, Assistant Professor of Geology    

Ph.D. (1995) University of Maryland

M.Sc (1991)  University of Manitoba

B.S. (1988) New Mexico Tech

Click here for c.v. (pdf file)

I joined the Oswego State Earth Science faculty in January, 2004.  Since then I have taught courses in Mineralogy (Geo 310+L), Surface Water Hydrology (Geo 335), Igneous/Metamorphic Petrology (Geo 416+L), Geochemistry (Geo/Che 475+L), Field Geology (Geo 481) and G.I.S. (Geo 390), in addition to Physical Geology (Geo 100+L) and the general education course Science, Pseudoscience and Fraud (Geo 306).

Click here for course web pages.

Contact info: tomascak@oswego.edu, 315.312.2786, Piez 207a

My research interests are mainly in the application of geochemical tools to solving geological problems. Geochemistry is not a material-specific discipline: whether you have interest in hydrogeology, ore formation, meteoritics, or tectonics, geochemistry can provide essential information to solve problems. I seek students who are interested in learning new skills that will be beneficial regardless of whether you go into a research career or not. Tasks include collecting and crushing rocks and separating minerals, dissolving rocks and minerals, collecting water samples, performing elemental analyses by atomic absorption spectrometry, and doing ion exchange chromatographic separation of elements for isotope analysis. Many of these projects involve a field component. My laboratory is set up for the basics of sample preparation and elemental separation, and I use ties with other institutions to accomplish analyses that cannot be performed in-house.

Click here for a page describing potential student research projects. (pdf file)

Current Research

Igneous processes and tectonics:   Geochemistry is but one tool by which complex processes like the tectonic assembly of an orogen may be understood. Igneous rocks are important to this process as they carry both critical information on timing of events and evidence of the age and composition of their sources. A proposal to the National Science Foundation with Dr. Gary Solar at Buffalo State College considered the geochemistry and geochronology of granitic rocks in Maine and New Hampshire, to look in greater detail at the interplay between deformation and magma transit through the crust.The proposal has been fully funded through summer 2007, so we are looking for students to carry out field and laboratory aspects of this project! Click here for sample status for this project. Our topical session at the Fall 2006 GSA meeting ("Crustal Melt Flow in Orogenic Belts: Integrated Field, Microstructural, Geochemical and Geochronological Analysis of Migmatites and Associated Granites") was a great success--thanks to all who contributed and participated! Click here to look at undergraduate student Ashley Cirmo's talk at the meeting.

The origin and development of granitic pegmatites in orogenic belts continue to be vexing problems. Few studies have taken an adequate measure of the granite-pegmatite connection, although geochemical tools now exist to begin to address such questions. Radiogenic isotopes afford opportunities to explore links in granite-pegmatite systems, whereas Li isotopes may ultimately allow us to better understand the magmatic-hydrothermal transition as well as the nature of fluid flow during orogensis. Aside from ongoing work in Maine, I have collaborations on pegmatitic rocks in central Manitoba and Scandinavia. 

Lithium isotope studies:   One of the exciting areas of modern isotope study is in natural variations in stable Li isotopes (d⁷Li). In the last several years I developed techniques for the isolation and measurement of these isotopes, primarily in mantle rocks. Nowadays I am focusing more on the untapped potential of Li to shed light on crustal processes: magmatic/hydrothermal evolution, metamorphic and metasomatic fluid flow, and weathering and hydrologic records in lake sediments.

The Li work has been applied to hydrogeochemistry in saline lakes of the western U.S. Great Basin. I have ongoing collaborations on hydrogeochemistry and sedimentary geochemistry of Mono Lake and the Great Salt Lake, as well as in Antarctic lakes. Click here to see some images from the 2007 field work in the Great Basin. Previously I demonstrated that Li might be a tracer of groundwater flow in small, agricultural watersheds. Using Li as an environmental tracer adds another group of potential interesting projects.

 Contact info: tomascak@oswego.edu, 315.312.2786, Piez 207a

Publications (click here for reprints):

Tomascak PB, Langmuir CH, LeRoux P, and Shirey SB (in revision) Lithium isotopes in global mid-ocean ridge basalts. Geochim Cosmochim Acta.

