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Fall 2012 Colloquia

Thursday September 13th

Dr. Chad Deering
University of Wisconsin-Oshkosh
Title: The Temporal and Spatial Distribution of Volatile Transfer From Source to Surface in the Taupo Volcanic Zone, New Zealand

Abstract:
The Taupo Volcanic Zone (TVZ) is a rifted-arc where dominantly silicic volcanism has evolved intimately with tectonics. Two distinct rhyolite magma types (dry-reducing and wet-oxidizing) have erupted from the central TVZ over the past ~550kyrs. Using a combination of parameters measured in the rhyolitic magmas and surface fluid geochemistry we show that the quantity of slab-derived fluid fluxed through the magmatic system has changed in space and time and is related to rift structure in the Taupo Volcanic Zone.  Slab-derived aqueous fluid components (Ba, Cl, B, d11B, dD) correlate well with oxygen fugacity, and other well defined characteristics of silicic magmas in the Taupo Volcanic Zone (TVZ) between a cold-wet-oxidizing magma type (R1: amphibole ± biotite; high Sr, low Zr and FeO*/MgO, depleted MREE) and a hot-dry-reducing magma type (R2: orthopyroxene ± clinopyroxene; low Sr, high Zr, and FeO*/MgO, less depleted MREE). A geochemical evolution and distribution can be tracked in time and space throughout the central region of the TVZ from 550 ka to present and has revealed two apparent magmatic ‘cycles’ that vary in length. The first cycle included widespread R1 type magmatism across the central TVZ beginning ca. 550 ka and was directly associated with previously unreported dome-building and ignimbrite-forming volcanism, and led to a voluminous (>3000 km3) ignimbrite ‘flare-up’ between ca. 340 and 240 ka. The second cycle began roughly 180 ka, erupting ca. 800 km3 of magma, and continues to the present.   Although several studies of surface fluids from hot springs and fumaroles have used elemental ratios (e.g. B/Cl and Li/Cs) to argue that crustal fluids in the TVZ are derived from two spatially discrete sources: an arc-type fluid in the eastern TVZ and a rift-type fluid in the western TVZ, our re-evaluation of a newly compiled dataset of surface chemistry do not exhibit an east-west spatial control on fluid chemistry. Rather, higher B/Cl ratios occur on both the eastern and western margins of the TVZ implying that local structures and permeability are perhaps more significant controls of this fluid chemistry in the TVZ than the fluid source(s). The results of this comprehensive study suggest that: 1) the duration, rate, and composition of magma production within the TVZ is governed by the flux of fluid released from the subducting slab, 2) surface fluid chemistry does not reflect a simple geometric relationship to the slab trench as previously suggested, and 3) the distribution of distinct magma types is governed more by fluid focusing related to extension along the central rift-axis rather than distance from the subduction trench.

Thursday September 20th

Dr. Masako Tominaga
Michigan State University
Title: The cutting edge of underwater marine geophysics: new insights from the (very) recent AUV magnetic survey in the western Pacific Jurassic ocean basin and potential application for lake research.

