Geoscience Colloquia for Fall 2011 Semester

Thursday September 15, 2011 4 PM
Dr. Whitey Hagadorn
Assistant Professor of Geology
Tim and Kathryn Ryan Curator of Geology, Denver Museum of Nature & Science
Title: "Death of a Megapredator"

The first predators are thought to have been giant flapped beasts called anomalocaridids - who cruised the Cambrian seas 520 million years ago, munching on hapless trilobites and anything else unlucky enough to cross their paths. Yet new data suggests that these extinct animals may not have been the great white sharks of their time, but rather were more like a friendly manatee or walrus.

Lapham Hall 257
Refreshments served prior to the colloquium at 3:30 in Lapham 168.

Thursday September 22, 2011 4 PM
Scott Schaefer and Robert Graziano
UW-Milwaukee PaleoClub
Title: Letting Fossils Tell Their Tails: 450 Million Years In 7 Days.

In Spring 2011, the Department offered an elective paleontology field trip course called ‘450 MY in 7 Days!’. This unique course was developed in response to outstanding research and planning efforts of the ‘Paleo Club.’ The course, lead by Rob Graziano and Gina Szablewski, featured a 7-day road trip to Florida over spring break that included Paleozoic fossil collection sites in Indiana and Ohio, Cenozoic collection sites in northern Florida and on a nearshore island in the Gulf of Mexico, a two-day canoeing, camping and fossil collecting excursion on the Peace River in south Florida, and a tour of the Florida Museum of Natural History collections. The ‘rewards’ of the trip included spectacular Paleozoic marine fauna, unique Cenozoic mammal bones and teeth, and numerous shark teeth. Some of the best specimens collected on the trip will be on display in the Thomas Greene Geological Gallery in Lapham Hall 168.

Lapham Hall N101
Refreshments served prior to the colloquium at 3:15 in Lapham 168.

Thursday September 29, 2011 4 PM
B. Brandon Curry
Senior Geologist; University of Illinois at Urbana-Champaign
Title: Timing and rates of deglaciation of the Lake Michigan lobe

I have been exploring the age and content of fossiliferous, rhythmically bedded silt and very fine sand found in pancake-shaped periglacial landforms known as ice-walled lake plains. I will discuss the problems geologists have had in pinning down the origins of these landforms, and reflect on what the fossils tell us about the climate. The chronology of the deposits in Illinois is revealed through radiocarbon dating of tundra plant fossils that were washed or blown into the lakes. The ages of plant fossils recovered from ice-walled lake plain successions on laterally successive moraines do not overlap, providing Quaternary geologists with a more precise and accurate picture of rates of ice movement. A growing database of ice margin ages will help refine regional correlations of ice lobe activity as well as pinning down the ages of large discharge events.

Lapham Hall N101
Refreshments served prior to the colloquium at 3:15 in Lapham 168.

Thursday October 20, 2011 4 PM
Dr. Marty Frisbee
Project Hydrogeologist at AMEC Earth & Environmental
Title: What Can Stream Flow Generation Processes Tell Us About the Long-Term Stream Flow Response to Climate Change?

I investigated the role of deep, basin-scale groundwater on the generation, geochemical evolution, and structure of apparent ages of stream flow across multiple scales in a large, alpine watershed. Reductionist approaches have largely been applied to understand hydrological process behavior at the large watershed scale. My research indicates that these approaches may not capture process behavior that is important at one scale and not another (e.g., interactions between stream flow and intermediate and/or regional groundwater flow with increasing scale) and that groundwater is a dominant control on stream flow processes across multiple scales in this watershed. More importantly, my research suggests that stream flow from large watersheds may be buffered, at least initially, against rapid change. This may be especially true for large watersheds where stream flow is dominated by components of deep, basin-scale groundwater and by extension, larger storage volumes in the subsurface.

Lapham Hall N101
Refreshments served prior to the colloquium at 3:15 in Lapham 168.

