Accretionary Wedge #54- On The Rocks: Geo-brews and Geo-cocktails

One of the perks of being a geologist (from the fantastic geo-tumblr “geology is hard”)

If you look up the word “geologist” on the internets, you’ll probably come across this entry from the Urban Dictionary. However, the most apt part of it is the following:

There is a considerable, and still growing body of scientific literature that suggests that geologists are in fact the world’s first alcohol-based life form.

Hence the theme of this month’s Accretionary Wedge #54- One The Rocks: Geo-brews and Geo-cocktails.

This idea came about as Michael Klass, Julian Lozos and I sat at a cocktail place in Portland discussing geology, beer and cocktails. Naturally, rock themed booze ideas came out of it and this AW was born.

Our submissions for this month were few, but mighty.

  • Elli Goeke at Life In Plane Light shakes up a couple of great drinks in the form of a lava-rock filtered vodka from Iceland and a cocktail based on the Boston Molasses Flood.
  • My fellow PNW blogger, Michael Klaas at the Cascadia Blog, decided on two submissions for this month’s theme:  The Magma Chamber for those who like a little heat in their libations and a boozy coffee concoction worthy of any nightcap, or ahem… any start to one’s day.
  • David Bressan at the History of Geology talks about the chemistry of the most important aspect of our preferred beverages: water.
meteor beer

Our one lone bottle of the mythical Meteor beer.

And my submission for this booze soaked Wedge? Meteor Beer! This one comes to us from the Alsace region of North-East France. According to the website it’s one of the oldest breweries in the country and was founded in 1640. I went with this beer, not just because it’s named Meteor, but because the meteorite Orgueil was found in France. This meteorite is important because it belongs to class of meteorites whose chemical composition closely approximates that of the sun. We use it as a standard when looking at how the solar system evolved chemically over time. Meteor beer and Orgueil have something in common: they’re both precursors to that which would come afterwards in their respective realms.

I have a confession though: I haven’t tried this beer. Trying to hunt it down has been nearly impossible- even in the great beer capitol that is Portland, OR. We have an empty bottle of it down in the meteorite lab though and it’s my goal to try one at some point in my life.

If after reading these entries you feel inspired to write about your own geology themed drink, or you wrote one and I missed it, post it in the comments section below and I’ll add it to this Wedge.

Here’s a few extra posts to add to the Wedge:

A paleontology themed beer from Silver Fox over at Looking for Detachment.

Ann muses on her favorite beer, Rolling Rock.

Ian at Hypocentre gives us a look at how geology effects the chemistry of the water in the brewing powerhouses that are the British Isles and Czech Republic.

And @meaganhogg shares an ale that was brewed a little closer to home:

Ontherocks at the Geosciblog presents an impressive collection of geo themed beer cans.

A Quick Reminder: Accretionary Wedge #54

Just wanted to put out a reminder to the geoblogosphere about this month’s Accretionary Wedge #54- On The Rocks: Geo-Brews and Geo-Cocktails. This month we’re celebrating our favorite geology themed libations. You can either come up with a geology inspired cocktail, brew or even just share your favorite, all-ready made drink. And if you don’t drink, that’s okay, too. Feel free to come up with a non-boozy version of your preferred beverage. Need inspiration? Check out Michael Klass’s contribution on his blog over at Cascadia Blog. When you’ve come up with your contribution, post a link in the comment section of this post and I’ll compile all the posts at the end of the month. I’m looking to have the posts collected by the 28th or 29th, so they can be ready to go on the 31st (hey… it’s still January). Have fun!

When not hitting rocks, we're probably drinking it on the rocks.

When not hitting rocks, we’re probably drinking it on the rocks.

A Few Pictures From My Stratigraphy Trip To The Oregon Coast.

I’m not going to mince any words: it’s been a busy term. Hence my month long hiatus on the blog. My term has been busy with stratigraphy and sedimentation, scanning electron microscopy, a course on the history of modern science, and my usual work in the meteorite lab. The greatest amount of my time has been dominated by stratigraphy. A couple weeks ago I spent four days on the the southwestern coast of Oregon studying uplifted marine terraces and more shale than I ever wanted to see. In all honesty, it was like the twilight zone of geology. At one stop, the rocks got progressively younger as we went from south to north along the beach. Drive north a few miles and the rocks actually got older as we went in the same direction. To further add panic to the confusion, our instructor would ask which way was upsection, or in which direction were the rocks getting younger, and if you got the answer wrong you did push-ups or sit-ups. Not wanting a repeat of junior high hell, I learned to become very comfortable with my compass and topo map. Staying out of my professors line of sight was effective, too.