Abstract:
The western Pacific Ocean has the largest extent of Jurassic ocean crust (158-180 My) where the Mesozoic geomagnetic field behavior is recorded. The area encompassed by three magnetic lineation sets (Japanese, Hawaiian, and Phoenix) is marked by low amplitude and relatively indistinct anomalies (“tiny wiggles”) that together are called the Jurassic Quiet Zone (JQZ). The JQZ was originally thought to be a period of few, if any, polarity reversals, similar to the Cretaceous Quiet Zone. However, subsequent near-bottom magnetic surveys of the Japanese lineations in 1992 and 2002/03 reveal that this region is marked by remarkably fast reversals that are lineated and decrease in intensity back in time until M41, prior to which, the magnetic anomalies recover in amplitude. A geomagnetic polarity timescale (GPTS) was constructed from this Japanese anomaly sequence, but the overall global significance of the reversal sequence and systematic field intensity changes require a confirmation of such a GPTS on crust created at different spreading centers. To evaluate the global coherence of geomagnetic field behavior during the Jurassic, we conducted a comprehensive magnetic survey in the Hawaiian Jurassic crust using three different magnetic sensor platforms, including state-of-art Autonomous Underwater Vehicle (AUV) Sentry for super-high resolution near-bottom data collection, along with a crustal seismic profiling component to survey a spreading corridor in the Hawaiian lineations. Preliminary sea surface and mid-water level magnetic data display a similar anomaly sequence to the Japanese sequence: an overall decrease in anomaly amplitude from M19 to M29, followed by a period of low amplitude, which in turn is preceded by a return to stronger amplitude anomalies. The magnetic anomaly correlations between Hawaiian and Japanese sea-surface level profiles confirm the reversal record back in time, at least, to M38. At the mid-water level and near-bottom AUV level, the magnetic data clearly show the short-wavelength anomaly character of the M29-M38 sequence, indicating that the fast reversals observed in the Japanese lineations are also present in the Hawaiian lineation set. The strong similarity of overall anomaly patterns between Japanese and Hawaiian sequences supports the following preliminary conclusions that: (1) the global coherence of the geomagnetic field behavior during the Jurassic and (2) Earth’s geomagnetic field during the JQZ period was “NOT” so quiet.

Thursday September 27th

Dr. Kue-Young Kim
Korea Institute of Geoscience & Mineral Resources
Title: Characteristics of salt-precipitation and the associated pressure build-up during CO2 storage in saline aquifers.

Abstract:
Mitigation and control of borehole pressure at the bottom of an injection well is directly related to the effective management of well injectivity during geologic carbon sequestration activity. Researchers have generally accepted the idea that high rates of CO2 injection into low permeability strata results in increased bottom-hole pressure in a well. However, the results of this study suggested that this is not always the case, due to the occurrence of localized salt precipitation adjacent to the injection well. A series of numerical simulations indicated that in some cases, a low rate of CO2 injection into high permeability formation induced greater pressure build-up. This occurred because of the different types of salt precipitation pattern controlled by buoyancy-driven CO2 plume migration. The first type is non-localized salt precipitation, which is characterized by uniform salt precipitation within the dry-out zone. The second type, localized salt precipitation, is characterized by an abnormally high level of salt precipitation at the dry-out front. This localized salt precipitation acts as a barrier that hampers the propagation of both CO2 and pressure to the far field as well as counter-flowing brine migration toward the injection well. These dynamic processes caused a drastic pressure build-up in the well, which decreased injectivity. By modeling a series of test cases, it was found that low-rate CO2 injection into high permeability formation was likely to cause localized salt precipitation. Sensitivity studies revealed that brine salinity linearly affected the level of salt precipitation, and that vertical permeability enhanced the buoyancy effect which increased the growth of the salt barrier. The porosity also affected both the level of localized salt precipitation and dry-out zone extension depending on injection rates. High temperature injected CO2 promoted the vertical movement of the CO2 plume, which accelerated localized salt precipitation, but at the same time caused a decrease in the density of the injected CO2. The combination of these two effects eventually decreased bottomhole pressure. Considering the injectivity degradation, a method is proposed for decreasing the pressure build-up and increasing injectivity by assigning a ‘skin zone’ that represents a local region with a transmissivity different from that of the surrounding aquifer.

Thursday October 4th

Dr. Steve Hasiotis
The University of Kansas
Title: Traces of Permo-Triassic Antarctic Life on Land and Sea from the Beacon Supergroup, Beardmore Glacier region, Central Transantarctic Mountains, Antarctica: Implications for Diversity, Environment, and the Greatest Mass Extinction of All Time.

