Research
Processes in the Lower Oceanic Crust
My research on the oceanic crust focuses primarily on the thermal evolution and cooling rates in the lower oceanic crust at spreading ridges. Specifically, I am interested in quantifying the variation in cooling rates with depth in lower crustal gabbros in the Oman ophiolite. This work is important for understanding the role of hydrothermal convection throughout the lower crust as well as mechanisms of lower crustal accretion at ridges.
Geochemical and Thermal Evolution of Large Magma Chambers
My research on the evolution of large magma chambers has focused primarily on the Upper Zone of the Bushveld Complex of South Africa. The Bushveld Complex is the world’s largest layered mafic intrusion and is one of the world’s largest sources of precious metals. The Upper Zone is thought to represent the final pulse of magma into the Bushveld, and is ideal for investigating the effects of heat loss and extreme differentiation of large magma bodies.
Ultimately...
All magmas undergo some degree of crystallization and geochemical evolution prior to eruption or solidification. I am particularly interested in understanding the chemical and dynamic links between cumulate rocks and their eruptive products. Some of the questions that I am working to address include:
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(1)What is the nature of extreme differentiation in large magma bodies (Fe-rich or Si-rich residual liquids)?
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(2)How do large volume high Si rhyolites form? How do volatiles like Cl and F affect their viscosity and ability to flow?
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(3)What can the evolution of parent magma compositions of large layered intrusions tell us about magma source regions and early earth tectonics? How can phase equilibria help us to understand the stability of oceanic and continental crust in the earth earth?
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(4)How do the processes of magma storage and transport through the continental crust affect the final liquid composition at/near the surface?
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(5)Where is magma sourced within the lower crust at mid-ocean ridges? and how does cooling and crystallization affect the inter-eruption variability of MORB?
Comparisons between crystallization and cooling in layered intrusions and mid oceanic ridges will ultimately be important in our understanding of igneous differentiation and magma evolution in a variety of tectonic settings.
Me with layered gabbros in Oman.
Stream through the Main Magnetite Seam in the eastern Bushveld.
Early Earth Tectonics
VanTongeren and Korenaga (2012) IGC Meeting Poster Presentation
The construction of oceanic crust in the modern day can inform our understanding of how the crust might have formed in the Archean, when mantle potential temperatures were hotter, magma compositions were more magnesian, and oceanic crust was much thicker. My work is focused on how changing magma composition influences the phase equilibria present within the crust. The results have implications for the density of the Archean crust, the onset of plate tectonics, and possibly the creation of the ‘building blocks’ of continental crust.
Johnson, Brown, & VanTongeren (in review, Nature Geoscience)
Abbott, Mooney, & VanTongeren (in revision, Tectonophysics)
VanTongeren & Mathez, Geology, (2012)
VanTongeren et al., J. Petrology, (2010)
VanTongeren & Mathez, J. Petrology, (in press, 2013)
Mathez, VanTongeren, Schweitzer, Contrib. Mineral. Petrol. (accepted pending revision, 2013)
VanTongeren, Nature (in review)