Paleomagnetism conglomerate test on Archean conglomerate rock from Jack Hills, Australia

Abstract

A paleomagnetism study known as a conglomerate test was run on an Archean sandstone conglomerate rock to determine if the sample contained a remnant magnetization from the time of its formation. Twenty-nine clasts from a thin section of the sample were thermally demagnetized up to a temperature of 395°C. The heating revealed two components of magnetization which were unblocked at low and mid temperatures, revealing a magnetic mineralogy of Pyrrhotite.Eight matrix samples were heated to a temperature of 650°C which revealed two components of magnetization at mid and high temperatures, providing evidence for a magnetic mineralogy of Hematite.The direction of measured magnetic moment of the clasts were statistically similar, indicating that the rock failed the conglomerate test and was remagnetized after the rock formed.