Ramblings about what I encounter within the realm of the geosciences, as well as the occasional rant about nonsense.

31 March 2009

Intro Geology Concept #1: Superposition

Geology grad students end up doing a lot of grading (I imagine the other sciences are the same). In the course of grading, we come across some answers that make us step back and re-evaluate our life choices. This series won't go into repeating these misconceptions, instead I will try and cover some aspect of geology that I (and other geologists I imagine) consider common knowledge. Hopefully this prevents the spread of geology grads with red palm shaped impressions on their foreheads. First few posts will focus on Steno's principles of stratigraphy. No reason to start here, I just am fond of stratigraphy.

Superposition

The best thing about some of the introductory concepts in geology is how practical and sensible they are. Superposition is no different. Superposition states that in an undisturbed section, younger material rests atop older material. How awesomely simple is that? Very.

To put it another way, in a section that has not been flipped upside-down (via tectonics), the oldest material will be at the bottom and the youngest material will be at the top. Or "stuff won't float in mid-air waiting for material to be deposited under it", which is how my TA phrased it.

The implications for this principle is that it is a tool that allows us to make relative statements about a sequence of events. If we have a mudstone at the base of an undisturbed section, and a sandstone at the top, we can make the statement that the mudstone was laid down before the sandstone. More importantly, we can talk about the depositional environment changing between two time periods, from one that favored deposition of mud, to one that deposited sand. We can't say anything specific about the timing of the events yet (except to say the mudstone is before the sandstone), but this relative sequence of events is a start to understanding a locations geologic story.

Here is a basic figure of the concept (click to animate): The first, and oldest layer, is the gray layer. This is overlain by the blue layer (the second oldest). And the overlying purple layer is the youngest. See, geologic concepts are, generally, very practical.


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Edit: On a similar note About Geology has many excellent posts along these lines. Most recently, one on How to Look at a Rock.

27 March 2009

Glacier Photos V: Ride the Magic Bus

So I loaded these photos up to conclude my series on Glacier National Park Photos, then I promptly forgot about them. I just rediscovered them while perusing through my draft posts folder. So here it is, Part V: Ride the Magic Bus. Parts I, II, III, and IV are available by clicking on their respective numbers.

If you, for some reason, would like more information on the development of these buses, including how/why they were retrofitted, I recommend clicking here.
These buses have been retrofitted to run on propane, which is significantly cleaner than when the buses were first in the 1930s.

Here is an action shot of one of the buses.

These buses were originally produced by the White Company, which went belly up in 1980. However, for the first decade of their existence, they specialized in steam powered cars. In 1918, they left the market of personal cars and focused on mass transit.
The above an below images were just nice decals that have been added to the cars. My brother works with model railroads, so I took these photos so that he could make a replica of these one day.

These two shots are just the look of the car from 3/4 behind and 3/4 front. Once again for the same reason as the close ups on the decals. Plus this shows the placement of the decals on the body of the car.

26 March 2009

Martian Mud Volcanoes

Wow, this is pretty awesome if it pans out. BBC news is reporting that there are possible mud volcanoes on Mars. Here is the link. This was presented, recently, at the Lunar and Planetary Science conference in Texas. I just found out about this via geologynews twitter feed. So I don't know much about it yet myself, but if I find anything more than the BBC article I will make sure to update people.

If this is correct, it could explain the source of the methane that we observe in Mars' atmosphere. So far the only criticism I have found is that this might be a relic of glacial retreat. But I don't know if I would be willing to rule out the mud volcano aspect. Clearly, more research needs to be done on this!
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Edit: Apparently this should not come as a surprise to the geobloggers, I just realized a lot of you are over there too and also subscribe to the geologynews twitter feed. Bloggers ALSO on Twitter.... who would've guessed? Apparently, not me.

23 March 2009

I Better Not Receive Any Telemarketing Calls From Mars Now

I just learned that NASA is recording a series of names on a microchip. This microchip isn't just some tawdry "enemies list", as far as I know, it's even better. It will be sent to Mars on the next Rover mission in 2011! How awesome is that? The answer.... fantastically awesome.

