Development of a field-based geochemistry course in the Dallas-Fort Worth Metroplex

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Development of a Field-Based Geochemistry Course in the Dallas-Fort Worth MetroplexThis project develops a national model for a field and laboratory based coursein geochemistry at the undergraduate (and graduate) levels. Geosciences majors at the University of Texas at Dallas enrolled in Geochemistry (a required course for B.Sc.majors) will spend a total of 10 days in the field working from a pontoon boat on LakeTexoma, a large impoundment north of the Dallas-Fort Worth (DFW) metroplex. Duringthe field exercises students will collect data and samples for analysis in the ICP analyticalfacility (inductively coupled plasma mass spectrometer and optical emission spectrometerinstruments). The purpose of the field and laboratory work is to incorporate Problem-Based Learning (PBL) methods into geochemistry instruction. The incorporation of thefield work into the geochemistry course work is intended to stimulate students interest ingeochemistry, provide hands-on experience with state-of-the-art sampling and analyticalmethodologies, and mesh research with learning to foster student understanding of realworld problems. The study area, Lake Texoma receives input from two major river systems, the Red River and the Washita River. The Red River drains west Texas and Oklahoma and as a result typically has elevated salinity (typically 1200 - 2000 mg/L total dissolved solids, TDS, where it enters the lake and 12,000 mg/L TDS in some of the headwater reaches), making the Red River one of the saltiest major rivers in the world. In contrast, the Washita River drains west-central Oklahoma and is much fresher (typically 500 mg/L TDS). Mixing between these two rivers results in horizontal chemical gradients in addition to vertical chemical gradients that occur during development of a summer thermocline. Large deltas are forming where both the Red and Washita rivers enter Lake Texoma, as a result of elevated suspended loads. This dynamic geochemical and sedimentological system is therefore ideal for students to develop hypotheses, collect the necessary data to test those hypotheses and then communicate the results as term papers and oral presentations. Following the semester-length course, a graduate student and two undergraduates will be involved in sampling the lake through the summer to track geochemical changes as the thermocline develops. After year one of the project, the course will be assessed by two external experts in geology and pedagogy. Their recommendations will be incorporated to improve the course for year two.