Category: Uncategorized

Short and sweet, since I’m trying to work on my grad school application today. I’ve gotten to the most terrifying part – the “statement of purpose.”

Banded Iron Formations: A New Depositional Model

I don’t personally know that much about banded iron formations (BIFs); we talked about them a little in geochemistry. They’re basically very old rocks (between 1.7 and 3.8 billion years old) that show a very distinctive banding of iron rich and iron deficient layers. There’s been a lot of debate about how they might have formed, so the new possible model is interesting. If nothing else, BIFs tell us something very important, just like the old komatiites we can still find, namely that you can’t find any younger than 1.7 billion years. That means around that time, something big changed in the Earth’s geochemistry, as well as in its internal heating system. (Or really, several interconnected somethings.) I’m looking forward to when we know what exactly the change was, because that has a lot of implications in regards to how planets like ours form and change over time.

Dr. Novella writes about a study by Ira Hyman et al.

This was the most interesting bit of what Dr. Novella had to say:

What this all might mean is that there is something about talking on a cell phone that is particularly demanding of our attention – more so than listening to music or talking with someone who is physically present. These results also support the hypothesis that talking with a passenger is not as dangerous because the extra pair of eyes increases the chance that someone will notice a sudden obstacle or unexpected traffic pattern.

Anecdotally, I would certainly agree. I notice things just fine walking down the street when I’m listening to my iPod or walking to the bus station with Mike. If I’m having to return a phone call while I’m walking, I wouldn’t even notice a full marching band unless they were making enough noise to keep me from hearing the person on the other end of the phone. I once dropped my USB drive and walked off, and a really nice guy had to chase me half a block to give it back to me because I was talking on my phone and didn’t notice someone shouting to get my attention.

I’ve pretty much thought hands-free laws were crap from the beginning. It doesn’t help if you’ve only got one hand on the wheel when it comes to maneuvering, but frankly I’d bet that most people only keep one hand on the wheel unless they’re turning anyway. (On a side note, I don’t know how people who drive manuals can manage to talk on a cell phone like that anyway, unless they’re on the highway and don’t have to shift.) It really is the distraction that causes accidents and kills.

In my opinion, even freakier: people who text and drive. Actually, I’ll own up. The only car accident I’ve been in since becoming a driver was my own fault, and caused by me attempting to text and drive. (This was seven or eight years ago when it happened.) I rear ended someone at about five miles an hour on the highway when we were in complete gridlock. At that point, I realized how I literally had not seen it coming, and since then I refuse to even touch my cell phone when I’m in the driver’s seat. If someone calls me, I toss it to my passenger and make them check it. (Another reason not to drive with me?)

So we know it’s dangerous to be on a cell phone and drive, particularly now whether it’s hands free or not. I don’t know if there’s really anything you could do about it. Sure, you can make laws, but enforcing them is another matter. The biggest problem is that if it were just people deciding they’d rather take the risk than be separated from their precious cell phone for the duration of a drive, fine. But they’re on the road with everyone else, including people who probably aren’t happy accepting that risk since they’re the ones that will get rear-ended by the jackass that won’t just hang up and drive.

When I put it like that… well. Driving while on a cell phone: the new driving while intoxicated.

One thing I’d like to see more on scientifically is why talking on a cell phone is more distracting than talking to someone else while walking. I don’t know if I buy that it’s just the other pair of eyes that makes the difference, since I’d think both people would be distracted by the conversation. If we assume that one conversation is as distracting as the other, then you’d expect that people in pairs would still pay attention better, but I don’t know if it would be as much better as it was.

Only 25% of the cell phone users had noticed the clown and many turned around at that point to see what they had missed. In essence, 75% of the cell phone users experienced inattentional blindness to the unicycling clown. In contrast, over half of the people in the other conditions reported seeing the clown (51% of single individuals, 61% of music player users, and 71% of people in pairs).

(Note: the clown thing was testing for inattention blindness by putting a clown on a unicycle very visibly along the path and seeing who noticed him.) The gap here is 25% as compared to 71% – that’s a difference of 46%. That’s pretty impressive. Maybe cell phones are more distracting because you’re missing out on most of the nonverbal side of the conversation?

Also, I wonder why people listening to music did better than people just walking along. That seems odd, but very interesting.

A bit belated, but such is the life of a college student who is attempting to beat her Worst Jane Eyre Essay Ever in to something a bit tamer, hopefully even a Not Quite The Worst Jane Eyre Essay Ever. If I’m lucky. I may just have to settle for the I Was Going To Set It On Fire But Realized That Some Grade Is Better Than No Grade So Here It Is Try Not To Let It Drive You Mad And Summon Dark Elder Gods Jane Eyre Essay.

