Thursday, April 4th. Arrivals at ONT throughout the day with shuttles picking up attendees. Keck reps meeting starts at (dinner provided). All others have free time. Dinner will be on participants’ own dime.
Friday, April 5th. Field trips (Mecca Hills and San Onofre) Dinner on Pomona campus with all Keck participants. After dinner-project meetings. Room assignments for meetings will be provided in packets up on arrival.
Saturday, April 6th. Symposium, lunch, and evening banquet and speaker. Red-eye departures. Detailed TBA.
Sunday, April 7th. Departure.
Reps Meeting: Thursday from 6:15-10 pm (Business starts at 7:00pm).
Fieldtrips (Friday): Mecca Hills and San Onofre State Beach. Bus and vans will pick up participants at 8:00. Breakfast will be provided at pick-up and lunch and refreshments will be provided on the trip. These are all day trips where away from the hotel and campus, so plan accordingly. A list of recommended items for a day in the field will be posted soon.
Presentations (Saturday) – Schedule TBA.
Posters: All students present posters (dimensions are 4 feet x 8 feet wide maximum). It is recommended that posters be sized somewhat smaller for ensuring fit to the poster boards.
SYMPOSIUM RESEARCH VOLUME
Each student must submit a Short Contribution prior to the Symposium in April
Cretaceous to Miocene evolution of the northern Snake Range metamorphic core complex, Nevada
Intensely deformed lower plate rocks (bottom of image) juxtaposed with brittlely deformed upper plate sedimentary rocks (top of image) across the Northern Snake Range Decollement
What: This project will be a field-based study of the structural, tectonic, metamorphic and thermal history of the spectacular northern Snake Range in eastern Nevada. The Snake Range is a classic example of a metamorphic core complex where mid-crustal metamorphic rocks have been penetratively deformed and exhumed by tectonic extension along a major low-angle normal fault and shear zone.
When: July 20-August 18
Fieldwork portion (~2.5 weeks): The northern Snake Range (Mount Moriah Wilderness Area) in eastern Nevada. Ely, Nevada is the closest town (about 1.5 hours away).
Sample preparation and analytical work (~1.5 weeks): UC Santa Barbara. Students will fly into Las Vegas, NV and fly out of Santa Barbara or Los Angeles, CA.
Who: Project Directors: Phil Gans (UC Santa Barbara) and Martin Wong (Colgate University), Student Participants: 6 students
Project description and goals
The 2012 Snake Range project will investigate the tectonic evolution of the northern Snake Range metamorphic core complex in eastern Nevada. The Snake Range is one of the archetypical examples of a metamorphic core complex, where large-scale crustal extension associated with slip on a presently low-angle “detachment” fault (the northern Snake Range Decollement) has juxtaposed mid-crustal, highly strained and metamorphosed rocks in the footwall and imbricately normal faulted supracrustal rocks in the hanging wall. The Snake Range has played a central role in our understanding of extensional tectonics, and yet many fundamental questions about the tectonic and structural development of this feature remain controversial. This goal of this project is to provide new constraints on the structural and tectonic development of this core complex by combining structural field mapping, strain analyses, and microstructural studies together with thermobarometric studies and U-Pb geochronology and 40Ar/39Ar thermochronology. Our study will focus mainly on the lower plate of the core complex and examine in detail the spatial variations in the magnitude, timing, and kinematics of penetrative strain, metamorphism, and exhumation in the metasedimentary and plutonic rocks of the football. The project will spend approximately 2.5 weeks in the Snake Range, followed by 1.5 weeks at the University of California, Santa Barbara for sample preparation and geochronologic analyses.
