Department of Geology and Geophysics University of Minnesota 310 Pillsbury Drive SE Minneapolis, MN 55455 bair0042@umn.edu

    Meso-scale ductile shear zones, thin (cm. to m. thick) tabular zones of high strain, are common in many orogens. Flattening (oblate) strains in meso-scale ductile shear zones are often observed and require components of both simple and pure shear to form this type of strain, and therefore the shear zone as well. The pure shear component of deformation can be produced either by the extrusion of material out of the shear zone or by the removal of mobile components from within the shear zone by syn-kinematic fluids (volume loss). Extrusion, if it occurs, could produce space compatibility problems unless the shear zones form an interlinked 3-D array; while volume loss should produce bulk chemical differences between the shear zone and lesser deformed wall rock, though this is rarely observed. The role of volume loss and extrusion in forming meso-scale ductile shear zones is unclear but is significant when making interpretations regarding the deformation and regional tectonics associated with shear zone formation.
    The Diana Syenite within the Carthage-Colton Mylonite Zone of the Northwest Adirondacks possess many excellent examples of meso-scale ductile shear zones for which 3-D strain can be determined. One example, located near Harrisville, NY, possesses oblate strain consistent with either extrusion, volume loss, or a combination of both. The slight bulk chemical differences between the shear zone and lesser deformed wall rock suggest that volume loss probably was not an important process in forming this particular shear zone. This could indicate that significant extrusion occurs from within the shear zone to produce the observed strain. However, the nature of this extrusion appears unrealistic and suggests that the strain analysis maybe inaccurate. Methods of improving strain data collection are currently being investigated and may show that only simple shear is required to form this ductile shear zone.

Geologists can play an important role in helping to preserve our remaining open and rural areas by using our skills to assist the various private and public enterprises involved with land protection. I will discuss how I came to be involved with land conservancy in northeastern Ohio as a guide for SLU undergraduates to use for their own activities associated with non-profit organizations. Further, as geologists with liberal arts educations, we have numerous skills, not normally considered as part of our degree that can be applied to our philanthropic causes. For those interested in land conservancy, I will also discuss what skill sets might be useful

Department of Geoscience, Univ. of Iowa, Iowa City, IA 52242, scott-j-carpenter@uiowa.edu, ERICKSON, J. Mark, Geology Department, St. Lawrence Univ., Canton, NY 13617, HOGANSON, John W., North Dakota Geol Survey, 600 East Boulevard Avenue, Bismarck, ND 58505, BLESIUS, Leonhard, Iowa Institute of Hydraulic Research, Univ. of Iowa, Iowa City, IA 52242, and WEIRICH, Frank, Department of Geoscience, Univ. of Iowa, Iowa City, IA 52242The ?¹³C values of freshwater mollusk shells have long been considered the ugly stepsister of the paleo-climate world. Carbon isotope data collected and never interpreted -- ignored as useful proxies of ambient water conditions. The reason for this appears to be concern about ‘vital effects' that could obscure accurate interpretation of these data. While biological fractionation is problematic, researchers should nonetheless attempt to interpret these data. Several datasets from modern and ancient freshwater mollusks indicate that ?¹³C values can provide important information regarding seasonal changes in primary productivity, stratification, and sources of dissolved inorganic carbon in surface waters. Case studies of the utility of molluscan ?¹³C values will be presented from a variety of latitudes and ages. These include: 1) a Late Cretaceous-Early Paleocene river in North Dakota, 2) the Mackenzie River in the Canadian Arctic, 3) a modern lake in New Jersey, and 4) modern and Pleistocene rivers in Indonesia. Among these case studies is the seasonal variation in primary productivity observed in proglacial river systems that is out of phase with temperature and insolation due to variation in discharge and turbidity. Another case study describes a lacustrine system that records springtime increases in productivity, summer stratification, a fall overturn, and wintertime oxidation of plant organic matter. A third case study examines tropical mollusks that faithfully record local vegetation changes (C4 to C3 variation) in their overall ?¹³C values. Carbon isotope data interpreted in conjunction with oxygen isotope data and in the context of regional geography and stratigraphy can yield important paleo-climate information. While problematic, attempts should be made at interpreting these very useful and interesting data.

Jeffrey R. Chiarenzelli ’81

Chair, Department of Geology, State University of New York, Potsdam, NY 13676 (chiarejr@potsdam.edu)

Although many of us have ideas about what type of career we would like to have, few know how to plan for, and achieve, these goals. Drawing on real-life experience, this talk will explore ways that you can help yourself prepare for a rewarding career in whatever endeavor you wish to pursue. In particular, simple suggestions for distinguishing yourself during your undergraduate career, preparing for and seeking desirable post-graduate employment and/or graduate school positions, and what to do if complications arrive will be presented.

