to do with it), and are still digging away in deposit 1. Deposit 5B is newly opened. 14 is currently slated to go next. For a better sense of scale, here's a photo of the compound from a couple months ago:

From New Year, New Dirt

And here's a photo from shortly thereafter:

From New Year, New Dirt

Woah! What happened to 5B??? Well I will tell you.

From New Year, New Dirt

We took the sides off! Deposit 5B's box had warped somewhat treacherously from the get-go; its base was damaged in the move from LACMA to here. Rather than working around unweildy boards, we decided to experiment and take all the sides off at once. We hoped this would allow us to get a look at the deposit's stratigraphy straight away, so we can better anticipate where fossils will and will not be. We also hoped that the deposit wouldn't immediately fall apart...

Jack is so proud! From New Year, New Dirt

As you can see in the photo above, we were fortunately (mostly) right on both counts: after removing all the boards, we were greeted by some really neat looking strata, and the block remained largely intact....

Pat Simun wins MVV (most valuable volunteer) From New Year, New Dirt

...after removing some of the looser chunks of earth. If we do this sort of thing again, I think we'll only remove the top half of the wooden crate. That way we'll still see the layers, but with some extra stability.

If only lasers actually worked this well. From New Year, New Dirt

As in other deposits we divided this one up into grids, and are excavating one grid "column" at a time, and creating detailed stratigraphic drawings and lots of photos as we go.

So, as I said, one of the benefits of this excavation method is that we are getting a much better idea of the deposit's geology than we otherwise would, because we're looking at so much of it at one time. The contact between the asphalt and the surrounding silts and clays is much more defined than we've seen in the other deposits from Project 23.

From New Year, New Dirt

And as excavation has progressed, we've found that there are some truly unique and interesting things about this deposit:

1) there are two very distinct layers of asphalt within 5B-- likely from two different venting/entrapment episodes, and possibly thousands of years apart from one another... or maybe only 10 -- we won't know until we start carbon dating things. You can hopefully see them in the photo below -- one near the top surface of the deposit, and on near the bottom.

2) there is a partially articulated CAMEL (Camelops hesternus) skeleton in the top layer! This is huge -- camels are fairly rare in our collections, and articulated skeletons are rarer still.

From New Year, New Dirt

So far we've recovered its humerus:

From New Year, New Dirt

its lower jaw and skull:

From New Year, New Dirt

and about 6-7 thoracic vertebrae:

Kristen's forearms are awesomely recognizable. From New Year, New Dirt

That's the camel's skull up top, and a line of four thoracic verts below. Very exciting.

Meanwhile, in deposit 1, we are still digging away:

From New Year, New Dirt

As I think I've mentioned before, there are several grids worth of broken bones in very hard sediment -- the dirt is harder than the fossils. It's difficult, slow work. We've started taking them out of large bone masses like this:

From New Year, New Dirt

Awful looking, right? However, the strategic breaks made while taking the bone mass out of the ground SHOULD be easier to repair than the accidental ones made while trying to take each individual bone fragment out.

That having been said, after the block has been run through our brand new degreaser...

From New Year, New Dirt

From New Year, New Dirt

From New Year, New Dirt

From New Year, New Dirt

The bones come out looking great. This particular chunk had three dire wolf metapodials in it -- perhaps all from the same wolf paw:

From New Year, New Dirt

Note how little of that matrix is made up of actual dirt -- by and large it's plant and bone material. We're still working the kinks out of our degreasing system: figuring out how best to operate it, how many people we need to run it, how best to sort through the resulting thousands of microfossils...

Well, I suppose that's better than a fork... From New Year, New Dirt

It's frankly overwhelming. We degreased a bucket of bones from the original APRMI salvage of the LACMA parking lot -- it was about 1/4 of the way full, and labeled "spoils" (i.e. not in situ, from pulled out of the ground by a tractor and left off to the side). The results:

From New Year, New Dirt

Thousands of bones. In one 1/4 filled bucket. Eagle beaks, rodent teeth, a bird synsacrum...

From New Year, New Dirt

a complete and perfect weasel dentary...

From New Year, New Dirt

several dozen assorted rabbit, rodent, and bird elements...

From New Year, New Dirt

tarsometatarsi from at least 4 different species of birds...

From New Year, New Dirt

and last but not least a lizard jaw.

And that's just 1 out of 327 spoils buckets, not to mention the who-knows-how-many-hundred matrix buckets scattered throughout the compound...

From New Year, New Dirt

Long story short: there's a lot of work to be done.

So, speaking of working: in the hopes of revitalizing this poor ignored blog, I'm thinking future posts will be faaaar shorter -- like, one photo and a paragraph -- but hopefully far more frequent. That way, you get more posts, and I can spend my Sundays doing Important Weekend Things like cleaning the tar out from my fingernails, getting the tar out from my laundry, and rollerblading (all at the same time? perhaps!), rather than writing about work when I'm not... actually... at... work. Not that I don't love the tar ranch! I just also love Venice Beach.