|
Teaching Interests and Philosophy
For majors in Earth & Environmental Sciences, I teach Mineralogy (EES 12), Analytical Methods in the Earth Sciences (EES 100), and Igneous and Metamorphic Petrology (EES 101). At the graduate level, I teach Volcanology (EES 271) and various versions of Magmatism and Tectonics of the Western U.S. (EES 250T). In 250T, we usually investigate problems of magmatism and/or tectonics that can at least be partially tested by the examination of field data. Each such trip then, involves a 5-day to 1-week field trip, usually to the western Basin and Range, the Grand Canyon region, or the lower Colorado River (between AZ and CA). Research is a key component to an Earth Science education and so students in my classes conduct research projects, which involve field and laboratory experiences. Our X-ray fluorescence (XRF) and X-ray diffraction (XRD) instruments are utilized as lab components in these courses. For non-majors, I teach Environmental Earth and Life Science (NSCI 115). A goal in this course is to illustrate how a scientific understanding of our planet is crucial to many aspects of our daily lives.
Research Activities in Mineralogy and Igneous Petrology
My research interests are several. I am interested in how the internal engine of our planet works. My research group thus attempts to estimate the depths and pressures of partial melting in Earth’s mantle, to better understand mantle circulation. The questions I am attempting to answer are: How hot are mantle plumes, and at what depth does melting begin? How can plumes be identified? What is the composition of Earth’s mantle, and do mantle plumes sample a distinct mantle source? I am also interested in understating how volcanoes work. On this topic, my students and I investigate the ascent and transport of magma through the crust and uppermost mantle, and attempt to determine the various controls on magma transport and eruption. The relevant questions here are: How deeply rooted are magma plumbing systems, and at what depths are magmas stored prior to eruption? Do such storage depths change over time, or vary with tectonic environment? What are the controls on the transport of magma through the crust? Finally, I have recently begun investing plutons in the western Sierra Nevada. In this part of the range, it is possible to see deep-level exposures, which provide insights as to how structurally high levels of plutons (the granitoids, that comprise the bedrock of most of the range) are developed? Key questions here are: What are the compositions of primitive magmas that give rise to granitoid batholiths? Which processes are most important for deriving granitic magmas: crustal partial melting, or differentiation. Can mafic enclaves provide clues regarding the differentiation and magma mixing processes that generate batholiths?
Presently, several students are working, in collaboration with Michael Clynne of the U.S.G.S., at the Lassen Volcanic Center in northern California, in particular at Lassen Peak and Chaos Crags. Some students are also investigating “ancestral” Cascade volcanism, in the central Sierra Nevada, in collaboration with Cathy Busby, at UC Santa Barbara. Several students of mine are also working in collaboration with Scott Paterson at USC, to understand various Sierran granitic plutons, and the Guadalupe Igneous Complex (in the Sierra foothills, below Mariposa) in particular. Finally, I have some new collaborators in Pisa (Pietro Armienti) and Rome (Silvio Mollo). Pietro and I are investigating means to estimate deep-level ascent rates of magmas, while Silvio and I are using his experimental results to better understand mineral growth rates and kinetics.
Downloads: I have put together several spreadsheets that can be used to calculate the P-T conditions of crystallization or partial melting, and mantle potential temperatures.
