HR: 1340h
AN: ED43A-0840    [Abstracts]
TI: The Geologic and Geochemical Setting of Lago Fagnano, Tierra del Fuego, Argentina
AU: * Tingle, D
ED43A-0840 AF: Boerne High School, Boerne ISD, 123 West Johns Road, Boerne, TX 78006 United States
AU: Odle, K
ED43A-0840 AF: Boerne High School, Boerne ISD, 123 West Johns Road, Boerne, TX 78006 United States
AU: Knettel, P
ED43A-0840 AF: Boerne High School, Boerne ISD, 123 West Johns Road, Boerne, TX 78006 United States
AU: Redding, S
ED43A-0840 AF: Boerne High School, Boerne ISD, 123 West Johns Road, Boerne, TX 78006 United States
AU: Perry, E
EM: ethan.perry@mail.utexas.edu
AF: Department of Geological Sciences, Jackson School of Geosciences, P.O. Box B, University Station, Austin, TX 78713 United States
AU: Perry, E
EM: ethan.perry@mail.utexas.edu
AF: University of Texas Institute for Geophysics, Jackson School of Geosciences, 4412 Spicewood Springs Road, Austin, TX 78759 United States
AU: Ellins, K
EM: kellins@ig.utexas.edu
AF: University of Texas Institute for Geophysics, Jackson School of Geosciences, 4412 Spicewood Springs Road, Austin, TX 78759 United States
AU: Ormiston, C
EM: chris.ormiston@boerne-isd.net
AF: Boerne High School, Boerne ISD, 123 West Johns Road, Boerne, TX 78006 United States
AU: Dovzak, N
EM: nick.dovzak@boerne-isd.net
AF: Boerne High School, Boerne ISD, 123 West Johns Road, Boerne, TX 78006 United States
AU: Anderson, S
EM: sarah.anderson@boerne-isd.net
AF: Boerne High School, Boerne ISD, 123 West Johns Road, Boerne, TX 78006 United States
AB: Lago Fagnano, Tierra del Fuego, Argentina is the largest and southernmost ice-free lake on Earth. The isolated lake is unique because the geographic and geologic context provides information relating to the westerly wind patterns, interaction of multiple water sources (hot springs, glacial meltwater, precipitation, groundwater), and tectonic dynamics along a major transform fault. In March, 2005, four students and three teachers from Boerne High School, south-central Texas joined scientists from the United States, Argentina and Switzerland engaged in a geophysical survey of this lake. Lago Fagnano potentially contains within its sediments an undisturbed record of the geotectonic and global climate variability of past 20,000 years. The science team imaged the lake floor with a boat specially equipped to collect both high resolution data (high frequency), imaging the upper 10-15 meters of the sediment, and long range data (low frequency), penetrating 100 or more meters into the sediment. The group conducted field research of existing tectonic features at the eastern end of Tierra del Fuego, an activity directly tied to the research objectives of the science team. They also collected water and soil samples to assess chemical and isotopic trends in the Lago Fagnano region. The research performed can help to characterize the modern geochemical setting of the lake. Analyses of dissolved oxygen, NH4+, PO42-, pH (water) and N, P, and pH (soils) demonstrate a link between low nutrient levels and low biodiversity (which was confirmed by observation) in Tierra del Fuego. Water and soil data are incorporated into a database to facilitate comparisons to North American samples collected and analyzed during the Boerne High School summer field courses. Twenty-three „18O and „D analyses yielded a south-north isotopic trend across the Lago Fagnano region. „18O and „D transition from -11.92 to -3.53% and -87.81 to -40.26%, respectively, moving south to the Beagle Channel. These isotopic data, in addition to the soil and water physical and chemical data, provide a snapshot of the geochemical dynamics of the Lago Fagnano watershed. They are valuable because interpretations of paleoclimate will be based on the geochemical history preserved within the lake sediment record. Identification of modern isotopic trends in the Lago Fagnano watershed is helpful for accurate interpretations of the sediment record.
UR: http://www.ig.utexas.edu/outreach/ttif/lago_fagnano/
DE: 0815 Informal education
DE: 1030 Geochemical cycles (0330)
DE: 6630 Workforce
DE: 8106 Continental margins: transform
DE: 9360 South America
SC: Education and Human Resources [ED]
MN: Fall Meeting 2005