The Hunters Cove Formation at Gold Beach in Southern Oregon. This formation is composed of deep marine muds- meaning it’s more susceptible to folding than the sandstone formations on either side of it.

I wasn’t sure what frightened me more on this trip: Houses built on mud, such as this one:

Wanna know why you make friends with geologists? So you never make the mistake of building your house on marine muds. This house will probably be on the beach before next winter. (Picture taken at Light House Beach)

Or the tectonics off Oregon’s coast with the ability to turn once horizonal rock layers on their side:

These layers of sandstone and mud used to be horizontal. Now they’re nearly 90 degrees.

My favorite stop was Cape Arago. It was here that I finally understood what I was seeing. I spent most of the trip feeling lost, confused and cursing every layer of mud that I had to map. Cape Arago used to be an old submarine canyon. Then the ocean receded and slowly exposed the canyon and its cut and fill sequence from a probable paleodelta.  And I saw a lot of seals. Double win.

Cape Arago from the lookout. Tides came in and covered up much of our work area as we completed all our tasks.

It was also at Cape Arago that I learned how quickly I can map an area. Nothing makes you work faster than hearing your instructor say you have three hours and the tides are coming in.

Then there was Shore Acres. This was our last stop on the trip and it proved to be the most mind-boggling of all the sites we visited. And the weather turned to crap, too. Mother Nature decided to keep the wind and rain to herself until us lowly undergrad geology majors were exposed on the point. It was at this site that I learned even rite-in-the-rain notebooks have their limits.

One of the lagoonal areas at Shore Acres. We were charged with mapping the formations here and interpreting the depositional setting.

 

Day Two of my stratigraphy trip: Tygh Valley- White River Gorge section

Day two of our trip found us doing much of the same thing as yesterday: mapping fluvial and volcanoclastic deposits. This time we learned how to measure strike and dip of the observed bedding. Here’s an aerial view of our work area:

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This out crop is where we spent most of our time taking measurements. What you’re seeing is some severely tilted beds of volcanoclastic material. The dip is nearly 60 degrees at the top and becomes less angled as the bed continues dipping.

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A slightly closer shot of the same area:

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Here’s a close-up of the clasts present in some of the bedding:

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The source of the tilting is probably some plutonic intrusion. I’m inferring this based on the presence of a sill that sits just to the left of the first set of tilted bedding.

Here’s the view at the top of the basaltic rimmed plateau. Not sure if my camera got it, but you can see Mt. Hood in the background.

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Day one of my stratigraphy trip: Cove Palisades Park

Day one of my strat trip found us mapping fluvial and volcanoclastic deposits in the Cove Palisades State Park. It was nearly four hours of hiking up the road, examining the road cut, and taking measurements. What did we find? Lots of fluvial deposits such as rounded cobbles and sand stone towards the lake and volcanic teffra towards the top. Here’s a few pictures to show the sequence. I included scale where it was safe to do so. I can’t get into too much detail because I’m posting this from my phone.

Our work area seen from the top

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Layer of cross-bedded sandstone on the bottom with rounded cobble on the top. All indicative of fluvial deposition.

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Welded ash with pumice

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An example of beautiful cross-bedding in sandstone

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The meeting of fire and water. The rounded cobbles at the bottom were deposited in a fluvial environment. The thick layer in the middle is from an ash flow, while the layer directly above it is ash fall. The later directly above that is more rounded cobble.

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Another example of beautiful cross-bedded sandstone and gravel.

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And to end it all, nice columnar basalts.

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Geology 101: Deep Time, or Geologists as Time Lords

I’ve often suspected that the Doctor from Doctor Who is somewhat modeled after geologists. You see, we have a lot in common with the Time Lord. He works in a bow tie and coat…

He works in a bowtie... (image from doctorwho.tumblr.com)

And so do we (well most of us anyways)…

West Virginia Geologists from 1897 (Image from USGS)

The Doctor has his trademark tools such as the sonic screwdriver and the eponymous TARDIS and we have our tools of the trade, the rock hammer and our hand lens. Both sets of tools allow us to be time travelers much in the same way that the Doctor uses his TARDIS. Instead of flying around in a blue box though, our travels take place through the history that is set in the earth’s stratigraphy, or the multiple layers of rock whose deposition records the conditions of that location at a point in history.