Abstract:
Permo-Triassic sections were studied for their ichnologic, sedimentologic, and paleopedologic characteristics in the Beacon Supergroup of the Beardmore Glacier region, Central Transantarctic Mountains, Antarctica. Units studied include the Lower Permian Mackellar Formation (MF), Lower to Middle Permian Fairchild Formation (FF), Upper Permian Buckley Formation (BF) and the Lower Triassic Fremouw Formation (FrF). Trace fossils can be used as proxies for hidden biodiversity and indicators of environment, hydrology, and climate. Changes in trace fossil composition, occurrences, and sedimentary facies relations from the MF to the FrF at Turnabout Ridge, Lamping Peak, Coalsack Bluff, Wahl Glacier, and Graphite Peak provide excellent proxy evidence for life that existed in those depositional environments. For example, traces and lithofacies in the MF and FF indicate marine organisms living in fluviodeltaic environments influenced by freshwater physicochemical processes. Ichnological changes across the Permian-Triassic boundary recorded in the BF and FrF suggest a decrease in ichnodiversity reflecting a shift from high to low soil moisture and water table conditions and overall improved landscape drainage. Trace fossils across the P-T boundary do not show any major gap in fossil evidence reported elsewhere in terrestrial sections. Many of the same behavioral groups and likely the same families and genera continue across the boundary section. Comparisons of ichnodiversity between high and low paleolatitude settings also demonstrate that diversity was higher a lower latitudes but both share many of the same ichnotaxa.

Thursday October 11th

Dr. Hahn Chul Jung
NASA Goddard Space Flight Center
Title: Wetland Hydrologic Studies Using Remote Sensing and Modeling.

Abstract:
Permo-Triassic sections were studied for their ichnologic, sedimentologic, and paleopedologic characteristics in the Beacon Supergroup of the Beardmore Glacier region, Central Transantarctic Mountains, Antarctica. Units studied include the Lower Permian Mackellar Formation (MF), Lower to Middle Permian Fairchild Formation (FF), Upper Permian Buckley Formation (BF) and the Lower Triassic Fremouw Formation (FrF). Trace fossils can be used as proxies for hidden biodiversity and indicators of environment, hydrology, and climate. Changes in trace fossil composition, occurrences, and sedimentary facies relations from the MF to the FrF at Turnabout Ridge, Lamping Peak, Coalsack Bluff, Wahl Glacier, and Graphite Peak provide excellent proxy evidence for life that existed in those depositional environments. For example, traces and lithofacies in the MF and FF indicate marine organisms living in fluviodeltaic environments influenced by freshwater physicochemical processes. Ichnological changes across the Permian-Triassic boundary recorded in the BF and FrF suggest a decrease in ichnodiversity reflecting a shift from high to low soil moisture and water table conditions and overall improved landscape drainage. Trace fossils across the P-T boundary do not show any major gap in fossil evidence reported elsewhere in terrestrial sections. Many of the same behavioral groups and likely the same families and genera continue across the boundary section. Comparisons of ichnodiversity between high and low paleolatitude settings also demonstrate that diversity was higher a lower latitudes but both share many of the same ichnotaxa.

Thursday October 18th

Dr. Laodong Guo
UW-Milwaukee, School of Freshwater Sciences
Title: Remobilization of permafrost soil organic carbon in a changing environment

Abstract:
Terrestrial arctic ecosystems have accumulated vast quantities of soil organic carbon throughout much of the Holocene and are estimated to store 30-50% of the world’s soil carbon. Old soil organic carbon in permafrost could actively participate in biogeochemical cycles if liberated by permafrost thawing and coastal erosion, causing positive feedback to climate change. However, the fate and transport of permafrost soil organic carbon in northern high latitude regions and the manner in which soil organic carbon interacts with the hydrologic cycle remains poorly understood, even though release of organic carbon from this large pool promises to be an important manifestation of warming in the cryosphere. This presentation will focus on the transport of nutrient and carbon species across the permafrost-water interface in a changing environment.

Thursday October 25th

Dr. Alycia Stigall, Associate Professor of Geological Sciences at Ohio University
Title: Tracking species through space and time: The impact of invasive species during the Late Devonian Mass Extinction and Late Ordovician Richmondian Invasion.

