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William P. Leeman
Professor Emeritus
Professor Emeritus of Earth Science
e-mail:[email protected]
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B.A., 1967, Rice University
M.A., Rice University, 1969
Ph.D., University of Oregon, 1974
Websites
Bill Leeman's Personal Webpage
Research Areas
Geochemistry and igneous petrology with emphasis on relations between volcanism and
tectonic evolution of the western U.S. and volcanic arcs worldwide. Geochemistry of boron and
boron isotopes.
Research Statement
Main research topics concern the origin of magmas and their relation to specific tectonic
settings:
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Hot-spot related magmatism (e.g., Hawaii, Snake River Plain)
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Extension-related magmatism (e.g., Cordilleran U.S.)
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Subduction-related magmatism (e.g. Cascades range)
In particular, I have focused on the geochemistry of boron and other trace elements and their
isotopes in understanding the origins of volcanic rocks, magmatic and other fluids, and
borosilicate minerals.
Geochemistry and Petrology of Convergent Margin Magmatism
Volcanic arcs at convergent plate margins account for roughly 25% of modern magmatism on
the Earth. In addition, high volatile contents (mainly water) cause them to erupt in an
explosive manner, and the volatile fluxes associated with this activity contribute significantly
to greenhouse gases in the atmosphere, thereby affecting global climate. Because of their
locations, many such volcanoes also pose direct hazards to densely populated areas.
Understanding the origin of volcanic arc magmas is critical to predicting volcano behavior and
the underlying processes that promote melting in these settings.
My work uses geochemical and petrologic methods to investigate this problem. For example,
studies of mineral and lava chemistry provide direct means to estimate magmatic
temperatures and depths of segregation from the underlying mantle. This information
provides critical constraints needed to construct and assess physical models of the mantle and
the melting processes involved. Geochemical tracers also provide important constraints on the
types of materials that contribute to magma formation, and models of how they become
involved. At continental margins, the dominant processes include subduction of oceanic
lithosphere (the ¿slab¿) beneath overriding tectonic plates and convective upwelling of warm
mantle in the wedge-shaped regions (the ¿mantle wedge¿) between these plates. As
subducting plate descend into the mantle, they undergo heating and metamorphism that
causes dehydration fluids to percolate into the mantle wedge, lowering its melting point and
triggering melting. Upwelling of warm mantle within the wedge is driven by shear-coupling
with the descending slab, and can undergo decompression melting as pressure decreases and
the material crosses its solidus curve. These processes can be quantified via studies of specific
trace element and isotopic parameters. As an example, the highly fluid-mobile element B is
particularly useful in understanding the dehydration history of subducting slabs and in
monitoring the amounts of slab-derived fluid that are added to the mantle wedge to produce
melts. Both its concentration and isotopic composition have been found to vary systematically
with inferred slab temperature, and these parameters can be used to assess the thermal state
of subduction zones as well as the role of flux-melting of the wedge. The combination of
geochemical and petrologic constraints then helps us understand the dynamic processes that
underpin arc magmatism.
Geochemistry of boron
The element B is a useful tracer of fluid-related processes in the Earth. My work focuses on
variations in its concentration and isotopic composition in a variety of projects, including (a)
subduction zone magmatism, (b) mass transport in plutonic aureoles, (b) studies of volcanic
fluid emission, (d) hydrologic systems, and (e) crustal metamorphism.
NSF Research: Resolving the paradox of fO2 in arcs using V/Sc systematics of
primitive lavas as a proxy for mantle fO2: towards an internally consistent
dataset
This work addresses redox conditions in subarc mantle domains. This information is critical to
understanding the origins of volcanic arc magmas and the effects of subduction worldwide.
The relation between magmatism and tectonics
Many tectonic settings are associated with distinctive styles of magmatism, in which the style
and compositions of volcanic and plutonic rocks carry characteristic signatures of their sources
as well as the processes that cause melting. My work has focused on how these are linked and
how the magmatic record can be used to understand the physical processes leading to
magmatism in the past. An example is the western US, where late Cenozoic magmatism is
associated with continental extension (Basin and Range province), hot spot migration
(Yellowstone ¿ Snake River Plain province), and subduction (Cascades arc). We have been
involved in topical studies in all these areas, using field-controlled petrologic studies to
evaluate models of magma production.
