Gail Mahood
Professor of Geological Sciences, Emerita
Earth & Planetary Sciences
Web page: http://pangea.stanford.edu/research/mahood/
Bio
Gail Mahood is a Professor Emerita, having retired in 2019 from the Department of Geological Sciences at Stanford University after 40 years of service as a faculty member and administrator. Her research interests have focused on field-based petrologic studies of silicic magmatism based on the records contained in the rhyolitic caldera complexes that are the sources of "super eruptions" that spread ash continent-wide, and in the deep-level plumbing systems for these volcanoes preserved in granite plutons. In the last decade her group mapped rhyolite calderas in Nevada, Oregon, and Idaho that were caused by intrusion of flood basalt about 16 million years ago, and are the initiation point for the Snake River Plain-Yellowstone “hot spot” track. A practical application of this work was the development of a new model for the formation of lithium deposits in calderas. In addition to teaching and research, Professor Mahood has extensive university governance and administrative experience, including serving as Department Chair, Chair of the Stanford Faculty Senate, and Associate Vice Provost of Graduate Education. She was elected to and chaired the Advisory Board, a 7-member faculty group that evaluates all appointments and promotions throughout Stanford University. Mahood also served on then-Provost Condoleeza Rice’s budget and strategic planning group.
Administrative Appointments
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Professor Emerita, Department of Geological Sciences, Stanford University (2020 - Present)
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Professor, Department of Geological Sciences, Stanford University (1993 - 2019)
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Chair, Faculty Senate, Stanford University (1995 - 1996)
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Member, Provost Condoleeza Rice's advisory committee on budget and strategic planning, Stanford University (1994 - 1998)
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Member, Board of Trustees Committee on Land and Buildings, Stanford University (2003 - 2005)
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Associate Vice Provost for Graduate Education, Stanford University (2005 - 2007)
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Chair, Advisory Board (elected7-member board that reviews all faculty appointments and promotions), Stanford University (1996 - 2001)
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Chair, Department of Geological and Environmental Sciences, Stanford University (1996 - 1998)
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Member, Provost’s Diversity Cabinet, Stanford University (2005 - 2006)
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Member, NCAA Compliance Committee (intercollegiate athletics), Stanford University (2000 - 2001)
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Member, Faculty Steering Committee on the Campaign for Undergraduate Education, Stanford University (1999 - 2003)
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Member, President's Commission on Undergraduate Education, Stanford University (1993 - 1994)
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Member, Executive Committee, Archaeology Center, Stanford University (2000 - 2008)
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Associate Professor of Geology, Stanford University (1987 - 1993)
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Assistant Professor of Geology, Stanford University (1979 - 1987)
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Geoarchaeologist, Proyecto Arqueologico Copan, Honduras (1978 - 1978)
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Sr. Engineering Aide, Nevada Geothermal Exploration Project, Lawrence Livermore Laboratory (1974 - 1974)
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Research Associate, Geothermex (1974 - 1974)
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Physical Science Aide, Division of Mining and Minerals, U.S. National Park Service (1973 - 1974)
Honors & Awards
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Top geoscience paper of 2016, Geosphere (2017)
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Fellow, Society of Economic Geologists (2014)
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Fellow, Geological Society of America (1987)
Boards, Advisory Committees, Professional Organizations
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Faculty leader, Travel Study trips to Mongolia, Argentina, New Zealand, Iceland, Baja CA, Alaska, Stanford Alumni Association (1999 - 2019)
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Evaluator, Crafoord Prize (Nobel equivalent for geosciences), Royal Swedish Society (2017 - 2017)
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Geologist, Assessment of volcanic hazards for holy city of Al Madinah, U.S. Geological Survey and Saudi Geological Survey (2014 - 2016)
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Associate Editor, Bulletin of the Geological Society of America, Geological Society of America (1997 - 2000)
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Councillor and member of the Audit Committee, Geological Society of America (1996 - 1999)
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Congressional testimony concerning the role of the U.S. Geological Survey, U.S. House of Representatives (1995 - 1995)
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Founding Editor, Proceedings in Volcanology, International Association of Volcanology and Chemistry of the Earth's Interior (1988 - 1994)
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Editor, Bulletin of Volcanology, Springer (1990 - 1992)
Professional Education
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Ph.D., University of California, Geology (1980)
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M.A., University of California, Geology (1976)
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A.B., University of California, Geology (1974)
Current Research and Scholarly Interests
Research
I am interested in understanding the processes that assemble and occur in the bodies of silicic magma that give rise to huge, explosive eruptions that spread ash continent-wide. We study young volcanoes to determine how large and how explosive future eruptions might be, how frequently they are likely to occur, and what mechanisms trigger eruptions. We also do field-based studies in mountainous areas where plutons and the guts of volcanoes are well-exposed, mapping them and then analyzing their products in the laboratory, in order to reconstruct the life histories of these systems. To these ends we make extension use of 40Ar-39Ar geochronology and use the Stanford-USGS ion probe to determine U-Pb and U-series ages. The main foci of our current research are (1) widespread Mid-Miocene silicic volcanism and calderas associated with emplacement of the Columbia River flood basalts and initiation of the Yellowstone plume; (2) controls on the pre-eruptive concentrations of energy-critical elements in silicic magmas as evidenced by melt inclusions; (3) models for for the formation of lithium deposits in volcanic settings; (4) petrologic evidence for volcanic hazards in the Long Valley--Mammoth Mountain--Mono Craters--Mono Basin region; and (5) volcanic hazards of western Saudi Arabia at Harrat Rahat and petrologic study of the origin of trachytes associated with young basaltic lavas. I also have an interest in geoarchaeology, especially in the application of petrologic and geochemical techniques to determining the provenance of obsidian and ceramics.
