Acquisition of a Sensitive Magnetic Susceptibility System and a Reflected Light Microscope for Studies of Self-Reversal in Titanomaghemite

University Of Rochester, Rochester NY

Investigators

Abstract

0236383 Tarduno The remarkable ability of some rocks to acquire a magnetization in a direction antiparallel to the Earth's geomagnetic field, or self-reversal of natural remanent magnetization, is thought to be rare; it has been established only in a few igneous rocks bearing hemoilmenite. The paleomagnetism lab at Rochester has reported on two, nearly antipodal components of magnetization, revealed through detailed thermal demagnetization studies, from pillow basalts in which hemoilmenite is absent. Application of laboratory partial thermoremanent magnetizations have shown that the component isolated at lower temperatures represents a partial self-reversal of the primary magnetization. Because maghemitization of oceanic crust is ubiquitous, partial self-reversals may make an important contribution to the decrease in marine magnetic anomaly amplitudes with age observed for crust formed during the last 30 million years. Funds from this grant will be used to acquire two equipment systems to assist in further investigations of the extent and mechanism of self-reversal carried by titanomaghemite in oceanic basalt: (1) a magnetic susceptibility system with a furnace apparatus for Curie point determinations and (2) a reflected light microscope system for basic characterization of magnetic phases. The equipment will support a Ph.D. thesis and the thesis studies of several undergraduate students. The equipment will also support the continuing work of other graduate students, undergraduates and postdoctoral researchers conducting studies in geomagnetism, tectonics, rock magnetism and environmental magnetism, and in formal course instruction at the University of Rochester. ***