You too can add yourself to the next rover. Just click here, type your name and country, and bingo off you go to The Red Planet, well your name at least. You even get a little certificate that you can print out and hang up on a wall, it you are into that thing. I just saved mine as a pdf. Here it is, slightly modified, to show ITV's name instead of mine:

22 March 2009

What every geologist should know: Florida Edition

A short while back, there was a fun meme running around where you were asked to list 10 things every geology student should know. The catch was not listing anything that had previously been listed. It was a fun way to think outside the standard list that, I am pretty sure, all of us had running through our heads.
Well, not to feel left out, the state of Florida, specifically the University of Florida Administration, has joined in on the fun! Since it hasn't posted its criteria in any list form, I have decided to list out their 10 things every geology student should know:

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.

Wow, now THAT is a comprehensive list. What? The list is blank you say? Well, obviously it is because the University of Florida (one of America's 5 largest universities) has decided to CUT GEOLOGY from the curriculum. Now, I could rant about how incomprehensibly stupid this is for a state like Florida to do. I mean, unless they have somehow managed to solve problems like sinkholes, floods, and coastal erosion, not to mention the potential for a tsunami (related to submarine slides, and another article here). But instead I think I will let this comment, from the Florida Citizens for Science, do that for me:
In an era of ‘green technology’, environmental awareness, the need for natural resource management, global climate change and the need to preserve access to freshwater, the thought of decimating a Geology Department borders on insanity. This is especially true of a flagship university that sits about 150 feet above sea level in a state where the top three revenue generators are, in order, tourism, agriculture and mining.
So, what can you do about this? Simple. Contact the Dean, Provost, and President to voice your support for The Geology Department (contact info follows). Also, it would be a good idea, if you are a Floridian, to contact your state representatives and tell them to stop cutting money from higher education. If, like me, you just care about the erosion of higher education due to incessant budget cutbacks, I would recommend you contact your own state representatives and make sure they know that Florida's actions are not advisable.

Website: http://www.geology.ufl.edu

Addresses:
Dean Paul D’Anieri
College of Liberal Arts and Sciences
2014 Turlington Hall
P.O Box 117300
Gainesville FL 32611
danieri@clas.ufl.edu
P: 352.392.0780
F: 352.392.3584

Dr. Joseph Glover
Office of the Provost and Academic Affairs
Provost and Senior Vice President for Academic Affairs
jglover@aa.ufl.edu
235 Tigert Hall
Box 113175
Gainesville, FL, 32611-3175
352-392-2404

Dr. Bernie Machen
President University of Florida
226 Tigert Hall
PO Box 113150
University of Florida
Gainesville, FL 32611
Ph: 352-392-1311
Fax: 352-392-9506

hat tip to Pharyngula, where I first found out about this.
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Update: The higher ups have put off making a final decision until they know what their financial situation is (here). I would still contact the university officials and your state representatives. Don't let them consider the prospect of dismantling an effective science program as a viable option to save money in the short term.

20 March 2009

Permo-Triassic Boundary NOT the Event of the Season

ResearchBlogging.orgHave you ever had one of those moments, where you read a paper, and you realize the paper is saying...pretty much everything you have been working on for the past few seasons? I just had one of these precious moments. Fortunately, I don't think negates my efforts though. In this case, the paper's location is on the opposite side of the world and approximately 190 Ma earlier. So I think I am safe. *Phew*

The paper in question is Gastaldo et al, 2009 (availble here). This was published in the March issue of Geology, which means you will have to meander over to your local library/university computer to gain access, or just join the GSA.

The deposits spanning the terrestrial Permo-Triassic (P-Tr) boundary are fluvio-lacustrine, with the placement of the boundary based on the position of a succession of laminated beds. Gastaldo et al. seek to determine the legitimacy of using lithostratigraphic means to evaluate the position of the P-Tr boundary. For those not in the know, lithostratigraphy is a subset of stratigraphy which focuses only on characteristics of the rocks themselves to define stratigraphic relationships. In other words, sandstones correlate with sandstones, mudstones with mudstones, etc. Lithostratigraphy is a fairly useful tool for some purposes, but it is inadequate for other purposes. So if you are using lithostratigraphy to help examine some aspect of the geologic record, you better make certain that lithostratigraphy can do what you think it can do.

