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

在达拉斯-沃斯堡大都市区开发基于野外的地球化学课程这个项目开发了一个全国性的模式，在本科生（和研究生）水平上以野外和实验室为基础的地球化学课程。德克萨斯大学达拉斯分校的地球科学专业的学生参加了地球化学（B.Sc.专业的必修课程），他们将在德克萨斯湖的一艘浮桥上工作10天，德克萨斯湖是达拉斯-沃思堡（DFW）大都市北部的一个大型蓄水池。在野外实习期间，学生将收集数据和样品，用于ICP分析设备（电感耦合等离子体质谱仪和光发射光谱仪仪器）的分析.野外和实验室工作的目的是将基于问题的学习（PBL）方法纳入地球化学教学。将野外工作纳入地球化学课程工作的目的是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，以促进学生对现实世界问题的理解。研究区，特克索马湖接收输入两个主要的河流系统，红河和沃希托河。红河流经德克萨斯州西部和俄克拉荷马州，因此通常具有较高的盐度（通常为1200 - 2000 mg/L的总溶解固体，TDS，在其进入湖泊的地方，在一些源头河段的TDS为12，000 mg/L），使红河成为世界上最咸的主要河流之一。相比之下，沃希托河流经俄克拉荷马州中西部，水质更清新（TDS通常为500 mg/L）。这两条河流之间的混合导致水平的化学梯度，除了垂直的化学梯度，发生在夏季温跃层的发展。由于悬浮物的升高，在红河和沃希托河进入特克索马湖的地方形成了大型三角洲。因此，这种动态地球化学和沉积学系统是学生发展假设，收集必要的数据来验证这些假设，然后将结果作为学期论文和口头报告进行交流的理想选择。在整个学期的课程结束后，一名研究生和两名本科生将在整个夏天对湖泊进行采样，以跟踪温跃层发展过程中的地球化学变化。项目第一年结束后，将由地质学和教育学方面的两名外部专家对课程进行评估。将采纳他们的建议，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.