PALEOMAGNETIC STUDIES OF BULK MINERAL SEPARATES FROM THE BARK LAKE DIORITE, ONTARIO

The separation of superimposed stable remanent magnetizations, increasingly a problem in the study of paleomagnetism of metamorphosed terrains, has usually been attempted using indirect techniques such as vector subtraction. In the coarse-grained Bark Lake diorite of the Grenville Province, two stable and one unstable component, often superimposed in individual samples, are shown to reside in different rock-forming mineral fractions. They are directly separated by orienting small aggregates of dark or light grains and are measured and demagnetized using standard paleomagnetic equipment.-Author