In the case of fluvial (rivers) deposits and lacustrine (lake) deposits, lithostratigraphy is rife with internal discontinuities. To put it another way, rivers move and lakes can dry up. The upshot of this is that moving laterally in these depositional environments might mean that you are crossing timelines as well. If workers don't take this into account when they are recording their observations, they will have transcribed errors into their data set. For some studies, this is a trivial problem. However, when workers are examining an extinction event, like the one that happened at the P-Tr boundary, these subtle internal discontinuities can lead to erroneous interpretations.

And, in point of fact, the authors determine that the P-Tr boundary (the laminated beds) are diachronous. Which means that these beds were not laid down at the same time, and should not be used to interpret a basin-wide event.

The only problem I have with this paper is how they established their stratigraphic framework. The authors set out to evaluate the utility of lithostratigraphy as a proxy for basin-wide events. Yet, when they set up their stratigraphic framework, they based it on.... lithostratigraphy. To me, this seems akin to using a word to define itself. It doesn't invalidate the conclusions, but I think they could have made a better point by evaluating the lithostratigraphy with some other form of stratigraphy. For example, this paper would have been a much stronger argument if they set up the stratigraphic framework based on some chronostratigraphic criteria.

Chronostratigraphy is essentially "Time Stratigraphy". By looking at deposits that could only have been deposited at approximately the same time (or, in the case of ash deposits, at the same time), it is possible to evaluate the timing of depositional events throughout a basin. A commonly used chronostratigraphic marker, in a terrestrial setting, is palynology (looking at pollen preserved in the rocks). This will provide some "fuzziness" in the data set, because the pollen can be reworked, but this is a better chronostratigraphic framework than nothing. The best chronostratigraphic markers are event beds, like an ash deposit. These can be radiometrically dated, and best of all, they can't be reworked without diluting the ash to the point where it is unrecognizable (it turns out ash deposits have a VERY low preservation potential in most terrestrial settings).

That critique aside, this paper still makes a valid point. Lithostratigraphy, on its own, is an inadequate tool to evaluate the timing of non-localized events (events limited to ~ 1km radius) in terrestrial settings.

citation:

Gastaldo, R., Neveling, J., Clark, C., & Newbury, S. (2009). The terrestrial Permian-Triassic boundary event bed is a nonevent Geology, 37 (3), 199-202 DOI: 10.1130/G25255A.1

18 March 2009

Sun Column

I was just returning to my apartment after picking up some groceries when I looked up and noticed a sun column. I had never seen one before, so I was reasonably excited. I quickly put down my groceries in my kitchen, grabbed my camera and started clicking away. The cause of this phenomenon is sunlight being refracted up into the atmosphere by ice. Here is one of the better pictures, where the sun column isn't just blotted out by, you know, it being a picture of the sun: Now, I should probably get back to packing away the groceries.
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Edit: If you read the comments, you will see that Chuck, from Lounge of the Lab Lemming, also has an excellent picture of a sun column. I recommend that everyone check it out.

16 March 2009

While in the meme mood....

There is another one of these.
“What are ten things that every geology major ought to know about? The only restriction is you're not allowed to list anything that has already been listed by a previous geoblogger. You don't have to list everything, just ten important things."
My ten things:

1. Gravity happens
2. The Earth is a Dynamic Entity
3. Uniformitarianism
4. The Earth is not a closed system
5. Radiometric dating is not synonymous with C14 dating. While we are at it, let's get them to understand how radiometric dating works and how some creationists manipulate the results.
6. I guess this would lead nicely into Deep Time (Not limited to age of Earth, cover the Time Scale, 85% of Earth's history is dominated by single celled organisms, etc).
7. There were more than one Mass Extinction (Dinos weren't even killed by the biggest)
8. The Earth has a finite amount of resources and that ALL of our resources (with the exception of solar power I suppose) are directly derived FROM the Earth.
9. Steno's Principles of Stratigraphy (Superposition, Lateral Continuity, Inclusions, Cross-cutting relationships, and Original Horizontality)
10. Faunal Succession

Hmmm. Some of these get awful close to Mel's and Callan's lists. I'm not changing them, because I think they are slight modifications on a theme. Eric also has a list up. I agree with him that this will get very difficult as the meme progresses. Good Luck!
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Edit: It is also up at Good Schist Hmmm.... I more or less mirrored the radiometric dating requirement... Oh well, number 9 can be broken into 5 separate principles if the meme overlords are that picky about no repetitions. I'm still not changing it ;P

Spring Meme? Not Yet....