Teaching
I have taught introductory geology courses, including those that culminate in a field trip to Death Valley or to Mt. Shasta and Mt. Lassen, or involve field trips closer to home in the Santa Cruz Mountains and coast. My upper-division-level course on volcanology included a field trip to young volcanism of the eastern Sierra Nevada (Long Valley, Mammoth Mountain, Mono Craters, Mono Lake). Graduate-level courses include those on igneous petrogenesis, and field seminars in physical volcanology of the southern Cascade arc and transform-related volcanism in the Coast Range of California, as well as specialized graduate seminars in petrology and physical volcanology.
Projects
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Widespread Mid-Miocene rhyolitic magmatism associated with flood basalts in western U.S., Stanford University
Location
Denio, Nevada
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Formation of lithium deposits in volcanic settings
Location
Nevada
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Volcanic hazards of Harrat Rahat for the holy city of Al Madiinah, Kingdom of Saudi Arabia, cooperative study with the U.S. Geological Survey and the Saudi Geologic Survey
Location
Medina, Saudi Arabia
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Magma mixing as a trigger for eruptions in Long Valley, Mammoth Mountain, and Mono Basin, Stanford University, U.S. Geological Survey
Location
Mammoth Lakes, CA
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Controls on concentrations of energy-critical elements in rhyolitic magmas based on analysis of melt inclusions, Stanford University, U.S. Geological Survey
Location
Stanford, CA
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Timing of Mid-Miocene climate events relative to flood basalt and rhyolite eruptions in the Pacific Northwest, Stanford University
Location
southeastern Oregon, northern Nevada, western Idaho
2021-22 Courses
- Physical Volcanology
GEOPHYS 385R (Sum) -
Independent Studies (1)
- Teaching in Geological Sciences
GEOLSCI 398 (Win, Spr)
- Teaching in Geological Sciences
All Publications
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The timing and compositional evolution of volcanism within northern Harrat Rahat, Kingdom of Saudi Arabia
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
2020; 132 (7-8): 1381–1403
View details for DOI 10.1130/B35337.1
View details for Web of Science ID 000545115400003
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Timescales of magmatic differentiation from alkali basalt to trachyte within the Harrat Rahat volcanic field, Kingdom of Saudi Arabia
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
2018; 173 (8)
View details for DOI 10.1007/s00410-018-1495-9
View details for Web of Science ID 000440650500001
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Using Ar-40/Ar-39 ages of intercalated silicic tuffs to date flood basalts: Precise ages for Steens Basalt Member of the Columbia River Basalt Group
EARTH AND PLANETARY SCIENCE LETTERS
2017; 459: 340-351
View details for DOI 10.1016/j.epsl.2016.11.038
View details for Web of Science ID 000393006500032
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Lithium enrichment in intracontinental rhyolite magmas leads to Li deposits in caldera basins
NATURE COMMUNICATIONS
2017; 8: 1-9
Abstract
The omnipresence of lithium-ion batteries in mobile electronics, and hybrid and electric vehicles necessitates discovery of new lithium resources to meet rising demand and to diversify the global lithium supply chain. Here we demonstrate that lake sediments preserved within intracontinental rhyolitic calderas formed on eruption and weathering of lithium-enriched magmas have the potential to host large lithium clay deposits. We compare lithium concentrations of magmas formed in a variety of tectonic settings using in situ trace-element measurements of quartz-hosted melt inclusions to demonstrate that moderate to extreme lithium enrichment occurs in magmas that incorporate felsic continental crust. Cenozoic calderas in western North America and in other intracontinental settings that generated such magmas are promising new targets for lithium exploration because lithium leached from the eruptive products by meteoric and hydrothermal fluids becomes concentrated in clays within caldera lake sediments to potentially economically extractable levels.Lithium is increasingly being utilized for modern technology in the form of lithium-ion batteries. Here, using in situ measurements of quartz-hosted melt inclusions, the authors demonstrate that preserved lake sediments within rhyolitic calderas have the potential to host large lithium-rich clay deposits.