NSF Collaborative Research: On the origins of primitive magmas in the
Cascade volcanic arc
Convergent margin magmatism is a significant process contributing to the evolution of the
Earth, and impacts humanity locally due to proximity to many populous areas and globally
through its influence on atmospheric chemistry and climate effects. Understanding of the
fundamental energy and mass budgets that drive this magmatism is relevant to many
important issues. As a contribution to that understanding we propose to address several
unresolved questions, using the Cascade volcanic arc as a natural laboratory.
The prevailing model for arc magmatism involves mantle melting in response to additions of
fluids produced by dehydration of subducting (underthrusting) plates of oceanic lithosphere.
However, because the Cascade arc is associated with slow subduction of young oceanic
lithosphere, it is one of the warmest subduction zones known. For this extreme end member
case, it is likely that the subducting plate is extensively metamorphosed and dehydrated as it
descends to subarc depths, that the supply of slab-derived fluids beneath the arc is low, and
that temperatures may even be high enough to promote direct melting of the slab at those
depths. In this case the familiar subduction zone ?flux melting? paradigm may not strictly
apply. Yet, the Cascades arc is characterized by voluminous basaltic magmatism. To explain
this enigma, alternative mechanisms and/or magma sources are seemingly required, and the
solution to this paradox may shed new light on origins of primitive arc magmas worldwide.
Our project focuses on basaltic magmatism because such lavas are likely to carry relevant
information concerning fundamental mantle processes underpinning volcanic arc magmatism.
A basic question that we address concerns the extent to which slab-derived fluids contribute
to magma generation in this setting. In the southern Washington Cascades, primitive basaltic
lavas lacking slab-derived chemical signatures have erupted over the entire width of the arc.
From this observation we infer that much of the mantle wedge has received negligible slab
contributions. In contrast, in the northern California Cascades (e.g., Mt. Shasta area),
primitive lavas appear to be significantly hydrated, and prevailing interpretations suggest that
slab-derived fluids do contribute significantly to magma formation in this area.
We propose a comparative study to investigate the nature and extent of slab contributions
beneath both areas, using sensitive geochemical tracers for slab-derived fluids ? Be and B
isotopes, fluid-mobile trace elements, and radiogenic isotopes (Sr, Pb, and Os). If slab
contributions are significant in the latter region, we can better define the origin and
composition of that signature with respect to these compositional parameters. If this is not the
case, we will investigate other scenarios (e.g., decompression melting) to explain the
characteristics and origins of primitive magmas in these settings. This study will better define
the relative contributions between competing melting processes, and allow us to address how
they are influenced by external forcing functions related to subduction zone dynamics.
Intellectual merit: This work will provide, for the Cascades, a deeper understanding of the
causes for magmatic diversity, the relative contributions of different melting processes, the
influence of compositional diversity within the mantle wedge, and ultimately the thermal
structure and processes underpinning this magmatism. This knowledge may be difficult to
extract from more typical, cooler subduction systems.
Broader impact of the proposed research: Ultimately, the knowledge gained will be useful in
understanding arc magmatism on a global scale in terms of relative differences in arc thermal
structures and contribute to development of a ?unified theory? linking magmatism to the
physical characteristics of convergent margins. Graduate and undergraduate students involved
in this work will gain basic scientific training and experience. Collaboration between
researchers at Rice University, University of Arizona, and Washington University at St. Louis,
and the Istituto di Geoscienze e Georisorse in Pisa, Italy, will foster intellectual exchange and
provide access to a broad range of analytical approaches. Transfer of this knowledge through
participation at national and international meetings will contribute to the overall benefit of
many scientists studying the dynamics of convergent margins.
Teaching Areas
Petrology, Geochemistry, Geologic Hazards/Volcanology
Selected Publications
Abstracts
Leeman, W.P. "Evolution of Snake River Plain (SRP) silicic magmas - the Magic Reservoir
eruptive center." Abstracts with Program, 36 (2004) : 24.
Leeman, W.P. "Fluid-mobile element constraints on processes within subduction zones:
Applications of B and Be geochemistry to arc volcanic rocks." (2004)
Leeman, W.P. "Lithospheric vs. asthenospheric contributions to basaltic magmatism in the
Snake River Plain - Yellowstone Hot-spot track." (2004)
Leeman, W.P., Evarts, R.C., and Conrey, R.M. "Cascadia mafic magmatism and
heterogeneities in the mantle wedge." Instituto de Geologia, UNAM Publication Especial 2,
Neogene-Quaternary Continental Margin Magmatism (2004) : 42-44.