There is a Spring meme running around providing the tantalizing prospect of getting outdoors. Not so where I am. It is a bad sign when the Google weather app doesn't even show the snow symbol, just a snowman. Here is the view from my apartment of the Gallatin Range
I promise there is a mountain range back behind all the snow and low lying clouds. Previous participants in the Spring meme include: Kim, Silver Fox, Callan, and Geology Happens. Actually this is probably a good thing. We didn't really get any snow this fall. So, unless dry grass and trees become fire proof, this is the best way to avoid a miserably smokey summer.

12 March 2009

Martian Fans

ResearchBlogging.orgIn the recent issue of Geology, there is a report by Schon et al. on constraining the age of depositional fans by using impact crater density and cratering rays. The title of the paper is "Unique Chronostratigraphic Marker in Depositional Fan Stratigraphy on Mars: Evidence for ca. 1.25 Ma Gully Activity and Surficial Meltwater Origin"

These depositional fans have several potential mechanisms of formation. Schon et al. divide these mechanisms into 3 categories: Dry mechanisms, wet mechanisms invoking groundwater release (from a confined aquifer or similar feature), and wet mechanisms invoking surficial meltwater. However, testing these hypotheses is difficult. This is further complicated by an inability to constrain the ages of depositional events.

The authors attempt to overcome the latter problem by applying impact crater densities in conjunction with cratering rays. The concept of impact crater density is commonly used to date surfaces in planetary geology. The technique measures crater density over certain areas and uses this density as a proxy to determine how long that surface has existed. The implication is the longer a surface is exposed, the greater the proportion of impact craters compared to surface area. This method is only limited by bodies that recycle their surfaces (like Earth having active plate tectonics) and has limited utility on bodies that readily recover their surface (like Io having active volcanism). However, another problem presents itself when scientists try and constrain the age of a surface that is relatively small. This is the major obstacle to applying this technique to martian depositional fans.

Schon et al. have proposed using secondary craters and rays that can be traced back to other primary craters. These primary craters will, ideally, be located in regions of sufficient surface area that impact crater density is a viable tool for age constraint. Then by applying a little bit of super-position and, bingo, you have constrained the age of the depositional fan. In order for a secondary crater, or a crater ray, to be preserved on the surface of the depositional fan, the depositional fan had to have been present before the primary crater.

Below is the second figure from this paper, showing an image of the depositional fan being studied. The authors have outlined several depositional lobes. The clearest application of the authors method would be contrasting the crater rich area that defines lobe 1 with the other lobes (2-4) which post-date secondary cratering. Since lobe 1 is the oldest depo-center, it would have the highest crater density. Comparing this with subsequent depositional centers, it is clear that the lack of cratering indicates that the subsequent lobes formed after the intial cratering event. This constrains the formation of the younger lobes to within 1.25 Ma (the age of the primary crater).
I thought that this was a very good example of how surficial features can be applied to determining general stratigraphic patterns. This is, to my eyes, an excellent method for constraining the maximum age of deposition. However, this study did not have any method to examine depositional mechanisms. The authors argument, that this study supports an interpretation of meltwater as the depositional process, rests on the fact that there are multiple depositional events forming this fan. I don't argue this contention, I just don't think that surficial meltwater is the only possible mechanism that can display this pattern of deposition. Therefore, I don't know if there is enough evidence yet to make the assertion that liquid water is (was) present as recently as 1.25 Maa.
Citations:
Schon, S., Head, J., & Fassett, C. (2009). Unique chronostratigraphic marker in depositional fan stratigraphy on Mars: Evidence for ca. 1.25 Ma gully activity and surficial meltwater origin Geology, 37 (3), 207-210 DOI: 10.1130/G25398A.1

11 March 2009

But Your Hamster Already Knew This...

