Plate tectonics: a little of everything

Overall, I consider myself a generalist (despite that I’m going for a PhD right now). That means I like to know at least a little bit about a lot of different things. There are also specialists, or people who know a lot about one or a few related things. I’m also a bit of a specialist in that I’m seeking to know a lot about my dissertation research but my dissertation research combines many concepts that span multiple disciplines.

For example, I use computers to understand how plate motion affects the outermost layer of the earth. That means I need to know about computers, software, and coding in addition to the geological concepts that I use. Further, the geological concepts I need to know combine mathematics, physics, chemistry, and materials science. The physics of the processes that result in mountains are described mathematically using numerical models for heat and material transport. Also, the way stress affects rocks (which occurs due to plate motion) depends on chemistry or mineral composition and is a function of temperature. Then there’s the geology which incorporates a lot of subdisciplines like computational geodynamics, structural geology, isotope geochemistry, geomorphology, seismology, and mineral physics, to name a few.

So when people ask me what I do, I often have a different answer depending on the situation and the person asking. Basically, I have a lot of options for responses. But if I want to put it into one term: I say I’m a tectonicist.

It works because Plate Tectonics is the grand, unifying theory of geology. That is, it ties together all of the aspects of earth science, which makes it pretty darn important.

This week, my lab students have elected to learn about plate tectonics. They cast votes – unbiased by me – and chose my favorite topic. So I’m using this blog to teach them (and you!) some basics.

The simple idea behind plate tectonics is that the lithosphere – the outermost portion of the earth which includes the continental and oceanic crust and the uppermost mantle – is broken up into rigid sections called plates that “float” on a weak part of the mantle called the asthenosphere. Below the plates, the mantle convects – similar to how water convects in the pot when you’re boiling it on the stove – and this convection results in motion of the overlying tectonic plates.

Plates move relative to each other in three different ways at plate boundaries. They can push into each other – which is known as a convergent plate boundary, they can move away from each other – which is known as a divergent plate boundary, and they can move past one another – which is known as a transform plate boundary. The interactions at plate boundaries result in many geologic features and phenomena that are observed on earth. For example, mountains, volcanoes, and earthquakes are all related to motion at plate boundaries. Sometimes, some of these features occur inside of a plate instead of at a boundary but that’s due to a different phenomenon you can learn about here.

Different types of plate boundaries and where they occur on earth.

My lab students will learn about the different features associated with these types of plate boundaries as well as the hazards associated with each.

Hopefully, I’ve piqued your interest in plate tectonics and if you want to learn more, continue reading my blog because plate tectonics has it all and is always on my mind!

From mountains to microscopes

I like pretty things, which is why I’m drawn to geology as a discipline. There is beauty to be found in many aspects of the science – at all scales.

You may have guessed that I’m a fan of large scale formations that result from large-scale processes (mountains! tectonics!). But I’m also a fan of the micro-scale – things that can be observed using a microscope.

Geologists call the special optical microscopes that they use petrographic microscopes and the study of rocks that uses such a microscope is called petrography.

To study rocks under the petrographic microscope, it has to be cut thin enough for light to pass through. Geologists use something called a thin section – or thin slices (usually 30 microns or 30/1,000,000 meters thick) – of a rock or mineral sample. Thin sections are usually mounted on a slide with adhesive and measure 26 x 46 mm but the size and shape can vary depending on the application. Also, there are different ways to treat thin sections, like embedding them with different media, staining them to highlight different minerals, or coating, covering, or polishing them differently so that they are compatible with different types of light or microscopes. If you want to learn more about making thin sections see this excellent website.

Petrographers use polarized light microscopy to observe features in the thin sections. Polarization acts as a filter to isolate waves of light along particular planes. If you think of the way a guitar string vibrates up and down along the length of the string it’s similar to how light propagates through space. The difference is that there are different orientations of the waves and polarized light takes out some of the orientations. The graphic below illustrates how light travels in directional waves and how the polarizer works to filter it.

Cartoon of how polarization affects light.

Polarizers are used by petrographers because the minerals that make up rocks exhibit an optical property called birefringence which means the mineral looks different depending on the nature of polarization. The way the mineral looks under different polarization (plane-polarized versus cross-polarized, for example) can be used diagnostically – that is, it is useful for identifying and characterizing the mineral and it’s history.

Plane polarization is when only a lower polarizer is used and cross polarization is when a lower polarizer and an upper polarizer (also called the analyzer) are used. Properties that can be observed using plane-polarized light microscopy include opacity (degree to which a material transmits light), color, pleochroism (when a material changes color as it rotates relative to the polarizer), refractive index (the speed of light in the material relative to that in a vacuum), and relief (the difference in refractive index between a material and its surroundings).

Under cross-polarized light, minerals reveal very interesting properties, many of which are slightly too technical to describe in detail here. One example; however, is called twinning and it occurs in plagioclase and some other minerals (see below).

Twinning in plagioclase, source.

The textures and patterns that can be observed in thin sections of rocks using a petrographic microscope and not only beautiful but also aid in scientific investigation. For example, petrologists use microscopy to study things like the metamorphic and deformational history of rocks. Further, chemical analysis can be combined with mineral identification from thin sections to determine the environmental conditions under which igneous rocks form, which can be useful in understanding magmatic processes.