OK, so maybe there’s some hyperbole and pomp in the previous statement. After all, we’re not the only scientists whose work spans millions and, in some cases, billions of years of time. Astrophysicists and astronomers work on scales that start 14 billion years ago with the Big Bang. However, as my friend Jamie pointed out, what makes geology unique is that we get to physically interact with our 3 billion year old rocks. We can touch them, examine them with our hands lens and chip at them with our hammers. And, if you’re feeling particularly old school, you can taste them. Go ahead and chuckle, my non-geologist friends, but this is how some rock identification is accomplished.

Geologists use different tools for determining the age of geological structures. One set of tools allows us to determine the relative age of rock- that is, the age of rock layers relative to one another. What’s really nice about this technique is that anyone can use it. All you need to practice relative dating is your eyes and maybe a journal to draw what you’re seeing. There are a few basic principles to look for:

  • Original Horizontality and Superposition- This is the idea that rock layers are deposited in a horizontal fashion with the oldest rocks being on the bottom and the youngest being on the top. This generally holds true unless you’re dealing with thrust faults that shift and bend layers.
  • Cross-cutting relations- If a geologic feature such as a volcanic dike or fault cuts across other geologic layers,  then those cut layers are older than the layer doing the cutting. A similar principle involves that of “baked contacts”. If you have something like a volcanic sill or dike that injects magma into the local bedrock, then the border between the dike/sill and bedrock will experience some thermal changes, or metamorphism. This injection of magma is called an intrusion and can be inferred to be younger than the surrounding bed rock.

(adapted from Steven Marshak’s  Essentials of Geology, 2009.)

A classic example of these principles is the Grand Canyon:

This cross section of the Grand Canyon illustrates the principles of Original Horizontality, Superposition, and "baked contacts" (Image from Wikipedia)

You can think of these rock layers like pages from a history book. You start at page one (the top layer and the youngest) and as you work your way through the book, you begin to get a sense of when things happened and why. However, there are times when our geological text book is not only missing a page or two, but entire chapters. We call these pages of missing history unconformities and they generally come in three flavors:

  • Disconformity- This is where you have two layers of sediment parallel to one another, but were not deposited one after the other. This could occur when a layer of sediment is deposited, is slowly eroded away and another layer of sediment is deposited where the old one used to be.
  • Nonconformity- These are present where you see a layer of younger sedimentary rocks on top of older intrusive metamorphic or magmatic rocks. This ties directly into the principle of Cross-Cutting Relations and “baked contacts”. If you have a layer of, let’s say river sediments, deposited on top of a dike (magmatic intrusion), then you have a nonconformity.

    An artists rendition of a nonconformity. The area below the black line represents the older intrusive rock and the rocks above are younger sedimentary rocks (Image from Wikipedia)

  • Angular unconformity- This occurs if the older bottom layer of rocks has been tilted at an angle and the younger top layer is relatively horizontal.  This is also called Hutton’s Unconformity, and a well known example is Siccar Point in Scotland.

    The top layers of sandstone are horizontal compared to the nearly vertical rocks underneath it. (Image from Wikipedia)

These concepts give geologists a relative age of the rocks they’re working with. It’s not meant to give a conclusive age, but rather constrain the time line that we’re working with.
If we want to obtain an actual age we turn to radiometric dating.
This form of dating gives us an absolute age value that allows us to assign a numerical value to the rock layers. While decidedly more sophisticated than relative dating, this is a technique that is most familiar to the public and also the least understood. Radiometric dating involves the measurement of isotopes. An isotope is an atom that has an unequal ratio of neutrons to protons (Edit: In my efforts to simplify the chemistry behind radiometric dating, I used a definition of isotope that is not entirely true. An isotope, such as carbon-12 which has 6 protons and 6 neutrons, can have an equal ratio of protons to neutrons. A couple readers pointed this mistake out. I posted those comments in the comment section for clarification). This makes the atom pretty unstable and causes it to undergo radioactive decay whereby it becomes the atom of a different element. For example, the atom that allowed us to determine the age of the earth, uranium 238, decays into lead 206. The original atom is called the parent isotope and the new atom is called the daughter isotope.
The amount of time it takes for a parent isotope to decay into a daughter isotope is called the half-life. This decay occurs with regularity and allows us to obtain an accurate age of the rocks we’re studying. To clarify this example, and pick up with our Doctor Who theme, let’s imagine we have 32 Daleks. In one hour 16 of those Daleks decay into Cybermen. Another hour passes and 8 of the 16 remaining Daleks become Cybermen. After those two hours we have a total of 8 Daleks and 24 Cybermen. At the start of the third hour 4 of those poor Daleks have gone over to the Cybermen side. For an explanation of what happens when there is less than one atom present, click here.
Now, this is a highly simplified explanation of a rather difficult process. Truth be told, there are some beastly equations that deal with this decay process, but the idea is relatively straightforward.
However, isotopes do have their limits. For example, carbon dating has a limit of about 60,000 years and as such is excellent for dating human artifacts and fossils, but not so great for volcanic rock. Beyond that 60,000 year mark it becomes wildly inaccurate and we need to use atoms such as Uranium 238. This is the atom that has allowed us to determine that the earth is 4.5 billion years old and not 6,000 years.
Well, I don’t know about you folks, but my brain is completely fried and as such I have no fitting conclusion to end this, the most epic post I have ever taken on. So, instead I will leave you with a quote from the good Doctor that somewhat applies to everything we’ve discussed-
People assume that time is a strict progression of cause to effect, but *actually* from a non-linear, non-subjective viewpoint – it’s more like a big ball of wibbly wobbly… time-y wimey… stuff. – from Doctor Who “Blink” (2007)

