Tuesday, January 4, 2011

Odontocete skull excavation 2

Around 4 o'clock in the afternoon along the central California coast, the winter sun gets low on the horizon, giving a few minutes of lengthened shadows and rich, golden light, before it disappears behind a fog bank shortly afterward. The resulting decrease in light marks a premature sunset that can be barely workable sometimes. Winter field work is difficult even in California due to the shortened days, extreme tide fluctuations (even worse in Northern California), stormy weather, muddy trails, and low amount of sand on the beach (which results in a decrease in the number of access points and thus, fewer choices in access route). Oh, and not to mention poison oak, which during the winter, lacks its distinctive leaves). In this case, one of our access points was a small canyon which opens up towards the beach; during the winter, the stream fills the landward side of the canyon up with fetid, organic rich water while waves buildup a barrier bar, which dams the creek and forms a nice, disgusting little lagoon. When we arrived at this locality, the creek had pooled up, and was extremely cold as it had still been in the shade when we got there. The creek water hovered just over freezing, and was a good ten degrees colder than the ocean. It was still just as cold when we left; by the time we were done with the jacket, it was twilight. Oddly enough, on our way out, we came across a couple teenagers going down to the beach (the hard way, staying dry, but going up above the water-filled canyon on the side of a cliff) with only their cellphones for light. They must have made it out safely, although I'm not sure how (I never read in the paper about anyone dying out there).

Here's the excavated pit after the pedestal popped out.

Because the fossil-bearing pedestal had already popped off, we had to place the pedestal on a mound of sand to jacket it.

Chris takes burlap strips back to the excavation. I quite like this photo.

Just before we started the jacketing process. You can see in the background where the hole is, and that just a small sliver of the former 'fairweather' beach was left to stand on in order to reach the fossil. Within a few days, this was all gone. The sand surface you see there (where the red jacket is laying) is the higher surface of the beach from over the summer - just a small remnant of it remains. After this sliver is gone, the fossil would have been many feet out of reach above the beach.

A beautiful sunset (and advancing rainclouds) heralded our completion of the excavation.

The odontocete skull is halfway jacketed, and as the temperature begins to drop, our hands were beginning to go numb.

Chris cuts more burlap strips for the second half of the jacket.

Finally! Just before dark, the plaster jacket is completed, and we're ready to lug all the gear and fossils back up the trail.


Mere said...

Hey, are you seriously complaining about working on a beach when the rest of the country is under snow?! :-) Great photos. Good luck with the skull!

Robert Boessenecker said...

Naw, I'm not complaining - there are certain aspects of coastal fieldwork that are unusual and hazardous, and sometimes just kind of a real drag (i.e. tides and the access limits they pose).

The combination of the scenery and the fossils makes it totally worth it, though.