INTEGRATING ROCK IDENTIFICATION WITH DEPOSITIONAL ENVIRONMENT TO ENHANCE LEARNING IN INTRODUCTORY EARTH SCIENCE CLASSES

One challenge in teaching students with limited earth science experience is to make hand sample identification engaging and effective. Our goal was to create an inquiry based identification activity and to show the fundamental importance of rock identification in field geology. We introduced students to modern depositional environments and sediments at the same time we gave them hand samples of rocks representing these locations. This reinforces geologic concepts such as the origin of sedimentary rocks and the principle of uniformitarianism.

The desired outcome of the lesson was for students to identify and describe hand samples of basic clastic, carbonate and evaporite rocks. Students worked in small groups at six stations that represented various depositional environments and the rocks associated with them: fluvial, beach, lacustrine, reef, marine shoal, and lagoonal deposits. Our examples came from Texas and the Gulf of Mexico to familiarize students with regional geology. To prepare the students for this lab we introduced them to the properties of sedimentary rocks by having them construct some equipment a geologist might use in the field, for example, a grain size chart. During the lab, students filled out mock field notebooks with their observations and then made interpretations about the environments. Afterwards we gave the students a more complete picture of the sedimentary environment and asked them to evaluate their interpretations. This activity helped students to recognize that sedimentary rocks and their depositional environment are inextricably linked, improving the student’s ability to identify rocks and the environments in which they are formed.

This laboratory was developed as part of UT-Austin’s GK-12 program and was used in seventh grade science classes. The lab focused on sedimentary rocks but it could be expanded to include metamorphic and igneous rocks. Specific questions were geared to the seventh grade, but could be easily modified for all middle school, or higher education levels. State educational standards covered in this lab include the following TEKS 6:1, 2, 3, 4, 6, 14; 7:1, 2, 3, 4, 7, 12, 14; 8:1, 2, 3, 4, 9, 10, 12, 14.