Tentative Student projects
A view up Hendrys Creek on the eastern flank of the Snake Range
Structural studies of the footwall mylonitic fabrics (3-4 students): Despite a number of previous studies, the timing, kinematics, and tectonic significance of the mylonitic fabrics in the footwall rock of the Snake Range remains enigmatic. Do these rocks record a single or multiple phases of penetrative strain? What is the relationship between the footwall mylonites and the overlying detachment fault? What were the P-T conditions of deformation? What was the partitioning between coaxial and non-coaxial deformation? Deformed rocks in the shear zone provides outstanding opportunities for a variety of structural studies on a variety of scales from map scale to the outcrop to hand sample to microscopic. All structural projects will involve a component of detailed geologic mapping and field measurements complemented by appropriate laboratory/analytical work. Specific projects could include finite strain studies using various strain markers (Formation and bedding thicknesses, stretched pebble conglomerates), petrographic observations of micro-structures and kinematic indicators, and electron backscatter diffraction (EBSD) analyses of crystallographic preferred orientations (CPO) in mylonitic quartzite and granite. These studies will provide new information on the footwall strain history and temperature conditions during deformation.
Footwall metamorphism and thermobarometry (1-2 students): Footwall schist units contain peak Cretaceous metamorphic assemblages of garnet + biotite + muscovite ± plagioclase ± staurolite ± kyanite. These units offer an excellent opportunity for traditional metamorphic petrology using petrographic and SEM observations. In addition, these and other assemblages are suitable for several thermobarometers such as GARB thermometry and GMBP and GASP barometers using an electron microprobe, depending on the proximity of the home institution to a microprobe and on-campus faculty expertise.
U-Pb zircon and sphene geochronology (1-2 students): A number of important footwall granite units that bear on the magmatic, metamorphic and strain history of the footwall remain undated. In addition, the precise timing and spatial variations in peak metamorphism remain only loosely constrained. Possible student projects would be to date a variety of footwall granites, dikes and sills that intrude the footwall. Another possible project is to conduct U-Pb geochronology on igneous and metamorphic sphene from footwall samples. The U-Pb sphene system is increasingly being employed as a thermochronometer sensitive to cooling through ~550°C, depending on grain size. Thus, U-Pb sphene dating can provide new insight into the high-temperature cooling history of the footwall shear zone. All U-Pb geochronology will be conducted at UC Santa Barbara Laser ablation ICPMS laboratory during the on-campus portion of the project.
40Ar/39Ar thermochronology (1 student): The thermal history of the footwall can provide insights into the timing of metamorphism as well as the timing and geometry of tectonic exhumation during extensional events. A fairly large thermochronological data base (argon, fission track) already exisits for the Snake Range, but we will conduct much more detailed and targeted thermochronological transects aimed at understanding spatial variations in the burial and exhumation history. One student project may involve 40Ar/39Ar thermochronologic analyses of footwall muscovite, biotite and K-feldspar to further constrain the footwall thermal history. K-feldspar analyses will include multiple-diffusion domain (MDD) modeling of the 40Ar/39Ar results to assess a continuous cooling history from ~300-150°C. We anticipate that most of the mineral separation for 40Ar/39Ar analyses will be done during the on-campus portion of the project and all 40Ar/39Ar analyses will be done at UC Santa Barbara.
Highly strained quartzite with a pronounced foliation and lineation.
Most of the project will be conducted in the field. Topography in the Snake Range is relatively rugged and valley elevations are at ~5,000 feet and climb to over 11,000 feet in the highest peaks, although most of the work will be conducted in valleys. Typical temperatures in August during the day are in the high-70’s to low-90’s and nighttime temps are high-40’s to mid-50’s. Participants should be in good physical condition to be able to hike in rugged terrain off-trail. Wildlife (elk, deer, bighorn sheep) is abundant and some (rattlesnakes, mountain lions) pose a possible but unlikely danger. We will be camping in tents adjacent to a small stream during the field portion of the trip and will be without electricity or refrigeration. The project directors will provide tables, chairs, cook stoves, large water jugs, pots and pans, dishes, camp lanterns, and other “communal” equipment
Sleeping bag (a reasonably warm at least ~30°F rated bag is best)
Personal tent (2-person size; we have some available for loan if you don’t have one)
Rain gear (waterproof, jacket and pants if possible)
Sturdy hiking boots
Warm clothes for evenings
Standard field clothing and gear (hiking pants, water bottles, etc)
Please bring if you have it (we’ll have some to loan out as needed):
Brunton compass (or similar)
Field notebook pouch
Map-board – preferably something about 12×15″ with a clear plexiglass cover
Students should have taken courses in structural geology, a basic mineralogy and/or petrology course. Any field experience or field camp is a plus but not required.
