A broad group of research geoscientists make up the SDSU user group. Isotope geochemical research at SDSU is directed towards understanding geochemical and isotopic variations in a wide variety of regions, geologic settings, and disciplines including mid-ocean ridge volcanism, oceanic and continental hotspot volcanism, Western US magmatism, marine chemistry, biogeochemistry, environmental geology, and development of laser-wave mixing for isotope measurement. The following paragraphs describe the individual and collaborative isotope geochemical research and development projects of SDSU faculty members, collaborators, and external users.

Australian-Antarctic Discordance (Hanan–SDSU, Pyle–Univ. Hawaii, Blichert-Toft–ENS, Lyon, Christie–Oregon State Univ.

We have analyzed 43 basalt glasses from the AAD region of Southeast Indian Ridge for Sr, Nd, Hf and Pb isotope ratios. The MORB glass isotopic results from across the Indian-Pacific mantle boundary in the Australian-Antarctic Discordance region of the Southeast Indian Ridge define cross-cutting linear mixing arrays which demonstrate that the Indian upper mantle in the AAD region is polluted by EM-1-like lower continental crust (LCG) entrained during Gondwana rifting, whereas the Pacific upper mantle is influenced predominantly by subduction-related processes with C-like radiogenic isotope signatures (Hanan et al., 2000, 2003, 2004).

Iceland Hotspot (Hanan–SDSU, Schilling–Univ. Rhode Island)

We have been conducting a long-term investigation of the Iceland ridge-centered hotspot (Hanan and Schilling, 1997; Hanan et al., 2000) with the goal to provide a uniform map of spatial and temporal geochemical variations over the Iceland paleo- and neo-rift zones for the purpose of testing and refining current models for the origin, evolution and interaction of the Iceland mantle plume with the Mid-Atlantic Ridge. We recently (OCE-0095714) extended our research, so far concentrated on the Tertiary basalts >3 Ma, to younger Tertiary basalts (0-3 Ma). Over 100 basalts from the Skagi and Borgarfjordur Tertiary paleo-rift zones have been analyzed for major and 44 trace elements each, and have separated Pb, Sr, Nd, and Hf for isotope analyses from each basalt. The Hf, Nd, and Pb are currently being run on the Nu Plasma HR and the Sr on the SECTOR 54.

Magma Generation in the Early Mariana Arc System (Reagan–Univ. Iowa, Hickey-Vargas–Florida Intl. Univ., Hanan–SDSU)

With MARGINS OCE-0001824 (Hanan-SDSU) we began a comprehensive geo-chemical and geo-chronologic investi-gation of Eocene to Miocene volcanism in the southern Izu-Bonin Mariana Subduction System. Lavas from the fore-arc islands of Guam, Rota, and Saipan, and DSDP sites 458 have been analyzed for major element and trace-element concentrations, as well as Sr, Nd, Pb, and Hf isotopic compositions (2004-5), to investigate the evolution of volcanism in the Mariana arc from the initiation of subduction of the Pacific plate beneath the Philippine plate in the Eocene through the Miocene. The preliminary results are summarized in Reagan et al. (2003) and on-line at http://www.margins.wustl.edu/MARGINS_Review/nuggethome.htm.

Chemical Geodynamics of the Galapagos Plume-Spreading Center System (Christie/Duncan/Graham–Oregon State Univ., Hanan–SDSU, Ito–Univ. Hawaii)

This research (OCE-0241546-Hanan, SDSU) encompasses an integrated geochemical and geophysical investigation of the processes of material transfer from the mantle plume beneath the Galápagos Archipelago to the nearby Galápagos Spreading Center (GSC). Our principal objective is to produce a geochemical map of the GSC and adjacent young seafloor by analysis of seafloor lavas dredged along the spreading axis and from numerous small off-axis seamounts. Using this map, we will identify the pathways along which plume material is transferred to the GSC, quantify melting conditions across the region, and evaluate the fluid dynamic principles that control these processes. The results will be integrated with existing geochemical data from the GSC and Galápagos archipelago, new and existing geophysical data, and with numerical simulations of mantle flow and melting. This work is a collaborative venture with scientists from GEOMAR (Leibniz Institute of Marine Sciences), as part of the MEGAPRINT Expedition aboard the R/V Sonne in the summer of 2001 (Christie et al., 2002, 2004a, 2005). Thirty basalt glasses have been hand-picked and the Hf, Pb, Sr, and Nd separated for isotope analyses. Preliminary results are shown above. These data and additional isotope data from the GEOMAR group have been combined for a joint publication that is in preparation (Hauff et al., in preparaton).