Today, the West Coast of North America has a varied landscape in which extension played an important role. It is important to understand the mechanism of extension to understand the reasons for divergence and to produce better models for recent geological processes on the West Coast. Volcanoes are insightful tools used to understand processes in the crust and mantle.The composition and location of volcanoes are controlled by the dominant tectonic regime. Major, trace element geochemistry and isotopic compositions can be used to model the percentage of crustal and mantle input in the evolution of volcanic centers. Approximately 40 Ma the West Coast transitioned from a compressional to extensional tectonic boundary. Early eruptions initially occurred in northeastern New Mexico; over time volcanism migrated to the southwest off of the Colorado Plateau and into the American Southwest. To understand extension in Arizona, a series of Tertiary latitic and trachytic domes in the Transition Zone were studied to determine the onset of extension in the Basin and Range province. Trachytes are unique volcanic rocks that have high percentages of Na₂O and K₂O. Concentrations of trace elements (Ba, Rb, Sr and Cr) in the trachyte were used to unravel the input of mantle and crustal melts.Reversed zoned phenocrysts and lower crustal xenoliths complicated the petrogenetic picture. Data from models are consistent with melting in the upper enriched mantle mixing with an increased input from the mantle as slab break-up, increased heat input and extension occurred

Other complications of the Lawrence Formation on this project include the high percentage of kaolinite minerals, which poses an increased risk for slides once wet. The high clay content causes the Lawrence Shale Formation to have a high swelling percentage and will likely have unloading problems when several feet are removed. Archer 1992, stated that the upper portion of the Lawrence Formation was the “worst of all possible cases in the finely laminated shales; this includes kaolinitic clays which once moistened become very slick combined with thin sand layers that allow the clays to become readily saturated with groundwater and/or infiltration from rainwater or snowmelt. For these reasons the pinstriped to flaser bedded facies of shales are not suitable for normal grade slopes and are particularly unsuitable as fill materials.” There are also several high angle slide planes in a variety of angles, with secondary mineralization which give more evidence for irregular instability within the finely bedded portion of the Formation.

There will still be several problems facing the geotech section of KDOT during the design phase, construction phase and ongoing maintenance; which may include over excavation of the problematic shales, lowering the angles of backslopes of the Lawrence Formation, retaining walls, soil nails, and auger cast piling.

References:

Archer, Allen, 1992, Analysis of microfabric and its relationships to mineralogy and structural failure. K-TRAN: KSU 91-6, Final Report, 58p.

Space Station Payloads Office, Mail Code OZ4, NASA-Johnson Space Center, Houston, TX 77058

The operational and logistical experience associated with putting a team of four scientists in a hostile environment was investigated as part of the Antarctic Search for Meteorites (ANSMET) project during the austral summer of 2002-2003. Operational time data, when compared with similar data from the Apollo J-series missions, suggests that crew time available to science on future exploration missions will be no more than 20% of the available surface time, due to the logistical requirements of staying alive in a hostile environment. Comparison of statistics derived from ANSMET meteorite search traverses to similar traverses from Apollo is inconclusive, other than reinforcing the requirement for robust rover capability in order to cover as much ground as necessary. Lastly, data associated with deploying equipment and supplies for the four person team to the field suggest that supplying a Mars or lunar mission with the necessary “buggies, beans and oil” would take up a significant amount of the upmass prior to initiating trans-Mars or lunar injection.

Andrew Fetterman ‘94

Retail Gasoline Service Station: Boyertown, PA

In December 1999, pin-hole leaks were discovered in two, unleaded gasoline underground storage tanks (USTs) during the excavation and closure of UST systems at a retail gasoline service station (the Site). Initial site characterization activity included installation of approximately 20 soil borings and 10 shallow groundwater monitor wells. During the initial soil investigation, it was determined that petroleum impacted soil remained on the subject property in the general vicinity of the garage to depths exceeding 30 feet below ground surface. It was also determined that unleaded gasoline had impacted groundwater in the bedrock aquifer zone. Due to the weathered nature of the underlying carbonate bedrock and complexities of groundwater fracture flow, 4 additional deep groundwater monitor wells were installed to vertically delineate MTBE and other unleaded gasoline target compounds. The deeper of the bedrock wells was installed to 315 feet bgs where MTBE was detected at concentrations exceeding 50 µg/l.

