Professor Emeritus
Vita (11/6/2023)


Igneous Petrology, analytical geochemistry, trace element modeling, phase equilibria, electron microprobe analysis

Research Interests

Computer modeling of the crystallization of magma within volcanoes; the measurement of trace metals in the crystals and liquids formed during experimental melting and crystallization of volcanic rocks; the study of natural inclusions of magma within crystals. Volcanology, Igneous Petrology and Economic Research Group


BS Geology, University of Arizona, 1976
MS Geology, University of Arizona, 1978
PhD Geology, Southern Methodist University, 1983


GEO 101 - The Solid Earth
GEO 310 - Earth Materials I-Mineralogy
GEO 315 - Earth Materials II-Petrology
GEO 415 Earth Materials III-Igneous Petrography
GEO 412/512 - Igneous Petrology
GEO/OC 508 - Workshop on Microanalysis
GEO 518 - Geosciences Communication
eGEO 518 - Geosciences Communication (ecampus version)
GEO/OC 528 - Microprobe Analysis
OC 668 - Theoretical Petrology
GEO/OC 688 - Trace Element Petrology
Plus many other topical graduate seminars and reading and conference

Graduate Students

Amy Lange (PhD 2013) Magmatic Processes Beneath Mid-Ocean Ridges:  Insights from Mineral and Glass Chemistry in Plagioclase Ultraphyric Basalts

Jennifer Cunningham (MS 2012) Quantification of the Temperature, Pressure and Compositional Dependence of
Trace Element Partitioning: An Experimental and Theoretical Study

Andrew Burleigh (MS 2012) Provenance and Trace Element Signatures of MORB Anorthitic Plagioclase

Hatfield, Ashley C., MS, 2008
Snow Peak, OR: Late Miocene to Early Pliocene Volcanism in the Central Cascadia Forearc

Rowe, Michael C., PhD, 2006
The role of subduction fluids in generating compositionally diverse basalts in the Cascadia Subduction Zone.

Kohut, Edward J. PhD, 2004
Olivine and plagioclase hosted melt inclusions and their appliation to determining parental arc magmas.

Sours-Page, Rachel E., PhD, 2000
Magmatic Processes at Mid-Ocean Ridges: Evidence from Lavas and Melt Inclusions from the Southeast Indian Ridge, the Endeavour Segment of the Juan de Fuca Ridge, and the Northern East Pacific Rise.

Hilyard, Mark D., M.S., 1997
Partitioning of Rare Earth and High Field Strength Elements Between Pargasitic Amphibole and Silicate Melts.

Forsythe, Lance M., PhD, 1994
Trace Element Distributions in Igneous Minerals and Liquids.


Weinsteiger, A. W., Nielsen, R.L. Kent, A.J., Tepley, F.S. (submitted) The trace element diversity of anorthitic MORB plagioclase and their associated melt inclusions, Lithos.

Hatfield, A.K., Nielsen, R.L., Kent, A.J.R., Rowe, M.C., Duncan, R.A. (in press) Snow Peak, Oregon: latest Miocene low-K tholeiite volcanism in the Cascadia forearc, Lithos

Ustunisik, G.U., Kilinc, A., Nielsen, R.L., 2014, New Insights into the Processes Controlling Compositional Zoning in Plagioclase, Lithos 200–20, 80–93

Lange, A.E., Nielsen, R.L., Tepley, F.S., Kent, A.J., 2013,  The petrogenesis of plagioclase-phyric basalts at mid-ocean ridges, Geochem Geophys Geosystems. v. 14, #8, doi: 10.1002/ggge.20207

Lange, A.E., Nielsen, R.L. Kent, A.J., Tepley, F.S., 2012.  Diverse Sr isotope signatures preserved in MORB plagioclase,, Geology, 41; # 2; 279–282; doi:10.1130/G33739.1

Nielsen, R.L., 2011, The Effects of Re-homogenization on Plagioclase Hosted Melt Inclusions, Geochem Geophys Geosys, #2011GC003822R

Adams, D.T., Nielsen, R.L. Kent, A.J., Tepley, F.S., 2011. Origin of minor and trace element compositional diversity in melt inclusions: Evidence from anorthitic feldspar phenocrysts from the Juan de Fuca Ridge.  Geochem Geophys Geosys, #2011GC003778R

Rowe, M.C., Nielsen, R.L., A.J.R. Kent, 2009, Subduction Influence on Basaltic Oxygen Fugacity and Trace- and Volatile-Elements Across the Cascade Volcanic Arc, Journal of Petrology, 50, 61-91.

