Saturday, December 25, 2010

Merry Christmas!

 

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(We’re taking the lazy Trendy-Tacky Table-Top Tree Tactic this year.)

Friday, December 17, 2010

Two-sided Dike

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

Wednesday, December 8, 2010

Slick-n-slide

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Ok, so the technical name for this is “slickenside,” but I find “slickenslide” easier to remember.

(I loved the concept of slip n’ slides as a child.)

Anyway, a slickenside is created as the two sections of rock alongside a fault move past each other, slowly polishing the surfaces of the rock. This creates smooth, slick rock faces along a fault line. Sometimes you can find “slickenlines” on the slickenside, which are small, directional scrap marks left by the movement.

In the above picture, the slickenside (and fault) cross at about 35 degrees from the left to the right. In the below picture, the slickenside is more difficult to see, but is at about 60 degrees.

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That, it should be noted, is the definition of slickenside that I learned on a field trip – if anyone has a more technical definition, I would be really interested to hear it!

Thursday, December 2, 2010

Adorable, Rabies-Ridden Critters

Many years ago, I was 13, and hiking in the Grand Canyon with my family. We paused near a French family: a mother, a father, and a boy – a cute boy. He was feeding trail-mix to a chipmunk, despite the numerous, multi-lingual signs to the contrary. Luckily, my mother is fluent in French, and was willing to explain the problem to him.

Excusez-moi,” she said. “You are not allowed to feed the animals.”

The boy looked at her like she was crazy. “Pouquoi?” He asked, empty hand dangling in the air.

“Well, feeding the animals can make them sick. Also, it makes them not afraid of humans. They can become aggressive.”

Agressifs?’ he asked – just as the chipmunk lashed out and bit a chunk out of his hand.

There was shouting, and shooing, and bleeding… and my mother, explaining to his mother how to get rabies shots.

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The moral here? Don’t feed the animals, or assume cute French boys are intelligent.

Tuesday, November 30, 2010

The Upsides and Downsides of Mountains

I’ve lived in Western Washington for a total of twenty-one years, so it’s really easy for me to answer this month’s Accretionary Wedge (#29!) as posed by Ann at Ann's Musings on Geology & Other Things: "What Geological features about the area you call 'home' do you love? and what do you not like?"

Washington can be divided very roughly into thirds: Eastern Washington, home to the Missoula Flood-carved Columbia River Flood Basalts; Western Washington, with thick glacial deposits and steep stratovolcanoes in the Cascade Mountains; and the Olympic Penninsula, which is an accretionary wedge, with the uplifted Olympic Mountains.

My favorite geological features are the volcanoes. These result from the subduction of the Juan de Fuca plate beneath the North American plate:
Map, Plate Tectonics and the Cascade Range, [18K,GIF]

Cascades Volcano Observatory

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Mt. Rainier

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Mt. St. Helens

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Mt. Adams

 

Now, my least favorite geological features of Western Washington are also the Cascades, because they help cause the massive, constant amounts of rain.

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The Olympics create a rain shadow, but they aren’t so high that all the moisture condenses and falls: the rest is carried over the Puget Sound. As it does so, it picks up more moisture, which then condenses as it rises over the Cascades, dropping all over Western Washington.

That’s why it rains 365 days out of the year (or at least feels like it!)

Thus, my Theory of Seattle: the rain nourishes the trees and shrubbery, which grows profusely and blocks out the light. Between the rain and the trees, everyone wants to stay indoors – thus, the major IT industry begins. Between the masses of commuters and the nasty dim weather, rush hour runs rampant. Since everyone codes late into the night and has to get up early to beat the traffic, the immense coffee culture is started. Thus, the population has a Vitamin D deficiency, stares at computers constantly, is always struck in traffic, and gets regularly strung out on coffee, resulting in perpetual depression and tweakiness. Thus leading to the reign of 90s grunge music, which also contributes to the high suicide rate.

That’s my theory, at least. And I’m sticking to it.

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I’ll be honest: I’ve had my fill of the dreary rain and endless rush hour.

So, I’m going to study Geology at Boise State University next year!

Thursday, November 18, 2010

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.

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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.

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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.

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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.

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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.


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!)


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.

