ISGS - May 2007 Activity Highlights
ISGS - Home Page of the Illinois State Geological Survey
300-million-year-old Tropical Forest Captures the Public Eye
Media attention stemming from the discovery of a fossil forest has been international in scope and still continues. Articles were printed in major newspapers such as the St. Louis Post-Dispatch in the United States and internationally in Journal do Brasil. Internet stories were on all major science news sites, including sciencenews.com, livescience.com, science.com, nationalgeographic.com, and as far away as the official Iranian, state-sponsored Internet new site. Interviews were given to area radio stations such as WDAN AM and to national stations CNN radio news, "Day to Day" on National Public Radio, and WDEL talk radio, which serves the East Coast. Television coverage included a morning television appearance on CBS affiliate WCIA Channel 3 news in east-central Illinois and a remote interview (voice only) with Comcast Cable News that broadcast to all of the East Coast. Interest exists for possible articles in a variety of general science magazines, and a science television show has expressed interest in documenting the discovery as well.
The media attention followed publication of the discovery by two geologists from the Coal Section of the Illinois State Geological Survey, in cooperation with geologists from the Smithsonian Institute in Washington, DC, University of Bristol in the United Kingdom, and Peabody Energy in Illinois. The publication described a 300-million-year-old Pennsylvanian-age mire forest beneath the flat plains of east-central Illinois in the largest study of its kind. The study investigated extensive, well-preserved plant fossils lying just above the Herrin Coal seam. The fossils stretch over 2,500 football fields (1,000 hectares) in area and represent multiple niches of the forest environment, allowing the scientists to examine the subtle ecology of an ancient forest on an unprecedented scale. The research was able to demonstrate the emergence of ecological gradients at the landscape scale for these ancient forests and show the correctness of previously hypothesized theories about the structure of the Pennsylvanian-age mire forest. (Contact: S. Elrick)
Sequestration Site Selected for Carbon Dioxide Injection
A site in Western Wabash County has been selected as one of the demonstration locations for research on carbon dioxide (CO2) sequestration. The research is being conducted by the Illinois State Geological Survey (ISGS) and is sponsored by U.S. Department of Energy. The ISGS will work closely with the landowner and an oil and gas drilling company to conduct this investigation. Three closely spaced wells will be drilled to about 1,100 feet, one for CO2 injection and two for monitoring the movement of displaced gases. The test will determine the rate and capacity of a coal seam to adsorb CO2, a greenhouse gas. Up to 600 tons of CO2 will be injected over a period of up to 30 days. Coal adsorbs this gas while releasing methane, a potentially recoverable natural gas fuel that might add financial incentive to sequester the CO2. Extensive shallower monitoring of groundwater and soil gases will verify that the CO2 remains in the coal. Drilling is expected to begin July 2007 and CO2 injection is scheduled for May 2008, after completion of numerous analyses on the coal. (Contact: D. Morse)
Publication Plan for Greater St. Louis Metropolitan Area Earthquake Scenario
A representative of the Illinois State Geological Survey is part of the executive committee for a proposed project to produce a document showing impacts from a major earthquake in the greater St. Louis Metropolitan area. The first meeting for the project included participants from across the nation. It is hoped that the participants could produce the document for the 200th anniversary of the series of New Madrid earthquakes that rocked the central United States in 1811-1812. This scenario document is being produced with partial support from a national professional society, Earthquake Engineering Research Institute (EERI). The document will provide a sobering look at the impacts of a major earthquake on area infrastructure and infrastructure that passes through the New Madrid Seismic Zone to other areas of the nation. This document for public and public officials will show impacts such as those on buildings, electricity, water supplies, business interruption, transportation systems of roads, railroads, river traffic, and pipelines. Direct and indirect costs will be estimated. Similar publications for Seattle and San Francisco have already been produced with partial support from EERI and other contributors. (Contact: R. Bauer)
Patent Application Filed for a New Process for Carbon Dioxide Capture
An integrated carbon dioxide (CO2) sequestration scheme includes three general steps: CO2 capture, transportation, and permanent storage. The vast majority of the fossil fuel-fired power plants, which are the most likely point sources for CO2 capture, generally produce diluted CO2 gas streams. Capture of CO2 from these sources is the most expensive step, consuming more than 70% of the total sequestration cost. Reducing the CO2 capture cost would clearly have the most significant impact on the economic performance of a sequestration process.