View details for DOI 10.1038/s41467-017-00234-y
View details for PubMedCentralID PMC5559592
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Geology and 40Ar/39Ar geochronology of the middle Miocene McDermitt volcanic field, Oregon and Nevada: Silicic volcanism associated with propagating flood basalt dikes at initiation of the Yellowstone hotspot
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
2017
View details for DOI 10.1130/B31642.1
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Geology of the High Rock caldera complex, northwest Nevada, and implications for intense rhyolitic volcanism associated with flood basalt magmatism and the initiation of the Snake River Plain-Yellowstone trend
GEOSPHERE
2016; 12 (1): 58-113
View details for DOI 10.1130/GES01162.1
View details for Web of Science ID 000369539200005
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Geology of the Mid-Miocene Rooster Comb Caldera and Lake Owyhee Volcanic Field, eastern Oregon: Silicic volcanism associated with Grande Ronde flood basalt
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
2016; 309: 96-117
View details for DOI 10.1016/j.jvolgeores.2015.11.011
View details for Web of Science ID 000370768800008
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Initial impingement of the Yellowstone plume located by widespread silicic volcanism contemporaneous with Columbia River flood basalts
GEOLOGY
2012; 40 (7): 655-658
View details for DOI 10.1130/G32692.1
View details for Web of Science ID 000305818900020
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Silicic calderas in arc settings: Characteristics, distribution, and tectonic controls
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
2011; 123 (7-8): 1577-1595
View details for DOI 10.1130/B30232.1
View details for Web of Science ID 000291248800020
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Strontium Isotopic Evidence for Prehistoric Transport of Gray-Ware Ceramic Materials in the Eastern Grand Canyon Region, USA
GEOARCHAEOLOGY-AN INTERNATIONAL JOURNAL
2011; 26 (2): 189-218
View details for DOI 10.1002/gea.20348
View details for Web of Science ID 000287371900002
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New Ar-40/Ar-39 ages reveal contemporaneous mafic and silicic eruptions during the past 160,000 years at Mammoth Mountain and Long Valley caldera, California
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
2010; 122 (3-4): 396-407
View details for DOI 10.1130/B26396.1
View details for Web of Science ID 000274210600004
- Geology of the Sheldon National Antelope Refuge, Oregon and Nevada U.S. Geological Survey Administrative Report 2010: 53
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Tectonic controls on the nature of large silicic calderas in volcanic arcs
GEOLOGY
2008; 36 (8): 627-630
View details for DOI 10.1130/G24796A.1
View details for Web of Science ID 000258017700009
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New ages for the climactic eruptions at Yellowstone: Single-crystal Ar-40/Ar-39 dating identifies contamination
GEOLOGY
1998; 26 (4): 343-346
View details for Web of Science ID 000073061500014
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Seeing past the effects of re-equilibration to reconstruct magmatic gradients in plutons: La Gloria Pluton, central Chilean Andes
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
1997; 127 (1-2): 159-175
View details for Web of Science ID A1997WW32400013
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Ar-40/Ar-39 geochronology of rhyolites erupted following collapse of the Yellowstone caldera, Yellowstone Plateau volcanic field: Implications for crustal contamination
EARTH AND PLANETARY SCIENCE LETTERS
1996; 142 (1-2): 91-107
View details for Web of Science ID A1996UZ23000008
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Zoning patterns and petrologic processes in peraluminous magma chambers: Hall canyon pluton, Panamint mountains, California
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
1996; 108 (4): 437-453
View details for Web of Science ID A1996UE64700004
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ISOTOPIC CONSTRAINTS ON THE PRODUCTION-RATES, CRYSTALLIZATION HISTORIES AND RESIDENCE TIMES OF PRE-CALDERA SILIC MAGMAS, LONG VALLEY, CALIFORNIA
