Saturday, January 3, 2009

One More From the Coast

As I mentioned in my post on Sea Lion Caves, it was pretty rainy and blustery the day we went over there (two weeks ago today). Below is the view south from the headland into which the cave is eroded.
The N/S fault that formed the major plane of weakness that allowed erosion to create the cave cuts off the stack in the midground. The coastal town of Florence lies somewhere out there in the gloom. Between Florence and the next town to the north, Yachats (pronounced yah-hahts; Oregonians get very touchy about mispronounced place names), lies a beautiful stretch of rocky headlands. These rocks, the Yachats Basalt, are younger than the Siletz River Volcanics that make up most of the Coast Range accreted terrane known as Sileztia. (More on Siletzia at the end of this post) I have never been clear about the origin and age of the Yachats Basalt, but fortunately, my focus in this post is more on the much younger stuff to the south.
The above GoogleEarth image shows fairly clearly the boundary between the basaltic headlands to the north and the dunes southward into Florence. (I have moved the scale bar to the middle of the picture.) Sea Lion Cave is about where the label "Cox Rock" is. This stretch of dunes continues south to Coos Bay, 40 to 45 miles as the crow flies. Some of the dunes rise over 500 feet high, and make for great field trip stops. From a geological perspective, dunes are pretty straightforward (i.e. simple), and for some reason I find them much more interesting when they're lithified. From an ecological and biological perspective, though, they are even more fascinating.
The above photo shows a couple of interesting features: first, there is a constant tension between colonizing plants and moving sand- the two don't play well together. Moving sand swamps and suffocates plants, while plants stabilize the sand and prevent it from moving. I imagine this as a constantly shifting patchwork of green and beige. Second, the flow of sand is fast enough that most smaller streams in this area never reach the ocean. They are impounded behind a wall of sand, then drain out to the ocean as groundwater. In the above case the two small pools have neither inflowing surface water nor outflowing surface water. I'm presuming that during drier periods these basins are excavated and eroded by strong coastal winds and local vortices. During wet periods (as during this trip), the groundwater rises above the ground's surface.
I suspect that the above lake does have an inflowing stream, but drains through the permiable sandy substrate.

Since the sand is dominantly quartz, with the remainder fresh lithic fragments, as soils go the ground is very poor in nutrients. Forest with quite large trees can become established, but only after hundreds of years of succesion, typically going through beach grasses, brushy plants like salal and Oregon grape, and finally young trees, creating and storing enough organic matter that the ground can support a mature forest.In the above picture, the leaves with a "normal" shape are salal. Since standing water prevents the oxidation and decay of organic material, nitrogen tends to be in short supply in wetlands within the dunes. The odd cobra shaped leaves are those of Darlingtonia Californica, a plant that has evolved a surprising set of charateristics to deal with this situation.
A denser patch of the plant that makes it more obvious why its common name is the Cobra Lily. While not venemous like its namesake, it is carnivorous. Unlike the well-known Venus Flytrap, pitcher plant are passive carnivores; they don't actually move to capture their prey. I had been planning to write out the various adaptations they use to do this, but Wikipedia has a photo of the sign from this wayside that explains it as well as I could. The photo linked above is from the article that discusses this small but fascinating break from geologizing along the Oregon Coast- though as I have implied here, the geology plays an important role in creating an environment where the specialized features of this plant allow it to successfully compete with other species.
The crop above is from the lower right of the previous picture, and shows the opening to the interior of one of the pitcher-shaped leaves. The upright leaf in the lower middle shows the lighter spots, or "skylights." These are translucent spots that fool flying insects into trying to fly through the "roof" of the leaf, rather than exiting from the lower opening.

Strategery I Support

Speaking only for myself, geology can be both pleasingly and frustratingly confusing. It's nice to know that anything I don't understand can henceforth be blamed on giant protists. I was tired of blaming God, anyway. (From LOLScience)

The End of the World

And I feel fine? (From Night Deposits)

Which reminds me of another self-created joke I meant to pass on a week ago...
Q: Where does the Earth hang its Christmas Stocking?
A: From the mantle.