Tonarini, S., Leeman, W.P., and Leat, P.T. "Boron isotope systematics in South Sandwich
island arc." Geochimica et Cosmochimica Acta, 68 (2004) : A599.
Chan, L. H., and Leeman, W. P. "Lithium isotopic composition of global arc systems: Source
components and controls." (2003)
Conrey, R.M., Leeman, W.P., Streck, M.J., and Evarts, R.C. "The Boring Volcanic Field of the
Portland Basin: Diverse primitive mafic magmas erupted in a frontal arc setting." EOS,
Transactions of the American Geophysical Union, 84 (2003)
Leeman, W.P., Evarts, R.C., Conrey, R.M., and Streck, M.A. "Reevaluation of Cascadia mafic
magmatism ¿ new perspectives on the subduction factory." (2003)
Leeman, W.P., Evarts, R.C., Conrey, R.M., and Streck, M.J. "Mafic magmatism and new
perspectives on Cascadia subduction." Geological Society of. America Abstracts with Program,
35 (2003) : 643.
Refereed articles
Lee, C.-T.A., Leeman, W.P., Canil D., and Li, Z.A. "Similar oxygen fugacities in arc and MORB
mantle source regions: Evidence from V/Sc systematics." Journal of PetrologyIn Revision
Leeman W.P., Tonarini S., Pennisi M., and Ferrara G. "Boron isotopic variations in fumarolic
condensates and thermal waters from Vulcano Island, Italy: Implications for evolution of
volcanic fluids." Geochimica et Cosmochimica Acta, 69 (2005) : 143-163.
Leeman, W.P., Lewis, J.F., Evarts, R.C., Conrey, R.M., and Streck, M.A. "Petrologic Constraints
on the Thermal Structure of the Cascades arc." J. Volcanology and Geothermal Research
(2004) In Press
Leeman, W.P., Tonarini, S., and Chan, L.H. "Boron and lithium isotopic variations in a hot
subduction zone - the southern Washington Cascades." Chemical Geology, 212 (2004) : 101124.
Leeman, W.P., and Davidson, J.P. "Energy and mass fluxes in volcanic arcs: a preface to the
special SOTA issue." J. Volcanology and Geothermal Research (2004) In Press
Leeman, W.P., and Honjo, N. "Petrogenesis of anomalous rhyolites from the Magic Reservoir
eruptive center, north-central Snake River Plain." Bulletin of Volcanology (2005) Submitted
Righter K., Leeman W.P., and Hervig R.L. "Partitioning of Ni, Co and V between spinelstructured oxides and silicate melts: importance of spinel composition." Chemical Geology
(2004) In Revision
Smith, D.R., and Leeman, W.P. "Chromian spinel-olivine phase chemistry and the origin of
primitive basalts of the southern Washington Cascades." J. Volcanology and Geothermal
Research (2004) In Press
Tonarini S., Leeman W.P., Civetta, L., D'Antonio M., Ferrara G., and Necco A. "B/Nb and d11B
systematics in the Phlegrean Volcanic District, Italy." J. Volcanology and Geothermal
Research, 133 (2004) : 123-139.
Leeman, W.P., Davidson, J., Fischer, T., Grunder, A., Reagan, M., and Streck, M. J. "Current
perspectives on energy and mass fluxes in volcanic arcs." EOS, Transactions of the American
Geophysical Union, 84 (2003) : 531.
Leeman, W.P., Lewis, J.F., Evarts, R.C., Conrey, R.M., and Streck, M.J. "Petrologic Constraints
on the Thermal Structure of the Southern Washington Cascades." Journal of Volcanology and
Geothermal ResearchSubmitted
Leeman, W.P., Tonarini, S., Pennisi, M., and Ferrara, G. "Boron isotopic variation in fumarolic
condensates and thermal waters from Vulcano Island, Italy: Implications for evolution of
volcanic fluids." Geochimica et Cosmochimica Acta, 68In Revision
Tonarini, S., Leeman, W.P., Civetta, L., D'Antonio, M., Ferrara, G., and Necco, A. "B/Nb and
d11B systematics in the Phlegrean Volcanic District (PVD), Italy." Journal of Volcanology and
Geothermal Research (2004) In Press
Articles
Chan, L.H., Leeman, W.P., and You, C.F. "Lithium isotopic composition of Central American
volcanic arc lavas: Implications for modification of subarc mantle by slab-derived fluids:
Correction." Chemical Geology, 182 (2002) : 293-300.