The Geochemistry of Western Pacific Seamounts (Staudigel/Koppers–UCSD, Hanan–SDSU, Plank-Boston University)

Oceanic intraplate volcanoes have been the major source of information for the large-scale geochemical composition of the mantle and, hence, the data foundation for the field of chemical geodynamics. To date, most of these data are limited to ocean islands, restricting the sampling to a relatively recent and rather small fraction of all oceanic intra-plate volcanoes. In our study, we are focusing on the geochemistry of lavas from seamount chains and groups in the Western Pacific that are currently largely unstudied, where isotopic ages suggest that they record predominantly southern Pacific intra-plate volcanism over an age range well older than 100 Ma. These seamounts offer an opportunity to expand the ocean intra-plate volcano data base back in time, permitting us to explore the temporal geochemical evolution of a volcanic province by adding a time axis to our spatial mapping of large scale mantle heterogeneity. This work focuses in particular on determination of the Sr, Pb, Nd, and Hf isotopic and trace element signatures of a very wide suite of seamounts that all have been or will be dated with high-precision Ar/Ar geochronology. This work will comprise a substantial fraction of a Ph. D. thesis. We were told that this research would be approved for funding (NSF OCE 0451316) pending ship time scheduling. However, it was later declined. We have resubmitted for the February 15, 2006 submission date.

Isotopic Constraints on Mantle Source Origin of Basaltic Volcanism in the East African Rift (Furman–Penn State Univ.)

T. Furman's Penn State research group use the SDSU labs to acquire Sr, Nd, Pb and Hf isotopic data on basalts from a variety of tectonic settings. The goal is to understand the genesis and emplacement of mafic lavas in extensional continental settings. The first project, carried out in collaboration with J. Bryce (UNH), is funded by EAR-0207764 (Continental Dynamics) as part of a multi-disciplinary international program investigating the structure of the Main Ethiopian Rift. Isotopic work focuses on lavas from a suite of Quaternary volcanic centers located within the rift, as well as a contemporaneous rift-parallel series of basaltic centers where explosive activity has yielded new mantle xenoliths (Bryce et al., 2003). The isotopic data, in conjunction with major and trace element analyses and mineral chemistry allow exploration of the relationship between Quaternary volcanism and the Afar mantle plume. This project involves Ph. D. student T. Rooney, who spent the 2004 and 2005 summers at SDSU learning Pb, Sr, Hf and Nd isotope techniques while analyzing 25 lavas and clinopyroxene separates. Publications to date resulting from this work include Furman et al., 2005a,b and Rooney et al., 2005. The second project, partially supported by EAR-0230208 and by a TUBITAK fellowship to B. Kürkçüoglu (Hacettepe University, Ankara, Turkey), investigates magmatic activity in the Northern Anatolian region of Turkey. The Nd and Sr isotopic data for this study were obtained at SDSU in the summer of 2003 by Kürkçüoglu. He spent six weeks with Hanan learning the techniques and making the measurements. These data are used to constrain the nature and origin of heterogeneities within the source region beneath northern Turkey. Kürkçüoglu is currently setting up a laboratory in Turkey for Sr and Nd separations based on the procedures he learned at SDSU. He plans to use the SDSU facilities to make his mass spec measurements.

