The abstracts deadline has now passed. If you have a question about your abstract, please contact Nancy Wright, +1-303-357-1061, .
Abstracts may be submitted to one of the Theme Sessions below, or to a general Discipline such as structural geology, petrology, hydrogeology, geophysics, etc, for which sessions will be created on demand based on abstracts received.
- T1. Tectonic Processes that Build the Stratigraphic and Structural Record of Ancient and Modern Convergent Margins. David Scholl, USGS, dschollusgs.gov; Roland von Huene, University of California–Davis, rhuenemindspring.com; Trevor A. Dumitru, Stanford University, tdumitrustanford.edu; John Wakabayashi, California State University–Fresno, jwakabayashicsufresno.edu.
- Description: It is becoming clear that the structural and stratigraphic complexity of modern and ancient convergent margins is the net product of multiple interacting tectonic, mass wasting, and depositional processes. These in particular include
1. Deposition and tectonic involvement of large depositional and mass wasting bodies,
2. Frontal and basal (underplating) subduction accretion,
3. Sediment and forearc debris subduction,
4. Frontal and basal subduction erosion,
5. Massive redistribution and destruction of forearc material by subducting seafloor relief, and
6. Exhumation and upward-directed emplacement of deep-seated material.
This session encourages abstracts to present onshore and offshore evidence about how the interactive workings of these and linked processes are (1) presently building the larger-scale rock fabric of modern convergent margins, and (2) built those of ancient ones exposed in coastal and interior mountain belts.
Relevant Field Trips: F7: Mélanges, HP Metamorphism, Subduction Accretion and Erosion, Subduction Megathrusts, and Ophiolites: The Franciscan and Related Rocks; F3: From Deep to Modern Time along the Western Sierra Nevada Foothills–San Joaquin to Kern Drainages; F5: Locked Rocks: Hard-to-Access Outcrops of the Mesozoic Metasedimentary Framework and Gabbroids of the Early Cretaceous Sierra Nevada Batholith.
- T2. Mélanges: Comparison and Contrast between Circum-Pacific and Tethyan Chaotic Rock Bodies and Modern Submarine Analogues. Yildirim Dilek, Miami University, dilekymuohio.edu; Andrea Festa, Università di Torino, andrea.festaunito.it; Yujiro Ogawa, Century Tsukuba-Miraidaira, fyogawa45yahoo.co.jp.
- Description: Our current knowledge of mélanges and chaotic rock bodies has been derived to the largest extent from the U.S. Cordillera concept of mélanges and its comparison with the Circum-Pacific and Tethyan mélange occurrences. However, there are some major differences, as well as strong similarities, between the mélange-forming processes that have been documented from the Cordilleran and Tethyan orogenic systems. Mélange-forming processes in Tethyan-type orogenic belts are commonly associated with passive margin evolution, subduction, and obduction of oceanic lithosphere, continental collision, and intra-continental deformation. Mélanges in Cordilleran-type orogenic belts are commonly involved, on the other hand, in the dynamics and mechanical stability of accretionary wedges, and hence are mostly the products of offscraping, underplating, mass-transport movements (olistostromes), subduction channel dynamics (flow mélanges), and mud diapirism. This session will provide an international forum for the exchange of current ideas and information about mélanges and chaotic rock bodies from the Circum-Pacific and Tethyan case studies, across the disciplinary boundaries (e.g., stratigraphy, structural geology, tectonics, sedimentology, marine geology, geochemistry, and thermochronology). Contributions covering a large spectrum of geological and geodynamic environments both on land and in modern submarine settings, in which mélanges, other chaotic rock bodies, and mud diapirs/volcanoes develop are welcome.
Relevant Field Trips: F7: Mélanges, HP Metamorphism, Subduction Accretion and Erosion, Subduction Megathrusts and Ophiolites: The Franciscan and Related Rocks; F3: From Deep to Modern Time along the Western Sierra Nevada Foothills–San Joaquin to Kern Drainages.
- T3. Oceanic Petrogenesis of Pacific-Type Convergent Margins. Tatsuki Tsujimori, Okayama University–Misasa, tatsukixmisasa.okayama-u.ac.jp; W.G. Ernst, Stanford University, wernststanford.edu; John Wakabayashi, California State University–Fresno, jwakabayashicsufresno.edu.