EARTH AND PLANETARY SCIENCE LETTERS
1994; 125 (1-4): 17-37
View details for Web of Science ID A1994PC44200002
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THE OCCURRENCE AND DISTRIBUTION OF MO AND MOLYBDENITE IN UNALTERED PERALKALINE RHYOLITES FROM PANTELLERIA, ITALY
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
1993; 114 (1): 119-129
View details for Web of Science ID A1993LB07800009
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FLUID INCLUSIONS IN XENOLITHS YIELD EVIDENCE FOR FLUID EVOLUTION IN PERALKALINE GRANITIC BODIES AT PANTELLERIA (ITALY)
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
1992; 52 (4): 295-301
View details for Web of Science ID A1992JZ33500005
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EVIDENCE FOR ASCENT OF DIFFERENTIATED LIQUIDS IN A SILICIC MAGMA CHAMBER FOUND IN A GRANITIC PLUTON
2ND HUTTON SYMP ON THE ORIGIN OF GRANITES AND RELATED ROCKS
ROYAL SOC EDINBURGH. 1992: 63–69
View details for Web of Science ID A1992JL99500005
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PETROGENESIS OF HIGH-SILICA RHYOLITE ON THE ALASKA PENINSULA
GEOPHYSICAL RESEARCH LETTERS
1991; 18 (8): 1565-1568
View details for Web of Science ID A1991GB15000049
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EVIDENCE FOR EXTREME PARTITIONING OF COPPER INTO A MAGMATIC VAPOR-PHASE
SCIENCE
1991; 252 (5011): 1405-1409
Abstract
The discovery of copper sulfides in carbon dioxide- and chlorine-bearing bubbles in phenocryst-hosted melt inclusions shows that copper resides in a vapor phase in some shallow magma chambers. Copper is several hundred times more concentrated in magmatic vapor than in coexisting pantellerite melt. The volatile behavior of copper should be considered when modeling the volcanogenic contribution of metals to the atmosphere and may be important in the formation of copper porphyry ore deposits.
View details for Web of Science ID A1991FP86800027
View details for PubMedID 17772911
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DEVELOPMENT OF THE LONG VALLEY, CALIFORNIA, MAGMA CHAMBER RECORDED IN PRECALDERA RHYOLITE LAVAS OF GLASS MOUNTAIN
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
1991; 106 (3): 379-397
View details for Web of Science ID A1991EU97900010
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TRACE-ELEMENT PARTITIONING IN PANTELLERITES AND TRACHYTES
GEOCHIMICA ET COSMOCHIMICA ACTA
1990; 54 (8): 2257-2276
View details for Web of Science ID A1990DW46200011
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EVIDENCE FOR LONG RESIDENCE TIMES OF RHYOLITIC MAGMA IN THE LONG VALLEY MAGMATIC SYSTEM - THE ISOTOPIC RECORD IN PRECALDERA LAVAS OF GLASS MOUNTAIN
EARTH AND PLANETARY SCIENCE LETTERS
1989; 94 (3-4): 274-290
View details for Web of Science ID A1989AU95000010
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MECHANICAL MODELS FOR CORRELATION OF RING-FRACTURE ERUPTIONS AT PANTELLERIA, STRAIT OF SICILY, WITH GLACIAL SEA-LEVEL DRAWDOWN
BULLETIN OF VOLCANOLOGY
1988; 50 (5): 327-339
View details for Web of Science ID A1988Q044600003
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PHYSICAL AND CHEMICAL-MODELS OF ZONED SILICIC MAGMAS - THE LOMA SECA TUFF AND CALABOZOS CALDERA, SOUTHERN ANDES
JOURNAL OF PETROLOGY
1988; 29 (4): 831-867
View details for Web of Science ID A1988R424400004
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GENERATION OF HIGH-SILICA RHYOLITE - A ND, SR, AND O ISOTOPIC STUDY OF SIERRA-LA-PRIMAVERA, MEXICAN NEOVOLCANIC BELT
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
1988; 100 (2): 183-191
View details for Web of Science ID A1988Q354500005
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FIELD, CHEMICAL, AND PHYSICAL CONSTRAINTS ON MAFIC-FELSIC MAGMA INTERACTION IN THE LAMARCK GRANODIORITE, SIERRA-NEVADA, CALIFORNIA
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
1987; 99 (2): 272-291
View details for Web of Science ID A1987J604100010
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COMPOSITIONAL LAYERS IN THE ZONED MAGMA CHAMBER OF THE GRIZZLY PEAK TUFF
GEOLOGY
1987; 15 (4): 299-303
View details for Web of Science ID A1987G865100003
