Behind the Rocks

Meet Yvette Kuiper

Yvette Field

I grew up in the Netherlands, where geology is not a big thing. After all, there aren’t really any rocks to see until you cross the border into Germany or Belgium. After high school I wanted to do science, any science, but with a tangible part. I was thinking biology, until my mom learned about geology at a funeral, from one of my second-generation cousins. That funeral changed my life. Geology it was.

First at Utrecht University in the Netherlands (MSc), then at the University of New Brunswick in Canada (PhD) and then the University of Waterloo in Canada (Postdoc). I am a structural geologist, studying how rocks deform at all scales. Structural geology is challenging and beautiful, just the way I like it. It involves a lot of three-dimensional thinking, and four-dimensional if the aspect of time is incorporated. Recently I am embarking more and more in the field of tectonics, also incorporating other fields of geology, in order to unravel how tectonic plates moved, through time. It is clear that the Earth is a beautiful place to study.

My first real job was as Assistant Professor at Boston College. It was there that I became hooked on Appalachian geology. I am now an Associate Professor at the Colorado School of Mines, where I took a job eight years ago, but still intrigued with the Appalachians. I was awarded a National Science Foundation Career grant, a five-year competitive early career award, just prior to departure from Boston College. For five years, my students and I returned to the Appalachians year after year, solving some problems and asking new questions. It was then that I started thinking about the Norumbega fault system.

The Norumbega fault system is a northeast-trending, subvertical, crustal-scale fault along the eastern margin of the northern Appalachians that was active about 390-350 million years ago, and reactivated after. It extends for more than 300 km from southwestern New Brunswick to southern Maine. Where I was working in eastern Massachusetts at the time, it is nowhere to be found, and it did not take long after I had thought that thought before I became obsessed with the question of why that might be.

A potential answer to that question is now published in the journal Geology (Kuiper, 2016), and in more detail in Tectonophysics (Kuiper and Wakabayashi, 2018). I came up with a model that is similar to the formation of the San Andreas Fault. Take the San Andreas fault system and the Cascades to the north, rotate it about 180 degrees, subtract about 360 million years, and you’ll have the Norumbega fault system and geology of eastern Massachusetts to the south. The model is a model, and difficult to prove. However, it explains a lot of the geology in the area. Will the model stand the test of time, or be proven wrong some day? Time will tell!

Rock pencil

Numerous geologists visit exposures of the Norumbega fault system. The thin section shown on this line of apparel is from an exposure at Appleton Ridge in Maine (Price et al., 2010; Frieman et al., 2013; Gentry, 2018). To the regulars, it is known as the ‘outcrop in the blueberry field’, though that is true for more than one outcrop. The image was taken under cross-polarized light. The yellow/gray bigger minerals are staurolite, while the colorful minerals are biotite and muscovite, which wrap around the staurolite and form an asymmetric fabric. The asymmetric fabric tells that the fault moved in a right-lateral manner. Details can be read in the references cited above. Perhaps most importantly, the fabric is pretty and will make you look good wherever you go.


Frieman, B.M., Gerbi, C.C., Johnson, S.E., 2013. The effect of microstructural and rheological heterogeneity on porphyroblast kinematics and bulk strength in porphyroblastic schists. Tectonophysics 587, 63–78. https://doi.org/10.1016/j.tecto.2012.11.007 

Gentry, E.N., 2018. Characterizing the southwestern extent of the Norumbega fault system, a mid-Paleozoic crustal-scale strike-slip fault system in the New England Appalachians. M.S. Thesis, Colorado School of Mines, Golden, CO, USA, 103 pp. https://hdl.handle.net/11124/72335

Kuiper, Y.D., 2016. Development of the Norumbega fault system in mid-Paleozoic New England, USA: an integrated subducted oceanic ridge model. Geology 44, 455–458. https://doi.org/10.1130/G37599.1

Kuiper, Y.D., Wakabayashi, J., 2018. A comparison between mid-Paleozoic New England, USA, and the modern western USA: subduction of an oceanic ridge-transform fault system. Tectonophysics 75, 278–292.
https://doi.org/10.1016/j.tecto.2018.08.020

Price, N.A., West, D.P., Johnson, S.E., Marsh, J.H., 2010. Coupled deformation and metamorphism, ultramylonite development, and evidence for paleoseismicity  during protracted dextral shearing in south-central Maine. In: Gerbi, C.C. and Yates, M, eds.: Guidebook for fieldtrips in coastal and interior Maine, 102nd New England Intercollegiate Geological Conference, 109–131.


 

Pelitic Schist

Transmitted, Cross-Polarized Light
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