2018 Posters on the Hill

The following posters represented the geosciences at CUR’s Posters on the Hill, April 18, 2018.

Alabama

Student: Angela R Burke
Research Institution: University of Alabama in Huntsville
Lead Student Home Institution: University of Alabama in Huntsville
Lead Student Home State: AL
Faculty Advisor: Mr. Ryan Wade
Division: Geosciences
Poster Title: Analyzing Tornadic Debris Signatures by Integrating Aerial Imagery and Polarimetric Radar Data in GIS
Funding Agency: NOAA OAR Office of Weather and Air Quality
Grant #: NA16OAR4590210

Abstract:The historic April 27th tornado outbreak of 2011 produced 62 tornadoes in Alabama, with the one of the strongest being the EF-5 Hackleburg-Tanner tornado. The UAH Department of Atmospheric Science contracted the Atlantic Group to fly the Hackleburg-Tanner EF-5 tornado track and capture high-resolution swaths of the damage path, as well as the paths for the violent Cullman and Cordova tornadoes.This case study involves detailed analysis of the aerial imagery, including digitizing tree-falls and damage points, and outlining a damage path for the tornado. These analyses are then merged with georeferenced TIFF files (GeoTIFF) of UAH ARMOR (Advanced Radar for Meteorological and Operational Research) polarimetric radar scans of Reflectivity Factor, Radial Velocity, Correlation Coefficient, Differential Reflectivity, and Spectrum width to analyze dual-polarization radarTornado Debris Signature (TDSs) associated with the Hackleburg-Tanner tornado.An analysis ofTDSs from this tornado allows for the characterization of the effects of debris loading as the tornado passed over different types of terrain. Additionally, a large gap in damage from Harvest, AL, to theTennessee state line is being investigated to determine the possibility that the Hackleburg-Tanner tornado dissipated before Franklin County,TN,and another formed along the same path.The combined analysis of aerial imagery and radar data will provide a detailed picture of how the physical damage and radar signatures correlate and the effects of debris loading over different terrain, which will add confidence to future forecasting of tornadic events.

Florida

Student: Sarah Elizabeth Coffey
Research Institution: Stetson University
Lead Student Home Institution: Stetson University
Lead Student Home State: VA
Faculty Advisor: Dr.Wendy B Anderson
Division: Geosciences
Poster Title: A Reconstr uction of Fire Histor y of the San Juan Islands, Washington
Funding Agency: BLM National Landscape Conservation System Research Support Program (BLM OR-WA District)
Grant #: L14AC00205

Abstract: Coast Salish peoples in the San Juan Islands have traditionally used fire in the grasslands as a way of managing native plant communities for agriculture. Natural fire frequency in the islands is among the lowest in Washington, suggesting that historical fire regimes reflect human influence. As Indigenous groups have largely been displaced since the arrival of Neo-Europeans in the archipelago, fire frequency has decreased, which has impacted the productivity of grassland flora. Using macroscopic charcoal as a proxy for fire frequency and radiocarbon analysis to approximate when these fires occurred, I attempted to reconstruct the fire history of San Juan Islands. I took my samples from four sites that were adjacent to the historical grasslands of Iceberg Point, Lopez Island, and Cattle Point, San Juan Island. Peaks in the macroscopic charcoal count signified unique fire events that were used to create mean fire return intervals (MFRIs).The site that was closest to the historical grasslands had the lowest MFRI of 42 years and the site furthest from historical grasslands had the greatest MFRI of 133 years. I also conducted interviews with Coast Salish individuals to glean more knowledge of traditional management techniques through the use of fire. Since there is a general concern about the encroachment of shrubs and invasive species into highly diverse grasslands not only in the San Juan Archipelago but throughout the Pacific Northwest, data on previous management techniques using fire could inform current management solutions.

Texas

Student: Alexandria M Weiskircher
Research Institution: Midwestern State University
Lead Student Home Institution: Midwestern State UniversityLead Student Home State: TX
Faculty Advisor: Dr. Jonathan D Price
Division: Geosciences
Poster Title: Magmatic Timing in an Ancient Rift

Abstract:The Wichita Mountains in southwestern Oklahoma expose approximately a dozen granite intrusive bodies (plutons), all part of magmatism within an ancient tectonic rift known as the Southern Oklahoma Aulacogen, a feature that stretched from Dallas, Texas, across Oklahoma, past Amarillo to eastern Utah. At the margin of one of the intrusive bodies, the Quanah Granite Pluton, we noted three rock types.These are (1) the typical coarse-grained facies (CF), (2) fine-grained facies (FF), and (3) porphyritic facies (PF).They are distinguishable based on grain size and mineral content. CF has 6mm mineral grains, FF has 2mm mineral grains, and PF has 5mm larger alkali- feldspar grains with a sub-millimeter matrix. Additionally, the intrusive margin contains several pegmatite bodies, these are coarse-grained igneous pods and linear, intrusive features. Mapping the FF and PF revealed these to have linear, intrusive geometries that cut the CF.To resolve relationships, we assessed the mineral content of the three rock types through petrological and geochemical techniques. Prior researchers noted CF’s distinct mineral populations, which include the sodic amphiboles. PF contains the minerals biotite and/or calcic amphibole. FF contains only biotite.The pegmatite bodies contain quartz ± orthoclase ± biotite or sodic amphibole.,The textures and mineral assemblages imply that the voluminous CF magma first intruded this area, followed by distinct magma(s) that gave rise to the FF and PF.The difference in texture suggests the FF and PF record the last gasps of magmatism in the rift.

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