Indiana University Bloomington

Spring 2004 Colloquia

Friday, January 16, 2004
Time and Location 4:00 pm, G143, Department of Geological Sciences
Speaker: Barbara Bekins, US Geological Survey · 2004 GSA Bridsall-Dreiss Lecturer
Title: Hydrogeology and the Weak Nature of Plate Boundary Faults

Abstract: There is evidence for low frictional strength along many plate-boundary faults, including the San Andreas and the Cascadia subduction megathrust. High pore pressure is a leading hypothesis to explain this behavior. Proposed mechanisms for generating excess pore pressures include consolidation, tectonic strain, metamorphic dehydration, mantle degassing, hydrocarbon generation, thermal expansion, and pressure solution. Regional-scale flow and transport models constrained by observations of fluid chemistry, heat flow, and pore pressure data can be used to test various pressure generation hypotheses. Ultimately, these results may be coupled to models of other processes such as frictional heating or strain to understand the importance of fluids.

In subduction zones, very high pressures result from rapid loading of saturated seafloor sediments during accretion and subduction. Evidence for excess fluid pressure includes direct measurements, mud volcanism, and dilated faults. The Ocean Drilling Program has installed seven seafloor wells in subduction zones. Data from the Cascadia margin off central Oregon shows that flow is both transient and focused along faults. In the Barbados complex, pore water chloride anomalies indicate that clay dehydration fluids flow from deep in the complex to the seafloor along the plate-boundary thrust. Model results constrain the duration of flow and the distance of transport. Future models will quantify deeper fluid sources, evaluate mechanisms for transient flow, and changes in pore pressure through the earthquake cycle.

Background: Barbara Bekins is a research hydrologist at the U. S. Geological Survey (USGS) in Menlo Park, California. After studying both geology and mathematics, Bekins received a B.A. in Mathematics from University of California, Los Angeles. She worked for eight years as a computer specialist in the Seismology Branch of the USGS, and studied part-time to earn an M.S. in Mathematics from San Jose State University. She then left the USGS to pursue Ph.D. studies at University of California, Santa Cruz, under the direction of Shirley Dreiss. Dreiss was the 1992 GSA Birdsall lecturer and the lectureship was renamed "Birdsall-Dreiss" after her untimely death in 1993.

Monday, January 26, 2004
Dr. Lauren Browning, Center for Nuclear Waste Regulatory Analyses
4:00 p.m., Geological Sciences GY143
Refreshments will be served at 3:30 pm in the Geology Building lobby.
Yucca Mountain, Nevada: A Potential Geologic Repository for High Level Nuclear Waste

Abstract: High-level radioactive materials have been accumulating in the United States since the mid-1940's, and are currently stored in temporary facilities in 39 different states. In 1987, Congress directed the Department of Energy to determine the viability of Yucca Mountain, Nevada, as a potential deep geologic repository for the long-term storage of the accumulated nuclear waste. For more than 20 years, diverse scientific and engineering studies have been performed to characterize the natural properties of Yucca Mountain, to design a robust engineered drift system for waste containment, and to predict the long-term performance of Yucca Mountain as a nuclear waste repository.

This presentation will provide an overview of the science, politics, and regulatory actions surrounding our nation's management of high level nuclear waste.

Tuesday, January 27, 2004
Dr. Curt White, National Energy Technology Laboratory
10:00 a.m., Indiana Geological Survey Building, S201
Refreshments will be served at 9:30 a.m. in S201.

Abstract: The topic of global warming will be introduced including a description of greenhouse gases and their linkage to rising average temperatures. The greenhouse effect will be described. The concept of climate change will be introduced and defined according to the United Nations Framework Convention on Climate Change (UNFCCC). The relationship between rising average global temperatures, and rising atmospheric CO2 concentrations will be clearly delineated using information from The Intergovernmental Panel on Climate Change (IPCC). Anthropogenic CO2 emission sources will be listed. A description of a plan to reduce CO2 emissions will be presented. The plan includes increased conservation, development of advanced zero emissions fossil fuel electric power generating plants that have improved efficiencies, development and deployment of electric appliances that use less energy, switching to less carbon intensive fuels such as natural gas and hydrogen, renewable forms of energy, and nuclear power. Lastly, the plan envisions the separation and capture of CO2 from large point sources and the subsequent transportation and storage of the CO2 in the geosphere and the ocean.

The review will cover various aspects of CO2 separation and capture from fossil fuel combustion and gasification facilities. Separation and capture of CO2 from both flue gas and fuel gas using wet scrubbing technologies, dry regenerable sorbents, membranes, cryogenics, pressure and temperature swing adsorption, physical solvents and advanced concepts will be described.

Existing commercial CO2 capture facilities at electric power generating stations based upon the use of monoethanolamine will be described. The Rectisol process used by Dakota Gasification to separate and capture CO2 will be reported. The Weyburn enhanced oil recovery project operated by Pan Canadian Petroleum Limited that uses the CO2 captured at Dakota Gasification for enhanced oil recovery will be presented. The CO2 production capacity at Dakota Gasification is in excess of 200 million standard cubic feet per day.

Two technologies for storage of the captured CO2 will be reviewed-sequestration in deep unmineable coalbeds with concomitant recovery of methane and sequestration in deep saline aquifers. The estimated storage capacity of US coals will be delineated, along with a description of gas storage mechanisms on coal. The physical and chemical phenomena that occur when CO2 is injected into a coal seam will be described. Lastly, sequestration of CO2 in brinefields will be examined including a description of their estimated storage capacity. The physical, chemical and geological phenomena that are expected to occur when CO2 is injected into a brinefield is outlined.