Interdisciplinary studies in the Critical Zone, Boulder Creek catchment, Front Range, Colorado
Keck Colorado group in the Green Lakes basin, highest of the three study catchments
What: The Keck Colorado 12 project will work with a large interdisciplinary study (Boulder Creek Critical Zone Observatory: Weathered profile development in a rocky environment and its influence on watershed hydrology and biogeochemistry-NSF 0724960) directed by Suzanne Anderson, Institute for Arctic and Alpine Studies (INSTAAR), University of Colorado. The Keck Project focus is measurement and sampling of geologic deposits and processes in the critical zone, “the heterogeneous carapace of rock in various stages of decay, overlying soil, and the ecosystems they support… fundamental characteristics of the critical zone, such as its thickness, the character of the weathered rock and soil layers and the biological activity within them, together control the passage of water, the chemical processes operating, the material strength, and the function of subsurface ecosystems.” The “observatory” consists of 3 small, instrumented sites in the Boulder Creek basin (Fig. 1): (1) Green Lakes Valley-a steep, glaciated alpine area in the Boulder watershed where “fresh” materials are exposed at the surface; (2) Gordon Gulch-a forested, mid-elevation catchment developed in weathered materials, and (3) Betasso-a steep, lower-elevation basin where surficial deposits are of variable thickness.
When: July 11-August 8
Where: Middle Boulder Creek catchment, Colorado Front Range
Who: David Dethier (Williams College) and 6 students with assistance from Will Ouimet (University of Connecticut) and Matthias Leopold (Technical University of Munic
Project description and goals:
General goals of the Keck Colorado Project include making field measurements and collecting samples to help characterize the critical zone and its development, geochemistry and hydrology, and gaining hands-on experience with field geophysical techniques used to investigate the shallow subsurface down to fresh bedrock. Broader research questions include:
“How does soil development and chemistry vary across erosional and ecological regimes in the study area?”
“How does the distribution of critical zone development control the hydrologic response of the catchments to both snow and rainfall?”
“How do weathering and nutrient fluxes vary across the study catchments?”
“How does land-use history, including mining and the 2010 4-Mile fire, impact stream sediment and geochemistry in the basin?”
“How fast is sediment transported on hillslopes and in the channels of the study catchments
Students and project faculty will collect data and/or solid or liquid samples at field sites. We will work on laboratory preparation and initial sample treatment at MSR, USGS or at the extensive analytical facilities at INSTAAR in Boulder. Participants will return to their home schools with field data, initial results of some laboratory measurements and samples ready for additional analysis. Data from geophysical (after post-processing) and geochemical analyses (as necessary) will probably return sometime in the fall semester. Analysis and interpretation of field and laboratory results at the home institution will be supervised by the student’s advisor and aided by the Project Director. Some potential student projects include:
Characterizing the chemistry of shallow groundwater and meltwater near late-lying snowfields in Green Lakes basin and/or from baseflow in deeply weathered areas.
Mapping the depth to bedrock and the structure of the shallow subsurface in Gordon Gulch using seismic refraction and ground-penetrating radar techniques.
Measuring variations in soil chemistry, morphology, sediment generation and transport processes along slope transects from ridge crest to channel.
Investigating the coupling between hillslope erosional processes, channel morphology and sediment transport in Betasso and Gordon Gulch
Assessing the contribution of eolian material to soils in the Green Lakes (alpine) catchment.
Characterizing the Boulder Creek ‘knickzone’ and its role in determining hillslope and channel processes throughout the CZO study area.
