4 February 2012

The top 10 reasons I love structure

Posted by Callan

In the past 24 hours, Erik Klemetti and Siim Sepp both gave us their top ten reasons for loving their branches of geo-science. Their lists demonstrated their passion for (respectively) volcanoes and sand, and so I feel inspired to make a list, too.

Here are the top 10 reasons I love structural geology:

10. It’s something. What I mean by this, is: If you’re going to go into geology or the earth sciences, you have to pick something to specialize in. You have to demonstrate competence with a graduate degree – show the world that you can do science. And the state of scientific knowledge is such that we know a lot, and the more we know, the more specific are the questions we have to answer. Occasionally, a surfeit of small insights leads to an avalanche of sudden insight on a bigger question, but mostly science proceeds incrementally. So you’ve gotta pick something: find a particular pile of understanding to which you can contribute a few incremental grains.

9. It’s important. Deformational structures in Earth’s crust have great importance for our species and the entire biosphere. Folding has produced petroleum traps and aquifers. Tectonics has raised mountain ranges that influence climate, soil quality, and human settlement. Faulting has thinned the crust in some areas, making them ideal for tapping geothermal power, or thickened the crust in other places, making ideal loci for the growth of glacial ice masses. Of course, earthquakes are also generated on faults, and knowledge of their behavior helps save human lives and property. Jointing provides fluid-flow pathways of low resistance, leading to cave systems, ore deposits, the practice of fracking, and inspirational landscapes. Shear zones accommodate displacement of large blocks of lithosphere, enabling continental motion and thereby driving biological evolution to pursue independent trajectories on different landmasses.

8. It’s everywhere. Structural geology is not just in the rocks! If you speak the language of structure, you’ll have conversations not only with landscapes, outcrops, and hand-samples, but also more prosaic substances: snow and tofu and cake.

7. It’s a good excuse to travel. I love going places, and it gives me a real thrill to visit structurally profound locations. The Giant’s Causeway, the Grand Canyon, the Lewis Thrust, the North Anatolian Fault, Cape Mendocino, the Glarus Thrust… while each of these locations is aesthetically pleasing, being there takes on a whole new level of meaning when you understand (at least partially) the structural phenomena that led to their coming into existence. In spite of structure’s ubiquity (reason #8), it’s best expressed in the great outdoors, and so the study of structural geology is a good reason to go outside.

6. It’s interesting. Structural problems are tricky four-dimensional stories about familiar substances acting in unfamiliar ways under very different conditions than the way we find them today. These puzzles reveal unexpected insights about the history of our planet — a ball of rock and metal with 4.6 billion year habit of constant change according to constant laws operating under myriad conditions, producing a vast variety of structures that fit into a suite of related themes.

5. It’s challenging. Structural insights have led to more complicated questions and more complicated models of how certain rock phenomena originate. Metamorphic core complexes, snowball garnets, and strain localization in transpressional shear zones come to mind as observations that we don’t totally understand. It strains our minds to grapple with their exact generative processes, and that mental exercise is a valuable thing, in and of itself, in a time in human history when mendacious charlatans can be elected to the highest offices of our ruling structure by an unthoughtful electorate, and our culture focuses its attention on “empty mental calories” in the form of video games, Jersey Shore, and online cat videos. Tricky problems keep our minds sharp in the face of dulling influences.

4. It’s complicated. Structural geology reveals complicated stories for the rocks beneath our feet. They have traveled, they have partied hard, they have been scarred from their adventures. The fact that many rocks reveal odd or anomalous backstories, conditions, and parables is a humbling reminder of how little we really know. Structural geology is not rocket science – Rocket science is far, far simpler because we control those rockets from blueprints to atmospheric re-entry. In contrast, structural stories take place over millions of years in unhuman conditions, at a range of temporal and spatial scales. They are influenced by fluids, strain rates, and material properties as well as dozens of other variables. Sorting all that out is sometimes (often?) quite difficult, and we find ourselves making it easier on our poor minds by making assumptions that we know aren’t realistic. I think it’s a lovely thing to remind ourselves of how little we know of this complex picture.

3. It’s beautiful. Structures are physical phenomena that we discern with our eyeballs. Structural geology begins with pattern recognition. They are often gorgeous, as I think the Friday fold series reveals. This, I think, can be an easy entryway for novices to be interested in structure: even if you don’t know what you’re looking at, some structures just look awesome. Their aesthetic beauty is an invitation to understand the forces that produced them.

2. It’s real. Unlike other forms of pattern recognition (the Virgin Mary on a grilled cheese sandwich, for instance, or a cumulus cloud shaped like a bunny rabbit), structural patterns are real. They are physical phenomena with causes that are (in theory) discernible, and the meanings that structural geologists ascribe to them lead to tangible results, such as the production of oil, the sequestering of carbon, a better understanding of how mountains rise, or predicting how contamination might find its way into a groundwater system.

1. It’s fun. I hope that one of the things I’ve managed to do with this blog is convey a sense of how reasons #2 through 9 combine to result in an enterprise that’s interesting and enjoyable. When I was choosing graduate programs back in 2001, I decided to pursue structural geology simply because it came easily to me as an undergraduate, and as I noted in reason #10, I had to pick something. In a way, my decision to delve into structure was initially an uninspired choice. As time has gone by, though, I’ve found that I care about structure more and more. My increased familiarity has led to a self-amplifying feedback of increased interest. It’s led me to a delightful state of giddy glee when I encounter a new and convivially-exposed structure. If you can’t pick something fun to study, then at least have fun studying what you’ve picked! By working my way towards structural insights, I experience “the happiness of pursuit.”