*I wanna give a big thank you to Dana at En Tequila Es Verdad and Suzanne at TwoTonGreenBlog for helping me put this post together!*

How a small Oregon town continues to teach me about geology

Our families land and house in Glide. The Little River is to the left of the image behind the trees.

About a year ago this month I wrote about the geology of Glide, Oregon. For those unfamiliar with the town, Glide is a few miles east of Roseburg in the Umpqua Valley of southern Oregon. It pretty much lies in the foothills off the Cascade mountains and it’s one of the last towns you’ll see heading out to Crater Lake on OR 138. My partners grandparents live down there and it’s been somewhat of a vacation spot of ours for the past four years.

When I wrote that post I’d only taken two general geology courses and a three day field trip to central Oregon. I knew just enough about geology to sound intelligent to the lay person, but grossly misinformed to anyone who knew the difference between dacite and andesite.

One of many serpentinite outcrops in the river bed

Regardless of my ignorance, I tried to write as thorough of a post as possible based on some of my observations. I also included pictures taken with my old eye-fone 3GS to illustrate my explanations. To be sure, there were a lot of things I couldn’t explain. Take for example the masses of green serpentinite in the river bed behind my grandparents house. I knew that it was a metamorphic rock that only formed at great depths. So, how did it find it’s way to the surface of the earth? The only explanation I could conceive was that the river carved it’s way through the valley, and with the aid of uplift, the serpentinite was exposed. It hadn’t really occurred to me that I was looking at an ophiolite- sea floor rocks exposed at the surface of the earth. (For a great explanation of an ophiolite, I highly recommend Evelyn Mervine’s O is for Ophiolite blog post.)

A very sneaky piece of serpentinite masquerading as gneiss

However, I didn’t let that stop me from trying to figure out the geology of the area. Every time we went down there, I brought my rock hammer, hand lens and a little bottle of hydrochloric acid to look for the signature fizz of a carbonate rock. I found the usual assortment of sedimentary river rock, more serpentinite, and rocks that developed a calcite band or crust from the flow of the river. One of the more unusual rocks I found was what I thought to be a piece of gneiss. It displayed the usual banding and as such I always referred to it as gneiss. However, on this last trip, I took a closer look at the rock and realized it was another piece of serpentinite sporting some gneiss-like banding.

Since that first blog post, I’ve had geomorphology, mineralogy and petrology. The latter of which did more to help my understanding of geology than anything I had taken up to that point. It was from the petrology field trip to eastern Oregon that I learned about the power of observation- and by this I mean the capacity to unravel the mysteries of a landscape by looking at the various rocks and landforms of the area. It was on that trip and on this one to Glide that I realized geology is a balancing act. It’s equal parts understanding the land for what it is and what it was. Focus too much on one or the other and you lose out on the majesty and greatness of what you’re studying.

An outcrop of heavily weathered serpentinite. Apparently it gets quite a few visits from other geology students.

With that experience and knowledge in hand, I decided to take a look at some of the outcrops around our families land. A few of the outcrops I figured were basalt. This was more assumption than observation. 9 times out of 10, if you guess a rock is basalt in the state of Oregon, chances are you’re right. After some whacking with the rock hammer, I realized that the outcrop was composed of serpentinite. In fact most of the road cuts in the area were composed of serpentinite. And since this is ophiolite country, the odds are good that the rest of the hills are composed of unexposed sheeted dikes, gabbros and, dare I say it, basalt. Just not of the Columbia River kind.