We’ll be at elevations ranging from 5,000 to 12,500 feet and working in environments from the hot semidesert to late-lying snowfields and summer hailstorms! Once in the field we’ll generally be hiking in rolling to steep terrain. Participants will stay at an elevation of 9500 ft at the University of Colorado’s Mountain Research Station on the shoulder of Niwot Ridge and within hiking distance of the Green Lakes site. Cabin accommodations are rustic and include bunk beds with mattresses, so you need to bring your own sleeping gear. Nederland, the nearest town, is about 20 minutes to the south and we’ll generally eat dinner there on Friday nights. The Boulder urban area is about an hour away. The Research Station has a laboratory building with a library, a few computers and wireless connections. On a regular basis we’ll work about 6 days a week and take Sundays off for other field trips, relaxation or catching up on sleep and other activities. We’ll have breakfast and dinner 6 days a week at the dining hall and we’ll make bag lunches to take to the field. Breakfast is at 6:45 AM and dinner at 6 PM. We’ll do our best to adjust our field schedule to hit both those times. Once we are working on our projects we’ll usually meet after dinner to look at data, figure out where we’ll go and what we’ll do the next day. Most of the field studies will result in cooperative work where two or all of us help with one person’s project on one day and then move to another project the next day, etc. When the project is running geophysical lines, taking cores or doing other things that require “extra hands”, we’ll all help.
Important for the fifth year of this interdisciplinary project is a strong interest in surface and near-surface processes and in interdisciplinary science, a record of hard work and the ability to follow through. We would prefer gregarious, “can-do” students with a background in geology or physical geography and coursework in:
Earth materials and/or geochemistry
Geomorphology/Quaternary geology or hydrology
Sedimentology and/or soils (valuable)
Structural geology, geophysics or field mapping (valuable)
GIS or a strong background in supporting science (useful)
Paleoenvironmental Records and Early Diagenesis of Marl Lake Sediments: A Case Study from Lough Carra, Western Ireland
What: The 2012 Lough Carra, Ireland project will investigate Holocene climate, aquatic productivity, and pollution records by collecting and analyzing lacustrine carbonate sediments. In addition, we will verify the fidelity of the marl delta 13C record by conducting a series of pore water incubation experiments. The summer program will consist of fieldwork in Ireland and laboratory analyses at Amherst College and Wesleyan University.
When: July 11-August 8
Where: 10-day field session in Lough Carra, Ireland then ~2.6 weeks at Amherst College and Wesleyan University.
Who: Anna Martini (Amherst College) and Tim Ku (Wesleyan University) with 3 students
Project Overview and Goals
This project involves a return for the PI to a marl lake that has within it a record of sedimentation that spans the Holocene. Previous expeditions were limited to short push cores, but the 2012 trip will include long piston cores from the deepest section of the lake, expanding both the quality and duration of the sedimentary record. In addition, on-site use of membrane-inlet mass spectrometry (MIMS) technology allows for a far more detailed understanding of biogeochemical processes that may complicate sedimentary paleoenvironmental interpretations.
Carbonate sediments from lacustrine environments have provided long term records of climate and land-use changes through the use of geochemical and biological proxies such as stable isotopic data, trace metal concentrations, faunal assemblages and pollen analyses. More specifically, the oxygen isotope composition of carbonate minerals precipitated via biological mediation is assumed to be in near isotopic equilibrium with delta18O of lake water and the delta 13C of the DIC pool. In lakes with good drainage (~relatively short residence times) the delta18O marl values reflect the isotopic composition of the meteoric precipitation, which is directly related to mean annual temperature. The marl delta 13C values reflect lake water delta 13C values, which, in turn, are controlled by lake productivity, inflowing water delta 13C values, and exchange with the atmosphere. Sediment concentrations of Hg, Pb, Cu, Cr, and Zn record anthropogenic activities and preserved invertebrate and pollen assemblages reveal vegetation and water quality changes. Overall, carbonate lake deposits can provide excellent long-term paleoenvironmental records, but careful interpretations of these proxies is necessary since post-depositional processes may significantly alter the signal and result in misleading conclusions.
