Washington to Idaho Road Trip, Featuring Basalt

About two weeks ago, in May, my mother and I set off from her house in Seattle to travel to Idaho. I live (and now work!) in Idaho, but was back home to visit my brother and sister-in-law, who were in town for a spell (and newly expecting a baby!) This trip was held together tenuously from the beginning, and quickly began to disintegrate along the way. Luckily, we got to see some awesome stuff along the way.

Our first stop was Mt. St. Helens, always a favorite stop. I’ve never been here so early in the season, so I’ve never seen it so snowy! This iconic view from the Johnston Ridge Observatory really lets you look into the crater and see the lava domes (here, due to the snow, they look like a vague bump towards the back of the crater.) This spot also gives you a good look at the Pumice Plain, (the low area in the foreground) that consists of debris avalanche hummocks mostly covered in pyroclastic flows and ash fall deposits.

This is a nice outcrop near the Johnston Ridge Observatory, that really clearly demonstrates the layered nature of stratovolcanoes. You can see different lava flows (andesitic and basaltic) alternating with layers of ash and possibly pyroclastic flows (in this instance, I’m not sure which it is, or whether it is a combination of both.) All the different colors are a result of hydrothermal alteration on groundwater that seeps into the deposits, is heated by the still warm deposits, and encounters pockets of gas.

Once we left Portland, the cold my mother had been fighting off finally caught up to her. We stopped in a town called Cascade Locks for the night, slept in late the next morning, and then got some restorative chowder before heading out.

We took a short side trip off I-84 on an Oregon 30 between Mosier, OR and The Dalles, OR. When I was first moving to Idaho, we discovered this scenic jaunt, and it was great to see it again. Partway through, there’s an overlook of the Columbia River and the Columbia River Flood Basalts at a place called Rowena Crest.

The road down from the overlook is this delightful road called the Rowena Loops. It’s quite exciting (especially for one’s passengers!)

Somewhere along the highway near Pendleton, we pulled off the highway to look at this cool cement plant. After this, though, we encountered some pretty intense rain, and ended up staying in La Grande for a night.

Once we got to Boise and picked up my car, we joyfully discovered that it had some sort of gas leak. (This heap – I mean, jeep is beginning to get on my nerves.) We dropped it off at the shop, and drove into the foothills above Boise to camp. Along the way, we stopped at Diversion Dam. It was built in 1909 to supply water to another, older system of canals, to irrigate nearby farmland.

One of the cooler things about it was the logway – a special portion of the dam constructed to allow logs from logging upstream to pass through the dam. (The area upstream is the Boise National Forest)

It was interesting to see how the water from the less constricted logway (on the left) interacted with the water that was forced through the dam. Despite having an initially smaller outlet, the greater force enabled it to travel farther & spread out more before the turbulence achieved equilibrium. (I’m sure there’s a better way to phrase that, but my engineering-oriented physics class didn’t cover fluid dynamics… which is what I personally wanted to study! Someday maybe I’ll get to.)

We passed by several reservoirs, including this one. The differential erosion happening in the basalt here was really fascinating – the lower flow must be much harder, to have resisted so much more than the upper flow.

The road passed through areas of this potassium feldspar rich granite. The best exposures were alongside one of the dams, where the road was quite literally one lane carved into the cliffside, frequented by large trucks hauling boats. Needless to say, we didn’t really stop for picture taking.

When we finally began pitching our tent, we realized that the rainfly was still in Washington – and rain was predicted. My mum had this great idea to make one out of free garbage sacks and little bits of tape – which luckily worked pretty well, though it didn’t rain.

After that, we picked up my car (which luckily only had a leak in the fuel lines!) and checked the weather forecast. Since it was predicted to rain more and my mum was still under the weather, we decided to part company that day, instead of camping through the weekend. She headed west to Washington, and I headed east to my summer job. Much as a few days of mother-daughter camping would have been fun, it was nice to just call it quits and end the stress.

Yellowstone Pictures, Pt. II

I’m over on the east coast, doing some family visits, and thought I’d use the occasion to post some photos from this past summer/fall, that have heretofore been unpublished. This first set is from a trip to Yellowstone – there are a few more pictures here.