Sunday, November 14, 2010

The People of Armero, 25 Years Later

It’s been 25 years since Nevado del Ruiz erupted on November 13, 1985. Despite being a relatively small eruption (VEI 3), this phreatic (magma + water) created a massive lahar (mudslide) and managed to wipe out an entire town, killing 23,000 people in the process. Good descriptions of the eruption can be found on History of Geology and Eruptions, so I’m not going to reinvent that wheel.
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From the USGS
Last spring, I researched Armero in the present day for a cultural project in Spanish class. The assignment was to communicate with a native Spanish speaker in Spanish, so I sent a (painstakingly composed) email to  Observatorio Vulcanológico y Sismológico de Manizales, one of the volcano observatories set up after the 1985 tragedy.
Now, it has been 25 years since Nevado del Ruiz erupted, and, in the aftermath of eruptions, frequently people return to the destroyed area. There could be a variety of reasons for this – they don’t think it’s likely to erupt again, they have nowhere else to go, for religious reasons, or they simply want to be “home.” A great example of this is Merapi, in Indonesia, which seems to erupt roughly every ten years, and its lahar deposits re-liquify into new lahars every monsoon season. That people still live nearby to be affected by the current eruption is a horrific testament to misplaced perseverance, determination, and religious conviction. After the 2002 eruption of Mt. Nyiragongo, in Congo, people moved back to the destroyed town of Goma before the lava had even finished cooling. However, habitation in an area previously destroyed by recorded natural disasters isn’t relegated to what we would consider “third-world” countries: people still live in New Orleans and near Mt. St. Helens, astonishingly enough. As time passes after an eruption, people are increasingly more willing to return to these areas – the valleys surrounding Mt. Rainier are filled chock-a-block with farms, industrial complexes, and towns.
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From here
In light of that, my curiosity about Armero was regarding where in that process the government and people were – had they begun to forget, or did the scale of the tragedy make it more difficult to ignore the hazard? Had I known more vocabulary, I might have asked more specific questions, but the ones I managed to include were thus: what is the town of Armero like today? How many people have returned to live there, and how do they perceive Nevado del Ruiz?
I got a fantastic response back from the volcano observatory, which, after some I looked up several words, answered most of my questions. The representative explained how the old site of Armero had been declared a National Cemetery, and habitation was no longer permitted there. Now, the survivors and municipal administrators had moved to the town of Guayabal, now called Guayabal-Armero. Apparently the area has become a destination for over 35,000 tourists a year, and there are volunteers available to provide tourist guidance.
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From the USGS
That led to some more focused googling, with the result that I found out about the Fundacion Armando Armero, an organization devoted to preserving the cultural heritage of Armero. They’ve set up an interpretive site in the old town, focusing on people and places found in Armero before the eruption. In addition, they are working on building a cultural-tourism route through Guayabal-Armero and Armero. One of their other projects includes collecting photos and stories of old life in Armero, some of which are available on their website.
From Wikipedia
It was interesting to learn a little more about how this area is recovering from such a devastating incident. It sounds like the government has more respect for volcanoes, that the people are coping, and the efforts of the Fundacion Armando Armero are laudable. Still, I wonder whether the cooperation of the people will last, or whether they will someday decide to reclaim their town.

Other Resources:
Observatorio Vulcanológico y Sismológico de Manizales
 USGS: Nevado del Ruiz
Global Volcanism Program: Nevado del Ruiz
No Apparent Danger, Victoria Bruce, HarperCollins Publishers, 1st Ed., 2001

Wednesday, November 3, 2010

A Couple Nice Eastern Washington Pictures

A few weeks ago, I spent a weekend near Prosser, WA with my parents and their friends. This was their annual bicycle-riding and wine-tasting weekend, so most of my pictures feature middle-aged folks in spandex. Much as I’ve become desensitized to such retinal injury, it seems rude to inflict it upon the internet. I did take some decent travel photos, however:

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The last one shows some hop trellises. Washington state produces much of the world’s hops, believe it or not.

Saturday, October 30, 2010

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.

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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.)

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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!” ?)

Tuesday, October 26, 2010

Summer GeoCorps Internship: Or, Caveapalooza 2010

This summer, I was an intern at Craters of the Moon National Monument and Preserve with the Bureau of Land Management in Idaho, through the Geological Society of America's GeoCorps Program.
It was a fantastic experience, but I haven’t previously discussed it here mainly because of uncertainties regarding legalities and whatnot. (My mum’s a lawyer: paranoia is in my genes.) So, let it be stated: 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. Caves are a federally protected resource, and thus I’m not going to disclose any cave locations, names, or, really, more information than is necessary.
If you are in south Idaho and would like to visit wild lava caves, that’s great! First, get your gear, read up on White Nose Syndrome, and then visit the Shoshone Field Office to request a list of caves open to the public.