The Paleoclimate Record of Lough Carra from the Last Glacial Maximum (LGM) to the Present: Using delta 13C, delta18O, and trace element chemistries (Ca/Mg) of carbonate marl sediments we will build a record of climate change for the Lough Carra region. Sediment ages and accumulation rates will be determined from 14C, 210Pb, pollen analyses, and radiogenic isotope measurements on carbonate minerals, organic matter, or tephra deposits. One main goal will be to better constrain the timing of deposition. Keck students will use the University of Massachusetts Stable Isotope facility for carbon and oxygen isotope analyses. Trace elemental composition of carbonate for climate signals and identification of ash falls will be analyzed using the ICP-OES at Amherst College.
The Paleoproductivity Record of Lough Carra. A Holocene record of paleoproductivity will be constructed by combining combining organic and inorganic carbon concentrations, C/N ratios, and organic matter delta 13C and delta15N measurements with bulk sediment accumulation rates (g/cm2/yr) based on bulk densities and linear sedimentation rates. The paleoproductivity record is crucial to the interpretation of the delta13CCaCO3 record. Recent sedimentation will be used to document cultural eutrophication and older sediments will supply materials for delta13C calculations, thus determining any changes in lake water delta13CDIC. Sedimentation rates and age models will be constructed from 210Pb, 14C, and/or U-Th measurements of suitable materials.
Metal Loading History of Lough Carra. Anthropogenic metal pollution has increased dramatically since the Industrial Revolution. Some metals, such as Pb and Hg, have experienced a rise in global atmospheric deposition since the dawn of metallurgy. A record of Roman mining is recorded in a marl lake in the Aran Islands, western Ireland (Schettler and Romer, 2006). Pollution histories of Cd, Hg, and Pb have been found in ombrotrophic peat bogs near Galway and show distinct peak concentrations over the course of industrialization since the mid-1800s (Coggins et al., 2006). Metal concentrations in lake sediments will aid in determining sediment chronologies as well as narrate the environmental legacy of the “anthropocene”. Students will compile a sediment metal data set by analyzing marl sediments by ICP-OES, XRF, and direct mercury combustion techniques.
Carbonate Diagenesis of Marl Lake Sediments. Calcite saturation states and pore water measurements will allow us to evaluate potentially rapid carbonate recrystallization processes that may shift delta13CCaCO3 values in Lough Carra sediments. Sediment pore waters will be analyzed for pH, DIC concentration, delta13CDIC, Ca+2/Cl–, PCO2, and PCH4. Solutes concentrations will be determined by standard analytical techniques, delta13CDIC aliquots will be sampled in Exetainers and analyzed at the UC-Davis Stable Isotope Facility, and gas partial pressures will be determined in whole cores by membrane-inlet mass spectrometry (MIMS; Lloyd et al., 2002). In addition, closed-system sediment incubation experiments will allow us to track carbonate dissolution / precipitation and delta13CDIC during early diagenesis. To help identify specific organic carbon and carbonate precipitation mechanisms, 13C-enriched organic matter or DIC will be added to a series of incubations and tracked by MIMS.
Students will be collecting lake waters and sediments on boats or coring platforms. All students are required to be proficient at swimming. Previous coring experience and analytical instrumentation experience is preferred. Lodging in Ireland will consist of a rustic bed-and-breakfast and lodging at Amherst or Wesleyan will be college housing.
Students should have some combination of hydrogeology, geochemistry, and/or sedimentology coursework. Students with interests in isotope geochemistry or with strong chemistry backgrounds are encouraged to apply.
Coggins, A.M., Jennings, S.G., and Ebinghaus, R., 2006. Accumulation rates of the heavy metals lead, mercury and cadmium in ombrotrophic peatlands in the west of Ireland: Atmospheric Environment, v. 40, p. 260-278.
Lloyd, D., Thomas, K. L., Cowie, G., Tammam, J. D., and Williams, A. G., 2002. Direct interface of chemistry to microbiological systems: membrane inlet mass spectrometry: Journal of Microbiological Methods, v. 48, p. 289-302.