The entrance sign near West Yellowstone, WY. (Which has an incredible 4th of July fireworks show!)

Mud pots! (I bet that’d make a great face mask… not that I advise trying!)

The view overlooking one of the geyser boardwalks. It was really comforting to think about so many people enjoying and learning about geology!

Spasm Geyser.

Near Prismatic Spring. (I overheard a private tour guide saying that the best viewpoint for Prismatic Spring was actually the parking lot for Fairy Falls, but we didn’t get a chance to check out that tip.)

Sunset Lake.

The Old Faithful Inn’s interior is spectacular! (And the ice-cream is very good also.)

Old Faithful Geyser.

Avoca Spring, possibly.

Hint: Madison campground has no showers - which means that you can frequently get a site without a reservation!

Another hint: Getting a back-country hiking/camping permit is pretty easy, but watching the Bear Country Camping video does take some time. As does buying the required bear spray and ropes for hanging food. Oh, and they like it if you research trails in advance, instead of showing up the day of and asking for whatever slots are open. We got a permit, but by the time we got to the trailhead, realized we couldn’t get to camp before sunset, when the bears come out to rummage through your groceries, and the rangers require you to be off the trails.

Another hint: advance planning is probably a good idea when visiting a major tourist attraction! We had a good time, but that would have made it a great time.

(Another note for unprepared/impromptu travellers: if want to hike the Grand Canyon, but lack the permit/reservations, you can sometimes get cancellations the morning of! My family’s actually had that work out twice. You definitely want to be in sufficient physical condition, however!)

Caving in Montana: Crystals Galore

These are well-known caves that are publically accessible with a permit. If you would like more information, or would like to view any of my site-specific references, please feel free to send me an email at helena.heliotrope at gmail.com. If you’d like to visit the caves, please contact the BLM Field Office in Cody at 307-578-5900, and ask about their caves!
In the fall of 2009, I got to go on an epic caving weekend near the Montana-Wyoming border. I talked briefly about some interesting chert nodules here, but I was honestly holding out on the best stuff: the formations.
The caves here are formed in the limestones and dolomites of the Madison group. These rocks formed between 360 to 325 million years ago, in the Mississippian, when a relatively tranquil, shallow sea covered the area. Like most seas, this one was filled with small organisms that had calcium shells or skeletons (such as corals or amoeboids.) When these organisms died, their decaying corpses were slowly compressed into limestone. Above the limestone lies a layer of reddish sandstone called the Amsden laid down in the Pennsylvanian, visible as the red streak in the above picture. After undergoing a sequence of uplift and subsidence, it was uplifted to its current level during the Laramide orogeny, about 70 million years ago. This created joints in the limestone that would someday become caves.
(It’s a really structurally interesting area – some of the nearby mountains are uplifted in a giant anticline, while the ones in the above picture are fault blocks that were tilted upwards.)
The Madison group stretches from South Dakota to eastern Idaho, and from Canada down into Colorado and Arizona, although the name differs regionally. Since limestone is very soluble, it’s chock-a-block with caves, including Lewis and Clark Caverns in Montana. Because of its solubility, it forms a very important aquifer, and has produced a prodigious amount of oil – over 1,400,000,000 barrels. (Pretty impressive for a bunch of dead sea critters!)These caves were eroded as the basin lay beneath the water table, in a process called phreatic erosion. Phreatic erosion occurs as the water flows through cracks and joints, eroding passages through the limestone. This passageways travel in all directions: the above photo shows a vertical, cream colored passage cutting through different bedding planes. Additionally, we saw some collapse along bedding planes, which created some fantastic flat roofs, visible here in the greyish section. Dating caves can be difficult (much like men), however some ash found in these caves is from an Yellowstone eruption 640 thousand years ago.
(I apologize for the poor picture – it’s quite difficult to take decent photos of large cave rooms without secondary light sources.)
This is a trace fossil we found on one of the bedding plane ceilings – it’s where a sea creature was burrowing, or eating, or squirming along. (The paleontologist on the trip provided some more details, but I’ve unfortunately forgotten.) I had never seen a fossil in the wild before, so this was one of the trip’s highlights.
The first cave we went to is the most challenging cave I’ve been in so far, despite being entirely horizontal. The entrance is through a 100’ long crawlway – which sometimes is only 15” tall. (I definitely got stuck a couple times!) The floor of this crawlway is thickly coated with radon-laden dust: to avoid developing radioactive cavers, the BLM limits the time you can spend in the cave each year. We wore dust masks, to cut down on the amount of junk we inhaled, but that only served to make me more claustrophobic.  This was even more heightened by the heat – it was the warmest cave I’ve ever been in. It was a pretty rough beginning, but we were richly rewarded for all that effort with masses and masses of my favorite formation – helictites.
I didn’t have my camera that day, but I did the next day, when we visited the second cave. The day of this trip, snow was predicted, so we only spent the morning underground. (The road to the caves requires a 4wd vehicle generally, but is reportedly impassable in bad weather.) Luckily, as we ascended out of the cave right as the snow began falling, and made it to paved roads just in time.
The caves have a wide variety of calcite formations, including helictites, rafts, and some really large cave popcorn. Additionally, they have gypsum flowers and crusts, epsomite crystal curls, and aragonite needles. These all form near each other, making for some truly impressive photographs.
This last photograph is an interesting chunk of yellow and red crystal crust that was forming in a hole in the ground. I still don’t know what it is…
This is the underside of a rock, absolutely encrusted with black crystals.
As we headed back to civilization, there was an antelope hanging out, clueless about what lay beneath its small cloven hoofs.

