Tag: geology

Meghalayan Days

Posted on by Liz Henry

From my years working at the Geology Library at the University of Texas (for Dennis Trombatore, a wonderful person, R.I.P.) I have a smattering of knowledge in the area. Aside from hiding in the stacks reading fascinating and fusty old books (as we all did) I took some classes and then got a bit obsessed with the Roadside Geology series of books when I lived in the Southwest. (Halka Chronic fans unite!)

Someone put a copy of “Rancho La Brea: A Record of Pleistocene Life in California” from 1949 in my little free library so I am plugging through it. It is not telling a compelling story with great writing, but I love it anyway because it is a key to all the knowledge they had at the time, systematically arranged. The book goes through the history of its discovery, the geology and stratigraphy of the area, a catalogue of all the kinds of creatures and plants found, and a beautiful bibliography and index. I have a million questions and became suddenly an absolute hound searching for tar pit facts.

The wild thing you will instantly notice is this is pre “Continental Drift” ie plate tectonics, and pre radiocarbon dating. So everything is relative ages via stratigraphy and who knows how it all happened. (A bit handwavy on how or why the climate changed for example).

People had noticed the bones in the bubbling asphalt but not really grokked that they were not just cows and coyotes and deer but were instead from the Pleistocene. (We now know they were gathering bones from around 50,000 years ago till the present.)

I was wondering what the oldest tar pits are. Still the Pleistocene, though much older than La Brea! The oldest might be the Binagadi Asphalt Lake pits in Azerbajan, at 96–120 thousand years old.

Can you extract DNA from the teeth from the tar pits? Someone has thought of this and written a neat paper! https://pmc.ncbi.nlm.nih.gov/articles/PMC3936381/ (Summary: probably not.)

I remember being a bit disappointed when I heard that the proposal to start a new geologic time division for the Anthropocene (1952 – ) had failed. But I never thought to look at what changes had been accepted! OMG! So many changes! I learned the word “Eonothem“! (And will be looking for some occasion to use it.) So, I learned the more recent eras as the Cenozonic (divided into Paeleocene, Eocene, Oligocene, Miocene, Pliocene) then Quaternary ( Pliestocene, Holocene (now)). Y’all there are so many new stages in the Cenozoic! Is the whole idea of “stages” new? Help! I feel my brain itching to memorize it all. But nowadays I don’t just automatically remember new facts and would have to work at it. (Unlikely).

Anyway, we are now in the Meghalayan Age. In case you were wondering! It started around 4200 years ago, the catchily named 4.2 kiloyear event, which seems to be hotly disputed but which is also very interesting to read about!

Reading older science books can be especially mind expanding. You get a glimpse of the state of knowledge of a particular time that is otherwise hard to grasp. Maybe tomorrow I will go up on the hallway book ladder and get down some old Encyclopedia Brittanica volumes to see if there is an article on the tarpits. I can’t remember if I have the 11th edition or the 12th.

(It is the 11th, in 1911, and Rancho Labrea is mentioned in the Los Angeles entry as containing the Salt Lake Oil Fields – nothing about the tar pits .)

Imagination and reality

Posted on by Liz

You already know what I’m about to say: imagination is part of reality! One thing I love about road trips is poring over the Roadside Geology books for the area I’m visiting and at this point 30 years in I’m pretty familiar with Roadside Geology of Northern California. On this visit to Calistoga I swore to finally go look at “Glass Mountain” roadcut with obsidian bits coming out of it and a bunch of baked rock and ash where the obsidian hit a layer of ash and tuff from volcanic eruptions millions of years ago.

My sister and I got into my car. As we drove down Old Silverado Trail past beautiful wineries and terrifying burnt hillsides I described how I had to unsubscribe from the arrowheads group on reddit because they are often such horrible looters. But then there will be a video of someone looking at the bottom of a stream bed to a jumble of rocks and then bending – zooming in – moving a couple of little rocks and BANG giant clovis point. Dammit! I could just SEE an arrowhead and admire it and NOT LOOT IT, someday, as a treat? But in any case I’d like a little chip of obsidian to bring home and put into a flowerpot as decoration.

The location was described pretty well in the book and in some articles online as north of St. Helena near Glass Mountain Road, showing (color!) photo of the roadcut. The sun was in my eyes but the red baked dirt and rock was super obvious in a small roadcut and there was a spot to pull out pretty close by! Close enough for me to walk to. (We actually stopped at a different cut than the one in this article very close by)

The problem was giant trucks barrelling by and a very narrow shoulder so we scrabbled up a few pieces of obsidian from the roadside gravel and dirt sliding down the face of the cut. Really beautiful conchoidal fracturing and fresh glassy surfaces in the tiny pebbles we picked up! And then fled in about 5 minutes because the trucks were terrifying.

A side jaunt up to Deer Park and back on Glass Mountain road did have some streambeds we could have picked over if we had better long sleeve shirt protection from poison oak, but all really not looking like public property. Then we saw a bunch of signs for Elmhaven, famous house of someone famous, and turned off for it while reading Wikipedia articles about 7th day adventists and Ellen G. White (whose house it was). Apparently she was hit in the face by a rock at age 9 and then had lifelong Visions of angels on other planets (sometimes planets with rings and several moons!) Apparently Satan is just on Earth and other planets are much nicer (I guess; not having read her 40+ books and journals of 2000+ Vision sessions) I love how she gazes ethereally and makes graceful motions as if traveling through space (WHAT DOES THAT LOOK LIKE EXACTLY) and always exclaims “Joy! Joy! Joy!” during, with an echo/receding effect like a song outro)

“‘One evening at the conference above mentioned [Topsham, Maine, 1846], in the house of Mr. Curtis, and in the presence of Elder (Captain) Bates, who was yet undecided in regard to the manifestations, Mrs. White, while in vision, began to talk about the stars, giving a glowing description of the rosy-tinted belts which she saw across the surface of some planet, and added, “I see four moons.” “Oh,” said Elder Bates, “she is viewing Jupiter.” Then, having made motions as though traveling through space, she began giving descriptions of belts and rings in their ever-varying beauty, and said, “I see eight moons.” “She is describing Saturn.” Next came a description of Uranus with his six moons, then a wonderful description of the “opening heavens.”’

So maybe we did not have time to soul-bond and time travel with the red bank of lava contact at the roadcut, but we did get another imaginary journey, even if also not consumnated since visiting hours at the victorian house and gardens started at 10am and it only opened at 11 and I was not gonna sit in the parking lot for an hour when I had to pee.