INTUITIVE SEQUENCE STRATIGRAPHY: REPLACING LECTURES WITH INQUIRY-BASED COMPUTER LABS

All undergraduate geology majors should understand the basics of sequence stratigraphy. However, complex terminology and diagrams commonly used to teach it act as barriers to an intuitive understanding of environmental shifts due to sea level change. These can be removed by teaching with graphically appealing computer models. Freeware Fuzzim (Nordland 1996, JSR v 66 p 689-698) and strategic questions teach basic sequence stratigraphy to sophomore and junior geology majors. Students adjust parameters and observe successive plots of sea level and sediment deposition/erosion in pseudo 3-d. Various sediment properties are plotted along user-chosen cross sections and Wheeler diagrams. Students gain an intuitive understanding of facies shifts, accommodation space, unconformity development, and gaps in the rock record in response to sea level change; they can interpret sea level changes from stratigraphic sequences. The first of four 6-hour labs introduces Fuzzim and sequence stratigraphy by stepping students through a series of defined exercises that show how time is represented in sediments. Next, they identify highstand and lowstand deposits in successive sequences and map sequence boundaries. Finally, they manipulate sea level with guidelines and then using a sea level curve of their own design. They are required to correlate their stratigraphic output to their sea level curve and interpret the integrity of the sea level record. At the end of the lab, the students observe a model of Baltimore Canyon (Norland 1996) tuned to mimic observed stratigraphy. They recognize sea level changes and appreciate the complexity of real applications. The following 2 labs require interpretation of real stratigraphic data using concepts learned. The last lab asks students to use their understanding of sequence stratigraphy to interpret: 1)Paleontological and stratigraphic data to decide whether or not a mass extinction occurred, which requires extensive used of Wheeler diagrams; and 2) Carbonate facies in a stratigraphic model of an atoll that is designed to reflect facies observed in a previous lab based on Bahamian sediment samples. These applications of Fuzzim data demonstrate how sequence stratigraphy is used and connect it to other parts of the course and major. Labs are available at http:www-geology.ucdavis.edu/~gel109