I was catching up on my blogs and got hit with the reminder that the Ig Nobel awards have once again come and gone for the year! I’m looking forward to when the full audio of it comes out. In the past, it’s been via Science Friday on NPR, so it’ll be a bit of a wait. But it’ll also be worth it.

Io9 has a detailed roundup of the winners. There’s also some extra fun currently on the front page of The Annals of Improbably Research, spread over several posts that I am far too lazy to link to individually.

I love the Ig Nobels, deeply. I think it’s a great bit of PR for science. Yes, it points out bizarre research, but frankly if people are going to complain about how ridiculous it is that scientists get paid actual money to study people getting beer bottles smashed over their heads, they’re going to do it no matter what. These are bitter, sad people who wouldn’t know the joy of inquiry if it bit them on the behind, and I would go so far as to say are probably just mad that they couldn’t find a way to have fun while making a living. These are also, as I mentioned before when talking about the studies done in the Mt. St. Helens area, people who think that reality actually complies with common sense and our own assumptions, which is just silly.

Really, I think the Ig Nobels reach the people who still remember how much fun it was, in grade school, to make a fake volcano and then giggle gleefully as it exploded all over their nice new pants. (Not that kids necessarily get to have that much fun these days.) You know, the ones with the cute frogs on them. These people may not be scientists now, but you don’t have to be a scientist to love science and see the fun and excitement in it. So the Ig Nobels are really just a post-it note on the nose of life that says, “Remember: Science is fun!”

My favorite part of the Ig Nobels is actually the 24/7 lectures. I love them. Love, love, love. To the point that I save old recordings of the awards and fast forward through them to listen to the little lectures. It’s fun to hear very learned people try to describe what they do in a rushed, breathless voice, and the seven word studies are always absolutely hilarious. Paul Krugman is this year’s wonderful example.

Love it!

Ancient Domes Reveal 3.45-billion-year-old Life History

Stromatolites are very cool. They’re basically mounds of cyanobacteria (aka blue-green algae), built up over a long period of time like a microbial layer cake. They start out as a layer of happy little bacteria hanging out in warm, shallow water. The bacteria have wild parties and eventually build up a dense mat (you know, those kinds of parties) that sediment sticks to. Well, once sediment has started building up, the bacteria have to get back on top so they can get to the sunlight. Rinse and repeat. Over hundreds or thousands of years, a stromatolite can build up into an impressive hump rising from the sea floor. They stick out of the water entirely during low tide.

We have stromatolites building up even today, though they’re not quite as common as they used to be. They’re mostly found in warm, shallow waters, such as those off the coast of the Bahamas – modern carbonate platforms. There hasn’t really been a time in Earth’s history since life appeared that we haven’t had at least a few of these shallow marine platforms, though during some periods of history they were far more common than in others.

As fossils, stromatolites are very distinctive. Relatively young (young being in geologic age, here) have a lot of organic material left over in them, which creates the dark bands. Much older stromatolites, like the ones referred to in the article, will have had the organic material “cooked” out of them by depth or perhaps some other mechanism of metamorphism. The internal structure of the fossil remains, however, even if the material has been chemically altered.

Dr. Allwood has a fascinating point when she mentions stromatolites in connection with mars. If there was life on Mars at any point, bacteria is definitely the place to start looking, and stromatolites are some of the most ancient evidence we have for the existence of bacteria on our own planet. It’s currently impossible to scope out single bacteria with a rover, but evidence of entire colonies of them? I could definitely see that happening. Our stromatolites can get impressively big, as seen in the shark bay picture. There aren’t that many things that would cause internal structure like you see from stromatolites, though there are inorganic processes that can. So finding a bump on Mars and cutting it open to reveal a stromatolite-like structure wouldn’t be definitive proof without further analysis, but it would still be pretty exciting.

Activity discovered at Yellowstone Supervolcano – I talked about supervolcanos a while back. Don’t worry, it’s still in no danger of blowing up any time soon. (And here, we’re talking geologically soon, which is a much, much longer span of time than a human soon.) The two cool things in this article are the discovery that the Tetons are getting shorter, and that there’s a “bulge” that’s expanded and deflated at Yellowstone.

