Spring 2009 Colloquia

January 26 Peter Burns (Notre Dame University). Title: From Mineral Structures to Nano-Scale Control of Uranium

February 2 No Colloquium

February 9 Evgenya Shelobolina (University of Wisconsin-Madison). Title: Microbially Mediated Structural Iron Redox Cycling in Phyllosilicates

Abstract Phyllosilicate Fe could represent an important form of reactive Fe in soils and sediments that may impact many biogeochemical processes. Geochemists have known for a long time that there are large quantities of phyllosilicate-Fe in soils and sediments but did not know that some of this Fe could be cycled by microorganisms. Microbial populations involved in structural Fe(III) reduction and Fe(II)oxidation in situ are still unknown. To date most of pure cultures of Fe(III) reducing organisms were isolated on Fe(III) oxide. When those organisms were examined for their ability to reduce structural Fe(III) in nontronite to support growth, not all of them could do so. This demonstrates that although microbial populations involved in Fe(III) reduction of Fe(III) oxides vs phyllosilicates might overlap, they are not congruent. Even less is known about microbially mediated structural Fe(II) oxidation. To study the potential for microbial involvement in the oxidation of Fe(II)-bearing phyllosilicates we used a neutral-pH lithoautotrophic nitrate depending Fe(II) oxidizing enrichment culture (MPI culture; Straub et al. 1996, AEM 62:1458-1460). Two mineral substrates were chosen: biotite and reduced nontronite. An important property of structural Fe in nontronite is its ability to undergo multiple redox cycles. In contrast to nontronite, biotite is incapable of redox cycling. Once Fe(II) is oxidized, biotite is weathered to expandable 2:1 phyllosilicates or kaolinite. MPI culture was capable of multiple transfers in both biotite and nontronite suspensions. Cell yields were about 107 cells/mM Fe(II) oxidized, which is comparable to cell yields observed for neutral-pH lithoautotrophic Fe(II)-oxidizing cultures growing on soluble Fe(II). The MPI culture study can serve as a starting point for further studies of microbial populations involved in structural Fe(II) oxidation in phyllosilicates.

February 25 Chip Feazel (American Association of Petroleum Geologists). Title: Using Modern Cave Systems as Analogs for Paleokarst Reservoirs

Abstract Karst processes, hydrology, dimensions and architecture are useful in understanding karsted rocks that serve as reservoirs for oil and natural gas. Three-dimensional cave surveys can be used to assign properties to “karst” cells in geocellular models. Surveys of long karst passages (e.g. Yucatan flooded caves) can be used to infer connectivity (i.e. how many "karst" cells can be neighbors?). Karst processes ranging from surface weathering to deep burial dissolution have affected numerous karst intervals that host petroleum accumulations. Recognition and prediction of subsurface paleokarst from seismic or borehole information involves addressing the following concerns:

  • Does the layer in question consist primarily of carbonate rocks?
  • Is there evidence to suggest subaerial exposure of the carbonates?
  • Can a humid paleoclimate be documented?
  • What was the paleo-relief?
  • Does the tectonic history include episodes of jointing, faulting, or fracturing that would focus flowing water in the paleo-hydrologic setting?
  • Is there reason to suspect burial dissolution?
  • Did karst dissolution pre-date petroleum migration?
  • What differences would karsting make to wellbore deliverability, well spacing, drilling operations, injec–tion strategies and production profiles?

Analogs and regional studies incorporating the elements of this list can be used in the exploration and production workflow to identify potential problems and opportunities, to constrain geo-model input, and to improve communication of subsurface risks and uncertainties.

March 2 Daniel S. Tudor Commemorative Lecture Series. Henry W. Posamentier Senior Consultant Geologist Chevron Energy Technology Company. Title: Using 3d seismic data to predict lithology in the subsurface: applications of seismic geomorphology and seismic stratigraphy from deep water to shelf.

Abstract: 3D seismic data can play a vital role in hydrocarbon exploration and development especially with regard to mitigating risk associated with presence of reservoir, source, and seal facies. Such data can afford direct imaging of depositional elements, which can then be analyzed by applying seismic stratigraphic and seismic geomorphologic principles to yield predictions of lithologic distribution, insights to compartmentalization, and identification of stratigraphic trapping possibilities. Benefits can be direct, whereby depositional elements at exploration depths can be identified and interpreted, or they can be indirect, whereby shallow-buried depositional systems can be clearly imaged and provide analogs to deeper exploration or development targets.

Examples of imaged depositional elements from both shallow- and deeply-buried sections are presented. Deep-water deposits, in particular, have benefited greatly from analyses of 3D seismic data. The understanding of the stratigraphic and geomorphological evolution of these deposits has increased significantly since the advent of 3D seismic-based analyses. In high-cost deep-water exploration settings, insights derived from such analyses are critical to reduce risk with regard to reservoir presence and reservoir compartmentalization to ensure economic success. Depositional elements in settings such as shoreface, shelf, estuarine, and fluvial, as well as in carbonate environments also benefit greatly from 3D seismic analyses. Numerous examples will be shown.

March 9 Horizons of Knowledge Lecture. Grant Heiken (Los Alamos National Laboratory) Volcanologist, Author. Title: Gods and Monsters: Human Perspectives of Volcanoes.

