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

在达拉斯-沃斯堡大都会开发基于野外的地球化学课程该项目为本科生(和研究生)的野外和实验室基础课程开发了一个全国性的模型。德克萨斯大学达拉斯分校地球科学专业的学生注册了地球化学(理科学士专业的必修课)，他们将在位于达拉斯-沃斯堡(DFW)大都市北部的一个大型蓄水池--特科索马湖上，在浮船上进行为期10天的实地工作。在实地练习中，学生将收集数据和样品，以便在电感耦合等离子体质谱仪和光学发射光谱仪等分析设施中进行分析。实地和实验室工作的目的是将以问题为基础的学习(PBL)方法融入到地球化学教学中。将野外工作融入到地球化学课程工作中，旨在激发学生对地球化学的兴趣，提供最先进的采样和分析方法的实践经验，并将研究与学习结合起来，以培养学生对现实世界问题的理解。在研究区，德克萨马湖从两个主要河流系统--红河和沃希塔河--获得输入。红河流经得克萨斯州西部和俄克拉何马州，因此通常盐度升高(通常为1200-2000毫克/L总溶解固体，TDS进入湖泊，在一些源头河段，TDS为12,000毫克/L)，使红河成为世界上含盐量最高的主要河流之一。相比之下，沃希塔河流经俄克拉何马州中西部，而且更新鲜(通常为500mgL TDS)。除了夏季温跃层形成过程中出现的垂直化学梯度外，这两条河流之间的混合还会导致水平的化学梯度。由于悬浮物升高，红河和沃希托河都进入德克索马湖的地方正在形成大型三角洲。因此，这种动态的地球化学和沉积学系统非常适合学生开发假说，收集必要的数据来检验这些假说，然后以学期论文和口头报告的形式交流结果。在整个学期的课程之后，一名研究生和两名本科生将参与整个夏天对湖水进行采样，以跟踪随着温跃层的发展而发生的地球化学变化。在项目第一年后，该课程将由两名外部地质学和教育学专家进行评估。他们的建议将被采纳，以改进第二年的课程。

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.