Wednesday, March 21, 2012

"Why would you want to study rocks?" Part 1: The Big Picture

This is the first in a short series of posts giving my response to a question that geologists often have to deal with:  What is it that is so interesting about rocks and why would anyone want to study them?

Please note that I intend to address this question in a manner that intentionally excludes economic and environmental/social reasons to study geology.  My goal is to demonstrate that geology is interesting in itself without factoring in economic or social issues that come into play in certain areas of the field.  There are a variety of geology bloggers out there who can and have written on the economic, environmental and social importance of geology and I don't feel it's necessary to add my voice to the chorus.

So, why do we want to study rocks?  I would like to start by illustrating the difference between what an average joe thinks of when they hear "rock" or "rocks" and what a geologist thinks of.

When an average person thinks of rocks, they tend to think of something like this:

Or this:

Or this:
Please note that this example is incorrect.  That is actually a plant.
The problem here is obvious.  Most people think of rocks as something bland, mundane, simply...there.  Things that get in your way when digging a hole, or something to fill a garden with.  Fortunately, they're much more than that.

When geologists think of rocks, we tend to think of something more along these lines*:

Image Credit: Dave Moser at Earth Science Picture of the Day.

Thanks to Anne Jefferson of Highly Allochtonous for allowing the use of this photo.

Each of these photos, in addition to being more beautiful than the rather bland pictures presented earlier, present a bigger picture with more information and -- just as importantly! -- more questions to be asked.

Look at the first photograph of Navajo Sandstone.  There are many questions that come to mind:  How did it get there?  How long did it take for it to form?  How old is it?  Why the odd colors?  Why do the formations hold the shape they do?  What about the striations (lines), and the way they dip and curve?  Many more questions could follow.

Many of the questions surrounding volcanoes should be immediately obvious to laymen, so I'll leave that photo alone.

Moving onto the third photo, a few questions arise immediately:  Why is it so big? (Look at the man posing in the picture to get a sense of the scale.)  Speaking of big, what about the large veins of lighter rock intruding into the darker material?  How did they get there?

The fourth photograph is particularly important precisely because it depicts a seemingly mundane scene:  It's a stream, so what?  A closer look reveals a much more interesting picture, however.  One can ask how the stream formed, why it took its current shape, and for that matter, how and why the water caused the underlying bedrock to develop the 'steps' and what effect, if any, the steps have on the flow of water. (The last question is dealt with in the blog post I linked to above.)

Within the field of geology there are methods available to help answer all of those questions, and many more, and the kinds of questions I've listed cover only a fraction of the things that geologists deal with.  There is a big picture that comes into play in geology that outsiders rarely see.  Geology is much more than just looking at and classifying rocks.  That said, there are also many issues focusing on a smaller picture that come into play within the field of geology and those are also important (and interesting!) but those are for another post.

*To the geologists:  Please note that I am not saying that hand samples are unimportant, or inherently boring.  I am merely trying to convey that there is a bigger picture that many outsiders are unaware of.  I will cover hand samples in a later post.

Part 2, Part 3, Part 4


  1. Nice post and I'm flattered that you chose my picture. One thing I should point out though (and I realize I was maybe less than clear in my original post) is that those rocks in the stream are not natural bedrock steps. They have been dug out of somewhere else and placed in the stream by heavy machinery to achieve some set of engineering and ecological goals in the name of "stream restoration." Of course, your point still holds...upon examining a "mundane" scene, there is a lot more than immediately meets the eye.

  2. Oops! I was wondering about that....I've seen one stream which a single, large natural 'step' (unfortunately it was located near a road in a city and thus had graffiti all over it - not photo material) but I'd never seen a series. In any case, thanks for helping educate me and whoever reads this.

  3. Ooohhh I _like_ the Navaho sandstone.
    Is that where the "Myst" people got their aesthetic from?
    Round here there's some lovely red swoopy-bedded sandstones of Carb. age, but the vile climate means they're permanently covered in veg and green slime, except for fresh exposures in quarries and the like.

  4. Dustbubble:

    I selected the Navajo Sandstone precisely because of it's beauty. That's a very good question, by the way. I don't know the answer, of course, but I've always appreciated the aesthetic, desert or desert-esque scenery is something rarely seen in video games, at least not in the form of something intended to be a beautiful landscape.

  5. The sandstone picture is from an area known as the Wave. It is a fairly short permit only hike between Kanab Utah and Page Arizona. Make it a life goal to see it. You won't be disappointed.

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  7. that rock looks really cool, that was amazing