So whether you’re looking at a rock through a microscope or observing global patterns there’s always something beautiful and interesting to see.

How to Pay for Graduate School in Geology

Money has never been an easy subject for me. Growing up, my parents were often stressed out about finances and were constantly searching for ways to make ends meet. Needless to say, I didn’t have a college fund set up so I had to figure out how to pay for my own education from the start. I saved some money by first attending community college and then transferring to a four-year university but I still had to figure out a way to pay for it all on my own.

I was fortunate to be eligible for Pell Grants which helped a lot. I also took out some federal loans that are partially being forgiven because I worked for the Federal Government for a few years prior to attending graduate school. Of course, one of the things that came to mind when thinking about leaving my job to return to school was how I was going to pay for it (or more correctly, have it paid for!).

So if you’re thinking about graduate school, or have already started graduate school, you may have realized that funding options are a bit different from what you may be used to from undergrad. The majority of graduate students in STEM fields in the U.S. are funded in one of the ways I discuss below: through fellowships, assistantships, scholarships, grants, or (forgivable) loans or some combination. Personally, I have received at least one from each category during my graduate career.


Fellowships are probably the most desirable funding option for graduate students because they allow you the freedom of working on a project that you can propose yourself and they don’t have to be repaid. Basically, you aren’t tied to a particular PI’s research grant which gives you more flexibility in terms of a research topic. They also sometimes pay a little better than some of the other funding sources. Because of their attractiveness; however, they are also often highly competitive.

I give a list of some below with links to each website. Fellowships have eligibility requirements which vary and typically require a project proposal which means you need to have research goals prior to applying. Applications also include a personal statement and letters of recommendation as well as other materials like short essays. Here is a list of some that I came up with but make sure you do your own search (for example, on university scholarship and financial aid websites) to see if you can find others that you may be eligible for.

American Association of University Women Fellowship

Department of Energy Computational Science Graduate Fellowship

National Defense Science & Engineering Graduate (NDSEG) Fellowship

National Science Foundation Graduate Research Fellowship Program (NSF-GRFP)

National Research Council Research Associateship Programs

Ford Foundation Fellowship

Fulbright US Student Program

GEM Fellowship

Hertz Fellowship

Quad Fellowship

Smithsonian Institution Fellowship


In this post, Callan Bentley does a great job explaining assistantships. I’d recommend reading what he wrote, but to sum it up: there are two types, teaching assistantships (TAs) or research assistantships (RAs). With a TA, you’re obligated to teach or assist in teaching a course, typically at the undergraduate level. With an RA, you’re obligated to do research that is tied to a grant that has been awarded to your research advisor or a collaborator. That means the research project you work on has already been proposed and funded so it can be less flexible than a fellowship in terms of the type of research you end up doing.

Also, TAs can be offered through the department and the department might have limits on the number of years you can serve as a TA (my department has a two year limit but that’s sometimes negotiable). If you plan on staying in academia and focusing on teaching over research, you may want more TAs than RAs.

Lastly, my advisor is a strong believer in having each of his students serve at least one term as a TA to get some teaching experience prior to finishing graduate education. I think he has the right idea considering that as an academic (even if your focus is research), you’re almost certainly going to need to teach in some capacity.


Scholarships are great and that once they are awarded, there are few restrictions on what you can use them for and there is no service to exchange for them. However, more often than not they have lower dollar amounts than other sources of funding so they are best thought of as a way to supplement other funding sources. There are A LOT of scholarships out there, again with different eligibility requirements and varying levels of competitiveness. I list a few here to get you started but I recommend performing your own search as well. Make sure to check your university and department websites too.

AIPG William J. Siok Graduate Scholarship

Association for Women Geoscientists Scholarships

Harriet Evelyn Wallace Scholarship for Women Geoscience Graduate Students

RMAG Foundation Scholarships

Society of Exploration Geophysicists Scholarships

Forgivable Loans

If you can avoid loans, I recommend you do that that because they usually have to be repaid and it can be hard for a lot of people to get themselves out of student debt once they accumulate it. Forgivable loans are slightly different, however. Forgivable loans are loans that once you meet some set of criteria, can be forgiven (that is, they don’t have to be paid back). One example includes federal loans under the the Public Service Loan Forgiveness Program. There are others too, like my university’s Gastwirth Graduate Student Loan. That one is forgiven if you secure a job outside of industry following graduation. Make sure you check your university, college, and departmental funding source websites to look for these.

Graduate Research Grants

Many organizations offer small grants to graduate students to support costs associated with thesis or dissertation research. I provide some examples below but you also want to look at organizations that are specific to your school or program (like graduate student unions, for example). Travel grants to support students presenting research at a conferences are also usually available through these same organizations. Below are some geology-specific ones.

AAPG Foundation Grants-in-Aid

AEG Foundation Funds

AGeS(3) – Advancing Geochronology Science, Spaces, and Systems

American Geophysical Union Grants

Cave Research Foundation Grants

Evolving Earth Foundation Student Grant Program

GSA Graduate Student Research Grants

Mineralogical Society of America Grant

Sigma Xi Grants in Aid of Research

Hopefully this serves as a good starting point for you on your journey to funding your graduate education. Also, please realize this is not a complete list and you may have to do quite a bit of your own research to find ones that are best suited to you as an individual.

Good luck!