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STRONG COMPOSITIONAL ZONATION IN A SILICIC MAGMATIC SYSTEM - LOS-HUMEROS, MEXICAN NEOVOLCANIC BELT
JOURNAL OF PETROLOGY
1987; 28 (1): 171-209
View details for Web of Science ID A1987L413700006
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RING-FRACTURE ERUPTION OF THE BISHOP TUFF
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
1986; 97 (4): 396-403
View details for Web of Science ID A1986A812500003
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RISE AND FALL OF A BASALT-TRACHYTE-RHYOLITE MAGMA SYSTEM AT THE KANE-SPRINGS WASH CALDERA, NEVADA
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
1986; 94 (3): 352-373
View details for Web of Science ID A1986F138900010
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EXPERIMENTAL CONSTRAINTS ON DEPTHS OF FRACTIONATION OF MILDLY ALKALIC BASALTS AND ASSOCIATED FELSIC ROCKS - PANTELLERIA, STRAIT OF SICILY
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
1986; 93 (2): 251-264
View details for Web of Science ID A1986C964300013
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VOLCANIC STRATIGRAPHY OF THE LOS AZUFRES GEOTHERMAL AREA, MEXICO
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
1985; 25 (3-4): 273-287
View details for Web of Science ID A1985AQA3900005
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PRECURSORS TO THE BISHOP TUFF ERUPTION - GLASS MOUNTAIN, LONG VALLEY, CALIFORNIA
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH AND PLANETS
1985; 90 (NB13): 1121-1126
View details for Web of Science ID A1985AUS3300002
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PERALKALINE AND METALUMINOUS MIXED-LIQUID IGNIMBRITES OF THE GUADALAJARA REGION, MEXICO
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
1985; 25 (3-4): 259-271
View details for Web of Science ID A1985AQA3900004
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CORRELATION OF ASH-FLOW TUFFS
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
1985; 96 (7): 968-974
View details for Web of Science ID A1985AMK3000016
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ERUPTION RATES AND COMPOSITIONAL TRENDS AT LOS-HUMEROS-VOLCANIC-CENTER, PUEBLA, MEXICO
JOURNAL OF GEOPHYSICAL RESEARCH
1984; 89 (NB10): 8511-8524
View details for Web of Science ID A1984TK56800021
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REVERSE ZONING IN THE RESURGENT INTRUSIONS OF THE GRIZZLY PEAK CAULDRON, SAWATCH RANGE, COLORADO
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
1984; 95 (7): 779-787
View details for Web of Science ID A1984TD11700003
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PYROCLASTIC ROCKS AND CALDERAS ASSOCIATED WITH STRONGLY PERALKALINE MAGMATISM
JOURNAL OF GEOPHYSICAL RESEARCH
1984; 89 (NB10): 8540-8552
View details for Web of Science ID A1984TK56800023
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LARGE PARTITION-COEFFICIENTS FOR TRACE-ELEMENTS IN HIGH-SILICA RHYOLITES
GEOCHIMICA ET COSMOCHIMICA ACTA
1983; 47 (1): 11-30
View details for Web of Science ID A1983PZ92600002
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A RECONNAISSANCE GEOCHEMICAL STUDY OF LA-PRIMAVERA GEOTHERMAL AREA, JALISCO, MEXICO
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
1983; 16 (3-4): 247-261
View details for Web of Science ID A1983QR98800005
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NESTED CALDERAS AND TRAPDOOR UPLIFT AT PANTELLERIA, STRAIT OF SICILY
GEOLOGY
1983; 11 (12): 722-726
View details for Web of Science ID A1983RU95000032
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K-AR DATING YOUNG RHYOLITIC ROCKS - A CASE-STUDY OF THE SIERRA-LA-PRIMAVERA, JALISCO, MEXICO
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
1982; 93 (12): 1232-1241
View details for Web of Science ID A1982PW64300003
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A SUMMARY OF THE GEOLOGY AND PETROLOGY OF THE SIERRA LA PRIMAVERA, JALISCO, MEXICO
JOURNAL OF GEOPHYSICAL RESEARCH
1981; 86 (NB11): 137-152
View details for Web of Science ID A1981MR66300002
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CHEMICAL EVOLUTION OF A PLEISTOCENE RHYOLITIC CENTER - SIERRA-LA-PRIMAVERA, JALISCO, MEXICO
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
1981; 77 (2): 129-149
View details for Web of Science ID A1981MH88300005