Between June 2001 and February 2004, MTBE was detected in 15 different private supply wells in the vicinity of the Site. Synergy currently monitors water quality at 36 private supply wells related to this project.

Synergy is presently operating a dual-phase, multi-point groundwater extraction system at the Site, to remediate soil and groundwater impacted from unleaded gasoline that leaked from two USTs. The system is a dual-phase system, designed to remediate soil and groundwater simultaneously. The principal goal of the system is to remove residual unleaded gasoline from soil and to control and remediate impacted groundwater. At present, the remediation dual-phase remediation system has been operational for approximately 18 months.

Water Supply Well Permitting: Montgomery County, PA

Project includes the installation and permitting of a public supply well for a residential development. Work completed to date has included: development of well installation plan, oversight of well installation, development of an aquifer testing plan, step testing, water quality sampling, coordination with state and local agencies, and the presentation of project and proposed testing at a public meeting. Work also included performance of a long term, constant-rate aquifer testing, hydrogeologic analytical modeling, preparation and presentation of aquifer characteristics, and an assessment of long term pumping effects on local aquifer system. Project currently involves multi-agency (Delaware River Basin Commission, Pennsylvania Department of Environmental Protection, and Marlborough Township) project coordination and permitting.

While the American Geological Institute serves as leadership for its’ 42 geoscience member societies, it also works to serve the academic and educational community by providing products and services to assist teachers, students, and professionals. 1998 SLU geology alumni Abi Howe has worked for over 3 years in the education, information, and technology departments at AGI, to help develop a variety of products for public use.

AGI’s focus has shifted over the years from information services, to including quality educational and outreach services that help to convey the importance of geosciences in today’s society. In this presentation, Abi will highlight some of AGI’s resources that are designed to help undergraduate students, faculty, and the general public – as well as some of the research AGI is working on regarding dwindling geoscience departments and the future of geology as a discipline.

Booth Platt Jr ‘00

Oribatid mites (suborder Oribatida or Cryptostigmata) are minute, 8 legged arthropods of vast morphological diversity and incredible adaptability. One way these small, heavily armored organisms differ from other groups of mites, such as ticks or dust mites, is having a moderately to heavily sclerotized exoskeleton that can be preserved in the fossil record. During the last two decades, scientists using fossil oribatid mites as a key component for paleohabitat reconstruction have expressed difficulty in refining the coarse resolution of their results. The reason for this coarse resolution is the lack of knowledge about extant oribatid mite habitat requirements.

My M.S. thesis project aims to create baseline data for oribatid mites with an aquatic affinity. Of all known oribatid mite taxa, only a few have adapted to aquatic habitats. Presently, 15 genera in 11 families are represented in freshwater habitats, which is just small fraction of the 1000+ described genera. Last summer, I sampled 16 sites in central and upstate New York that qualified as aquatic habitats according to the New York Heritage Project guidelines. Over 8800 oribatid mites representing 137 species resulted from the 320 collected samples. In addition to the mites, information regarding the nature of the sampled material was collected, which was subsequently used to group commonly sampled materials together between sites. Algae, aquatic moss, decaying non-woody plants are just a few of the material groups examined for their mite community structure. Preliminary results on a species-by-species basis show Hydrozetes lacustris, Trimalaconothrus maior, T. glaber and Trhypochthoniellus crassus as significantly associated to sample material of wholly aquatic nature.

The results from this project will provide useful information about many fossil mites’ original habitat. Other proxies for paleohabitat reconstruction, such as pollen and chironomid head capsules, could benefit from the promising information that fossil oribatid mites offer to this blossoming field.

John A. Rayburn ‘87

Center for Earth and Environmental Sciences, SUNY Plattsburgh

I have been working on the Quaternary history and geomorphology of the Champlain Valley for more than a decade. This research that started with some summer field mapping as an undergraduate, and later became the focus of my Ph.D. dissertation, is now part of a multi-proxi investigation involving SUNY Plattsburgh, Binghamton University, and the USGS. I have been evaluating ice retreat, proglacial lacustrine and marine deposits, discharge estimates, isostatic rebound, and chronology. After ice retreated from the northern flank of the Adirondack Uplands the large proglacial water bodies in the Champlain Valley (glacial Lake Vermont) and the St. Lawrence Lowland (glacial Lake Iroquois) became confluent. With the assistance of Donald Pair (SLU ‘83) I have been able to extend my models to the western side of the Adirondacks.