Schettler, G., and Romer, R.L., 2006. Atmospheric Pb-pollution by pre-medieval mining detected in the sediments of the brackish karst lake An Loch Mór, western Ireland: Applied Geochemistry, v. 21, p. 58-82.
Middle to Late Miocene eruptive and climatic history in the Grande Ronde Valley, Northeast Oregon
The Minam River winds through the layered basalts of the Columbia River Basalt Group
WHAT: A study of enigmatic rocks and ancient soils associated with the huge eruptions of the Miocene.
WHEN: July 11-August 7
WHERE: Our field area is in northeastern Oregon near the Grande Ronde River. We will be in these locations: (1) orientation at Whitman College in Walla Walla Washington, (2) two weeks of camping along the Minam River in northeastern Oregon and field work in the nearby mountains and valleys, (3) return to Whitman for preliminary analysis and sample preparation, and (4) XRF, ICP, and other analysis at Washington State University in Pullman.
WHO: Six students, and Professors Kirsten Nicolaysen (Whitman College), Nick Bader (Whitman College), and additional help from Mark Ferns (USGS).
Project Overview and Goals
Northeastern Oregon marks the center of the largest continental eruption of lavas in the Cenozoic (Coffin & Eldholm, 1994). The importance of this Large Igneous Province (LIP) is difficult to overestimate. It completely reshaped the landscape in much of Oregon, Washington, and Idaho. Furthermore, it may also have significantly changed global climate (Sheldon, 2006); atmospheric loading by volcanic gases from bigger LIPs in India and Siberia are associated with the terminal Cretaceous and Permian mass extinctions respectively, the largest extinctions in the Phanerozoic (Wignall, 2001). Distinct changes in lava compositions reveal a protracted Miocene transition from the vast effusion of the Columbia River Basalt Group (CRBG) to the isolated, small volume eruptions of the Powder River Volcanic Field (PRVF) exposed near La Grande, OR. Contemporaneous with the volcanism, sedimentation and soil development hold clues both to the changing climate that affected the erupted lavas and to lengths of the pauses between eruptions. In collaboration with six motivated student researchers, we propose to (1) describe stratigraphic relationships within and between CRB and PRVF lavas and sedimentary interbeds, (2) investigate models for the genesis of the PRVF magmas using mineral and isotopic compositions, (3) augment our understanding of the timing of lava eruption and interflow pauses, and (4) elucidate regional Miocene climatic conditions.
The lavas of Columbia River Basalt Group both obscure the underlying late Paleozoic-Jurassic accreted terranes (e.g., Schwartz et al., 2010 and references therein) and provide a defined surface later modified by folding, extensional faulting, and eruption (Figs. 1, 2). Although some CRBG lavas are compositionally as silicic as andesites, most of the 300+ flows are tholeiitic basalt and comprise a volume of ~224,000 cubic kilometers (Tolan et al., 2009 and references therein). In spite of complicating observations (Pierce and Morgan, 2009), mantle melts are thought to be largely responsible for the CRBG. Nonetheless clinopyroxene thermobarometry and isotopic compositions demonstrate that some CRBG lavas stalled in the crust and there assimilated partial melts of crustal material (e.g., Ramos et al., 2005; Caprarelli and Reidel, 2004). Although presumably the Yellowstone hotspot was under eastern Oregon when CRBG flows started effusing at Steens Mountain at approximately 16.6 Ma, the voluminous eruptions were finished by 14.7 Ma (Brueseke et al., 2007; Barry et al., 2010 and references therein). Synchronous with the waning eruptions of the CRBG, the Powder River Volcanic Field (PRVF) eruptions started as early as 14 Ma (Fig. 2; Bailey, 1990; Ferns et al., 2010). Throughout the ~12 million years of volcanism, PRVF lavas erupted lavas with truly diverse compositions, ranging from basalt to dacite and basanite to trachyandesite (Fig. 3; Bailey and Conrey, 1992; Ferns et al., 2010). In addition to being more siliceous and smaller in volume than most individual CRBG flows, PRVF lavas are calc-alkaline to alkaline in composition (i.e., higher in Na2O, K2O, and generally lower in MgO and FeO). These PRVF magma compositions cannot be explained by the same processes that produced the CRBG.
