9418405 Halgedahl Despite the great success of paleomagnetism, our understanding of the fine magnetic particles that carry the paleomagnetic record is still remarkably incomplete. Yet the behavior of these fine particles could provide diagnostic tools for deciphering the origin of NRM (natural remanent magnetization) in rocks, as well as the grain sizes and domain states of the NRM carriers. Such tools would be especially useful in interpreting the paleomagnetism of Paleozoic and older rocks, whose long and complex histories increase the probability that their original magnetizations were reset. A series of experiments will investigate the physical bases that govern AF demagnetization response of single particles carrying different types of remanences. Although previous workers have utilized assemblages of particles in such studies, single particles have several advantages over assemblages. The principal advantage is that, in a single particle, AF response can be directly linked to observed changes of domain structure and to observed microstructure. ***