Thursday October 27, 2011 4 PM
Dr. Stephen Reynolds
Professor, School of Earth and Space Exploration, Arizona State University
Title: Perception, Visualization, Cognition, and Learning in Introductory Geoscience Courses

Geology is arguably the most visual of the sciences, with much geologic data, interpretations, ideas, and models being conveyed with photographs and illustrations, many of which are specific to the geosciences, such as geologic maps and cross sections. There has been, however, surprisingly little research on how students learn from such images. Cognitive studies indicate that our brain uses two cognitive processing subsystems, one for words and another for images, a concept called dual coding. In dual coding, each subsystem has limited working memory, and much cognitive effort is required to reconcile information between the two subsystems. We have been investigating the implications of dual coding for learning in undergraduate geology courses, primarily using eye-tracking technology that can record where students look when presented with photographs, illustrations, and animations showing geologic features. Our results demonstrate that humans and other distractors in such images dominate the attention of novice learners and have a detrimental effect on learning. This can be partly counteracted by the use of signaling techniques, such as annotated overlays, which help students attend to what is most important in geologic photographs. We have also used eye-tracking technology to investigate how students interact with textbook-style materials, specifically comparing a traditional textbook layout with one specifically designed to facilitate dual coding by fully integrating figures and text. Previous research indicates that students should learn more from materials with an integrated text-figure approach. We have documented similar results, and further show that a main factor influencing student learning is how many times a student switches attention from the text to the figure, reconciling the two types of information – students with more figure-text transitions learn more than students with fewer transitions. This research provides guidance in better designing curricular materials and in explicitly providing students with some better learning strategies.

Lapham Hall N101
Refreshments served prior to the colloquium at 3:15 in Lapham 168.

Thursday November 3, 2011 4 PM
Dr. Neal Iverson
Professor and Smith Family Foundation Chair of Geology, Iowa State University
Title: A Theory of Glacial Quarrying for Landscape Evolution Models

Owing to climate as a potential driver for tectonic change, effects of glacial erosion on topographic relief and uplift of mountain belts have been widely debated. Increasingly this debate and related discussion of the genesis of distinctive glacial landforms, such as U-shaped valleys and overdeepened bedrock basins, is informed by results of landscape evolution models. They are grounded on a power-law rule that relates bedrock erosion rate to either glacier sliding speed or discharge. This rule is poorly linked to the principal process of glacial erosion: quarrying, in which bedrock blocks are dislodged from the bed by sliding ice.

A new model of quarrying allows this erosion rule to be evaluated. As in past quarrying models, increasing ice-bed separation is assumed to increase deviatoric stresses in the rock that cause subcritical crack growth. Unlike past quarrying models, bedrock strength heterogeneity resulting from pre-glacial fractures is included using a Weibull statistical distribution of rock strength. This strength distribution is predicated on a fundamental but neglected precept of rock mechanics: larger rock bodies have lower strengths because they have a greater probability of containing a large fracture. Including this effect in the model has a profound influence on the role of ice-bed separation in quarrying. Model results can, indeed, be closely fitted with a power-law erosion rule, but its nonlinearity, the range of sliding speed over which it applies, and erosion rates depend sensitively on bedrock strength heterogeneity and effective pressure. The model provides a vehicle for including rock strength variability in landscape evolution models and reinforces recent emphasis on the role of bedrock fractures in accelerating geomorphic processes.

Lapham Hall N101
Refreshments served prior to the colloquium at 3:15 in Lapham 168.

Thursday November 10, 2011 4 PM
Dr. Zhaohui Li
Professor of Mineralogy, Geochemistry, Groundwater Remediation, UW Parkside
Title: Interactions of antibiotics with Clay Minerals

Lapham Hall N101

Frequent detection of pharmaceuticals and personal care products (PPCPs) in groundwater and waste water has attracted extensive studies on their transport and fate in the environment, as well as technology development for their removal from water. As many of these PPCPs are hydrophilic, their removal using activated carbon was not successful in waste water treatment. In addition, many of these PPCPs are in cationic form in acidic to neutral solution, making them having strong interactions with negatively charged minerals surface. In this study, the interaction of selected antibiotics and antihistamines with different types of clay minerals, including non-swelling 1:1 layered kaolinite, 2:1 non-swelling illinte, 2:1 swelling clay mineral montmorillonite, and mixed layered clay mineral rectorite made of regular interstratification between an illite layer and a montmorillonite layer, we investigated under different physico-chemical conditions. The water quality and antimicrobial activity of adsorbed antibiotics was as affected by the antibiotic loading and desorption kinetics will also be addressed.