Montana, Chert, and the 1960s.

Two years ago, this rock really caught my eye while I was caving in the Madison Group of Montana.
First of all, there’s a nifty calcite or gypsum encrusted pocket, which looks much like a sparkly pothole…

(My assumption is that this formed as water seeped through the limestone into a small hole, and then crystallized on the hole’s walls.)
Then there’s the missing chunk, which gives a nice look at a crazy banded chert nodule.

If that chert nodule embodies John Lennon’s “Magical Mystery Tour” era, this nearby chert nodule is more Jackie Kennedy:

Way to keep it classy, chert.

Two-sided Dike

This is one of my favorite cave features here at Oregon Caves National Monument. It’s a quartz diorite dike encrusted with calcite.

Water (carrying minerals) flows through cracks in the marble bedrock. Quartz diorite is less permeable than marble, and when the water is unable to seep through. Instead, it flows down the surface of the dike, coating one side with calcite formations.
This is my favorite example of this, but there’s a much more prominent one along the tour route, so you should visit sometime!
If you’d like to learn more about the caves, you should read Ranger Gaelyn’s fantastic cave tour part one and part two!

Boil, Boil, Toil and Trouble: Lava Cave Features

 

Lava tubes frequently show fantastic features, and I saw some really cool features while I was interning through the GeoCorps Program with the BLM at Craters of the Moon National Monument and Preserve. Some of the more decorative formations are the result of boiling gases inside the lava. Honestly, I hadn’t seen many of these formations before this internship, so it was very exciting!

It was interesting to learn more about lava: how the tube walls themselves cool, how secondary flows erode the original tube, how both cohesiveness and fluidity contribute to form features, and how the pressure in the flow creates different landscapes (like pressure ridges and tumuli.) Being able to observe a great quantity of lava over the course of three months was highly educational - even if I can’t cite lava facts of statistics, I know more about the characteristics of lava by seeing so much of it.

I know I haven’t given much information on the region’s geology itself, but that’s because I get too darned excited about lava tubes.

As the ceiling of a lava tube is cooling: first the exterior layers, and then the interior. Once the exterior layer has begun congealing, gases in the interior lava can boil, squeezing lava out through the exterior layers. (Kind of like a pasta machine.) As this lava drips down, the sides of the drip cool, leaving the liquid lava inside. This liquid lava can then flow to the bottom of the stalactite, creating a hollow space. Sometimes the last bit of the drip falls off the stalactite, other times it plugs the stalactite up. The left picture shows some stubby stalactites from Craters of the Moon, and the right picture shows some really delicate “soda straw” stalactites from near Mt. St. Helens.

If the lava inside these stalactites drips onto the ground, it can pile up to form a stalagmite. I didn’t see many in Idaho, but the ones I did see were really tall. Unfortunately, I didn’t have a camera that day, but I also saw some good ones in Bend this summer.