As I mentioned in the last post, precognition in animals is a pervasive, troubling misconception. I'm sure you are all familiar with this myth in one of its many forms. Horses want to be outside before an seismic event, dogs "know" when their masters are returning home, or cows will lie down if it is going to rain. The problem with most of these claims is the phenomenon known as confirmation bias. To put it another way; you remember the hits (when the animal confirms this misconception), and forget the misses (the numerous times when the animal doesn't exhibit the behavior in question).
Animals and Seismicity
This is a poorly constrained hypothesis to test. First off what magnitude seismic event is required to trigger this "sense". Annually there are over a million estimated earthquakes, but the magnitude of most of these events is minor (source: USGS). Let's just limit this to magnitude 4 and above, and give the added caveat that it has to be an event that the USGS will bother to locate the epicenter. In 2008, there were 14,237 earthquakes that fit these criteria (528 in the USA alone). This translates that, worldwide, there were 39 earthquakes a day (1.45 a day in the USA). Part of this descrepancy can be explained away by the presence of oceanic plate boundaries. But that still leaves 1.45 Earthquakes/day in the USA alone.

Secondly, what observed behavior is expected to result in a "confirmed" observation. One site that claims that this is a verifiable fact defines the behavior of animals as "mild response to bizarre behavior". This is a poorly defined criterion to test at best. What constitutes bizarre behavior? How are the animals being observed. Most of the data appear to be reported annecdotally. Which is highly subjective under the best of circumstances. Rancher A might think it is perfectly normal that animal Q walks counter-clockwise instead of clockwise before sitting down, while Rancher X might view that as a bizarre deviation and prepares for the "big one".

Thirdly, what is the window where observed behavior is related to a seismic event? Is it one day, one hour, one year? It turns out, it is whatever time frame is required to support your hypothesis:
For the Tangshan earthquake (M = 7.8, July 28, 1976), reports of fish, rodents, and wolves were cited as early as a month or two before the event
Seriously? An animal acts "bizarrely" a month or two before an event is used as confirmation? You know, I went to Europe a month or two before, across the country, turkeys were killed and served up in a delicious feast dedicated to giving thanks. By this individuals logic, the two are probably related.

All these problems compound upon themselves into a confirmation bias that "explains" a potential cause for odd behavior after an unrelated event coincidentally happens at approximately the right time.
Pets "know" when you are coming home
Consider, if you will, you are coming home at the end of a busy day at the office. Eagerly awaiting your return is your dog. When you open the door, there your good buddy is waiting to jump up on you (no matter how hard you try to teach them not to). Clearly this is an example of your dog "knowing" that you will be returning home at any given minute. This can't possibly be explained as the dog heard your car, or your footsteps, or your key in the lock.

Granted, this is a simple scenario. Most people would be willing to concede this as a possibility. However, there are a number of individuals who take it a step further and claim that their pets know when they are leaving their office and start getting excited several minutes before any signs of the owner returning home are generated. For example, the following story:
The following case is typical of those cited as proof of ESP. It is unusual only in that it involves belief in a psychic dog, rather than a psychic human. The dog in question is a terrier who has achieved fame as having ESP as exhibited by his ability to know when his owner, Pam Smart, is deciding to come home when she is away shopping or on some other business. The dog's name is Jaytee. He has been featured on several television programs in Australia, the United States and England, where he resides with Pam and her parents, who were the first to perceive the dog's psychic abilities. They observed that the dog would run to the window facing the street at precisely the moment Pam was deciding to come home from several miles away. (How the parents knew the precise moment Pam was deciding to come home is unclear.) Parapsychologist Rupert Sheldrake investigated and declared the dog is truly psychic. Two scientists, Dr Richard Wiseman and Matthew Smith of the University of Hertfordshire, tested the dog under controlled conditions. The scientists synchronized their watches and set video cameras on both the dog and its owner. Alas, several experimental tries later, they had to conclude that the dog wasn't doing what had been alleged. He went to the window and did so quite frequently, but only once did he do so near the exact time his master was preparing to come home and that case was dismissed because the dog was clearly going to the window after hearing a car pull up outside his domicile. Four experiments were conducted and the results were published in the British Journal of Psychology (89:453, 1998).
There we go, nicely debunked. There have been other studies which propose possible explanations for why dogs, like Jaytee, may seem to exhibit precognition. Essentially the argument goes: Dogs are pack animals, and don't necessarily like being left alone. Being left alone will increase the amount of stress a dog experiences. Dogs also learn from where you (the owner) are likely to return from (i.e. the front door). When they go to look for you, they will typically start with where they expect to return. As the duration of their solitude increases, so does their anxiety to be reunited with the pack. This results in returning to the spot where they expect your return more often. As a result, some individuals misinterpret this behavior as a manifestation of ESP. More examples of Precognition in Dogs is available from How Dogs Think by Stanley Coren.
Animals and Weather
Every field trip, one of my friends in undergrad would tell the story of his childhood friend explaining that "Cows will sit down when it is going to rain". When my friend would show him pastures of cows (some sitting and some standing) his friend would explain it away by saying that it meant an x% chance of rain (x being the percentage of cows sitting).

