The Mini-Sedimentologist

Tania Anders, Texas A&M University Corpus Christi
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Keywords: scientific method, scientific writing, sediment cores, core description, smear slides, grain-size analysis

During this multi-week or semester-long assignment, students collect sediment cores in the field, perform a series of basic descriptive and analytical studies on the collected samples, and summarize their work in writing. Students will learn how to pre-survey an area, allowing them to pick the most suitable sampling location. In the field, students will gain first-hand sampling experience. After the study of their samples, students will have a basic understanding of some simple methods used by sedimentologists. They will learn how to prepare and work with samples, produce and present data, and summarize their finding graphically as well as in writing.

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Geology majors after completion of their first year. Ideally, students have taken Physical and Historical Geology and this activity is then embedded into a course focused on undergraduate research. Otherwise, activity could be part of a Historical Geology course (prerec: Physical Geology).

Skills and concepts that students must have mastered

Students should be familiar with the scientific method, and have a basic understanding of sediments and sedimentary rocks, e.g. their importance in reconstructing/understanding depositional environments and their value as a tool to sedimentologists.

How the activity is situated in the course

This activity is part of a sequence of exercises and field-based work in an undergraduate research course.


Content/concepts goals for this activity

Students will learn the basic skills required for sedimentological studies: how to formulate a research question, pick a sampling location to address the question, how to sample in the field, describe sediment samples using a variety of means, interpret and present findings.

Higher order thinking skills goals for this activity

Formulation of a hypothesis, analysis and evaluation of data, critical thinking.

Other skills goals for this activity

Team work, presenting data verbally and in writing, develop basic lab skills, ultimate goal is to prepare students for upper level geology courses and research.

Description and Teaching Materials

This activity is designed as a long-term (one semester) project for students in their second year of studies, from which sections can be cut or others added to best suit any given timeframe. The activity is meant to utilize a region's geology and address local geologic questions of interest. In the coastal community of Corpus Christi, TX, sediments can be sampled in Oso Bay, located within walking distance of the University's campus (Ward Island). Oso Bay is an enclosed shallow-water bay where saltwater from Corpus Christi Bay is exchanged with freshwater from Oso Creek (fig. 1). Other regions in the U.S. or beyond may offer sediment-sampling opportunities along rivers or in lakes.

Fig. 1: Location of Texas A&M University Corpus Christi (Ward Island) and the Oso Bay study area.

At the beginning of the semester, students, with guidance from the instructor, pose a geologic question to be addressed that semester and develop a working hypothesis. Ultimately, each student (or small groups) will choose subtopic(s) that best suits their interests, e.g. geochemistry or paleontology, in addition to the general sediment analysis performed by all students. The individual contributions will help create a bigger picture and to compile more data than otherwise possible.
Step 1 of the project revolves around brainstorming research questions for the study area. An example for Oso Bay could be: Have hurricanes that hit the region in the past century left a record in the sediments of Oso Bay? If so, what do those records look like? Geologic significance? Often, questions will not develop until the core samples have been taken and analysis begun. This is in line with true exploration and encourages students to think creatively.
Step 2: Sediment cores are taken in the field after the sampling locations have been carefully picked following group discussions in the class (fig 2). Students learn how to use GPS units and how to take sediment cores.

Fig. 2: 6 cm diameter gouge auger sediment core from the Blind Oso, Corpus Christi, TX. (Photo courtesy of Mark Besonen, TAMUCC)

Step 3: Introduction to the fundamentals of sediment core analysis. Students learn how to open cores, create a photographic record, and document a basic description of the cores followed by smear slide descriptions and a grain-size analysis. During this phase of the project it is important for students to learn time-management skills, record data, and how to work neatly, paying attention to details.
Step 4: Students work on their individual contributions (e.g. micro-organism study)
Step 5: Writing component of the project. Students learn how to summarize their findings, including suitable ways in which to present data (graphs, tables etc.). First introduction to writing a scientific abstract, a bibliography etc., all critical skills needed for upper level geology courses.
Step 6: Presentation of the data. Students will present their work to the class either in form of Power Point presentations or posters. This can vary from semester to semester. Either way, the presentations can be set up as a mock conference. Students will learn how to comply with rules and guidelines such as time limits for presentations, formatting guidelines for posters etc.

Teaching Notes and Tips

Throughout the entire project the instructor needs to keep in mind, that this activity is geared towards students in their second year of study. An adequate amount of time needs to be spent on basic skill development. Armed with this fundamental knowledge and work ethic, students will enter their upper level courses prepared to build on and further develop these essential competences.


Students will be assessed in three main component areas: field/laboratory work (which includes neatness of work, time management, reliability), description and summary of work (including evaluation of their scientific writing, presentation of data in graphs etc.), and thirdly their interpretation of their findings including presenting their work to the class.

References and Resources

Communicating Rocks-Writing, Speaking, and Thinking About Geology by Peter Copeland (2012); Pearson publishing; ISBN 13: 978-0-321-68967-2

Core Understanding – Core description and Lithostratigraphy

How to prepare smear slides for sediment analysis

Grain-size analysis

Regional Reading Material/ Resources Oso Bay