All that might seem kind of stern, but this is what happens when caves are destroyed:
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The left picture is from a cave heavily vandalized for its entire length, most of it vile in content, all of it lacking in artistry. The right picture shows detritus left behind by people who were clubbing and shooting pigeons in a cave; we also found two dead barn owls this summer. During my internship, several damaged cave gates were discovered as well: not only is this blatantly disrespectful, but also incurs an expenditure of governmental time and money, and frequently results in other cave damage.
Should someone committing acts of this nature be found, legal action can be taken against them under the 1988 Federal Cave Resources Protection Act. FCRPA states, essentially, that caves are super-awesome resources that should be protected, through inclusion in federal land management planning and communication between land management officials, cavers, and visitors. It also outlines punishments for those who damage or remove items from the cave: up to one year in prison and a fine for first time offenders, and up to three years for second time offenders. (Since many cave restoration projects take longer than this, I think this is a pretty light sentence.)
Rampant destruction of a sensitive and delicate ecosystem annoys the crap out of me. Not only is cave vandalism destructive to life-forms, but it also damages scientifically valuable features, cultural artifacts, pollutes aquifers, and ruins the cave for other visitors. In addition, partying in caves is unsafe – I watched a sober, helmeted person get a concussion this summer. The addition of booze, much less drugs, could create a much more serious situation, and result in a risky rescue situation. Also, it should be noted: caves don't clean themselves – someone else has to.
Cave vandals make me irrationally angry.

Craters of the Moon is run jointly by the National Park Service (NPS) and Bureau of Land Management (BLM.) My position was with the BLM, and focused mainly on cave conservation: completing the process to ensure legal protection under FCRPA, placing outreach/educational signs, and conducting cave surveillance. Additionally, I met the local caving club (grotto) members, led several tours through the caves, compiled a long-winded informational guide for interpreters, and found caves whose locations had been lost.
I thought that, in the next couple of posts, I’d share some of the cool things I saw and learned this summer. Frequently, caves seem to be misunderstood, feared, and ignored by the general public: this is a shame, because they’re really scientifically valuable, and provide recreational and educational opportunities for people of all ages, sizes, backgrounds, and experience levels.
(Unless otherwise noted, these pictures are from Craters of the Moon.)
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The most common process for a lava tube’s formation is thus: a smooth, laminar flow of pahoehoe lava travels across a landscape with a certain slope – not too steep, or it will turn into a’a lava, and not too shallow, or it will fail to flow. (I’ve been told between .5 and 1.5 degrees: the validity of this is uncertain, however.) Frequently, these lava flows will form channels, as seen in the above picture from Jordan Craters, OR. As the lava flows in these channels, it begins to form chunks of crust: these raft along the flow, stick to the sides, and bunch up against one another. Eventually, a roof is formed over the channel: this continues to cool and thicken, while the lava underneath is still flowing. Frequently, the lava in the tube will cool and block the tube; if the flow is diverted or ceases, the lava may flow out, leaving behind a lava cave.
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As the lava cave cools, the molecules in the lava are pulled towards one another, causing the lava to cool and contract. (This is standard for all liquids as they freeze, with the notable exception of water.) As it contracts, cracks form: it you’re lucky, a spot in the cave roof is weakened enough to collapse. This creates skylight entrances into the tube, like the ones in the above picture from Lava Beds, CA. (Skylights can also be formed when a section of roof fails to cool, although I have yet to see an example of this at a lava cave.) Skylights provide access to the cave for both organisms and cavers.
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This is a good example of a primary lava tube: it has a simple oval shape, indicating that a secondary flow hasn’t travelled through and eroded the floor. This cave also had very few features, which can indicate that there were few lava flows in the tube. In places, we saw chunks of pahoehoe that stuck to the walls as the flow cooled; however, the majority of the floor was thickly covered with fine sediment. Uptube, it was possible to see where loess from the surface was washed in with small rocks: these quickly settled out, and, at the downtube end, blocked the passageway. We followed an old record to this area on my last field day, and it really panned out: we found seven caves, all erupted from the same vent. It was a pretty great way to end my internship.
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This is the granddaddy of caves in the area: it’s the longest, and contains some really unique features (and some Silver Sage Grotto members for scale.) On the left, you can see an area where a secondary flow travelled through the cave, thermally eroding down the floor in the process, and thus increasing the tube’s height. This picture also shows a feature called benches/curbs/ledges: these show that a secondary lava flow travelled through the original tube, cooling onto the sides in the process. Benches frequently are characterized by their rectangular cross-sections, but they can have different shapes: in the right picture, you can see how there are benches stacked atop one another, and undercut at the bottom by a final flow. Also, the top of the right picture shows an spot in this cave where the secondary flow began to roof over, in a similar fashion to the creation of the original tube, creating a multi-layered tube. Depending on how you count, this lava tube has between three and seven levels.
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These two pictures are from my favorite grotto trip: we rappelled into a lava lake through a gas vent. As the lava in the lake cools, it contracts and cracks (much like the infamous columnar joints,) creating a sunken lake. The left picture shows what may have been the original level of the lake, and a caver perched on its present level – quite the change! The right picture shows how the lake cracked and collapsed as it contracted. This was a great cave!
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These are great examples of some important mineral deposits inside lava caves: gypsum, on the left, and calcite, on the right. These form as water drips through cracks in the cave’s roof, eroding it and picking up calcium and carbon. When this reaches the cave, the water evaporates, leaving behind the mineral. The calcite is a type of formation called coralloids, or popcorn.
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Caving isn’t all cool rocks, however: sometimes, the rocks really suck. As the pahoehoe flow in the tube begins to cool down, it begins transforming into a’a: this can create a clinker floor, such as the one in the left picture. Most people know that clinkers are kind of lame to walk over, but only after belly-crawling over them do you truly realize just how painful they can be. (I lost two shirts while at the Northwest Caving Association regional in Bend!)
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I had a great time this summer, learning first-hand about lava caves, lava fluid dynamics, cave management, and the BLM. The cavers in the area were really a treat, and the caves were fantastic!
I have another post about Idaho's lava tubes here.

