6 National Association of Geoscience Teachers Session: Classroom and Laboratory Demonstrations of Geologic Phenomena

Wednesday, 7 May 2003
3:00 PM - 5:05 PM

MEASURING AND DESCRIBING A STRATIGRAPHIC SECTION IN THE CLASSROOM: A CURE FOR GEOLOGIC CABIN FEVER

Paper number: 6-4
Program: THEME SESSIONS
Time: 3:35 PM – 3:50 PM

Authors

Abstract

Teaching stratigraphy without the benefit of field studies is extremely challenging, partly because weather and distances may hamper or prevent field opportunities. Paper exercises, similar to those found in many laboratory manuals, teach important concepts, but lack realism. Students often fail to understand how the “paper strat column” was generated in the first place. We have developed classroom exercises, based on actual stratigraphic sections, which provide a greater degree of realism.

Hand-sized, or larger, samples representing actual lithologic units are arranged at stations down a hall using a pre-established scale. Each “lithologic station” includes additional samples of associated fossils, sedimentary structures, and lateral and vertical variations in lithology. The juxtaposition of contrasting lithologies, as well as enlarged photographs, can be used to illustrate faults and larger scale geologic structures. An index card at each station provides the strike and dip of beds, or larger samples can be oriented in order for students to make actual measurements using a Brunton compass.

Students, working as individuals or in pairs, “measure” the stratigraphic section and trigonometrically correct their measured values to true thicknesses. They then describe, in detail, their observations and measurements in a field notebook, and later draft, by hand or computer, a stratigraphic column using standard symbols. Several “hallway strat sections” can be measured and linked to a regional map in order to illustrate lithostratigraphic correlations, reconstruct paleogeography, and describe lateral changes in depositional environments. Extensions of this basic exercise are virtually unlimited.