Introducing Field-Based Geologic Research Using Soil Geomorphology

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ABSTRACT

A field-based study of soils and the factors that influence their development is a strong, broad introduction to geologic concepts and research. A course blueprint is detailed where students design and complete a semester-long field-based soil geomorphology project. Students are first taught basic soil concepts and to describe soil, sediment and rock properties using standard description procedures. Then, with minimal geological or field experience, they are led to design and execute a project that examines how soil properties differ as a function of processes, parent material and time. By designing and executing the semester-long project, students gain familiarity with the entire geologic research process including basic field observation, hypothesis development and testing, interpretation and presentation skills. During the course, students learn 1) the basic knowledge necessary to describe geologic materials (soil, rock, sediment) in the field, 2) to make observations and interpret them in the context of geologic hypotheses which they have developed, 3) to develop, and execute a field-based research project, 4) to integrate and draw conclusions about complicated semi-quantitative data sets, 5) to map and survey in the field and 6) to present their research in a public forum. By the end of the semester students are able to make and test hypotheses relating soil properties to the depositional environment, age and/or type of geologic deposits in which they form. The knowledge, skills and research experience gained in this simple, semester-long project serve students well in upper-level courses and beyond. An example project is presented from a 2nd order stream and its adjacent tributary alluvial fans in the Piedmont of North Carolina.

INTRODUCTION

For a geologist or soil scientist, a soil is a naturally occurring body of roughly horizontal layers (horizons) located at the surface of the earth whose morphological, chemical, biological and morphological properties are altered from that of the original sediment or rock from which they have formed (parent material) (e.g. Buol et al., 1997). Soils defined this way are distinct from those defined by an engineer who considers any unconsolidated natural material a 'soil'. A geologist's 'soil' is essentially the weathering rind of the Earth's surface. Thus soil properties are directly related to- and provide insights into- the processes and characteristics of the atmosphere, biosphere, hydrosphere and lithosphere.

Over the past four years, a central component of the lower level undergraduate soil science course at the University of North Carolina at Charlotte (UNC Charlotte) is the development of a soil geomorphology study that examines how soil properties vary in a landscape as a function of the characteristics of local environmental conditions. For the majority of students, this course is one of the first that they have taken beyond introductory geology. Numerous similar soil geomorphology studies exist for the western United States (e.g. Gile et al., 1981, Busacca, 1987; McFadden et al., 1989; Reheis et al., 1992; Bockheim et al., 1996); however, very few have been undertaken in the temperate climates of the eastern seaboard, and fewer still in the Southeast (Levine and Ciolkosz, 1983, Markewich and Pavicrt, 1991; Lichter, 1998). Thus, the project allows students to collect original data that can contribute to the field of study.

This type of inquiry based learning is a recognized and recommended pedagogy (Barstow and Geary, 2002) that many find difficult to incorporate into lower level undergraduate course work (Apedoe et al., 2006). Nevertheless, numerous workers have demonstrated that such a teaching approach will improve students' overall science-related skills and understanding, including critical thinking and hypothesis development and testing (e.g. National Research Council, 2000; Keller et. al., 2000; Cavello et al., 2004; Garvey, 2002; Gomezdelcampo, 2006). …