Isotopic Fingerprinting of Mantle Source Components in Continental Basaltic Centers (Bryce–Univ. New Hampshire)

J. Bryce has visited SDSU on several occasions to carry out high-precision Pb isotopic analyses on samples from continental basaltic centers with the goals of improving models of magma genesis during continental rifting. The first project, in collaboration with T. Furman (PSU) and funded by EAR-0207764, focuses on Quaternary volcanic centers from the Main Ethiopian Rift (MER (Bryce et al., 2003). Other analyses conducted by Bryce at SDSU included high-precision Pb isotopic measurements on mafic lavas from the Mediterranean region with the goal of obtaining preliminary data to support an pending submission to the geochemistry and petrology program of EAR.

Chemical, Isotopic and Volatile Constraints on the Evolution of the Lau Basin (Hilton/Castillo/Hawkins–UCSD, Hanan/Pietruszka–SDSU)

This project (NSF OCE 0451318) is a comprehensive geochemical (major, trace and volatile elements) and isotopic (Sr, Nd, Hf, Pb, rare gases, and U-series) analytical program to determine the distinct mantle sources beneath the Lau Basin and to map their spatial distribution. This information will be used to constrain mantle flow and to investigate the geochemical processes operating in the supra-subduction zone (SSZ) mantle and its control on the evolution of the Lau back-arc basin. Our investigation builds on previous and existing information and sampling from 5 Scripps sampling cruises to the Lau Basin lead by J. Hawkins. The sample suite consists of about 400 lavas and glasses that represent a wide and extensive coverage of the Lau Basin with lavas from all the recognized spreading centers including the Northeastern Basin, the Northern Lau Spreading Center (which is rifting the part of the basin that may be influenced by the Samoan Hotspot/Plume), the Mangatolo Triple Junction, the Central Lau Spreading Center, the Eastern Lau Spreading Center, the Relay Zone between central and eastern spreading centers, and the Valu Fa Ridge. We also have samples from primitive seamounts such as the Zephyr Shoal and from old pre-existing crust (e.g., Donna Seamount and the western edge of the Peggy Ridge). The samples from the Mangatolo Triple Junction include those from one limb that impinges on crust proximal to the Tofua Arc and another limb that penetrates old OIB crust. With these samples we will investigate outstanding questions concerning the origin, nature, and evolution of the Lau Basin SSZ mantle. These questions include: (1) what is the spatial distribution and extent of Indian- and Pacific-type mantle in the basin; (2) can we map the spatial extent of Samoan plume material into the Lau Basin; (3) how does the proximity of the Tofua Arc affect mantle melting beneath the Lau Basin spreading centers, and (4) what proportion of volatile enrichment in the lavas is due to ridge-arc source interaction versus crustal assimilation. The results of the proposed investigation will be an invaluable resource for use in planning future investigations focused on the region. The project will support 2 Ph. D. students at UCSD (Hf and Pb isotope work at SDSU) and 2 MS students at SDSU.

Pacific Antarctic Ridge (Dosso–IFREMER, France, Hanan–SDSU)

Forty-four samples (Vlastevic et al., 1998, 1999) from the Pacific-Antarctic Ridge (PAC1) were analyzed for Hf isotopes in 2004-5. Hanan participated in a French supported cruise to the PAC Ridge in December-January 2004/5 to extend the sample coverage between the southern PAC and the latitude about of Easter Island. The Hf isotope analyses of 40 new samples is completed in 2005. Dosso plans to spend a year (2006-2007) for a sabbatical. Dosso will run the Pb isotopes for PAC I and II by MCPIMS, do Hf and Pb isotopes on PAC II off-axis samples and 10-41°N MAR samples (Dosso et al., 1991, 1993,1999) in collaboration with Hanan.

Post Doctoral Fellowship, Hf Isotope Research (Geldmacher-GEOMAR, Germany)

The Hf isotope chemical procedures we have established at SDSU were used extensively by post-doctoral investigator J. Geldmacher (2002-5. Geldmacher separated Hf from 284 basalts for isotopic analyses (OCE-0123416). The analyses will provide data for a number of projects between GEOMAR (K. Hoernle, F. Hauff, G. Warner) and SDSU (Hanan) including mantle geochemistry in the Canaries, the British Tertiary province (also with A. Kerr, Cardiff University, ongoing), and the Galapagos Plume track (also with K. Harpp (Colgate Univ.), and the Caribbean Large Igneous Province. This work led to several abstracts a published paper (Geldmacher et al., 2003), with several more in preparation. Geldmacher has set up the SDSU Hf isotope procedures at GEOMAR in Germany.