- Description: Pacific-type subduction zones including blueschist and forearc ophiolite assemblages have been documented for almost half a century in Phanerozoic orogenic belts. As a key proxy of oceanic plate underflow, the rocks have been intensively studied from various viewpoints and at various scales ranging from single crystals to mountain belts. However, questions remain concerning our interdisciplinary understanding of the modern and Phanerozoic style of oceanic subduction in Earth's history. This session is aimed at attracting the latest data and concepts regarding the petrogenesis of subducting oceanic slabs and forearc materials along Pacific-type orogenic belts. The classical and neoclassical multidisciplinary approaches continue to provide the opportunities to link high-pressure metamorphism to geophysical observations, to evaluate hydration and dehydration along the subduction channels and subsequent slab-mantle interaction, and to visualize more realistic ancient Pacific-type margins. Specific foci in this topical session include, but are not limited to (1) Pacific-type blueschist and eclogite facies metamorphism and related metasomatism; (2) serpentinization of the mantle wedge and emplacement of forearc ophiolites; (3) element mobility and the role of fluids within and overlying the descending oceanic slab; (4) provenance analysis of ancient blueschist belts; (5) multiple episodes and time-scales of Pacific-type mountain building; (6) comparisons between Pacific-type and Alpine-type petrogenesis; and (7) contrasting discrepancies between petrological observations and numerical modeling. The session also aims at exchanging ideas among international geoscientists applying different approaches, tests, and challenges on problems related to “Oceanic petrogenesis of Pacific convergent margins.” We especially encourage contributions exploring new directions with novel or interdisciplinary techniques regarding related themes.
Relevant Field Trips: F7: Mélanges, HP Metamorphism, Subduction Accretion and Erosion, Subduction Megathrusts and Ophiolites: The Franciscan and Related Rocks; F3: From Deep to Modern Time along the Western Sierra Nevada Foothills–San Joaquin to Kern Drainages; F5: Locked Rocks: Hard-to-Access Outcrops of the Mesozoic Metasedimentary Framework and Gabbroids of the Early Cretaceous Sierra Nevada Batholith.
- T4. Ophiolites and Suture Zones. Yildirim Dilek, Miami University, dilekymuohio.edu; John Wakabayashi, California State University–Fresno, jwakabayashicsufresno.edu; John Shervais, Utah State University, john.shervaisusu.edu.
- Description: Both accretionary and collisional orogenic belts are common around the Pacific Rim and in other regions of the world. These include different ophiolite types that formed in diverse tectonic settings, ranging from mid-ocean ridges, suprasubduction zone environments, and plumes. Emplacement of these ophiolites into continental margins is a first-order tectonic phenomenon, reflecting both the original igneous development of ophiolite, and subsequent tectonic evolution or transitions. The relationship of ophiolites to suture zones is more varied than commonly thought. Evaluation of the ages, regional structural context, tectonomagmatic affinity, and emplacement mechanisms of the existing ophiolites, and reexamination of the nature and distribution of the suture zones, will lead to a better understanding of the mountain building processes and continental growth. This session is aimed at providing a forum for presentations and discussions on all aspects of ophiolites and suture zones, based on interdisciplinary studies and latest data and interpretations. In addition to studies of on-land exposures, we encourage contributions from modern ophiolite factories (IBM, Tonga, Andaman Sea, Melanesia, Woodlark Basin) derived from drilling and diving results.
Relevant Field Trips: F7: Mélanges, HP Metamorphism, Subduction Accretion and Erosion, Subduction Megathrusts and Ophiolites: The Franciscan and Related Rocks; F3: From Deep to Modern Time along the Western Sierra Nevada Foothills-San Joaquin to Kern Drainages.
- T5. Critical Zone: Where Rock Meets Water and Life at Earth's Surface. Clifford S. Riebe, University of Wyoming, criebeuwyo.edu; Leonard S. Sklar, San Francisco State University, leonardsfsu.edu; Kate Maher, Stanford University, kmaherstanford.edu.
- Description: Understanding the chemical, physical, and biological processes that modulate Earth’s surface is important across a diverse range of problems, from assessing soil and water sustainability over human timescales to understanding weathering-related feedbacks in Earth’s long-term climate evolution. Sediment, as both the byproduct and matrix of weathering and erosion, is central to the interplay of climate, tectonics, and lithology in Earth-surface dynamics and the sedimentary record. Increasingly, questions about landscape evolution and its sedimentary byproducts are being tackled in exciting, cross-disciplinary studies of the “Critical Zone”—defined as the near-surface environment where water, rock, air, and life meet in a dynamic interplay that generates soils, sustains ecosystems, and shapes landscapes. This session solicits contributions that discuss studies of physical, chemical, hydrological, and biological aspects of Earth-surface dynamics. Contributions that address cross-disciplinary, process-based research are especially encouraged.
Relevant Field Trip: F1: Critical Zones in the NW Sierra Nevada.
- T6. Using Detrital Zircon Age Data to Reassemble the Cordilleran Jigsaw Puzzle. Trevor Dumitru, Stanford University, tdumitrustanford.edu; Elizabeth Miller, Stanford University, elmillerstanford.edu.