These are called “stalagpies” by the local cavers, but are more widely known as lava roses, especially when they have a clearly defined series of concentric rings. I think they look a bit gross, but they can form in a really nifty fashion: when lava boils from under a semi-cooled floor, the pressure of the gases pushes the lava up through the floor. As a result, these are also sometimes called “lava volcanoes.” These are identifiably by their “central conduit,” which can be easily seen in the bottom picture. These pictures are from a lava lake, so this explanation makes sense.

Because these don’t have a conduit, I think this is an example of the other way in which lava roses form: when larger clumps or sheets fall from the ceiling, and pile up, cooling, slumping, and cracking as they do so. (I think the right one is especially ugly – it resembles a miniature Horta.) These pictures are from a different cave than the previous lava roses – so a different origin is plausible.

These are lava helictites! These are created in a manner similar to the lava stalactites above, but the lava is pushed through weak spots in the developing crystal structure, forcing it into a twisted shape. Both lava and calcite helictites refuse to obey gravity.

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References:

If you want to learn more about lava caves and their features, here are some great resources:

The Virtual Lava Tube is an easily accessible resource, complete with beautiful pictures. This site is run by Dave Bunnell, editor of the National Speleological Society News. He also published the information in a book called Caves of Fire: Inside America's Lava Tubes, which is gorgeous.

Nomenclature of Lava Tube Features is an older article, but describes a greater number of features than the Virtual Lava Tube, including many different types of stalactites and pahoehoe lavas. It’s available in print form in the proceedings of the 6th International Symposium on Vulcanospeleology, and in illustrated form as An Illustrated Glossary of Lava Tube Features. (I wish I’d found the online copy earlier – I accidentally left my print copy in storage!)

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An aside: nothing I say on this blog represents the opinion of Craters of the Moon National Monument and Preserve, the BLM, the NPS, the Geological Society of America, GeoCorps, or the National Speleological Society and its internal organizations. I will not disclose any cave locations, but if you wish to go caving in Idaho, please visit Craters of the Moon National Monument (NPS,) the Shoshone Field Office (BLM),  or get in touch with your local caving club.

Accretionary Wedge 28: Familial Bookcase-crop

This Accretionary Wedge, hosted at Research at a snail's pace, is focused on desk-crops. Normally, this would be very exciting – I have a healthy assortment of rocks. But, unfortunately, I put all my rocks in my storage unit when I moved to Idaho for the summer.

I only remembered about this Accretionary Wedge once I arrived in Oregon with four boxes, none of them containing rocks. Luckily, before I went to Phoenix last week, I was helping clean a bookshelf at my parent’s house in Washington, and happened to take some pictures of my mother’s minerals.

My mother (a painter of caves – seriously!) has a soft spot for colorful minerals and rocks. These are actually examples from her stash of minerals inherited from my grandfather, who was into rock-hounding. My mum has some great childhood stories from these trips, including “Terrifying Mine Experiences Involving Cupcakes,” and “Innocent Encounters with Canadian Mounties.”

I haven’t studied mineralogy much yet, so I’m mainly going to reference that bastion of scientific accuracy: wikipedia.

This Death Tribble is a piece of dogtooth spar, or dogtooth calcite. This usually consists of acute scalenohedrons: twelve triangular faces roughly making up scalene triangles.  They need standing water to allow them to grow, and so are frequently found in limestone caves. (My grandfather, I’m sure, found this in a rock shop – he wasn’t a caver, much less a cave-vandal.)

The only spooky thing about orpiment is that it’s a highly toxic cocktail of arsenic and sulfide, originating through the rapid solidification of hot gases at fumaroles, hot springs, and hydrothermal veins. It can also occur as the decay byproduct of realgar, a mineral of a similar composition that is frequently also found in conjunction with orpiment. (I’m wondering if realgar is in this sample, based on its appearance in google images.) Orpiment has historically been used for poision, medicine, and paint pigment; its present uses include semiconductors, firework pigments, and as an ingredient in Indian depilatories. (Perhaps: “Extreme Hair Remover: Now with Arsenic!” ?)