Huang, S., Leeman, W.P., Sisson, V.B., and Kloucek, P. "Subduction zone thermal modeling
for a curved slab: A hybrid numerical approach." Geochemistry Geophysics & Geosystems
(2002) Submitted
K. Righter, R.L. Hervig, Leeman, W. P. "Partitioning of Ni, Co, and V between spinel-structured
oxides and silicate melt: Large effects of doping." Physics Earth Planetary Interiors (2002)
Leeman, W. P., S. Tonarini, G. Woerner "Boron isotopic systematics of the Kamchatka volcanic
arc." Geochimica et Cosmochimica Acta (2002) Submitted
Leeman, W., Huang S., Leeman W.P., Sisson V.B., and Klaocek, P. "Subduction Zone Thermal
Modeling: A Finite-Difference and Finite-Element Approach." Geochemistry, Geophysics, and
Geostatistics (G-cubed) (Dec 2002) Submitted
S. Tonarini, Leeman, W. P., L. Civetta, M. D'Antonio, G. Ferrara, A. Necco "B/Nb and boron
isotopic systematics in the Phlegrean Volcanic District (PVD), Italy." J. Volcanology and
Geothermal Research (2002) In Press
Other
Righter K., Hervig R.L., and Leeman W.P. "Partitioning of Ni, Co and V between spinelstructured oxides and silicate melt: Large effects of doping." Chemical GeologySubmitted
Dini, A., Tonarini, S., Leeman, W.P., Ertan, I.E., and Pezotta, F. "Geochemical behaviour of
boron at the magmatic-hydrothermal transition: insights from 11B of tourmaline in
peraluminous granites (Elba Island, Italy)." Water-Rock Interaction 10 (2001) : 1513-1516.
Dyar, M.D., Wiedenbeck, M., Robertson, D., Cross, L.R., Delaney, J.S., Ferguson, K., Francis,
C.A., Grew, E.S., Guidotti, C.V., Hervig, R.L., Hughes, J.M., Husler, J., Leeman, W.P.,
McGuire, A.V., Rhede, D., Rothe, H., Paul, R.L., Richard, I., and Yates, "Reference minerals for
microanalysis of light elements." Geostandards Newsletter, 25 (2001) : 441-463.
Leeman, W.P., and Tonarini, S. "Boron isotopic analysis of proposed borosilicate mineral
reference samples." Geostandards Newsletter, 25 (2001) : 399-403.
Tonarini S., Citetta L., D'Antonio M., Ferrara G., Leeman W.P., and Necco A "B/Nb and B
isotopic systematics in the Phlegraean Volcanic district (PVD)." GNV Framework Program
2000/2002, 26 (2001) : 72-77.
Tonarini, S. Leeman, W.P., and Ferrara, G. "Boron isotopic variations in lavas flows of the
Aeolian volcanic arc, Italy." Journal of Volcanology and Geothermal Research, 110 (2001) :
155-170.
Woodford, D.T., Sisson, V.B., and Leeman, W.P. "Boron infiltration of the Alta Stock contact
aureole, Utah: Evidence from mineral chemistry and geochemistry." American Mineralogist, 86
(2001) : 513-533.
Pennisi M., Leeman W.P., Tonarini S., Pennisi A., and Nabelek P.I. "Boron, Sr, O, and H
isotope geochemistry of groundwaters from Mt. Etna (Sicily) - hydrologic
implications." Geochimica et Cosmochimica Acta, 64 (2000) : 961-974.
Bebout, G.E., Ryan, J.G., Leeman, W.P., and Bebout, A.E. "Fractionation of trace elements by
subduction-zone metamorphism - Effect of convergent margin thermal evolution." Earth
Planet. Sci. Lett., 171 (1999) : 63-81.
Chan, L.H., Leeman, W.P., and You, C.-F. "Lithium isotopic composition of Central American
Volcanic Arc lavas: Implications for modification of subarc mantle by slab-derived
fluids." Chem. Geol., 160 (1999) : 255-280.
Ertan, I.E., and Leeman, W.P. "Fluid inclusions in mantle and lower crustal xenoliths from the
Simcoe volcanic field, Washington." Washington Chem. Geol., 154 (1999) : 83-95.