Two chemical engineers at the Illinois State Geological Survey have recently developed a novel process for capturing CO2 from coal-fired power plants. Preliminary economic analysis reveals that the CO2 avoidance cost of this process will be around $33/tonne compared with $55/tonne for the conventional amine-based processes. The Office of Technology Management at University of Illinois at Urbana-Champaign examined the invention disclosure submitted by the chemical engineers and concluded that the process contains sufficient intellectual properties and merit for U.S. patent application. A patent application entitled "Integrated Vacuum Absorption Steam Cycle Gas Separation" was filed with the U.S. Patent and Trademark Office on May 8, 2007. (Contact: S. Chen)
Geologists examine Foglepole Cave
Glaciation-Induced Formation of Illinois' Longest Cave
Geochemists from the Illinois State Geological Survey (ISGS) and Department of Geology at University of Illinois at Urbana-Champaign are currently investigating the origin and evolution of large, branchwork-type caves in southwestern Illinois. Caves are defined as openings in bedrock that are large enough for a human to enter and long enough for a visitor to experience total darkness. The large caves of southwestern Illinois, Fogelpole Cave and Illinois Caverns, are typically 100 feet below the surface and up to 15 miles long; these caves contain stream-filled passages over 25 feet in diameter. The questions of when the caves began to form and how they evolved are difficult to answer because the scientists are attempting to date and characterize an open space. Currently, ISGS scientists are taking an eclectic approach to investigating these caves and their deposits. Stalagmites and fine-grained sediments have been used to identify paleoclimatic and paleoflooding in the study area, and stalagmites are currently being used to explore earthquake activity as the area of the caves is in close proximity to the New Madrid Seismic Zone.
During the course of their work, ISGS scientists realized that deposits of surface-derived sediments, stalagmites, and flowstone located throughout the caves at a variety of different levels act as markers for cave development and downcutting after its initiation. Carbon-14 and uranium-series dating techniques were used to identify the ages of these materials at four different and far removed locations within Fogelpole Cave. The heights above the floor of the cave and the measured ages of these materials were used to calculate downcutting rates. Incision rates by the cave streams range from 0.032 to 0.048 cm/yr (about 1.25 to 1.9 inches per 100 years). Using these downcutting rates, it was determined that the caves were initiated between 140,000 and 170,000 years before present. That means that the caves were initiated near the end of the Illinois Glacial Episode and the beginning of the Sangamon interglacial interval. This timing suggests that, as the Illinoian glacier began to melt, the cold, chemically aggressive meltwaters began infiltrating into fractures and bedding planes in the limestone and dissolved pathways through the rock. Once these pathways were established, infiltrating rainwater and snowmelt subsequently used them as conduits to migrate through bedrock and discharge downgradient to the surface, again forming springs and streams. The continuous flow of water through these limestone conduits resulted in additional dissolution of rock that continues today. Flowstone ages near the ceiling of the cave suggest that the cave was only about three feet high about 110,000 years ago; the cave ceiling is about 25 feet high today. (Contacts: S. Panno and B. Curry)
Deep Observation Borehole into the Earthquake Source
A representative from the Illinois State Geological Survey participated in the first meeting concerning a deep borehole observatory project for the New Madrid Seismic Zone. Held in Memphis, Tennessee, May 3-4, 2007, the meeting informed interested scientists, engineers, and institutions about the working group and provided a forum for discussing relevant issues. The workshop defined scientific targets and priorities and developed some strategies to best implement the work. The project is similar to the deep borehole project in Southern California which has drilled through the San Andreas fault and resulted in a new understanding of the fault environment. During the New Madrid Seismic Zone project, instruments will be placed where the earthquakes take place, in the bedrock deep below the thick overlying sediments. Instruments in the bedrock, about a mile below the ground surface, will directly measure many parameters of the earthquakes, which are modified by the overlying sediments. Instruments installed within the seismic activity at depth could produce a better picture of the active faults which produce 100 to 200 small earthquakes each year. Monitoring of instruments in the bedrock could provide a better understanding of the fault location and extent. Samples of the deep bedrock in the seismic zone along with the direct measurements of the physical properties of the thick overlying sediments will produce a better understanding on how the materials will behave in transmitting large earthquake ground motions to the surface, leading to better estimates of damage on the ground surface and better designs to mitigate damage. (Contact: R. Bauer)
Updated 07/23/2012 SLD