The Tetons getting short is interesting because, in the normal course of things, mountains do get shorter. That’s just the way things work. Mountains are built, erosion wears them down. However, the Tetons are getting shorter much, much faster than they ought to be. Now why is that? Mountain ranges are normally criss-crossed with faults, some of which may be very, very large. The faults are from where the rock broke, unable to handle the strain, when the mountain range was thrust up. There’s a very large, active fault at the feet of the Tetons. The way such faults normally work when active is that the valley at the foot of the mountains drops, while the mountains move higher up. Except that the fault between the Tetons and their valley is going in the exact opposite direction as normal – the valley is rising, the mountains are sinking. It’ll be interesting to find out what the exact mechanism is. The current hypothesis is that this abnormal movement is due to the expansion and contraction of the Yellowstone volcano; the volcano puffs up, it pushes on the valley. The valley creeps up the side of the mountains, which forces them down.

Now, the “bulge” is actually a pretty normal thing, volcano-wise. Contrary to what you might think, rock is actually very elastic. If put under pressure (pressure that isn’t overwhelming, that is) for a long period of time, rocks will deform. When rocks are put under too much pressure too fast, they will break, which is what causes faults. Volcanoes tend to bulge as magma builds up, putting pressure on them from the inside. (One of the heralds of the Mt. Saint Helens eruption was the enormous bulge on the side of the mountain.) In many volcanoes, this bulge builds up and builds up until the volcano erupts. In this case, the bulge deflated a bit before rising again, which indicates a temporary relief of pressure; it also happened pretty rapidly – at seven inches in three years, that thing is sprinting when you think about things geologically. The bulge is probably caused by the movement of magma from the mantel plume that feeds Yellowstone.

* * *

Massive gypsum crystals in a cave in Mexico
These are SO COOL. Look at the first picture carefully – that’s a person in there for scale. These crystals are in a limestone cave, which was probably created by water from a hydrothermal vent coming in through a fault and dissolving the rock. (Limestone is very prone to dissolve when in contact with water.) The water deposited the minerals that formed these crystals (and the precious metal veins exploited in a nearby mine) and the crystals formed over time. The area is still very active as a hydrothermal vent; the temperature of the cave is around 125-150F and the air’s at a constant 100% humidity. Brutal!

If you didn’t know, hydrothermal activity is associated with volcanic activity. When rock is subducted at a plate boundary, it normally carries a lot of water with it. The water is superheated and seperates from the rock; it escapes rapidly through whatever avenues are available to it, normally through faults that form vents. Due to the nature of how the rock melts, the superheated water often carries rare elements with it (such as precious metals) that it deposits along the vents as it cools, moving to the surface.

The giant crystals in this picture are gypsum. Gypsum is a pretty cool mineral. It’s a 2 on Moh’s hardness scale, which means that you can scratch it with your fingernail. When you get a nice crystal that hasn’t been banged up (and it’s hard to find those, sometimes, because just about anything will mark gypsum because it’s so soft) they’re usually transparent. When you touch gypsum, it’s smooth and feels faintly soapy or waxy.

Today was my second field trip with my Sed Strat class. We went up to Settlers’ Park to look at some exposed facies there. (A Facies is a group of sedimentary structures you see in a rock that points to a particular environment that the sediment was deposited in.) If you’re ever in the Boulder area and up for a little bit of an uphill hike, I recommend it. The facies we looked at belonged to the Fountain Formation and the Lyons Formation.

The Fountain Formation is pretty famous, at least locally. A formation is a unit of rock that is geographically contiguous (it’s all connected) and clearly seperate from the formations above and below. Sometimes this seperation is due to a change in rock type, since formations are usually of a single lithology – which is to say composed of just one type of rock. However, sometimes formations are seperated by unconformities, which are boundaries caused by erosion and other events.

So calling it the Fountain Formation means that it’s a big unit of a single kind of rock that covers a definite geographical area. (In this case, a broad swath at the feet of the east face of the Rocky Mountains.) Fountain is the name of the formation. It is composed of sandstones and Arkose; the Arkose is the most famous and gives it its beautiful color. Arkose is a particular kind of sedimentary rock. Arkose is normally primarily quartz, but it has at least 25% Feldspar in it. This will give the rock a definite pink cast, or if its been exposed to any weathering, the Feldspar will cause iron oxide (remember: rust is iron oxide) that stains the rock anywhere from orange to a beautiful, deep red.