Hawaiian Arch Volcanism (Kani–Kumamoto Univ., Japan; Schilling-URI; Hanan-SDSU)

T. Kani, Kumamoto University, Japan, spent six months, January-June 2004, analyzing 60 Hawaiian Arch lavas for Nd, Sr, Pb, and Hf isotopes under the auspices of a Japan Society for the Promotion of Science Fellowship. Prior to coming to SDSU she spent six months with J.-G. Schilling analyzing the Hawaiian Arch lavas for trace element abundances. Kani, Hanan and Schiling are preparing a manuscript presenting the results. Kani returned to SDSU in August-October 2005, with her MS student, S. Yamasaki. Kani analyzed lavas from Mauritius and Yamasaki analyzed submarine lavas collected from western side of Hualalai, Hawai for Nd, Sr and Pb isotopes. The results of the Hawaii research was presented at the EUG General Assembly 2005 and the 2005 Fall AGU (Kani et al., 2005a,b; Yamasaki et al., 2005).

Western United States, Coast Range, Snake River Plain-Columbia River magmatism (Shervais-Utah, Vetter-Centenary College, Hanan and Camp-SDSU)

The Snake River Plain (SRP) work involves M.S. and PhD students in field and laboratory research (Sr, Nd, Pb isotopes at SDSU) on the origin of Neogene basaltic volcanism along the critical junction between the eastern SRP (which may represent the track of the Yellowstone hotspot) with the western SRP, a structural graben that connects the eastern SRP with the Columbia River Plateau flood basalt province (Shervais et al., 2002). The Coast Range Ophiolite research includes field mapping and geochemical studies of the Elder Creek ophiolite and the Stonyford volcanic complex. Recent publications include Shervais et al., 2005a,b. We have recently analyzed Steens Mt. basalts for Nd, Sr and Pb isotopes. The results suggest that their source is Picture Gorge-like rather than Imnaha or Grande Rhonde, as suggested by Camp and Ross (2004).

North American Lithosphere Stabilization Episodes Sinha -VT, Shirey-DTM, Hanan-SDSU

As part of the collaboration with Sinha (VT) and Steve Shirey (DTM) we plan to examine mantle xenoliths from the lithosphere of eastern North America and use Re-Os isotopic systematics and mantle ages to estimate the timing of melt depletion (e.g. lithosphere stabilization) during the creation of Proterozoic North America. Hanan will spend time with Shirey to learn whole rock Os isotope analysis during the project, and later set up and initiate the procedures at SDSU. It is also possible that lithosphere rifting during the opening of Iapetus and the North Atlantic, and the subduction that accompanied the formation of the Appalachians will be evident in the xenolith record. We have a proposal pending to acquire a laser to use with the Nu 1700. If successful, we will use Laser Ablation-MCPIMS to explore small-scale Os isotopic variations in sulfide veins in order to constrain the timing of metasomatic melt additions.

3.5 Byrs of Microbial Activity in Submarine Volcanoes and its Impact on Rb/Sr and U/Th/Pb Isotope Systematics, Staudigel-UCSD-SIO, Hanan-SDSU

