SPEED DATING!: ADVICE ON SAMPLING AND APPLICATIONS FOR PALEOMAGNETISM

This information booth provides researchers a unique opportunity to learn about paleomagnetism (pmag) and magnetostratigraphy (magstrat) from specialists in the field. Like other geochronologic methods, pmag and magstrat require researchers and paleomagnetists to work together from a project’s beginning to ensure that the sampling and analytical methods used are appropriate to address specific research goals and questions. Consultation with a pmag lab prior to field work will also help avoid collection of non-ideal/unsuitable material, and ensure the collection of a sufficient number of properly oriented samples. Paleomagnetic specialists will be on hand to help assess the paleomagnetic approach needed to produce the most accurate age result for a wide range of geologic settings.

Most U.S.-based laboratories use standardized demagnetization protocols, such as alternating field or thermal demagnetization techniques, to isolate the primary recording of Earth’s magnetic field acquired at the time a rock was cooled or deposited. Time series of primary magnetic directions are often compared to the geomagnetic polarity timescale, apparent polar wander paths, or other reference curves associated with paleointensity or paleomagnetic secular variation to determine the age of a section. Alternatively, in some sedimentary settings the concentration of magnetic minerals may co-vary with orbital or other cycles, and simple measurements of magnetic properties can serve as the foundation for rigorous cyclostratigraphic age models. Some pmag labs have greater expertise in applications such as examining archaeological pottery, lake and marine cores, igneous materials, speleothems and carbonates, and siliciclastics. Magnetic specialists will be able to route researchers to the most appropriate techniques and labs for analysis.

The Paleomagnetism SpeedDating! booth will provide researchers with information and points of contact with lead scientists in pmag and magstrat. This ‘ask an expert’ booth aims to provide one-on-one interaction with curious minds to provide demonstrations, examples of preferred sampling approaches and procedures, an overview of basic principles, a list of available labs, displays on new and innovative approaches, and examples of results from the method.