Tuesday, December 30, 2008


Dark Roasted Blend posts great stuff. Case in point:

This video was made by morphing between a number of images captured by Hubble, and shows the "light echo" created by a star burst of unknown origin as it illuminates gas and dust progressively further away from the star. You can picture the flash as an expanding shell... the radius expands at the speed of light, so the apparent diameter is expanding at twice the speed of light. As this shell reaches previously dark gas and dust, those clouds are illuminated, and the light then travels to the observer... the Hubble Telescope. Amazing and awe-inspring. A number of other astronomy-oriented pictures on this post.

And as long as I'm mentioning DRB, I got some good giggles from today's post, ridiculous signs. Following are a pair of examples, out of many

Hyperactive Squirrels

I enjoy watching squirrels, but the idea of tree rats hopped up on caffeine is disconcerting, to say the least.
funny pictures of cats with captions
more animals
On the other hand, maybe the reason they behave the way they do is that are always hopped up on caffeine...

Monday, December 29, 2008

Sea Lion Caves

More from our coast trip December 20th. Sea Lion Caves claims that it is recognized by Guinness as the largest sea cave in the world. It is the first hit in a Google search for "Worlds largest sea cave," but numerous other pages don't even mention it. I am very skeptical about commercial claims to any "most extreme" anything, and no less so here. Nevertheless, this is a very impressive sight. Is it worth ten bucks for an elevator ride? I guess my feeling is that when I have visitors, I enjoy taking them here. I wouldn't pay to go by myself, but then I've been down to the cave 5 or 6 times.

The cave is formed primarily along a fault that runs roughly north-south, and cuts through a prominant headland south of Heceta Head, and north of Florence, Oregon. A second fault running roughly east-west cuts into the headland; the intersection of these two faults has allowed wave action to erode out the cave.
The above sea lion was found dead after being shot, on a beach near Newport, Oregon. It was seven feet long. It is displayed in the corridor leading up to the north opening, where the next two pictures were taken.The linear structure is evident here; I suspect that the notch at the end of Heceta Head is where this same fault crosses the headland. Until 1961, this was the main entrance; tourists had to descend about 200 feet of steps. Weathered and storm-tossed lumber from the old staircase is still piled up on the floor of this cove. Now, as I mentioned, there is an elevator that brings visitors directly down into the cave. There is a short outdoor walk from the shop to the elevator, with about 30 or 40 steps, but most of the climb has been eliminated.
Zooming in, from the same spot, looking at the same spot. The notch is clearer, and the Heceta Head Lighthouse can be seen.
The south end, and most of the length, of the cave is fenced off with heavy chain link. Photographers are asked to forego flash pictures to avoid scaring the sea lions, so getting a sharp picture without a tripod is tricky. Remember, those fuzzy brown pinnepeds are five to eight feet long. Whether it's the biggest cave in the world or not, it really is big.
The best shot we got that day. You can see daylight coming into the cave from the left, from the main entrance opened up by the east-west fault, and off in the distance, the south opening. So we are standing basically on the north-south fault, looking south. Also visible is an ashy layer between two slabs of basalt. The ash layer is the third plane of weakness that has allowed this cave to erode out.
It smells overwhelmingly of fish, it's noisy with the sea lions barking and howling, but it's worth a visit. The link back at the beginning of the post provides several other photos, including some nice aerial photos of the outside.

Oregon Coast Aquarium

I enjoy this place, but have never had a chance to photograph it. Actually, these photos were taken by my brother Jonathon and nephew Andrew. From our coast trip Dec. 20.
Crustacea. No scale, but the carapace on that back one is about 18 inches across. This was about where I started commenting that the staff would not like me to be stuck in here over night with a frying pan, a camp stove, and some butter.Cephalapoda. About 6 feet across.
Chrondrichthyes got my brother Jonathon.
Another two primates, Jonathon's sons, Nat (left) and Andrew. From a viewing window inside the fish tank.
Cnidaria- sea nettle. This has long been one of my favorite displays at this aquarium. They are just beautiful, though I gather they can be very painful, even fatal. That's irrelevant when they're on the other side of a thick pane of glass.
Your turn... Do you recognize this critter? I don't think I would have without the label, but I'm not sure. It's the first time I've ever seen a living speciman. Another hint in the comments. Imaginary gold star, and actual admiration, for the first commenter to get it right.