Through the use of selective radiocarbon dating (using only samples of terrestrial origin) many researchers in the region are now favoring a younger chronology for deglacial events in the Champlain and St. Lawrence Valleys, with the result that key events in the glacial lacustrine and marine record now fall in line with significant climate changes recorded in the Greenland ice cores. Through the generosity of the USGS I will continue work to tighten the chronology and investigate the relationship between events recorded in the Champlain Valley and regional climate change.

Professor Emeritus of Geography.

During my last year at St. Lawrence, on a terminal sabbatical leave in Fall, 1992, I taught Oceanography and World Geography on a three-month round-the-world voyage run by the University of Pittsburgh's Semester at Sea Program. This began a "new career" for me as a shipboard lecturer on subjects geological and geographical. I've had the opportunity to work on ships pretty much all around the world. There have been over two dozen trips to the Antarctic aboard various expedition ships where, in addition to lecturing, I lead geology field trips ashore in some pretty exotic places. There have also been lecture "gigs" in the Caribbean, Mediterranean, Arctic and sub-Arctic regions, nort hern Europe, Alaska, South China Sea, and all along the Central and South American coasts, as well as other places including our own St. Lawrence River and Canadian Atlantic provinces. Here's a great way to continue to use your geological background and to learn more new geology than you can imagine. I'm following H.H. Read's advice that says the best geologists are the ones who have seen the most geology. Currently I'm spending about 3 months a year on the cruise circuit in hopes of becoming the best geologist I can be. Here's a great job for you to hope for!

Richard P. Standish ‘71, P.G., LSP, LEP

What kind of skills do employers look for when hiring geologists? What can differentiate you from other applicants? Based upon my experience of nearly thirty years in the workplace and having interviewed dozens of prospective employees, I believe that the desirable skills can be divided into three broad categories, each equally important. These categories are technical skills, communication skills, and personal skills. A successful applicant will be able to demonstrate some competence in these categories during the interview and selection process.

Technical Skills – These skills are the basic foundation for your work and would include the fundamental science and mathematic capabilities. For geologists, this would also encompass field and/or laboratory skills as appropriate. Computer skills such as word processing, spreadsheet formulation, database management, GIS and 3D data visualization and other computer graphics are also essential.

Communication Skills – Usually one of the weaker areas for geologists, effective communication is critical to all employers. Strong writing skills are absolutely necessary for geologists in producing reports, letters, memos and related correspondence to document their work. In addition, oral communication skills for various presentations, public hearings, papers, etc. can make a significant difference in acquiring work, discussing issues with the public, coordinating with various subcontractors or stakeholders or convincing someone of your ideas.

Personal Skills – Employers often look for at least some of the following personal attributes when selecting a candidate: maturity, attention to detail, confidence, enthusiasm, assertiveness, energy, and imagination. While no single person usually excels at all of the traits, it is often the interpersonal skills and the ability to work with others as part of a team that is important to an employer.

If you can combine and emphasize your strengths in these three broad skill areas, you will be well on your way toward being a candidate that any employer would die for.

Bonnie J. M. Swoger ‘99

Not all 17^th century naturalists accepted that every ‘fossil’ was the remains of a living organism. Most naturalists thought petrified wood had an organic origin. The majority also agreed that fossil bones were organic: “historical” records indicated the presence of giants, accounting for the size of some of the bones. The most disagreement occurred over the origin of fossil shells, and naturalists fell into three main groups. Some scholars, led by Steno and Hooke, believed that fossil shells were the remains of living organisms. Others felt that the shells were “tricks of nature,” rocks that mysteriously mimicked living creatures. A third group, led by Edward Lhywd, viewed fossils as the adult forms of “seeds” carried from the seashore to inland areas.

Scholars wrestled with two major problems. The first was whether any animal or plant species had become extinct. This question had some important theological implications. The second problem was transportation: how had marine organisms been deposited in the mountains.

Like many major questions in science, the issue was resolved over time. Scholars began to approach the natural world more systematically, and the idea of “mysterious forces” fell out of favor. At the same time the transport problem was being (temporarily) resolved. The debate over the origin of fossils was just one in a long history of scholarly debates leading us to our current understanding of the Earth and its processes.