A large portion of the Fountain Arkose was deposited by alluvial fans. Alluvial fans are a phenomena found at the base of mountains. What happens is that there are canyons through the mountains – formed by rivers. During the spring melt (or intense storms), massive amounts of water will flood through these canyons, picking up lots and lots of sediment along the way. These canyons let out at the base of the mountains, and the water suddenly spills out in a characteristic fan-shape. (To visualize this, turn on a hose that’s laying on the ground. Notice how the water spreads out in a fan at the end of the hose.)

While the water is shooting through the canyon, it’s going very, very fast. This translates to the water having a lot of energy – and the more energy water has, the bigger rocks it can carry. As the water spills out of the canyon, it loses a lot of that velocity because it’s no longer directed in a channel formed by the canyon walls. So it drops everything that it was carrying.

Alluvial fan deposits are very interesting to look at. They’re composed of layer after layer of different kinds of mudstones, sandstones, and conglomerates. When the water first comes out of the canyon, it drops all of the big rocks that it picked up – anything from coarse sand to even boulders! The rocks formed from that are conflomerates – there’s a wide range of how big the clasts (the bits of rock that the river dropped) are, and some of them are very large. At other times, the water wasn’t moving fast enough to carry large rocks, and it will just drop sand, or even mud. So you will layers with all different clast sizes in them. Mudstones are often far darker than the layers above and below them, so you will see stripes running through the formation.

The Fountain Arkose formed from the erosion of the Ancestral Rocky Mountains – the mounains that existed in the past before today’s Rockies. They were worn completely down, and then a new session of mountain building brought today’s Rockies up. The Ancestral Rockies were made of granite as well – that’s where the Feldspar in the Arkose comes from. Feldspar is an “unstable” mineral. It is subject to chemical weathering, and because of its physical properties, it breaks into tiny pieces easily. So large deposits of Feldspar are normally found close to their source. If they’re buried quickly, they can’t be weathered away!

If you want to see the Fountain Formation, there are many good places to see it in Colorado. In Boulder, you can go to Settlers’ Park, where its been uplifted into a hogback – the originally flat layers of rock are standing vertically. Also in Boulder, the Flatirons are part of that formation. Red Rocks Amphitheatre is built in another exposure of the Fountain Formation. It can also be seen in Garden of the Gods. If you ever have a chance to go to any of these places, I recommend it. They’re beautiful, and there’s some good hikes in those areas along with great geology!

New year, new semester, new tax return, new FAFSA. Where does the time go?

Mineralogy last semester ended well, though I can’t say I’m sorry to see it done. It takes a special kind of person to want to spend all your time staring into a petrographic microscope and thinking about 3-D crystalline forms. I got an A, and I wrote a rather boring paper about Enstatite, an igneous mineral that comes in rather pretty olive colored crystals. (Maybe I should post that paper here so you can look at it and… marvel, if that’s the word I want.)

This semester, my geology course is sedimentary stratigraphy.

Sedimentary rocks are pretty much the unsung heroes of the modern age. Well, to be precise, rocks in general are unsung heroes. They just sort of lay there, as far as most people are concerned, and they don’t actually do anything…

Except that they do. Off the top of my head, here’s what rocks have done for you lately:
1) Kept you from plummeting into an ocean of subsurface magma.
2) Supported your house, roads, office building, etc.
3) Provided some pretty scenary, if you live near mountains.
4) Acted as building materials (or storage for building materials) for at least half the objects you interact with on a daily basis.
5) And so on and so on.

But among the rocks, sedimentary rocks are the work horses for human concern. Now, all rocks are linked together, by something called the rock cycle. Sedimentary rocks are formed by the weathering and erosion of igenous, metamorphic, and even other sedimentary rocks. Weathering is the process by which rock is broken down into little pieces, and erosion is how those little pieces are carried away, most commonly by water, followed by wind and gravity. These little rock pieces are called clasts; they’re carried along by the wind or water and eventually dropped somewhere. This is called deposition. When enough clasts have been dropped in the same location, they build up, compact under their own weight, get covered with more clasts, and eventually get squished and cemented into a sedimentary rock.

That’s the really simple, basic view of it.

Unlike igenous or metamorphic rocks, sedimentary rocks don’t have to be melted or cooked or squished and twisted out of all recognizeable shape. This means that you find an absolute multitude of things in sedimentary rocks that you can’t possibly find in metamorphic or igneous rocks. Things like: Fossils (bones and footprints and things like that), oil, and drinking water.

