Thursday, October 30, 2014

Geo 730: October 30, Day 668: Panoramic Cross Beds

There's quite a lot going on in this photo of the base of Elephant rock at Seal Rock State Park. Directly below the lens cap (52 mm diameter) is a bundle of simple laminar beds, then below that is the featured feature, so to speak, a beautiful set off cross-bedded layers. In that set, below and a bit to the left of the lens cap is an example of soft sediment deformation; I'd call that a ball-and-pillow structure. In that same horizon, but about halfway between directly below the lens cap and the right edge, there's another likely example of ball-and-pillow deformation. These are a little amusing, because in a small way, they mimic the overall structure of the invasive Columbia River Basalt forming the resistant cap of this rock. Finally, on the right side, several minor faults cut through the sequence. The interaction of the left-most of them with the cross-bedding is interesting. I'm trying to get back into the habit of hosting these large panoramas elsewhere, so their size isn't so reduced by Blogger; you can right-click the photo and open it in a new tab for full size gloriosity.

Panorama stitched in HugIn. July 15, 2014. FlashEarth Location.

Wednesday, October 29, 2014

Geo 730: October 29, Day 667: Cross Bedded Astoria Formation

I'm told that the rock here, sediments under Columbia River Basalt of Elephant Rock at Seal Rock State Park, are also Astoria Formation. The tide was out far enough at this point that we could get down to beach level to get a good look at them. I was immediately struck by the terrific cross bedding visible below and to the right of the lens cap. In fact, I need to assemble a series of photos of these beds into a panorama for tomorrow.

Photo unmodified. July 15, 2014. FlashEarth Location.

Geo 730: October 28, Day 666: Seal Rock Sea Shore

Looking along the northward extent of the invasive dike(s) at Seal Rock State Park. There's a tombolo developing on the shoreward side of the large stack to the left. The stack blocks much of the incoming wave energy from the open ocean, which means the area behind it becomes a sediment trap. In this case the sediment is course cobbles and boulders; in other it might be sand. The odd light on the salal (which I mentioned a few days ago) in the foreground is the result of my camera flash, which often goes off unwanted and unneeded when I have it in automatic mode. In this case, I like the effect, though.

Photo unmodified. July 15, 2014. FlashEarth Location.

Geo 730: October 27, Day 665: Muddy Waters

We were quite taken by the visible wave-caused sediment transport from this vantage point. It's particularly obvious as the backwash pushes into the advancing wave. Out of frame to the left is a nice little sea cave Dana and I visited on our first visit to this park, at a much lower tide (direct link to relevant photo).

Photo unmodified. July 15, 2014. FlashEarth Location.

Geo 730: October 26, Day 664: Beverly Beach

Even though the Willamette Valley, about 50 miles inland, is generally in the 80's to low 90's in mid-July, the coast is often foggy, or as here, hazy. And cool. With the wind, it's not unfair to describe it as cold. We're looking to the south, toward Beverly Beach. The graceful bridge near the middle of the shoreline is the pedestrian walkway under Route 101 from the day use/camping areas out to the beach access area. The southern stretch, beginning maybe 150 yards south from the bridge, is chock full of fossil shells (see ~middle part of that post for some examples) as well awesome erosional and weathering patterns.

Photo unmodified. July 15, 2014. FlashEarth Location.