McMullan, R., Leeman, W.P., Harcombe, P., Martindill, A. "Defining the potential for
composting in a small urban university." Abst. National Biocycling Conf., Albuquerque, NM
(1999/May 17-18)
with S. Tonarini and M. Pennisi "Precise boron isotopic analysis of complex silicate (rock)
samples using alkali carbonate fusion and ion exchange separation." Chemical Geology, 142
(1998) : 129-137.
with S. Tonarini, A. Dini, and F. Pezotta. "Boron isotopic composition of zoned (schorl-elbaite)
tourmalines, Mt. Capanne Li-Cs pegmatites, Elba (Italy).." European Journal of Mineralogy, 10
(1998) : 941-951.
Presentations
Invited Talks
"Effects of Cenozoic magmatism and tectonics on evolution of continental lithosphere, N.
Rocky Mountains, USA." Rocky Mountain Earthscope Workshop, Socorro, NM. (16 Sept. 2004)
"Evolution of Snake River Plain (SRP) silicic magmas - the Magic Reservoir eruptive center."
Geological Society of America, Boise, ID. (3 May 2004)
"Fluid-mobile element constraints on processes within subduction zones: Applications of boron
geochemistry to arc volcanic rocks." IAVCEI General Assembly, Pucon, Chile. (15 Nov 2004)
"Similar oxygen fugacities in arc and MORB mantle source regions: evidence from V/Sc
systematics." American Geophysical Union, San Francisco, CA. (13 Dec. 2004) With Lee, C.T.A., Canil D., and Li, Z.A
"How arc volcanoes work." Trinity University, San Antonio, TX. (15 April 2003)
"Influence of subduction zone thermal conditions on compositions of arc magmas." Baylor
University, Department of Geology, Waco, TX. (7 March 2003)
"Mafic magmatism and new perspectives on Cascadia subduction." Geological Society of
America, Annual Meeting, Seattle, WA. (6 November 2003) With Evarts, R.C., Conrey, R.M.,
Streck, M.J.
"Comparative thermal models for subduction zones: Evaluation of slab contributions to
volcanic arc magmas." 12th Annual V.M. Goldschmidt Conference, Davos, Switzerland. (18
Aug 02) With S. Huang, S. Tonarini
"Geochemical tracers and comparative thermal models for subduction zones: Evaluation of
slab contributions to volcanic arc magmas." NSF Margins-IFREE Workshop on Izu-BoninMarianas Volcanic Arc, Honolulu, HI. (9 Sept 02) With S. Huang
"Geochemical tracers of slab contributions to arc magmas: The use of boron." 12th Annual
V.M. Goldschmidt Conference, Davos, Switzerland. (19 Aug 02) With S. Tonarini
"How Subduction Zones Work: A Perspective from Fluid-mobile Elements." Los Alamos
National Laboratory. (14 Feb 02)
"How Subduction Zones Work: Constraints from Boron Geochemistry." McGill University. (8
April 02)
"The relation between subduction zone thermal structure and geochemistry of associated arc
magmas." University of Pisa. (13 Nov 02)
Lectures
"Lithospheric vs. asthenospheric contributions to basaltic magmatism in the Snake River Plain
- Yellowstone Hot-spot track." IAVCEI General Assembly, Pucon, Chile. (14 Nov, 2004)
Other
"Approaches to comparative thermal modeling of subduction zones: goals and constraints."
NSF Workshop on Thermal Modeling of Subduction Zones, Ann Arbor, MI. (4 Oct 02) With S.
Huang
"B and Sr isotope variations induced by (hydro-)thermal effects on pelites." 12th Annual V.M.
Goldschmidt Conference, Davos, Switzerland. (20 Aug 02) With A. Dini, S. Tonarini
"Boron isotope systematics in south Italy volcanoes." 12th Annual V.M. Goldschmidt
Conference, Davos, Switzerland. (19 Aug 02) With S. Tonarini, L. Civetta, M. D'Antonio,
M.D.'Orazio, G. Ferrara, F. Innocenti
"Li and B isotopic constraints on the origin of Aleutian arc magmas." American Geophysical
Union Fall Meeting, San Francisco, CA. (Dec 2002) With L.H. Chan, S. Tonarini, B. Singer
"Relations between thermal structures of subduction zones and composition of associated arc
magmas." University of Pisa. (November 2002)
"Boron and fluid-mobile element (FME) fluxes across Kamchatka." European Union of
Geophysics, Straussbourg, France. (April, 2001) With Worner, G., Churikova, T., Tonarini, S.,
and Heuser, A
"Boron geochemistry in the Phlegrean Volcanic District (PVD): Role of subduction in the
magma genesis." European Union of Geophysics, Straussbourg, France. (April, 2001) With
Tonarini S., Civetta L., D'Antonio M., Ferrara G., and Necco A
"Comparative thermal structures of circum-Pacific subduction zones." American Geophysical
Union, San Francisco. (December, 2001) With Huang, S., Sisson, V.B., and Kloucek, P
"Lithium isotopic compositions of South Sandwich Arc and southwest Washington Cascades: A
comparative study." American Geophysical Union, San Francisco. (December, 2001) With
Chan, L.H., and Tonarini, S
"Partitioning of transition metals and platinum group elements (Ni, Cr, Ru and Rh) between
spinel-structured oxides and silicate melt." V.M. Goldschmidt Conference, Roanoke, VA. (June,
2001) With K. Righter, R. Hervig
"Petrological constraints on the thermal structure of the southern Washington Cascades."