Background: The seminar will be presented by Curt M. White, Carbon Sequestration Science Focus Area Leader at the National Energy Technology Laboratory. Dr. White has more than 30 years of industrial, government and academic research experience in various areas of fossil fuel science including polycyclic aromatic hydrocarbon chemistry, the analytical chemistry of fossil fuels, the geochemistry of sulfur in fossil fuels and supercritical fluid technologies including extraction and chromatography. The seminar at IU will contain information similar to that published in the June 2003 issue of the Journal of the Air and Waste Management Association and the presentation Curt made at the A&WMA 96th Annual Conference and Exhibition in San Diego, CA in June, 2003.

Tuesday, January 27, 2004
Brown Bag Lecture Series
Dr. Lauren Browning, Center for Nuclear Waste Regulatory Analyses
12:20 p.m. to 1:10 p.m., Indiana Geological Survey Building, S201
Reactive Transport Modeling of the Unsaturated Zone Hydrogeochemical System at Yucca Mountain, Nevada

Abstract: To assist in the technical review of a potential application for a geologic repository, a reactive transport model was developed for the ambient hydrogeochemical system at Yucca Mountain, Nevada. The model was developed using the MULTIFLO v. 1.5 code, and simulates two-phase, non-isothermal, advective and diffusive flow and transport through one-dimensional matrix and fracture continua (dual permeability) containing ten kinetically reactive hydrostratigraphic layers. This presentation will focus on discussion related to the development of a conceptual model for the natural ambient system, the identification of data and model uncertainties, and the implementation of calibration criteria used to increase confidence in model results.

Monday, February 2, 2004, 4:00 p.m. Colloquium
4:00 p.m., Geological Sciences GY143
Refreshments will be served at 3:30 pm in the Geology Building lobby.
Dennis Hubbard, Oberlin College
Coral Reef Decline: Past, Present and Future

Abstract: The past three decades have seen coral abundance on the world's reefs decline from over 60% to less than 5%. It has been recently estimated that two thirds of the world's coral reefs will be destroyed by 2020. The most often cited causes include overfishing of algal grazers, increased nutrient levels from runoff, dredging and other destruction of substrate, unabated coastal development, increasing coral diseases and global warming.

Effective mitigation and management solutions must start with a fundamental understanding of the positive interactions that occur naturally in one of the most complex biological systems on Earth. Central to the discussion is how much of the change that has been recently documented is anthropogenically induced and how much might be part of a natural boom-and-bust cycle that occurs on a time scale longer than recent monitoring studies... or the life of a researcher... or even the sciences of biology and geology.

The Quaternary record of coral-reef development provides an ideal place to look for longer-term data. Over the past several million years, the players have remained largely unchanged. Furthermore, the well-documented pattern of depth zonation in modern coral reefs dominates the fossil record throughout the region, despite major changes in Earth climate and major waxing and waning of coral reefs with the rise and fall of sea level. This has caused many investigators to posit that coral-reef community structure was fundamentally more stable in the recent geologic past than is the case today. From this, it has been proposed that the declines we are witnessing today are unprecedented and entirely human driven.

Coring investigations throughout the Caribbean region over the past two decades have provided a wealth of detailed information on reef development in the face of varying oceanographic and sea-level regimes. This talk will summarize the information that has been gathered thus far in an attempt to address three questions. First, does the spatial dominance of Caribbean reef species seen in the fossil record reflect temporal persistence of those organisms throughout the recent past? Second, how different are the patterns of change over the past two million years from those seen in recent decades? And finally, what might the geologic record tell us about present and proposed strategies of coral-reef management and protection?

Monday, February 9, 2004, 4:00 p.m.
4:00 p.m., Geological Sciences GY143
Refreshments will be served at 3:30 pm in the Geology Building lobby.
Enrique Merino, Indiana University
Insights into Dolomitization and other Metasomatic Reactions

Monday, February 16, 2004, 4:00 p.m. Colloquium
4:00 p.m., Geological Sciences GY143
Refreshments will be served at 3:30 pm in the Geology Building lobby.
Kathy Licht, IUPUI
The Ross Sea's contribution to eustatic sea level during meltwater pulse 1A

Abstract: Radiocarbon dates obtained from Ross Sea sediments, combined with constraints on maximum ice extent based on sedimentological data and ice sheet modeling results, indicate that the Ross Embayment, Antarctica is unlikely to have been a substantial contributor to meltwater pulse (mwp) 1A at ˜12.5 14C ka. The ice sheet in the Ross Embayment during the last glacial maximum is estimated to have contained ice volume equivalent to 3–6 m eustatic sea level rise and does not show evidence of rapid retreat. Grounded ice advance occurred during initial Late Pleistocene eustatic rise and ice sheet retreat began coeval with or subsequent to mwp-1A. Chronological and sedimentological data from the Ross Embayment indicate that deglaciation in this region has occurred throughout the Holocene and the maximum possible contribution of eustatic rise from the Ross Embayment is less than 1 m sea level equivalent. (in press, Sedimentary Geology)

Monday, April 12, 2004, 4:00 p.m.
Harrison "Jack" Schmitt, Astronaut-Geologist-Senator
Topic to be announced.
General Talk, Wittenberger Auditorium (time TBA, possibly in the early evening) on Tuesday April 13.