Rowe, M.C., A.J.R. Kent, R.L. Nielsen, 2007, Determination of sulfur speciation and oxidation of olivine hosted melt inclusions, Chemical Geology, 236, 303-322.

Kohut, E.J., Stern, R. J., Kent, A.J.R., Nielsen, R.L., Bloomer, S.H., and Leybourne, M, 2006, Evidence for adiabatic decompression melting in the Southern Mariana Arc from high-Mg lavas and melt inclusions, Contrib. Mineral. Petrol., 152, #2, 201-221

Rowe, M.C., Nielsen, R.L., and Kent, A.J., 2006, Anamalous Fe contents in rehomogenized olivine hosted melt inclusions from oxidized magmas, American Mineralogist, v. 91, #1, 82-95.

Kohut, E.J. and Nielsen, R.L., 2004, Melt inclusion formation mechanisms and compositional effects in high-An feldspar and high-Fo olivine in anhydrous mafic silicate liquids. Contrib. Mineral. Petrol., 147, 684-704

Kohut, E.J. and Nielsen, R.L., 2003, Low pressure phase equilibria of anhydrous anorthite bearing mafic magmas G-cubed, v. 4 #7, ISSN 1527-2027.

Zimmerman, C.E. and Nielsen, R.L., 2003, Effect of Analytical conditions on the measurement of Strontium/Calcium ratios in otoliths of anadromous salmonids using wavelength dispersive electron microprobe analysis. Fisheries Bulletin, 101, 712-718

Michael, P.J., McDonough, W.F., Nielsen, R.L., Cornell, W.C., 2002, Depleted Melt Inclusions in Plagioclase: Messages from the Mantle or Mirages from the Magma Chamber? Chem. Geol., 183, 43-61.

Sours-Page, R., Nielsen, R.L. and Batiza, R., 2002, Parental magma diversity on a fast-spreading ridge: Evidence from olivine and plagioclase-hosted melt inclusions in axial and seamount lavas from the northern East Pacific Rise Chem. Geol.,, 183, 237-262.

Norman, M., Garcia, M., Kamenetsky, D. and Nielsen, R.L., (2002) Melt inclusions in Hawaiian picrites: Melting and source compositions Chem. Geol.,, 183, 143-168.

Hilyard, MD, Nielsen, RL, Beard, JS, Patino-Duce, A, Blencoe, J., 2000, Partitioning of REE and HFSE between pargasitic amphibole and natural silicate melt, Geochim. Cosmochim. Acta, 64, 1103-1120.

Nielsen, RL and Beard, JS, 2000, Magnetite-melt HFSE partitioning, Chem. Geology, 164, 21-34

Nielsen, R.L, Sours-Page, R.E., and Harpp, K., 2000, The role of a Cl-bearing flux in the origin of depleted ocean floor magmas, G-cubed, 1, paper 1999GC000017.

Sours-Page, RE, Johnson, KTM, Nielsen, RL and Karsten, J., 1999, The petrogenesis of the diversity of parent magmas in the Endeavour Segment of the Juan de Fuca Ridge. Contrib. Mineral. Petrol. 134, 342-363.

Nielsen, RL, Michael, P. and Sours-Page, RE, 1998, Physical and chemical indicators of compromised melt inclusions. Geochim. Cosmochim. Acta, 61, 161-172

Nielsen, R.L., Crum, J., Bougouis, R., Forsythe, L.M., Fisk, M.R. and Christie, D.R., 1995, Melt Inclusions in High-An Plagioclase From the Gorda Ridge: An Example of the Local Diversity of MORB Parent Magmas. Contrib. Mineral. Petrol. 122, 34-50.