INTERPRETATION OF LOCAL ROCKS IN THE CONTEXT OF REGIONAL EVENTS IN UNDERGRADUATE STUDENT LABS

The purpose of the final sequence of four labs in our “Earth Systems History” class is to encourage students to interpret samples and data from the local area in the context of regional events they learned about in the lecture class. The labs take the geologic eras in turn, and follow a similar pattern of using maps, field reports, photographs and rock and fossil samples to discover the main rock types that formed during that era and where within Staten Island and New Jersey they are located. Students then interpret this information based on their knowledge of paleogeography, plate boundaries, and sedimentary environments. They should be able to explain how each group of rocks formed and came to create the landscape we see today.

One of the issues students experience is that the local rocks do not always resemble the idealized examples from the “rock box”. They discover that comparing the sample to a photograph does not help them to accurately identify a rock, and they come to understand the need to carefully observe and describe rock textures and mineralogy in order to make the identification.

The greatest difficulty the students have is in synthesizing all of the information from different sources into a coherent written report. They tend to start by describing each data source in turn, rather than taking each rock group and summarizing all relevant information before moving onto the next one. They also have trouble separating the results from the interpretation or discussion. Following the same structure in each of the four labs allows them to learn from their earlier mistakes.

The role of this class in the curriculum is to transition the students from an introductory physical geology class, to upper level courses such as sedimentology and stratigraphy. In using samples, maps and data from the local area, students develop the skills to interpret events and environments rather than simply observing and describing samples of rock. They also develop the writing skills that will be necessary for presenting their work in upper level courses in a coherent, structured report format.