Abstract:
Invasive species, such as zebra mussels and kudzu, cause billions of dollars’ worth of economic damage in America each year. These species include organisms that proliferate in environments outside their ancestral range following introduction by humans. Biologists are intensively studying the impacts of the invaders on native ecosystems, but they are limited to studies of years or decades. Species invasions, however, also happened in the geologic past due to natural causes, such as intervals of sea level rise. Paleontologists can study these ancient invasions to learn about the longer term (thousands of years) impacts of invasive species. In this presentation, I will analyze the impacts the invasive species have had during two different intervals in the geologic past: the Late Devonian mass extinction and the Late Ordovician Richmondian Invasion. During both of these intervals, the shallow seas that covered eastern North America experiences waves of interbasinal species invasions. The Late Devonian invasions triggered one of the largest biodiversity crises in Earth’s history, primarily by stopping the formation of new species. The Richmondian Invasion resulted in fundamental changes to ecosystem structure. The relative roles of invasive species in driving biodiversity change during these two intervals will be examined and then linked with the potential long-term impacts of modern invasive species.

Thursday November 1st

Geosciences Students
UW-Milwaukee
Title: GSA Practice Talks

3:30 pm:              Zach Watson – poster presentation
“Geochemical Evolution and Eruption Dynamics in Crystal Geyser – Green River, Utah”

3:45 pm:              Katie Pauls – poster presentation
“Paleoecology and Sedimentology of fossil-bearing, high-latitude Glaciogenic deposits in the Tepuel Basin, Patagonia, Argentina.”

4:00 pm:              Justin Calhoun – poster presentation
“Fabric and microstructural analysis of the Loch Borralan pluton, Northwest Highlands Scotland.”

4:15 pm:             Elise Iverson-Uphoff – oral presentation

“Enhancement of heat extraction from Geothermal Reservoirs using CO2 as a working fluid.”

4:30 pm:            Ashley Dineen – oral presentation
” ‘New normal’ in the Early and Middle Triassic: Novel views on Marine Community Recovery after the End-Permian Mass Extinction.”

Thursday November 15th

Dr. Scott Bradford
United States Department of Agriculture
Title: Colloids in the Subsurface: Applications, Theory, and Challenges

Abstract:
Colloids are particles with effective diameters of around 10 to 10000 nm. An understanding and ability to characterize the transport and retention of colloids in subsurface environments is needed for a wide variety of purposes, including: soil genesis and erosion; aquifer and petroleum reservoir production; bioremediation strategies; surface water and wastewater treatment processes based on passage through porous media; and risk assessment for pathogens, nanoparticles, and many inorganic and organic contaminants that associate with soil colloids. Hence, effective treatment processes for many colloids and contaminants rely on the optimization of colloid transport or retention in the subsurface. This presentation provides an overview of applications discussed above, as well as theory and challenges pertaining to colloids in the subsurface. In particular, colloid transport in porous media has traditionally been assumed to be controlled by chemical interactions between the colloid and the solid-water interface. The influence of pore space geometry, system hydrodynamics, colloid concentration, aggregation, surface macromolecules, and ion exchange has largely been neglected in classical retention models. Recent experimental and theoretical work, however, has demonstrated a complex coupling of these factors on colloid retention and release under unfavorable attachment conditions. Pore- and column-scale experimental evidence and simulation results demonstrating the importance of these factors will be briefly summarized.

Thursday November 29th

Dr. Pedro Marenco
Bryn Mawr College, PA
Title: Contrasting shallow and deep paleoenvironments and the biotic recovery from the End Permian mass extinction.

Abstract:
The greatest mass extinction of the Phanerozoic occurred at the end of the Permian.  This great event was followed by a delayed biotic recovery that was unusual in that it took up to five million years for most taxa to begin to diversify to pre-extinction levels.  Although the precise cause of the extinction and the delayed recovery remains elusive, the coincidence in time of both events with the emplacement of the Siberian Traps suggests that extreme volcanism and associated climate change likely played a role.  Recent work has revealed evidence to suggest that the biotic recovery developed differently in shallow environments versus deep environments.  In particular, while there is evidence for widespread deep ocean anoxia into the Middle Triassic, mid-shelf to nearshore environments contain evidence for well-oxygenated conditions, as indicated by the occurrence of sponge-stromatolite reefs as well as geochemical indicators.  It is likely that environmental factors other than anoxia were responsible for the delay in the recovery in the shallow realm.