American Geophysical Union, San Francisco. (December, 2001) With Lewis, J.F., and Evarts,
R.C
"The influence of subduction zone thermal structure on arc magma chemistry: B and fluidmobile elements." American Geophysical Union, San Francisco. (December, 2001)
"B/Nb and 11B systematics in the Phlegrean Volcanic District (PVD) and Aeolian Islands
(relationship between calcalkaline and potassic orogenic magmatism in southern Italy)." Tenth
Goldschmidt Conference, Oxford, U.K.. (August, 2000) With with Tonarini, S., Civetta, L.,
D'Antonio, M., Ferrara, G., and Necco, A
"Boron geochemical constraints on subduction contributions: Relations to slab thermal
structure and other subduction parameters." American Geophysical Union, San Francisco.
(December, 2000)
"Boron geochemical constraints on subduction contributions: Relations to slab thermal
structure and other subduction parameters." State of the Arc 2000 Conference, Ruapehu, New
Zealand. (Jan 23-29, 2000)
"Boron geochemical constraints on subduction contributions: Relations to subduction
parameters - an overview." Dip. di Scienzia della Terra, University of Pisa, Pisa, Italy. (April 5,
2000)
"Boron geochemical constraints on subduction contributions: relations to subduction
parameters - an overview." Dept. of Geological Sciences, University of New Mexico,
Albuquerque, NM. (April 27, 2000)
"Boron geochemical constraints on subduction processes." Dept. of Earth Sciences, New
Mexico State University, Soccorro, NM. (April 26, 2000)
"Boron geochemical constraints on subduction processes and related topics." Istituto di
Geocronolgia et Geochimica Isotopica, Consiglione Nazionale de Richerche, Pisa, Italy. (April
12, 2000)
"La sistematica isotopica del boro nei magmi d'arco." Geologica Nazionale Vulcanologia, Rome.
(September, 2000) With Tonarini, S
"Lithium and boron isotopic variations and source components in Aeolian Arc lavas." American
Geophysical Union, San Francisco. (December, 2000) With With Chan L.H., Tonarini S., and
Ferrara G
"Mineral standards for microanalysis of boron, lithium, and fluorine." 4th Intl. Conf. on the
Analysis of Geological and Environmental Materials, Pont a Mousson, Fra. (30 Aug-1 Sept)
With with Dyar, D., Wiedenbeck, M., Cross, L., Delaney, J.S., Francis, C.A., Grew, E.S.,
Guidotti, C.V., Hervig, R.I., Hughes, J.M., McGuire, A.V., Paul, R.L., Robertson, J.D., and
Yates, M
"Subducted components and mantle melting in the Central and Eastern Aleutian Arc: Insights
from the trace element and isotopic composition of basalt." American Geophysical Union, San
Francisco. (December 2000) With With Singer B., Thirlwall M., Ryan J., Sharp Z., and Rogers,
N
"B and Li geochemistry of Central America volcanic arc lavas - implications for subducted slab
contributions." Univ. Calif. Los Angeles. (17 Nov 1999)
"Boron and lithium geochemistry: geochemical applications." Los Alamos National Laboratory.
(Dec, 1999)
"Boron geochemical constraints on subduction contributions: relations to slab thermal
structure and other subduction parameters." State of the Arc 2000 Conference, Rotorua, New
Zealand. (23-29 Jan, 2000)
"Boron geochemical constraints on subduction contributions: relations to slab thermal
structure and other subduction parameters." Amer. Geophysical Union, San Francisco, CA.