We have a proposal pending (EAR-0617452) to study the geochemical effects of biotic vs abiotic alteration of basaltic glass in submarine lavas ranging in age from 5 Ma - 3.5 Ba taken from drill cores in situ ocean floor and subaerially exposed pillow lavas. We will compare fresh or minimally altered basalt with alteration products from biotic or abiotic alteration textures using in situ, laser ablation, techniques. We will study a range of elemental abundances but focus on the abundances of Rb, Sr, U, Th and Pb because they are most sensitive to seafloor alteration and because their isotopic systems play an important role in the geochemical evolution of the silicate earth. In particular the redox sensitive U may play a key role in biological fractionation and, Pb isotopic data from mantle rocks suggest that U recycling did not occur until earth had developed an oxygenated atmosphere and a significant biosphere. This study will be an extension of our ongoing collaboration with with H. Furnes (PI, U. Bergen/Norway), K. Muehlenbachs and A. Simonetti (Edmonton, Canada), and N. Banerjee (U. Western Ontario, Canada; currently at IODP in College Station, Texas). H Furnes and our team has recently received funding from the Norwegian Research Council to study eight well preserved Proterozoic and Archean (3.8-2.0 Ba) Greenstone belts that will provide samples for this study as well as general geological and geochemical context, and field work support. The laser ablation ICP mass spec work will be initially carried out in the labs of our Canadian colleagues, and also later at SDSU pending funding of our laser ablation acquisition proposal (MRI-0618873).

References

Christie D. M., R. Werner, F. Hauff, K. Hoernle, B. B. Hanan, Morphological and geochemical variations along the eastern Galápagos Spreading Center, Geochem. Geophys. Geosyst., 6, Q01006, doi:10.1029/2004GC000714, 2005.

Furman T, Rooney T, Bryce J, Yirgu G, Ayalew D & Hanan B, 2004, Continental rupture in the Main Ethiopian Rift: constraints from magma source compositions. Proceedings volume, International Conference on the East African Rift System: Development, Evolution and Resources.
Furman, T., Bryce, J., Hanan, B., Yirgu, G. and Ayalew, D., Heads and Tails 30 Million Years of the Afar Plume, Journal of the Geological Society, London, in press, 2006.

Furman, Tanya, Kaleta, Kelly M., Bryce, Julia G., Hanan, Barry B., Tertiary Mafic Lavas of Turkana, Kenya: Constraints on East African Plume Structureand the Occurrence of High-m Volcanism in Africa, Journal of Petrology, in press, 2006.

Geldmacher, J., B. B. Hanan, J. Blichert-Toft, K. Hoernle, K. Harpp, F. Hauff, R. Werner and A. Kerr, Hafnium isotopic variations in volcanic rocks from the Caribbean, Large Igneous Province and Galápagos paleo-hotspot track, Geochem. Geophys. Geosyst. Vol. 4, No. 7, doi:10.1029/2002GC000477, 19 July 2003.

Hamelin, C,. Dosso, L., Hanan, B.B., Moreira, M., Klingelhoefer, F., Barrat, J., Ondreas, H., The Pacific-Antarctic Ridge Axis Between 41 and 51° : First Sampling and Geochemical Data, Eos Trans. AGU, 86(52), Fall Meet. Suppl., Abstract V41C-1460, 2005.

Hanan, B. B., J. Blichert-Toft, D. Pyle, and D. Christie, Contrasting origins of the upper mantle MORB source revealed by Hf and Pb isotopes from the Australian-Antarctic Discordance, Nature 432, 91-94, 2004.

Hanan, B., Blichert-Toft, J., Pyle, D., Christie, D., Origin of Upper Mantle Mid-Ocean Ridge Basalt Source Isotope Signatures: Hafnium and Lead Isotope Constraints, AGU, 84(46), Fall Meet. Suppl., Abstract S21E-0360, 2003.

Hanan, B., J. Blichert-Toft, D. Pyle, and D. Christie, Contrasting origins of the upper mantle MORB source revealed by Hf and Pb isotopes from the Australian-Antarctic Discordance, Geochimica et Cosmochimica Acta 68 (11S), A553, 2004.

B.Hartman, B. S., M. K. Reagan, R. Hickey-Vargas, B. Hanan, J. Blichert-Toft, 2003, EOCENE TO OLIGOCENE VOLCANISM IN THEMARIANA FORE-ARC AND CRUSTAL MELTING, EGS-AGU-EUG Joint Assembly 2003, Geophysical Research Abstracts, Vol. 5, 12546.

