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.
1 comment:
The Oregeon beaches around and near the sea lion caves are my favorite beaches. I don't know about the "largest" claim, but now if you google "largest sea cave" this post comes up 4th! Wow!
Anyway, nice post on the geology, and good photos inside the cave - they are kind of hard to photograph, I think.
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