Sedimentary rocks often also preserve ingenious little clues that tell us a great deal about where they were formed and what the Earth was like at that time, and in that place. You can find ripples preserved in rocks, mud cracks, even the impression of rain drops falling on a desert plain in the distant past. These rocks are our window into a time so far back that human beings didn’t exist to write down what was happening. Remember, in the lifetime of the earth, we are barely the blink of an eye.

So, every time you go to the museum and look at the dinosaur bones, you’re looking at something that was preserved in a sedimentary rock. Every time you put gas in your car, you’re using a product made from oil, which forms in shale (a sedimentary rock formed in deep water conditions), and then hides in subsurface reservoirs, most of them found in either sandstone or limestone (also sedimentary rocks). If you drink water from an aquifer, that water often has filtered a long distance through a formation of sandstone, which has acted as a natural filter so it’s clean to drink.

Isn’t that a weird though, water or oil flowing through rocks? In some of these reservoirs, it’s just finding its way through cracks in the rock. But in the case of sandstone, it is literally travelling through the rock. This is because of the way sandstone is made.

Sandstone is made of sand-sized clasts. Now, these clasts can really be any sort of rock or mineral, but most commonly you’ll find them made of quartz. This is because quartz is pretty hard, and has a property called conchoidal fracture. That means that when a little piece of quartz gets rolled or bumped along by the wind or water, it breaks in a special way. It doesn’t get sharp corners – it breaks in a very round, smooth fashion. So quartz sand, once its old enough and has been moved around enough, tends to be the roundest, smoothest sand you’ll ever find. Then when you pack this quartz sand together, there’s space between the little sand grains. Think about what it looks like when you put a bunch of marbles in a bowl. There’s still plenty of space in between the marbles for liquid to fit in, even if they’re packed as tightly as possible.

So, when you get a whole load of these quartz sand grains together and pack them in tightly, then squish them some more and cement them together to make a piece of sandstone, even if the rock looks solid, there’s actually a lot of empty space in it, hiding between the quartz grains!

This space is what oil and water move through. So when someone drills a well down to contact the sandstone the oil or water is in, it happily moves into the well – because the pressue in a well that goes all the way to the surface is a lot less than the pressure all that oil or water is under when it’s in a rock, under the ground.

There’s a lot more to talk about with sedimentary rocks. Hopefully I’ll be able to ramble about them some more, soon!

NASA has just released a statement saying that they’ve got good evidence of liquid water making an appearence on Mars some time in the last seven years.

BBC News Story

This is very exciting for several reasons. There is water on Mars that we know of, but it’s all locked in ice. (As an aside, did you realize that ice is a mineral? It’s the lowest density mineral that occurs on Earth.) But the most likely cause of this new gully that you can see in the photograph is liquid water! Liquid water is important because it’s necessary for life as we know it (so it once again introduces the possibility that we may some day find some sort of single-celled life on the red planet) and it’s also very important if we ever want to consider the possibility of building some sort of base or research station on Mars. We need a lot of water to survive, and it would make getting there and setting up shop a lot easier if we didn’t have to haul all of the water necessary with us.

Now, there has been evidence suggesting liquid water, though all of that was for much less recent events. A lot of the erosional forms on the surface of the planet point toward liquid water, though it could also be argued that the erosion could be caused by wind as well. (If you’re not actually there to look at things, it can be very difficult to tell the difference between erosion caused by liquid, wind, and simple wasting of loose material.) And there still is a possibility that this new gully was caused by mass wasting or even liquid carbon dioxide.

But liquid water is currently the best explanation.

This is all very exciting stuff!

High resolution images from the Mars Global Surveyor.

Phil Plait comments.

Finals are about to eat my brain. I had no idea school was just so exhausting.

But this cheers my day – and hopefully will cheer yours too!

HiRISE

High resolution images of the surface of Mars, some in color, some in grayscale. The files are enormous, and worth it. You end up with a single pixel being about a meter on the ground – which is AMAZING, considering that we’re talking about Mars, here. Some of topography is just stunning.

Being able to look at geological structures on the surface of Earth is cool enough. But we can really start comparing to what we’re seeing on Mars. It’ll give us some ideas of how certain features on the Martian surface formed, which will answer a lot of questions. (Though there’s a big one we’ll probably need to get in closer to answer – was the agent of erosion water or wind?)

Seeing all of this information streaming in from Mars gives me a lot of hope. My dream is that some day we’ll be able to send up some seismic instrument packages, though that will take a lot of doing. But think about it – being able to take a look at the subterranian geologic structure, and what that could tell us about the history of the planet. (And that would just be scratching the surface!) Some day, I hope… some day.