Refreshments served prior to the colloquium at 3:15 in Lapham 168.

Thursday November 17, 2011 4 PM
Dr. Weon Shik Han
Assistant Professor of Hydrogeology, UW Milwaukee
Title: Lessons from Natural CO2 Leakage Analogue Site Studies and their Application to Secure CO2 Storage and Monitoring

At CO2 injection sites, CO2 leakage from the storage formation could be catastrophic. CO2 is a highly compressible fluid, typically injected at high pressure and temperature conditions. If this compressed CO2 reaches highly permeable conduits such as faults and fractures, CO2 could leak unabated to other formations (e.g. fresh water aquifers) and/or to the surface. Assuming a fast-flow path to the surface, CO2 escaping from the storage formation instantaneously reaches the surface while experiencing adiabatic expansion, which results in Joule-Thomson cooling. The addressed eruptive mechanisms are analogues to natural CO2 eruption mechanisms, which are found in CO2-driven cold-water geysers around the world. A notable example of a CO2-driven cold-water geyser is the Crystal Geyser in central Utah. The fluid mechanics of this regularly erupting geyser was investigated by instrumenting its conduit with pressure, temperature, pH, EC, and dissolved oxygen sensors, measuring every 1 minute during and between eruptions. This cold geyser’s eruptions are regular and predictable, and reflect pressure, temperature, EC, pH, and dissolved oxygen changes resulting from Joule-Thomson cooling, endothermic CO2 exsolution, and exothermic CO2 dissolution. Specifically, the perturbation of pressure and temperature data observed at the Crystal Geyser suggested the possibility of using temperature sensing technology within the observation well at the engineered CO2 sequestration site. With the lessons learned from the Crystal Geyser studies, we established the theoretical framework of temperature changes caused by CO2 related chemical reactions in the observation wells and tested with numerical simulation tools, which predicted thermal processes including solid NaCl precipitation, buoyancy-driven supercritical CO2 migration, and potential non-isothermal effects.

Lapham Hall N101
Refreshments served prior to the colloquium at 3:15 in Lapham 168.

Thursday December 1, 2011 4 PM
Daniel Feinstein
Hydrogeologist, USGS Wisconsin Water Science Center, Adjunct UW-Milwaukee
Title: Groundwater availability in the Lake Michigan Basin

Groundwater availability in the Lake Michigan Basin was studied as part of the Great Lakes Basin Pilot for a USGS assessment of water availability and use. A groundwater-flow model was constructed to quantify groundwater availability by simulating the system response to climatic and anthropogenic stresses. The study area extends over 83,000 miles2 and vertically from land surface to Precambrian bedrock in twenty layers representing heterogeneous glacial deposits overlying bedrock units dipping from the Wisconsin Arch into the Michigan Basin. Because of salinity in the Michigan Basin, the model was solved using the USGS density-dependent flow code SEAWAT. The finite-difference model has over two million cells and simulates the transient (1864-2005) response of the system to multiple pumping centers across several aquifer systems. Regional recharge was estimated using a soil-water balance approach applied to the model’s 13 stress periods. Calibration involved advanced techniques adapted to hundreds of parameters and thousands of observations. The model was used to show the source of water to wells through time. Direct discharge of groundwater to Lake Michigan was found to be approximately 2% of the available basin groundwater. Sustainability indicators were developed from the transient water budgets to evaluate the availability of groundwater to streams and wells at different scales. Because the regional model is too coarse to accurately examine groundwater/surface-water interactions, an inset model was extracted from the regional model to demonstrate techniques for evaluating the effect of pumping and climate change on a small watershed.

Lapham Hall N101
Refreshments served prior to the colloquium at 3:15 in Lapham 168.