(Fall Meeting, 12-17 Dec, 1999) With (Invited Speaker)
"Boron geochemical constraints on subduction processes." Louisiana State University. (5 Nov
1999) With L.J. Wilbert lecturer
"Boron geochemical constraints on subduction processes - a global view." Univ. Calif. Los
Angeles. (18 Nov 1999)
"Thermal modelling of subduction zones." Amer. Geophysical Union, Fall Meeting, San
Francisco, CA. (12-17 Dec 1999) With S. Huang, J. Sisson, and P. Klouchek
"Fluids in subduction zone magmatism: Boron isotopic variations in arc lavas. Min. Mag. 62A,
1525-1526." Eighth Goldschmidt Conference, Toulouse, France. (1998) With Tonarini, S.
"Fluids in subduction zone magmatism: Implications of boron geochemistry. Min. Mag. 62A,
873-874." Eighth Goldschmidt Conference, Toulouse, France. (1998) With Leeman, W.P., and
Ertan, I.E.
"Interdisciplinary Environmental Teaching." EOS 79, S345, (1998) With Few, A.A., Leeman,
W.P., and Sisson, V.B. Few, A.A., Leeman, W.P., and Sisson, V.B.
"Lithium isotopic composition of Central American volcanic arc lavas: Implications for
modification of subarc mantle by slab-derived fluids." EOS 79, F395, (1998) With Chan L.H.,
and You C.-F.
"The nature of Cascades subarc lower crust and upper mantle: where were the subducting
slab melts?." EOS 79, F924, (1998) With Ertan, I.E.
Posters
"Cascadia mafic magmatism and heterogeneities in the mantle wedge." GSA Penrose
Conference, Metepec, Puebla, Mexico. (13 January 2004) With Evarts, R.C., and Conrey, R.M.
"Chromian spinel-olivine phase chemistry and the origin of primitive basalts of the southern
Washington Cascades." State of the Arc, Timberline Lodge, Mt. Hood, OR. (17 August 2003)
With Smith, D.R., Kamenetsky, V.
"Lithium isotopic composition of global arc systems: Source components and controls." State
of the Arc, Timberline Lodge, Mt. Hood, OR. (17 August, 2003) With Chan, L.H.
"Reevaluation of Cascadia mafic magmatism ¿ new perspectives on the subduction factory."
State of the Arc, Timberline Lodge, Mt. Hood, OR. (17 August 2003) With Evarts, R.C.,
Conrey, R.M., Streck, M.J.
"The Boring Volcanic Field of the Portland Basin: Diverse primitive mafic magmas erupted in a
frontal arc setting." American Geophysical Union, Fall Meeting, San Francisco, CA. (12
December, 2003) With Conrey, R.M., Streck, M.J., Evarts, R.C.
Editorial Positions
Editor for Special Issue, J. of Volcanology and Geothermal Research. Elsevier. (2004 - 2004)
Editor for Special Issue, Bulletin of Volcanology. (2004 - 2004)
Supervised Theses & Dissertations
Saijin Huang, PhD Subduction Zone Thermal Models: Numerical Modeling and Data Analysis.
(2002) (Thesis or Dissertation Director)
Jared F. Lewis, M.A. Petrology of Cascades frontal-arc lavas. (2003) (Thesis or Dissertation
Director)
Jared F. Lewis, M.A. Petrology of Cascades frontal-arc lavas. (2003) (Thesis or Dissertation
Director)
Deanna C. Borchers, M.S. Mauna Loa's Submarine Western Flank: Evidence for Deep Volcanic
Spreading and Hydrothermal Alteration. (2004) (Committee Member)
Catherine Donohue, M.S. Regulation of Fluorine Chemistry and Carbonate Fluorapatite
Stability in Deep Sediments Near the Peruvian Upwelling Zone. (2004) (Committee Member)
Nathan Brill, M.A. TBA. (2005) (Thesis or Dissertation Director)
Nathan Brill, M.A. TBA. (2005) (Co-Director)
Awards, Prizes, & Fellowships
Keynote Speaker, International Assoc. Volcanology and Chemistry of the Earth's Interior (Nov
2004)
Outstanding Faculty Associate, Rice University (2002)
Chair: Organizing Committee for State of the Arc 2003 Conference, Intl. Assoc. Volcanology &
Chemistry of the Earth's Interior
Member, Geochemical Society
Fellow, Mineralogical Society of America
Life Member, American Geophysical Union