The spreadsheets Clinopyroxene and Orthopyroxene respectively calculate the P-T conditions for clinopyroxene-liquid and orthopyroxene-liquid equilibrium. The spreadsheet Feldspar-liquid calculates T and water contents for plagioclase-saturated liquids, and T for alkali feldspar-saturated liquids. The workbook Olivine and glass calculates the T of olivine-liquid equilibrium and the T for silicate liquid (glass) given only the composition of the liquid itself. This workbook also allows for the calculation of T using the graphical approach of Roeder and Emslie (1970) approach (see Putirka, 2005). The spreadsheets Two-feldspar and Two pyroxene respectively calculate the T of equilibration for equilibrium pairs of alkali and plagioclase feldspar and equilibrium pairs of ortho- and clino-pyroxene (no liquid composition required for input). The spreadsheet Silica activity calculates the equilibrium pressure for silicate liquids in equilibrium with olivine and orthopyroxene; T is required as input, which is best derived from one of the models presented in the Olivine and glass spreadsheet. The workbook Mantle Potential Temperatures allows for the calculation of mantle potential temperature, given a primitive liquid and olivine composition; P and T are calculated from olivine thermometry and Si activity, but can also be entered directly. In the same workbook, a separate spreadsheet allows for the calculation of mantle potential temperature if an olivine-liquid temperature and equilibration depth are known. Other parameters, like the heat of fusion or adiabatic gradient, can be easily changed. This workbook also contains a spreadsheet that allows one to calculate the composition of a liquid in equilibrium with mantle olivine (to use as input to obtain mantle pot. T) using a primitive olivine-saturated liquid as input; other required inputs are the Fo content of mantle olivine, and the Fo content of the olivine to be added or subtracted from the given liquid. This spreadsheet can only be used for putative liquids that are thought to be saturated with olivine only, and so lie on what is called an “olivine control line”.
Laboratory Facilities: We have an X-ray fluorescence (XRF) spectrometer (acquired in 2003) and a powder X-ray Diffractometer (XRD; acquired in 2005) here at CSU Fresno – both manufactured by PANalytical (formerly Phillips). The XRF is a MagiX Pro, with a 4 kW tube, and a Helium attachment that allows us to analyze loose powders and liquids. Our XRD is the X’Pert Pro with an X’Celerator detector. These instruments play important roles in the projects described below.
Selected Recent Publications
- Putirka, K.D., Canchola, J., McNaughton, M., Paterson, S.R., Smith, O., Torrez, G., and Ducea, M. (2014) Day 1: The Guadalupe Igneous Cmplex – From Gabbros to Granites, in: Formation of the Sierra Nevada Batholith: magmatic and tectonic processes and their tempos, GSA Field guide, Geological Society of America, 2014; Memeti, V., Paterson, S.R., and Putirka, K.D. [Editors]. (in press)
- Putirka, K. (2013) Editorial: Why publish your best papers in American Mineralogist: An International Journal of Earth and Planetary Materials, American Mineralogist, v. 98, p. 1377-1378.
- Putirka, K., Kunz, M., Swainson, I., and Thomson, J. (2013) Journal impact factors; their relevance and their influence on society-published scientific journals. American Mineralogist, v. 98, p. 1055-1065.
- Mollo, S., Putirka, K., Iezzi, G.,, and Scarlato, P. (2013) The control of cooling rate on titanomagnetite composition: Implications for a geospeedometry model applicable to alkaline rocks from Mt. Etna volcano. Contributions to Mineralogy and Petrology, v. 165, p. 457-475.
- Mollo, S., Putirka, K., Misiti, V., Soligo, M., and Scarlato, P. (2013) A new test for
equilibrium-based on clinopyroxene-melt pairs; clues on the solidification temperatures of Etnean alkaline melts at post-eruptive conditions. Chemical Geology,v. 352, p. 92-100.
- Putirka, K., and Platt, B. (2012) Basin-and-Range volcanism as a passive response to extensional tectonics, in review, Geosphere, v. 8, doi: 10.1130/GES00803.1.
- Armienti, P., Perinelli, C., and Putirka, K.D., 2012, Deep-level magma ascent rates at Mt. Etna (Sicily, Italy), in review, Journal of Petrology, accepted.
- Putirka, K., Jean, M., Sharma, R., Torrez, G., Carlson, C. (2012) Cenozoic volcanism in the Sierra Nevada, and a new model for lithosphere degradation, Geosphere, v. 8, p. 265-291, doi:10.1130/GES00728.1
- Putirka, K.D., Ryerson, F.J., Perfit, M., and Ridley, W.I. (2011) Mineralogy and
composition of the oceanic mantle, Journal of Petrology, v. 52, p. 279-313.
- Mollo, S., Putirka, K., Iezzi, G., Pierdomenico, D.G., and Scarlato, P. (2011) Plagioclase-melt (dis)equilibrium due to cooling dynamics: implications for thermometry, barometry and hygrometry, Lithos, v. 125, p. 221-235.
|