- Description: Detrital zircon dating is a powerful tool for deciphering ancient sediment dispersal pathways and using them to reconstruct ancient paleogeography, paleotopography, and orogenic evolution. This session welcomes contributions in these areas toward reconstructing portions of the North American Cordillera as well as orogenic belts worldwide.
Relevant Field Trips: F7: Mélanges, HP Metamorphism, Subduction Accretion and Erosion, Subduction Megathrusts and Ophiolites: The Franciscan and Related Rocks; F3: From Deep to Modern Time Along the Western Sierra Nevada Foothills-San Joaquin to Kern Drainages; F5: Locked Rocks: Hard-to-Access Outcrops of the Mesozoic Metasedimentary Framework and Gabbroids of the Early Cretaceous Sierra Nevada Batholith.
- T7. Hydrogeologic Issues of Irrigated Agricultural Regions—Problems and Solutions. C. John Suen, California State University–Fresno, johnscsufresno.edu; Dong Wang, USDA Agricultural Research Service, dwangfresno.ars.usda.gov.
- Description: The world’s food security hinges on irrigated agriculture. Yet such irrigated farmlands are currently facing a host of sustainability issues. They are being degraded by salinization, waterlogging, groundwater depletion, contamination, etc. The San Joaquin Valley, being the most productive agricultural region of the world, serves as an archetypical example. Researchers of these and related issues throughout the world are invited to present their findings and perspectives, and they may also offer possible mitigation plans or conceptual solutions.
- T8. Quantitative Approaches in Sedimentology and Stratigraphy. Mara Brady, California State University–Fresno, mebradycsufresno.edu.
- Description: Quantitative interrogation of sedimentary deposits provides powerful information that can be used to better constrain depositional controls and preservational biases in the stratigraphic record. This session seeks contributions from studies of a range of depositional systems throughout Earth’s history and seeks papers that highlight the use of quantitative methods in various topics within sedimentary geology, including but not limited to the following: sequence stratigraphy, cyclostratigraphy, allogenic versus autogenic forcings, chrono-, chemo-, and biostratigraphy, sedimentary basin modeling, and actualistic studies of modern depositional environments.
- T9. AFC Processes in the Formation of Intermediate Magmas from Mantle to Crust. Michael Farner, Rice University, mfarner01gmail.com; Cin-Ty Lee, Rice University, ctleerice.edu.
- Description: Andesites and granodiorites are the most common rocks in modern subduction zones. In addition, the composition of the continental crust appears to be andesitic in bulk, but, despite the prevalence of these intermediate compositions in the continents, the petrogenesis of intermediate rocks is not completely understood. One prevailing view is that intermediate rocks represent hybrid products of mixing between fractionating mafic and felsic end-members in AFC–type processes (e.g., assimilation fractional crystallization), resulting in cooling and fractional crystallization of mixed intrusions as well as assimilation of felsic country rock or melts derived from crustal anatexis. Exactly how such mixing occurs, however, is unclear. For example, an open question is how lithologies with such different bulk compositions can be efficiently mixed within magma chambers given that the solidi of mafic and felsic magmas are so different, and consequently, their rheological contrasts are high. Abstracts relating field, laboratory, and theoretical studies to better document and understand when and where in the crust AFC processes are likely to be most efficient are encouraged. In particular we are interested in, but not limited to, the following questions: What is the best way to quantify mixing in magma chambers? Where in the crust is mixing most efficient and does this position vary with tectonic environment or background deviatoric stress state?
Relevant Field Trips: F2: Granite, Glaciation, and Rockfall in Yosemite Valley, California; F3: From Deep to Modern Time along the Western Sierra Nevada Foothills-San Joaquin to Kern Drainages; F5: Locked Rocks: Hard-to-Access Outcrops of the Mesozoic Metasedimentary Framework and Gabbroids of the Early Cretaceous Sierra Nevada Batholith.
- T10. Reconstructing the Pacific–North America Plate Boundary Through Late Cenozoic Time. Scott Bennett, University of California–Davis, sekbennettucdavis.edu; Rebecca Dorsey, University of Oregon, rdorseyuoregon.edu; Michael Oskin, University of California–Davis, meoskinucdavis.edu; Michael Darin, ConocoPhillips, mike.h.darinconocophillips.com.
- Description: This session addresses long-standing questions concerning Pacific–North America relative plate motion on the San Andreas fault, Walker Lane, Eastern California Shear Zone, and Gulf of California transform fault system since its inception ca. 28 Ma. Insights from geologic mapping, stratigraphy, geochronology, paleomagnetism, geophysics, and related datasets provide critical constraints on the history of dextral offset along this 2,500-km-long transform plate boundary. Recent studies have made important new advances on this problem, but the challenge that remains is to integrate observations into a coherent model for the evolution of the plate boundary through time. Unresolved controversies include, but are not limited to (1) total dextral offset across the San Andreas fault north of the Transverse Ranges, (2) disparate estimates for total offset across the southern San Andreas fault, (3) cumulative distributed shear in the Walker Lane and Eastern California Shear Zone, (4) age of marine incursion in the Gulf of California–Salton Trough, and (5) distribution and timing of dextral strain across the Gulf of California since middle Miocene time. We invite contributions from local to regional to plate-boundary scale studies that offer new insights from constraints such as offset geologic markers, basin analysis, and geodetic studies, with particular interest in map-view reconstructions that integrate multiple, diverse datasets.
