Paleomagnetism and Environmental Magnetism
The Research Center for Paleomagnetism and Environmental Magnetism at the University of Florida currently has five professors and one research scientist. Research activities in recent years have involved almost all the continents and major oceans, and can be subdivided into three primary categories:
- Tectonic reconstructions
In the late 1950s, paleomagnetism provided the first quantification of continental drift. The method is still used to define, even more precisely, the relative motion of continents and continental fragments. In addition, the method is now being used more and more to determine the relative motions of individual thrust sheets, and is vital to palinspastic reconstructions of mountain belts. The researchers at this center are now actively applying paleomagnetics to reconstruct the paleogeographies of mountain belts, notably in the Himalayas, China, Alpine-Mediterranean, Africa and Central America.
- Magnetic stratigraphy
Magnetic polarity stratigraphy is the preferred means of global stratigraphic correlation. The geomagnetic polarity time scale provides the bridge between fossil zones and radiometric ages. The researchers at this center have been active in this field for years. The book entitled Magnetic Stratigraphy published by Drs. Opdyke and Channell (1996) from this center is an important reference in magnetostratigraphic studies.
- Environmental magnetism
Continuous, high-resolution measurements of rock magnetic parameters are being used to characterize the magnetic mineralogy and grain size of recent, a few million years old marine sediments, and to reconstruct depositional paleoenvironments. Researchers at the center also study the relative variations of the geomagnetic field paleointensity, which provide means for high-resolution correlation between sites. Successful studies of this type have been conducted on sediments from the Labrador Sea, the North Atlantic Ocean, the Antarctic Peninsula margin, and the South Atlantic Ocean.
James Channell (Email) investigates the application of paleomagnetism to paleogeographies in mountain belts, notably in the Alpine-Mediterranean area. The objective has been to reconstruct the pre-deformational relative position of rock bodies (on scales from individual thrust sheets to continents). He also applies magnetic polarity stratigraphy to the generation of geologic time scales. Modern studies of past climate require millennial-scale correlation of climate-proxy records that usually cannot be provided by the stable isotopes, biostratigraphy or radiocarbon ages. Variations in the intensity of the geomagnetic dipole field, when recorded in sediments, appear to provide the desired means of global correlation. High-resolution records of geomagnetic field behavior from deep-sea sediment drifts have provided a clearer picture of the spatial and temporal characteristics of geomagnetic (secular) variation that are now being used to constrain computer-generated models of the geodynamo.
Neil D. Opdyke (Email) Paleomagnetism, magnetostratigraphy, paleoclimatology, and paleogeography of the Phanerozoic. Fellow of the AGU and member of the National Academy of Sciences.
Joe Meert's (Email) research is aimed at deciphering the assembly and breakup of Proterozoic-Early Paleozoic supercontinents using a combination of paleomagnetism and geochronology. The research bears directly on issues regarding ancient paleoclimates (such as the Snowball Earth hypothesis), geodynamics (plate speed limits and true polar wander) and the evolutionary pulse and the beginning of the Phanerozoic. He is also interested in the evolutionary behavior of the earth's magnetic field and hypotheses regarding long-term non-dipole components.
John Jaeger (Email) in collaboration with Dr. J.E.T. Channell is interested in the shallow seabed diagenetic and sedimentological processes that influence the preservation of paleomagnetic records in marine sediments.
Bruce J. MacFadden Vertebrate paleontology, magnetic stratigraphy of Cenozoic mammal-bearing deposits in the New World, systematics of fossil horses, and stable isotope paleoecological reconstruction.
Kainian Huang Paleomagnetism and tectonics, especially the application of paleomagnetism to terrane motion, rotation and amalgamation in China. Management of the paleomagnetic laboratory.
University of Florida
Department of Geological Sciences
241 Williamson Hall
P.O. Box 112120
Gainesville, Florida 32611
Office: (352) 392-2231
Fax: (352) 392-9294
email: info@geology.ufl.edu