West DP Jr, Tomascak PB, Coish RA, Yates MG, and O'Reilly MJ (2007) Petrogenetic and tectonic significance of the Lincoln Syenite. Amer J Sci.

Tomascak PB, Brown M, Solar GS, Becker HJ, Centorbi TL, and Tian J (2005) Source contributions to Devonian granite magmatism near the Laurentian border, New Hampshire and western Maine, USA. Lithos 80, 75-99.

Teng FZ, McDonough WF, Rudnick RL, Dalpé C, Tomascak PB, Gao S, Chappell BW (2004) Lithium isotopic composition and concentration of the upper continental crust. Geochim Cosmochim Acta 68, 4181-4192.

Tomascak PB (2004) Developments in the understanding and application of lithium isotopes in the Earth and planetary sciences. In: Johnson CM, Beard BA, and Albarede F (eds) Geochemistry of Non-Traditional Isotope Systems, Min Soc Amer Reviews in Mineralogy and Geochemistry, vol. 55, 153-195.

West DP Jr, Coish RA, Tomascak PB (2004) Tectonic setting and regional correlation of Ordovician metavolcanic rocks of the Casco Bay Group, south-central Maine: Evidence from trace element and isotope geochemistry. Geol Mag 141, 125-140.

Tomascak PB, Hemming NG, and Hemming SR (2003) The lithium isotopic composition of waters of the Mono Basin, California. Geochim Cosmochim Acta 67 (4), 601-611.

Zack T, Tomascak PB, Rudnick RL, Dalpe C and McDonough WF (2003) Extremely light Li in orogenic eclogites: The role of fractionation during dehydration in subducted oceanic crust. Earth Planet Sci Lett 208, 279-290.

Tomascak PB, Widom E, Benton LD, Goldstein SL, Ryan JG, and Tera F (2002) The control of lithium budgets in island arcs. Earth Planetary Sci Lett 196, 227-238.

Owens BE and Tomascak PB (2002) Mesoproterozoic lamprophyres of the Labrieville Massif, Quebec: clues to the origin of alkalic anorthosites? Can J Earth Sci 39 (6), 983-997.

Tomascak PB, Ryan JG, and Defant MJ (2000) Lithium isotope evidence for light element decoupling in the Panama subarc mantle. Geology 28(6), 507-510.

Tomascak PB, Tera F, Helz RL, and Walker RJ (1999) The absence of lithium isotope fractionation during basalt differentiation: new measurements by multi-collector sector ICP-MS. Geochim Cosmochim Acta 63 (6), 907-910.

Tomascak PB, Carlson RW, and Shirey SB (1999) Accurate and precise determination of Li isotopic compositions by multi-collector sector ICP-MS. Chem Geol/Isotope Geosciences 158, 145-154.

Tomascak PB, Krogstad EJ and Walker RJ (1999) The significance of the Norumbega Fault Zone in southwestern Maine: clues from the geochemistry of granitic rocks. In: Ludman A and West Jr DP (eds) The Norumbega Fault Zone, Geol Soc Amer Special Paper 331, 105-119.

Meisel T, Melcher F, Tomascak PB, Dingeldey C, Koller F (1998) Re-Os isotopes in orogenic peridotite massifs from the Eastern Alps, Austria. Chem Geol 143, 217-229.

Tomascak PB, Krogstad EJ and Walker RJ (1998) Sm-Nd isotope systematics and the derivation of granitic pegmatites in southwestern Maine, USA. Can Mineral 36 (2), 327-337.

Tomascak PB, Krogstad EJ and Walker RJ (1996) Nature of the crust in Maine, USA: evidence from the Sebago batholith. Contrib Mineral Petrol 125, 45-59.

Tomascak PB, Krogstad EJ and Walker RJ (1996) U-Pb monazite geochronology in granitic rocks from Maine: Implications for late Paleozoic tectonics in the northern Appalachians. Jour Geol 104, 185-195.

updated 7/26/07