Abstract: Volcanoes are, in the long run, beneficial. They replenish soils, and leave deposits that can, in the future, be used for everything from building stone to kitty litter. However, they also have a darker side.  Complete devastation by pyroclastic flows (rapidly-moving currents of hot gas and ash), burial by ash fall, and asphyxiation by volcanic gases are a few of the reasons they strike fear into the hearts of people. In the past, the Romans viewed volcanoes Stromboli and Etna as entrances to Hell. Our perceptions of volcanic eruptions have improved in modern times, at least in the industrial world, in spite of the Hollywood movies and television series that perpetuate visions of chaos and mayhem. We have gone a long ways during the last century to increase our understanding of volcanic processes and risks. Have we improved our ability to communicate our understanding to the public at risk?

March 10 Horizons of Knowledge Lecture Grant Heiken (Los Alamos National Laboratory) Volcanologist, Author. Title: Geology and urban Sustainability: The View From Rome

Abstract: Applying science and technology to the urban condition is mandatory thinking as we move into the future. In many cities, for example, there is no holistic understanding of even the most basic aspects of their water systems. Robert Leggett, the foremost expert on urban geology in the 20th century, emphasized that the natural setting of a city is its foundation. In the past, most urban planning decisions were made with little or no regard for the role of the natural setting in the city’s long-term heath and stability. An understanding of geology has been shown to have a huge impact on urban management. Rome is a city where planning and management decisions are being made with careful attention to the city’s geologic setting. From its time as the historic center of the Roman world, Rome has been continuously a political, religious, and administrative capital.  Geologic and terrain factors assured its population growth and provided the conditions for survival of its culture in the ancient world. From lessons of urban development and prosperity, the Roman people developed a capacity to recognize and to manage the natural resources of the region. Modern Rome, born after the unification of Italy, was developed in a haphazard manner after WW II. Most residents have not been pleased with the results of rapid development, but have developed a strong awareness for a need to care for the city and to better manage its environment. There are new, detailed geologic maps of the city, programs for engineering and environmental geology, and cooperative work with archeologists - all within the city and regional governments. It is appropriate that the term urban geology has its origin in Urbs, which was the ancient name for the City of Rome. This work was done in collaboration with Renato Funiciello and  Donatella De Rita, Universitå di Roma, TRE.

March 16 Spring Break

March 23 No colloquium.

March 26 Eric Riggs, Purdue University. Title: Effectiveness in Problem Solving During Geologic Field Examinations: Insights from Analysis of GPS Tracks at Variable Time Scales

March 30 Robert Aller, Stony Brook University. Title: Sedimentary Carbon Cycling, Incineration, and Burial in Tropical Oceania: The Gulf of Papua Deltaic Complex.

April 6 Kevin Boyce, University of Chicago. Title: The Fossil Record of Leaf Physiology and Development

April 8 David Mohrig, NSF-Margins Speaker, Jackson School of Earth Sciences, University of Texas at Austin. Title: Comparing the Evolutions of Lowland Rivers and Submarine Channels

April 20 Owen Award Lecture: Mark S. Leonard, 2008 recipient of the Owen Award, President, Leonard Exploration Inc.

April 14 Title: Growth of a Dendritic Channel Network Daniel Rothman, Massachusetts Institute of Technology.

April 21 J. William Schopf, Department of Earth and Space Sciences, Center for the Study of Evolution and the Origin of Life, University of California-Los Angeles. Title: The Earliest History of Life: Solution to Darwin’s Dilemma.

Abstract: In 1859, Darwin stated the problem: “If the theory [of evolution] be true, it is indisputable that before the lowest Cambrian stratum was deposited, long periods elapsed … and the world swarmed with living creatures. [However] to the question why we do not find rich fossiliferous deposits belonging to these earliest periods … I can give no satisfactory answer.  The case at present must remain inexplicable; and may be truly urged as a valid argument against the views here entertained.” For the following 100 years, the missing fossil record of Precambrian life stood out as one of the greatest unsolved problems in natural science. 

In Darwin’s day, the oldest known fossils were Cambrian trilobites, lobster-like animals entombed in Cambrian-age rocks laid down about 550 million years ago.  But in the mid-1960s, understanding of the early history of life began to change as new finds -- not of animals, but of tiny microscopic microbes -- extended the fossil record into the remote reaches of geological time.  Today, life is known to have emerged on Earth at least 3,500 million years ago and may have been present even 300 million years earlier, a documented history more than seven times longer than was known to science only a few decades ago and an antiquity of life’s existence that no one had dared imagine.  Indeed, we now know that Earth's early biota was dominated by microbial "pond scum," with new technology now providing means to image such ancient fossils in cell-by-cell detail -- fully, in three dimensions, even though they are completely embedded inside rocks -- and to analyze both their cellular form and their coaly, organic chemical composition.

Darwin was right: the Precambrian world did, in fact, “swarm with living creatures.” The dilemma posed by the missing early record of life has been resolved -- the once unknown, and thought unknowable, has been discovered.

April 27: Title: A Geochemical Perspective of the Sedimentary Rock Cycle on Mars." Scott McLennan (Stony Brook University)

April 28: Owen Award Lecture David J. DesMarais, 2009 recipient of the Owen Award, NASA Ames Research Center. Title: From Biogeochemical Carbon Cycles to NASA Astrobiology and Then To Mars: A Journey That Began at Indiana.