Kani, T., B. B. Hanan, R. Kingsley, and J.- G. Schilling, 2005, Pb, Sr, Nd, Hf isotope geochemistry of the North Arch and South Arch lavas: Evidence for multiple sources in the Hawaiian Arch volcanisms, Geophysical Research Abstracts, Vol. 7, 05993.

Kani, T., Hanan, B.B., Kingsley, R., Schilling, J., Constraints on the Source Components Involved in the Magmatism of North Arch Volcanic Field and South Arch Volcanic Field, Hawaii, Eos Trans. AGU, 86(52), Fall Meet. Suppl., Abstract V51A-1470, 2005.

Konter, J.G., Staudigel, H., Blichert-Toft, J., Hanan, B.B., Polve, M., Davies, G., Shimizu, N., The Cause of Recurring OIB Stages: Insights From the Evolution of Jasper Seamount., Eos Trans. AGU, 86(52), Fall Meet. Suppl., Abstract V51A-1464, 2005.

Kurkcuoglu B., Furman T., and Hanan B., Melting model, trace element and isotopic constraints on post-collisional mafic lavas from the North Anatolian Fault Zone, Armutlu Peninsula, NW Turkey [Lithos], in preparation.

Marske J, AJ Pietruszka, M Garcia, JM Rhodes (2005), A new mantle source tapped during episode 55 of the Pu'u O'o eruption from Kilauea Volcano. Eos Trans. AGU. 86:V43E-03

Marske JP , AJ Pietruszka, MO Garcia, MD Norman, JM Rhodes (2004). Young Prehistoric Kilauea Lava Flows From Uwekahuna Bluff, Hawaii: Mixed Source or Hybrid Magmas? Eos Trans. AGU. 85:V53A-0609.

Marske JP, AJ Pietruszka, MO Garcia, MD Norman, JM Rhodes (2004), A geochemical investigation of magmatic plumbing relationships between Kilauea and Mauna Loa volcanoes, Hawaii. In 2004 General Assembly Meeting of the IAVCEI (CD-ROM). Pucón, Chile.

Pietruszka AJ, EH Hauri, F Albarede, J Blichert-Toft (2005). The 226Ra-230Th-238U disequilibria of enigmatic magmas from Piton de la Fournaise Volcano, Reunion Island (1950-1998). Eos Trans. AGU. 86:V13B-0557

Pietruszka AJ, RJ Walker, PA Candela (2006). Determination of mass-dependent molybdenum isotopic variations by MC-ICP-MS: an evaluation of matrix effects. Chemical Geology 225:121-136.

Pyle, D.; Duncan, R.; Graham, D.; Hanan, B.; Wells, R., 2003, Isotopic composition of early Tertiary volcanism in the Pacific Northwest (USA), EGS-AGU-EUG Joint Assembly 2003, Geophysical Research Abstracts, Vol. 5, 13445,.

Reagan, M. ; Mohler, D.; Hanan, R.; Hickey-Vargas, R.; Blichert-Toft, J., 2003, Sources and melting processes for the proto-Mariana arc, EGS-AGU-EUG Joint Assembly 2003, Geophysical Research Abstracts, Vol. 5, 14493.

Reagan, M. K., Mohler, D., Brian, H., Hickey-Vargas, R. Hanan, B., Chamges in Lava Compositionsand With Time From the Eocene Through the Miocene for the Mariana Forearc, . AGU, 84(46), Fall Meet. Suppl., Abstract T31A-02, 2003.

Reznik A, AJ Pietruszka (2005) Development of the molybdenum isotopic system for paleoenvironmental studies: evaluation of the MC-ICP-MS standard-sample bracketing technique for analyses of marine sediments. Eos Trans. AGU. 86:PP31B-1541

Rooney, T. O., Furman, T., Hanan, B., Istopically Defined Source Reservoirs of Primitive Magmas in the East African Rift, Eos Trans. AGU, 86(52), Fall Meet. Suppl., Abstract V33D-04, 2005.