I’ve been fortunate enough to have visited Glide during all seasons and see the way the Little River affects the rocks and surrounding area. During Summer months, the river runs at it’s lowest and is great for swimming and finding rocks. In the Spring the river tends to run at it’s highest and possesses a deafening roar. One can see the cycle of the river by looking at the tops of the outcrops in the middle of the river. On this last visit I noticed tree trunks on these outcrops that stand at least 20 feet.

That large tree trunk wasn't there last summer


Scour marks left behind from gravel in fast flowing water

When the water is low enough you can start to see scour marks and pot holes in the surrounding rocks. These are left by the pebbles and gravel of the river as they churn about in eddy’s from the fast flowing winter waters. The first time I saw those scour marks I was immediately reminded of the marks left behind by the advance of glaciers. Unlike glaciers though, rivers can also create pot holes in the underlying rock. I’m not terribly sure how it works, but I think it has to do with sediment getting trapped in the current and slowly being driven into the rock, much like a never ending jack hammer.

One of the much larger pot holes in the river bed. This one comes just a few feet away from the previous picture with the scour marks.

Now the point of this post isn’t to show off what I know or how much I’ve learned in the past year. In fact it’s quite the opposite. Regardless of the classes I take, the books I read, and the research done, there will always be something for me to learn. Doing geology, and science in particular, means becoming comfortable with the unknown and getting cozy with your ignorance. This doesn’t mean one should become complacent in their knowledge though. It just means for every piece of information you learn, there are at least a dozen other pieces of the puzzle that still need to be discovered. People don’t get involved in science because they know it all, but because they don’t know it all. And it’s for that reason I will continue beating rocks and playing in the river bed when we go to Glide.

Video of pillow basalt formation

A friend of mine posted this video to my Facebook page and I thought it was awesome enough to warrant sharing on the blog. What I find really fascinating about this video is that you get to see how the basalts get that pillow like shape. As the basaltic lava flow comes in contact with the water, it quickly quenches into that bulbous shape. The lava continues to build-up in the pillow, and like blowing too much air into a bubble, basically bursts open and the process repeats itself.

What’s even cooler is that, through a process called obduction, those pillow basalts get heaved up onto the continent. Think of it as the opposite of subduction; instead of the pillows getting swallowed by the oceanic crust as it dives under the continental crust, it gets uplifted onto the land. In what is surely a perverse joke by nature, some of these pillow basalts can be found in Oregon. It’s as if nature decided we didn’t have enough basalt from the Columbia River basalt group, so it gave us sea-floor basalt as well.

Cause everyone loves a good geology quote

Quote

“No Geologist worth anything is permanently bound to a desk or laboratory, but the charming notion that true science can only be based on unbiased observation of nature in the raw is mythology. Creative work, in geology and anywhere else, is interaction and synthesis: half-baked ideas from a bar room, rocks in the field, chains of thought from lonely walks, numbers squeezed from rocks in a laboratory, numbers from a calculator riveted to a desk, fancy equipment usually malfunctioning on expensive ships, cheap equipment in the human cranium, arguments before a road cut.”

Stephen Jay Gould (Urchin in the Storm: Essays About Books and Ideas)

Accretionary Wedge #35: Favorite geology word- welded tuff

Welded Tuff of the Dinner Creek Tuff Formation

I have a confession: welded tuff isn’t my only favorite geology word. Trying to narrow down a favorite geology word is like trying to choose a favorite beer. I love too many of them to pick just one. Welded tuff is one of my favorite geology words because of what it is. It’s super hot ash, rolling down the flanks of a volcano, incinerating all in its path and fusing together into a new pyroclastic rock. It can also pick up fragments of other rocks and weld them into the ash body.

This particular piece is of such origins and comes from my petrology field trip to eastern Oregon. It’s from the Dinner Creek Tuff formation that formed in central Oregon about 15 million years ago. That puts it at about the same age as the Columbia River Basalts (1). This beauty is studded with obsidian, pumice and other pieces of rock fragment that give this consolidated piece of ash a lot of character. Of all the rocks I picked up on the trip (and there’s a lot of them) this one is my favorite because It’s a reminder of the rather violent history of Oregon’s beginnings.

1.Streck, Martin J.; Ferns, Mark L.; Ricker, Christopher; Steiner, Arron. The Dinner Creek Tuff And Other Mid-Miocene Rhyolites At The Magmatic Focal Zone Of The Columbia River Basalt Group. May 2011