AGE DETERMINATION FOR DEEP-SEA CORES: INQUIRY-BASED LEARNING WITH AUTHENTIC SCIENTIFIC OCEAN DRILLING DATA

Marine sediment cores are some of our best archives of past climate change. Imagine that you have access to deep-sea core material from a region of interest. After describing the cores, what next? What would you like to know? Determining the relative age of the sediments provides historical context for the changes observed or measured in the cores. Age also provides a means of correlation to other regions, and it provides temporal calibration for rates of processes, such as sediment accumulation. Establishing an age model for deep-sea cores is a first-order priority in ocean-climate research. We have developed a suite of inquiry-based exercises specifically designed for undergraduate geoscience classes that incrementally demonstrate to students how age can be established for marine sediment records using authentic scientific ocean drilling data. Two four-part exercises cover the topics of marine microfossils and biostratigraphy, and paleomagnetism and magnetostratigraphy. Students gain exposure to the major marine microfossil groups, which are often major constituents of deep-sea sediments. There are other tangible topics investigated in these exercises including ecology, evolution, and biogeography, as well as seafloor spreading and the development of the Geomagnetic Polarity Timescale. Both units complement companion exercises built by our team on the nature and distribution of marine sediments and stable isotopes as tools in paleoclimate research, as well as case studies of Cenozoic ocean-climate change from Antarctica, the deep-sea, and Arctic. All exercises are designed so students explore the process of science by making observations and interpretations, plotting and analyzing data, posing hypotheses and investigating ways to test their hypotheses. The exercises can be used as a series of short exercises in both small and large lecture settings, or they can be used as a comprehensive package for laboratory sections. Instructors can use parts of an exercise in class and assign other parts as homework assignments. While the biostratigraphy and magnetostratigraphy exercises provide valuable lessons on how scientists establish the age control for our proxy records of global change, they also provide broader connections to the process of science and discovery, both past and present.