A novel vibrating-sample magnetometer used to measure magnetic hysteresis of rock at low temperature

A vibrating-sample magnetometer was constructed, calibrated and used to measure the magnetic hysteresis of rock samples. The magnetometer was designed around a large electromagnet capable of producing fields of approximately 3600 Oe (360 mT). Between the poles of this magnet, pick-up coils and a liquid nitrogen bath surrounded a sample port assembly in which the sample could be vibrated. The sample port assembly contained a heating element that allowed the sample temperature to be varied from room temperature to 98 K (;Seven magnetite-bearing Precambrian dolerite dyke samples which had likely retained their original remanence direction for over a billion years were studied. (Abstract shortened by UMI.).