Relevant Field Trips: F6: New Views on the Evolution of the San Andreas Fault Zone in Central California and the Carrizo Plain; F3: From Deep to Modern Time along the Western Sierra Nevada Foothills-San Joaquin to Kern Drainages; F1: Critical Zones in the NW Sierra Nevada.
- T11. The Engineering Geology of Transporting Water in the Western United States. Cosponsors: GSA Engineering Geology Division and Association of Environmental and Engineering Geologists (San Joaquin Valley Chapter, Sacramento Section). Jerome V. De Graff, USDA Forest Service, jdegraffcsufresno.edu.
- Description: Throughout the western United States, many miles of canals, pipelines, penstocks, and other water conveyances exist. These vital conveyances sustain irrigated agriculture, municipal water supply, industrial operations, and hydroelectric power generation and are built across a geologically diverse landscape, making them vulnerable to breaching due to earthquakes, landslides, and foundation soil conditions. This technical session will examine and describe the environmental impacts of breaching and efforts to address the vulnerability of these important engineering works.
Relevant Field Trips: F6: New Views on the Evolution of the San Andreas Fault Zone in Central California and the Carrizo Plain; F2: Granite, Glaciation, and Rockfall in Yosemite Valley, California; F8: Debris Flows in Recently Burned Watersheds in the Southeastern Sierra Nevada.
- T12. Quaternary Environmental Change; The Cordilleran Record and Its Implication for Our Future in a Changing World. Peter K. Van de Water, California State University–Fresno,pvandewatercsufresno.edu; Mathieu Richaud, California State University–Fresno, mathieucsufresno.edu.
- Description: The U.S. Cordilleran region provides a unique perspective on environmental change, with its wide range of elevations, steep gradients of precipitation and temperatures, and dynamic geomorphology that is responding to changing conditions. In addition, the bordering ocean drives much of the climate and is a major influence because of its proximity. The Quaternary history of this area provides not only the backdrop to the environment that we see today but also a greater understanding of the range of future events that we might expect. This session invites researchers to present detailed records of past and present changes to our environment that will provide a perspective on the likelihood and extent of future conditions. We look forward to including a wide range of paleo-environmental to geomorphological research that spans all periods of the Quaternary.
Relevant Field Trips: F6: New Views on the Evolution of the San Andreas Fault Zone in Central California and the Carrizo Plain; F2: Granite, Glaciation, and Rockfall in Yosemite Valley, California; F1: Critical Zones in the NW Sierra Nevada.
- T13. Irvingtonian Paleoecology of Western North America. Robert G. Dundas, California State University–Fresno, rdundascsufresno.edu; Eric Scott, San Bernardino County Museum, escottsbcm.sbcounty.gov.
- Description: This session will provide an opportunity for numerous Pleistocene researchers to present new data and synthesize earlier data concerning terrestrial paleontology, palynology, and paleoclimatology of the Irvingtonian North American Land Mammal Age (ca. 1.9–0.24 Ma).
Relevant Field Trip: F4: Middle Irvingotonian Fairmead Landfill Fossil Site and Fossil Discovery Center of Madera County, California.
- T14. Quaternary Geology of California’s Central Valley and Its Relevance to Water Infrastructure. Justin Pearce, j.pearcefugro.com; Janet Sowers, j.sowersfugro.com; Jennifer Wilson, jm.wilsonfugro.com; Cooper Brossy, c.brossyfugro.com—all with Fugro Consultants Inc.
- Description: The performance of California’s water conveyance and flood protection infrastructure within the Central Valley impacts nearly all California residents. Understanding the diverse geologic deposits and structures that underlie this vital system of levees, canals, pipelines, dams, and reservoirs is critical to identifying the potential vulnerabilities to the system and developing appropriate solutions. We invite contributions from studies of the Quaternary geology of the Central Valley by academics, consultants, agencies, and researchers whose work has direct relevance to the development, performance, reliability, and maintenance of California’s water conveyance and flood protection infrastructure.
Relevant Field Trip: F3: From Deep to Modern Time along the Western Sierra Nevada Foothills–San Joaquin to Kern Drainages.
- T15. Undergraduate Research Posters. Chris Pluhar, California State University–Fresno, cpluharcsufresno.edu.
- Description: This session provides an opportunity for undergraduates to present their research. All topics and areas of research are welcome.