Also a natural history stop

Prisoners Rock is also known as Petroglyph Point and is protected as a small portion of Lava Beds National Monument. The below picture is the western cliff of the tuff cone that reveals numerous wave cut benches that formed when Tule Lake (Modoc Lake) was at a higher level. The Tule Lake basin was filled with water until 1905, after which the lake was drained for agricultural use. Also in the picture is the fence that protects the petroglyphs from being defaced.

There are over 5,000 different petroglyphs that date around 4,500 to 2,500 years ago. So why the petroglyphs at this locations and who completed the rock art? It is believed that the Modoc people used canoes to cross Tule Lake to the island and then complete the petroglyphs unlike other Great Basin rock art. Below are some of my favorite petroglyphs.

Tread lightly if ever visiting Prisoners Rock or

"Someday Kamookumpts will surely wake up and look out over the world he made. He may be angry at how things have changed and bring the water back to cover Tule Lake again, changing the world to be like it was when he first made it."

Tuff Cones!

The photos in today's blog are my traverse on top of Prisoners Rock.

This photo shows some of the palagonitic rock (orange rust color). Palagonite is a hydration and oxidation of volcanic rocks.

This is the view across the entire tuff cone. The vent area is buried somewhere out in the middle.

This is a piece of juvenile lava that was erupted out. When dealing with phreatic eruptions, it sometimes is problematic to determine if the lava erupted is juvenile or non juvenile. A clue is that juvenile lava is very fragile and has a cauliflower texture.

This is a view to the north showing The Peninsula, a bigger tuff cone in the distance.

Here is the entire view of The Peninsula. It is roughly the same age as Prisoners Rock, but once the tuff cone was above lake level, a small lava lake formed and is represented by the small ledge in the left middle of the photo.

It was cold!

Like I said in the previous post, I knew it was going to be cold on my trip and indeed it was! The advanced volcanology class had to arrive at the Devils Homestead flow lookout in Lava Beds National Monument by Saturday noon, which meant me leaving Modesto at 4AM to get to Sacramento by 5:30AM and after we got the van packed, we left Sac State at 6AM. Traveling by Interstate 5 to Weed, because I was map girl and instructed we could not go over the Medicine Lake Highland. Mt. Shasta was beautiful with a fresh covering of snow and surrounded by clouds. MacDougal and Dorris on Highway 97 are unchanged. There wasn't many birds in the Klamath Basin Preserve, but of course it was hunting season, so I would want to be there either! Arriving in Lava Beds around 11AM and not able to find the undergrad volcanology class (we actually did look), we went to the visitor center, but having been an organizer for a conference last fall at Lava Beds I was wanting to wonder around. The biggest change I noticed was that Cave Loop road was closed from sunset to 8AM, but I was so tired, I didn't get to do any lava tubing.

The undergrads found us and they were sent home and our field trip started. We spent the rest of the day at Prisoners Rock (also called Petroglyph Point for thousand of petroglyphs that are present). Prisoners Rock is a tuff cone that formed approximately 270,000 years ago. Types of hydrovolcanic deposits include armored lapilli (second photo), beds dipping 25-40 degrees from the vent area, lithic clasts, juvenile lava, and massive deposits (fourth photo). The third photo is an interesting feature that was unknown to any of us and not described in any papers we had with us.



It was very windy and a little cold, but I could of been warmer because I was only wearing a pair of workout pants. It got in the lower 20's for the night. The weather made me sleep in a tent for the first time in several years and I was glad I bought it. I had three blankets, lots of heat warmers and a nalgene bottle with hot water at the bottom of my sleeping bag. It was the best I had ever slept in cold weather. So I will leave you with a photo of a freshly covered Mt. Shasta from on top of Prisoners Rock.

I will be on the road again this weekend....

but I am going to freeze my behind off! My advanced volcanology class is taking a trip to Lava Beds National Monument-Tule Lake basin area and High Rock Caldera in northwest Nevada. The caldera is suggested to be the oldest volcanic area in the Yellowstone hotspot track, so that basically means it is out in the middle of nowhere and has not been studied very much. I just was checking temperatures, it is going to be a nice warm toasty 50 degrees in the daytime and 20 degrees at night. At least we will have a lot of firewood! The focus of the trip is hydrovolcanism, so I when I get back I hope to post a bunch of interesting photos, that is if we aren't frozen to the Nevadan high desert!