A second component of this project is ancient soils or paleosols. Paleosols are affected by processes occurring at the Earth’s surface. After controlling for diagenetic alteration, paleosols can therefore allow us to reconstruct paleoclimates (Sheldon and Tabor, 2009), paleoenvironments (Kraus, 1999) or paleotopography (Takeuchi, 2007) depending upon the variables held constant by the analysis.
Because most soils are in actively eroding landscapes, the global distribution of paleosols is sparse compared to the distribution of modern soils. However, widespread aggradation in the volcanically-active Cenozoic landscapes of eastern Oregon has preserved numerous paleosols. Especially well-studied examples include the late Eocene and Oligocene paleosols of the Clarno and John Day Formations (e.g., Retallack et al., 2000), which record the dramatic cooling at the Eocene-Oligocene transition. We will use the paleosols of the CRBG and the PRVF to examine Miocene climate and eruptive history.
View east across the upper Grande Ronde Valley from Mount Emily of the rocks of the Powder River Volcanic Field
Potential Student Projects:
Crustal history of alkaline magmas of the PRVF/EVF (1-2 students): Some small buttes and ridges are interpreted as monogenetic eruptions of trachyandesite and andesite. Investigation of amphibole phenocrysts and pyroxene microphenocryst compositions could reveal crystallization depths and pre-eruptive volatile content.
Parental magmas of the PRVG/EVF (1 student): We’ll collect targeted rock samples for Sr, Nd, Pb isotopic analysis and petrogenetic modeling in order to understand the role of mantle melts and crustal contamination in the genesis of the lavas of the Powder River and Elgin Volcanic Fields.
Age relationships and post-emplacement extension of PRVF/EVF flows (1 student): The age relationships among the PRVF lavas are crucial to both aspects of the project. This project will focus on argon dating. With the appropriate home-institution adviser, the same student could drill paleomagnetic cores from a stratigraphic sequence of lavas to determine the paleoflow direction or the effect of regional extension on flow orientation.
Comparative clay mineralogy and microtexture of paleosols (1 student): This project has two components: a detailed field description and measurement of the Cricket Flats paleosol and a detailed mineralogical comparison of the Cricket Flats paleosol with an older CRBG paleosol using X-ray diffraction.
Geochemical analysis of weathering in two Middle Miocene paleosols (1 student): One student will use XRF and ICP-MS analysis of major and trace elements to compare two interesting paleosols developed on different volcanic units. This data will be used to generate weathering indices and reconstruct temperature and moisture profiles in conjunction with the paleosol mineralogy project.
Changes in weathering on CRBG flows after the Middle Miocene thermal maximum (1 student): The interested student will use portable XRF to identify promising CRBG paleosols on Minam Grade Road, and collect samples for XRF and ICP-MS analysis at WSU Pullman. The resulting elemental abundance data will be used to reconstruct weathering profiles relative to the parent flow and to relate these soil processes to Middle Miocene paleoclimate.
We will be outside for the main part of this project. For several projects we will be walking and sampling on steep slopes that form the sides of deep canyons. Students should have good depth perception, good physical condition, and be comfortable climbing rough ground off-trail. Temperatures may be in the 90’s during the day and the 40’s at night. Rain is unlikely but possible. Rattlesnakes are a possible danger. Our field accommodations will be primitive (tent-based for two weeks) and far from big cities, with vault toilets and no electricity or refrigeration.