The Adirondack Highlands form a north/south trending oval exposure of Proterozoic (ca. 1.3-1.0 Ga) high-grade metamorphic rocks in a rugged terrain that locally rises over 4,000 ft and reaches approximately 1 km of relief. This study investigates the origin of the landscape in the High Peaks and southeastern regions of the Adirondack Highlands. Through the application of specific sampling strategies using the apatite fission track and (U-Th)/He thermochronometers, this study tests whether the landscape in these regions formed during the Middle Jurassic-Early Tertiary and/or resulted from normal faulting after the region cooled below the apatite fission track closure temperature (~100°C). In addition to thermochronologic analysis, a kinematic and dynamic analysis of brittle faults exposed in both study regions is underway.

In the High Peaks region, a vertical profile has been collected down Mount Marcy covering approximately 900 m of relief with a sampling interval of 100 m. In the southeastern Adirondacks, a vertical profile has been collected down Prospect Mountain that covers approximately 500 m of relief. Amounts and rates of Middle Jurassic to Early Tertiary denudation will be constrained from these profiles through analysis of age vs. elevation plots and computer modeling of apatite fission track and (U-Th)/He data.

It has been suggested by others (Roden-Tice et al., 2000) that Late Mesozoic faulting has occurred across the numerous northeast/southwest striking faults found throughout the southeastern region. In the present study, samples were collected across the western boundary fault of the Lake George graben. Apatite fission track stratigraphy will be used to test whether any substantial normal movement has occurred across this feature subsequent to cooling below the apatite fission track closure temperature.

The preliminary results in the southeastern Adirondacks suggest changes in denudation rates during the Cretaceous and are consistent with Late to post Cretaceous normal faulting.

David Wald ‘84

The devastating, magnitude 9.0 Dec 26, 2004 Sumatra earthquake was the largest in the past 40 years; It alone released more seismic energy than all the earthquakes in the previous decade combined. First, I will describe how the U.S. Geological Survey's National Earthquake Information Center (NEIC) in Golden determines magnitude and delivers earthquake information worldwide. I will then provide and overview of the tectonic environment and conditions that led to the occurrence of such a rare event and discuss the nature of the slippage on the fault that ruptured (extending over 1200 km in length!). This remarkable release of seismic energy also had notable effects around the globe, the surrounding epicentral region, and on nearby faults. For example, the mainshock was followed by more than 40 aftershocks in the source region with magnitudes greater than 6, and these continue. Likewise the Earth is still(!) ringing like a bell and we show these and other seismic observations recorded around the globe that document the widespread reach of a magnitude 9 earthquake.

This earthquake also generated the most historically devastating tsunami in terms of loss of life and wave runups from this tsunami are among the highest ever recorded. I follow the evolution of this tsunami starting from generation in the deep ocean near the Sunda Trench to propagation in the Indian Ocean and around the world. To do this, I will review how earthquake rupture leads to the generation of tsunamis and show how a computational fluid dynamic model for the tsunami is constructed and compare results with instrumental observations of the tsunamis. Finally, we discuss several unresolved issues regarding this event and future research, notification, and response directions.

Michael Ward ‘72

Since the discovery of gold in poverty gulch by ranch-hand-prospector Bob Womack in the 1880’s, the Cripple Creek Mining district has produced over 22 million ounces of gold. Most of the gold was produced between 1891 and about 1917. Modern mining began with experimental leaching studies in the early 1980’s in response to the rise in the gold price.

Gold deposits at Cripple Creek are low-sulfidation epithermal systems associated with, and hosted by an Oligocene alkaline diatreme complex. Alkaline volcanism began in the mid-Tertiary as part of regionally extensive event. The diatreme erupted at a juncture of four Precambrian terrains about 33 ma. and volcanic activity continued through the intrusion of the last lamprophyres at 28.4 ma (Jenssen, 2003). This last event was followed closely by hydrothermal venting and pervasive K-metosomatism and the deposition of gold and gold-tellurides.

Gold bearing hydrothermal fluids are predominantly magmatic in origin and temporally related to the last phase of lamprophyre volcanism. Current Open pit mining and definition drilling has allowed for a detailed three-dimensional model of this volcanic vent. Many of the high-grade gold veins follow dikes which occupy regional fracture sets. Some of these fractures were occupied by more than one intrusive rock unit and subsequent multi-stage vein systems, indicating a long period of dilation.Current mining takes advantage of the disseminated nature of the mineralization between the vein systems which allows for the bulk mining and heap leaching of very low grade ore. The current average grade of the open pit resource at Cripple Creek is about 1ppm Au. Mineralization associated with breccia pipes and stockwork zones are the type of targets that would be amenable to modern underground mining techniques. The Cripple Creek Mining district continues to have the potential for the discovery of new world class gold deposits.