Aside from my friends anecdote, I have not come across this one often. Usually the person telling the story is the most open to the possibility of a "mundane" explanation. The mundane explanation being they heard thunder in the distance, or some similar notion. But every time I go into the field these days, I can't help but think about cows standing around in a pasture. One of these days I will remember to take a photo of cows standing around in a rain storm. Until then, this photo I found on the internet of cows in a driving rain will have to do:

EDIT: 15 Feb 2010
Just found out on Twitter (via Mactavish) that there is a video of a dog 'sensing' an earthquake before people do in the same building. Scrolling through the comments, one individual got the answer right away:

rbelloq:Actually, if you watch closely, especially the light at the top right corner (it's the white pixels at the very top of the frame on the right), you can see the pixels start to jiggle at nearly the same instant the dog gets up.
It looks like a very fast reaction to the tremor.
Nice catch.

10 March 2009

Riding the Storm: Landslides and the Real World

You might have noticed it getting a bit sparse around ITV of late. There are multiple reasons: fighting a devious virus, working on making my figures comprehensible, finishing another draft of the damnable tome (just turned it in. As the kids say, w00t!1!), and keeping up with readings. In other words, I got blindsided by the real world.

One of the cool things I received at the last GSA annual meeting was a copy of the USGS' latest documentary on landslides. It is called "Riding the Storm". I highly recommend this movie. It focuses on two landslide events in California, along with a brief description of what is the cause of landslides. The video covers swift debris flows and slower deepseated slides.

The swift slide is represented by the Love Creek Slide in the Santa Cruz Mountains. It relates the stories of several of the survivors and how they are coping with landslide danger. The common theme is that none of the families expected a landslide.

It also covers a small community being slowly torn apart by a deepseated slide. Most of the families are now the proud owners of worthless homes and have since been forced to move. The government (through FEMA) have helped cushion the financial impact, but the community was still destroyed as the result of insufficient comprehension of earth's processes.

By and large it is an excellent introduction for students into landslides and their impacts. Hopefully, it imparts an understanding to the lay public that geology does not have to happen slowly and they live on the surface of a highly dynamic planet.

My only complaint with the movie is a very brief aside by one of the individuals who helped with landslided mitigation after the Love Creek Slide occured. He made the statement that the landslide happened so fast that the animals weren't even able to sense it was coming. He was making a reference to precognition in animals. I am surprised at high widespread this nonsense has become. I have even heard of a professor use it as an example in a class I TA'd for (I had to keep giving credit for animal precognition as a sign of a potential natural event, though I would always add the note "there is no evidence for this, but okay since the prof. used it in lecture). But this is the topic for another rant.

If you want to view the movie yourself, it is available for download here. I highly recommend it. Plus, at a little under an hour, it makes for a good substitute lecture should anybody need it.

Disclaimer

All the Latin on this page is from my vague recollections from High School. There are mistakes in the text. I just was trying to get the point across

Between Los Alamos,NM and White Rock, NM

Between Los Alamos,NM and White Rock, NM
The photo of the travertine spring was taken in the small opening in the center of the image.

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