You will need to bring camping gear for a two-week trip including a sleeping bag and tent. Have clothes for both heat and cold and possibly rain. Sturdy boots are essential, as are standard camping items such as hats, sunscreen, water bottles. You should bring a field notebook, writing utensils, and a hand lens. We’ll provide rock hammers, GPS, Brunton compasses, and other equipment. We’ll be staying in campus housing for part of the time but you will still need your sleeping bags as bedding is not provided. We’ll provide a more complete equipment list later on.
Historical geology or sedimentology/stratigraphy; mineralogy and petrology. Courses in soils, geochemistry, and field courses are recommended but not required.
Bailey, D.G., 1990, Geochemistry and petrogenesis of Miocene volcanic rocks in the Powder River Volcanic Field, northeastern OR [Ph.D. thesis]: Pullman, WSU, 346 p.
Bailey, D.G., and Conrey, R.M., 1992, Common parent magma for Miocene to Holocene mafic volcanism in the northwestern United States. Geology 20, 1131-11-34.
Barry, T.L., Self, S., Kelley, S.P., Reidel, S., Hooper, P., & Widdowson, M., 2010, New 40Ar/39Ar dating of the Grande Ronde lavas, Columbia River Basalts, USA: Implications for duration of flood basalt eruption episodes. Lithos, 118(3-4), 213-222.
Brueseke, M.E. et al., 2007. Distribution and geochronology of Oregon Plateau (U.S.A.) flood basalt volcanism: The Steens Basalt revisited. Journal of Volcanology and Geothermal Research, 161(3), 187-214.
Caprarelli, G., and Reidel, S.P., 2005, A clinopyroxene-basalt geothermobarometry perspective of Columbia Plateau (NW USA) Miocene magmatism, Terra Nova, 17, 265-277.
Coffin, M. F., & Eldholm, O., 1994, Large Igneous Provinces – Crustal Structure, Dimensions, and External Consequences. Reviews of Geophysics, 32(1), 1-36.
Dorsey W., Garcia, M.O., Rhodes, M.J., Weis, D., Norman, M.D., 2006, Shield-stage alkalic volcanism on Mauna Loa Volcano, Hawaii: J. Volcan. & Geotherm. Res., 151, 141-155,
Ferns, M.L., McConnell, V.S., & Madin, I.P., 2010, Geology of the Upper Grande Ronde River Basin, Union County, Oregon. OR Dept. of Geology and Mineral Industries Bulletin 107.
Kraus, M., 1999, Paleosols in clastic sedimentary rocks: their geologic applications. Earth-Science Reviews, 47, 41-70.
Pierce, K.L., and Morgan, L.A., 2009, Is the track of the Yellowstone hotstpot driven by a deep mantle plume? Review of volcanism, faulting and uplift in light of new data. J. Volcan. Geotherm. Res. 188(1-3), 1-25.
Retallack, G., & Bestland, E., 2000, Eocene and Oligocene paleosols of central Oregon (Special Papers. p. 192). The Geological Society of America.
Ramos, FD, Wolff, J.A., Tollstrup, D.L., 2011, Sr isotope disequilibrium in Columbia River flood basalts: Evidence for rapid shallow-level open-system processes. Geology, 33, 457-460
Schwartz, J.J., Snoke, A.W., Frost, C.D., Barnes, C.G., Gromet, L.P., Johnson, K., 2010, Analysis of the Wallowa-Baker terrane boundary: Implications for tectonic accretion in the Blue Mountains province, northeastern Oregon. GSA Bulletin, 122, 517-536.
Sheldon, N., 2006, Using paleosols of the picture Gorge Basalt to reconstruct the middle Miocene climatic optimum. PaleoBios, 26(2), 27-36.
Sheldon, N. D., & Tabor, N. J., 2009, Quantitative paleoenvironmental and paleoclimatic reconstruction using paleosols. Earth-Science Reviews, 95(1-2), 1-52.
Takeuchi, A., Larson, P. B., & Suzuki, K., 2007, Influence of paleorelief on the Mid-Miocene climate variation in southeastern Washington, northeastern Oregon, and western Idaho, USA. Palaeogeography, Palaeoclimatology, Palaeoecology, 254(3-4), 462-476.
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