Friday, October 22, 2010

Sight-seeing, Airplane Style

Yesterday, my family flew down to Phoenix to watch my brother graduate from UTI (at the head of his class, no less.) Our plane flight was luckily during the day, so we got an aerial view of some great mountains:

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Mt. St. Helens

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Mt. Hood

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The Three Sisters.

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I think this is Mt. Wheeler.

I’ve always wanted to see Mt. St. Helens from the air, and I was so excited to spot it!

Tuesday, October 5, 2010

A Hornito and Cow Walk Into a Bar

 

What do you call a cow that’s just given birth?

Decaffeinated.

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What do you call a cow with two legs?

Lean beef.

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What do you call a cow with no legs?

Ground beef.

Monday, October 4, 2010

Stalagmite: definitely not limestone.

 

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In a lava cave roof, hot gases boil and push molten lava through cracks in the roof’s cooled crust. This lava can spooge out of its stalactite and drop to the ground, creating a stalagmite like this. This formation has a really nice metallic glaze to it, and I saw it in a cave near Bend, OR.

Sunday, October 3, 2010

Columbia River Basalt Columns

Much as the heyday of the columnar jointing meme seems to be past, I’d like to jump on the bandwagon in support of Washington’s columns as championed on Northwest Geology Field Trips.

Washington is home to what I would argue is some of the raddest columnar jointing around, as it’s easily reached and highly extensive. And by “highly extensive",” I mean Spans-63,000-Square-Miles extensive.

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These columns (near Grand Coulee, WA) show an unevacuated lava tube.* The arch of columns would have been the tube’s roof, as those cooled and cracked perpendicularly to the cooling surface (the air.) Underneath this is a layer of lava that cooled in the tube, and beneath that are more columns from the bottom of the flow. Above this tube is the middle section (the entablature) that cooled in a different fashion and thus has some pretty fugly hackly jointing.

 

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Dry Falls, whose walls are composed of columns. You just can’t tell that because it’s so stinkin’ huge from this vantage point.

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These columns are the Ellensburg formation, and this exposure is over near Naches, WA.

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This is Frenchman Coulee, and is once again composed of columns too distant to see.

P1170467But here they from a closer viewpoint – in addition to the columnar joints, you can see horizontal weak areas perpendicular to cooling along the column’s side.**

Oh, and you know what else Washington has that’s better than anywhere else?

Plaid-clad junkies who don’t shower.***

My advice: visit the Columbia River flood basalts, but avoid Aberdeen after dark.

 

*At least, that is what an unevacuated lava tube has been pointed out to me as. As always, I could be really incorrect.

**I think.

***I really like plaid.