Shervais, John W., Geist, Dennis J., Hughes Scott S, Vetter, Scott, and Hanan, Barry B., 2003, Intermediate Depth Drilling of the Snake River Plain: Tracking the Yellowstone Hotspot (?) Through Space and Time: A call to Action, Geological Society of America Abstracts with Programs, Vol. 36, No. 4, p. 99.

Shervais, J., Hanan, B., Vetter, S. K., Chemical Stratigraphy of Basalts From the 5000’ Borehole NPR-E/WO-2, Eastern Snakeriver Plai, Idaho: Evidence for Mixed Athenosphere-Lithosphere Sources. AGU, 84(46), Fall Meet. Suppl., Abstract V32H-03, 2003.

Shervais, John W., David L. Kimbrough, Paul Renne, Barry B. Hanan, Benita Murchey, Cameron Snow, Marchell M. Zoglman, and Joe Beaman, 2004, Multi-Stage Origin of the Coast Range Ophiolite, California: Implications for the Life Cycle of Supre-Subduction Zone Ophiolites, International Geology Review 46, 289-315.

Shervais, John W., Vetter, Scott, Hanan, Barry B., 2004, Basaltic Volcanism of the Central Snake River Plain, Idaho, Geological Society of America Abstracts with Programs, Vol. 36, No. 4, p. 98.

Shervais, J.W., Zoglman-Schuman, M.M., and Hanan , B.B., 2005a, The Stonyford Volcanic Complex: A Forearc Seamount in the Northern California Coast Ranges, Journal of Petrology, doi:10.1093/petrology/egi048, v. 46 (10), 2091-2128.

Shervais, J.W., Murchey, B., Kimbrough, D.L., Renne, P., and Hanan, B.B., 2005b, Radioisotopic and Biostratigraphic Age Relations in the Coast Range Ophiolite, Northern California: Implications for the Tectonic Evolution of the Western Cordillera, Geological Society of America Bulletin, v. 117, no 5/6, p.633-653.

Shervais, John W., Geist, Dennis, Hughes, Scott, Branney, M.J., Hanan, Barry B., Vetter, Scott, Williams, Douglas, and Prokopenko, Alexander, 2005, The Snake River Plain Scientific Drilling Project (SRP-SDP): Tracking thee Yellowstone Plume through Space and Time, Geological Society of America Abstracts with Programs, Vol. 37, No. 7, p. 202.

Shervais, John W., Vetter, Scott, Hanan, Barry B., Basaltic Volcanism of the Snake River Plain and its Relation to the Yellowstone Hotspot: an Overview, Geological Society of America Abstracts with Programs, Vol. 37, No. 7, p. 201, 2005.

Shervais, J.W., Vetter, S.K. and Hanan, B.B., 2006, A Layered Mafic Sill Complex beneath the Eastern Snake River Plain: Evidence from Cyclic Geochemical Variations in Basalt, Geology, in press.

Vetter, S., Hanan, B., Shervais, J., Basaltic Volcanism of the Bruneau-Jarbidge Eruptive Center and its Surroundings, Southwest Idaho: Chemical Evidence for Multiple Mantle Sources, AGU, 84(46), Fall Meet. Suppl., Abstract V31E-0979, 2003.

Vetter, Scott, Shervais, J. W., Hanan, Barry B., Geochemical Variations in the Basaltic Volcanism of the Bruneau-Jarbridge Eruptive Center and its Surroundings, Southwest, Idaho, Geological Society of America Abstracts with Programs, Vol. 36, No. 4, p. 95, 2004.

Vetter, Scott, Shervais, John W., Hanan, Barry B., Evidence for Mixed Asthenosphere-Litosphere Sources for Basalts of the Eastern Snake River Plain, Idaho, Geological Society of America Abstracts with Programs, Vol. 36, No. 4, p. 98, 2004.

Yamasaki, S., Kani, T, Hanan, B.B., Nohda, S., Hf, Pb, Sr, and Nd Isotope Geochemistry of Submarine Lavas from Hualalai Volcano, Hawaii, Eos Trans. AGU, 86(52), Fall Meet. Suppl., Abstract V41C-1468, 2005.