Geology and Development of Modern Africa

Barbara A. Tewksbury

Stephen Harper Kirner Chair of Science
Department of Geology
Hamilton College
Clinton, NY 13323
phone 315-859-4713
e-mail: btewksbu@hamilton.edu

Abstract

The Geology and Development of Modern Africa is a writing-intensive, laboratory based, introductory geology course that has been taught at Hamilton College since 1994. The course is predicated on the idea that an understanding of geology is instrumental in recovering our human past, understanding the present, and predicting the future, and that a significant number of human events cannot be completely understood without understanding the underlying role played by geology, geologic processes, and the natural environment.

Students in the course gain a rigorous understanding of geology and geologic processes through the exploration of a series of scientific topics that have direct relevance to particular historical, cultural, political, or economic issues in Africa, such as the fluvial processes of the Nile River System, hydrogeology and climate change in North Africa, the structure and evolution of the East African Rift Zone, and the concentration of mineral resources. Some of the many complex topics explored during the semester include: long-term fluctuations in fluvial activity and the rise and fall of dynasties along the Nile, climate change, bedrock geology, the location and timing of development of Egyptian civilization, the economic implications and environmental consequences of damming the Nile at Aswan, and the relationship between geological resources, such as gold and diamonds, and black oppression in South Africa.

A centerpiece of the course is a month-long diamond exploration project where students are organized into virtual teams of geologists prospecting for diamonds in different areas of southern Algeria. The goal is to develop a presentation to a group of "investors" that will convince them to fund further exploration of likely target areas. Teams plan and implement simulated airborne magnetic surveys using scaled models, collect data and samples for analysis, create contour maps, and test for ground resistivity. Because each group is dealing with a different exploration area and different material conditions, they must make choices and decisions based on their data, and there is no single "correct" result.

This course emphasizes collaborative and self-directed learning, as well as critical thinking skills. It encourages students to see the connection between science and "real life" by revealing the complexity and ambiguity that scientists encounter in their research, and by providing them with opportunities to put their knowledge to use in solving immediate problems.

Teaching and Learning Strategies

Because the overarching goal of the course is not just to teach students about connections between geology and human events but rather to enable them to draw connections on their own in the future, the course gives students practice in teaching themselves about both geologic and non-geologic topics and in drawing connections themselves. The course consists of a set of in-class and out-of-class exercises and activities that require students in the course to take responsibility for their own learning. Students work repeatedly in small groups using real data sets, articles from the literature, and materials that I have written for them in order to work out both the geologic story and the connections to non-geologic topics (including public policy issues). The course uses a variety of teaching strategies, including daily written preparation for class, small-group discussion, jigsaw, simulations of international negotiations and press conferences, debates, field and laboratory activities, posters, and summary reports. This course engages students actively in the classroom; lecture forms a very small percentage of the classroom time. Here is one specific example: Influence of geology and geologic processes on the timing of development of ancient Egyptian civilization: Many investigators have contributed to a picture of climate change in the Sahara between about 9000 years ago and 5000 years ago that strongly suggests a habitable, Sahel-type climate throughout much of the Sahara early in the Holocene followed by decreases in rainfall leading ultimately to the hyperarid conditions that have characterized the Sahara for the past few thousand years. The timing of development of agriculture in the Nile Delta also appears to be related to climate change and deceleration in sea level rise following Late Pleistocene deglaciation. The timing of development of civilization in the Nile Valley appears to be no accident and closely follows the time period during which Neolithic peoples would have been driven out of the Sahara by decreasing rainfall and into an increasingly habitable and farmable Nile Valley with annual floods of reasonable magnitude.

I designed a series of activities for students to explore both the climatologic evolution of the Sahara and the influence of climate change on the timing of Egyptian civilization. I begin by having students examine the sedimentologic record in four Early Holocene Saharan paleolakes using real-world data. I use the jigsaw technique, having each team unravel the geologic record in one stratigraphic column. Mixed groups with one member from each team then compare stratigraphic columns and evidence for rainfall changes and are charged with developing an overall picture of temporal and spatial changes in rainfall in the Sahara between about 9000 years ago and 4000 years ago. The goal could be accomplished by lecture and presentation of stratigraphic evidence by the instructor, but having students examine the data for themselves allows them to experience first hand how geologists use the rock record to determine something about the geologic past. Not only are the students quite capable of drawing these conclusions themselves, the strategy gives them practice being geologists, marshalling evidence, defending a point of view, speaking the language, and solving a geologic problem.

As a follow-up assignment, each student prepares an essay of significant length drawing together everything we have considered about the location and timing of Egyptian civilization to evaluate the connection overall between geologic processes (including climate change) and the development of Egyptian civilization. This assignment provides an opportunity to see how well students can individually synthesize a large body of information and draw disparate pieces of evidence together to argue a point of view.

The month-long diamond exploration project in Version 1 of the course provides a longterm group task for students that is both complicated and open-ended. The project provides an experience in data collection, sample analysis, map work, project planning, time management, and teamwork. The final presentation to an outside expert on international mineral exploration has proven to be a very successful way of setting high external standards for performance and having student meet those challenges.