Outside The Interzone: Feb 15, 2015

Saturday, February 21, 2015

Geo 1095: February 21, Day 782: Splash!

In a move borne of sheer, dumb luck, I happened to take this shot just after a droplet of water hit the little depression in the top of the stalagmite near the center of the photo. The resultant splash can be seen above and to the left of that small bowl. I'm not sure about this, but it looks as if the little dip in the top of the stalagmite is the result of dissolution of the calcite making it up. In other words, it looks as if this speleothem has seen a reversal from calcite deposition to calcite erosion. This would not be a terribly surprising or unusual event over the history of such a cave. The chemistry of groundwater such as this is delicately hinged on its pH, which in turn is highly dependent upon and sensitive to the chemistry of the air and materials it passes through on its journey from the surface to its reemergence in the open air of the cavern. As a leading and scaffolding question, what do you know (or, what would you expect or guess) about the concentration of CO2 in soil air versus its concentration in open air?

Photo unmodified. May 9, 2013. FlashEarth Location. (Since we're underground, I have only a vague idea where this is with respect to the surface.)

Friday, February 20, 2015

Geo 1095: February 20, Day 781: Humpty Dumpty

Like Humpty Dumpty, this (now dry) set of pool terraces was as delicate as eggshells. Unlike Humpty Dumpty, it didn't fall off a wall, but rather was trampled by tour groups earlier in the cave's history. You can't see that from the trail now, because happily, also unlike Humpty Dumpty, Park employees, such as internet geology friend @helenasrox and her mother, were able to painstakingly piece it back together again. Somehow, this makes me feel like the hundreds of hours I've spent with jigsaw puzzles weren't entirely wasted.

Photo unmodified. May 9, 2013. FlashEarth Location. (Since we're underground, I have only a vague idea where this is with respect to the surface.)

Thursday, February 19, 2015

Geo 1095: February 19, Day 780: Goin' to the Chapel

Joaquin Miller's Chapel (page 19), to be more precise. I know I've seen photos of marriages being conducted in Oregon Caves, historically, but I don't know whether private reservations of that type are still available. In terms of geology, there's a nice example of a stalactite/stalagmite pair on the right, and a column near the middle. The various speleothems, along with those three, appear to be along a distinct line, and are therefore probably structurally controlled.

Photo unmodified. May 9, 2013. FlashEarth Location. (Since we're underground, I have only a vague idea where this is with respect to the surface.)

Wednesday, February 18, 2015

Geo 1095: February 18, Day 779: Not All THAT Grand

Here we see Dana for scale with the "Grand Column" in Oregon Caves. As I commented yesterday, it's not all that grand, but a very nice example of this kind of speleothem, nevertheless. As I didn't mention yesterday, you can see the neck, the tight point, where the stalactite and stalagmite met, right about the same height as Dana's knees. Stalactites tend to be narrower and grow faster vertically, than stalagmites, which tend to be stumpier and grow vertically less quickly. So necks on columns such as this tend to be closer to the floor of a cavern than to the ceiling. (Yes the pose is a bit odd, but I asked her to look away from the camera so she wasn't blinded by the flash. Despite the fact we were a group of ~25, you see very few other people in this set of photos, for the same reason: I tried to shoot away from others to prevent blinding them.)

Photo unmodified. May 9, 2013. FlashEarth Location. (Since we're underground, I have only a vague idea where this is with respect to the surface.)

Tuesday, February 17, 2015

Geo 1095: February 17, Day 778: Grand Column

Columns form when stalactites, growing down from the ceiling, meet and join with stalagmites growing up from the ground. This so-called Grand Column (page 18) is not terribly large, which is what the prefix "grand" is usually taken to imply. However it has very nice form, and it's right on the trail, so not only can you get a good close look at, but you can take another photo with Dana for scale...

Photo unmodified. May 9, 2013. FlashEarth Location. (Since we're underground, I have only a vague idea where this is with respect to the surface.)

Monday, February 16, 2015

Geo 1095: February 16, Day 777: Into the Maw

Backing out and looking a bit more vertically compared to yesterday's photo at the spiral staircase, it feels like we are looking into the tentacled mouth of some antediluvian Old God. It's gorgeous, and I escaped without being eaten.

Photo unmodified. May 9, 2013. FlashEarth Location. (Since we're underground, I have only a vague idea where this is with respect to the surface.)

Sunday, February 15, 2015

Geo 1095: February 15, Day 776: Spiral Staircase

To be honest, I don't remember a spiral staircase, but that's where the photographic guide (page 17) says this was taken. I was probably rapt looking at the gorgeous examples of draperies, flowstone and stalactites. If you look at the lower left-middle, you can see where a number of the drapes have been broken off, probably as souvenirs. If you were to attempt that in this day and age, you'd be arrested and charged with a federal crime, so I urge you not to consider it. Though I haven't seen a fixed date, it looks as if efforts to suppress this sort of vandalism date to about 100 to 110 years ago. While regrettable, given a rough knowledge (within a few decades) of when this happened, we can get good information on rates of change in this environment. Towards the end of this set, I think I have a photo of an area with some of the highest speleothem growth rates in this cave system; it is not uniform from one spot to another. Rates of groundwater and air flow vary enormously, which influence rates of dissolution or deposition.

Photo unmodified. May 9, 2013. FlashEarth Location. (Since we're underground, I have only a vague idea where this is with respect to the surface.)