Figure F43. Results of composite IRM acquisition and thermal demagnetization experiments. A. Equal area projection of magnetization directions after imparting magnetic field with a pulse magnetizer in (1) +z (2.9 T), (2) +y (0.4 T), and (3) +x (0.12 T) successively on Samples 322-C0011B-3R-4, 8–10 cm (blue; tuffaceous sandstone), and 6R-1, 34–36 cm (red; silty claystone). Open circles = projection onto lower hemisphere, closed circles = projection onto upper hemisphere. Note the acquisition of magnetization for Sample 322-C0011B-3R-4, 8–10 cm (blue), in opposite directions of pulse magnetic field. B. Magnetization change through stepwise thermal demagnetization from room temperature to 600°C on Sample 322-C0011B-3R-4, 8–10 cm, after IRM acquisition. Polarity of x magnetization component (0.12 T: low-coercivity component) changes from negative to positive at temperatures between 400°C and 450°C. C. All three magnetization components for Sample 322-C0011B-6R-1, 34–36 cm, show shift from positive to negative between 450°C and 500°C. D. Close-up of Sample 322-C0011B-6R-1, 34–36 cm, shows unblocking temperature of ~350°C for low- (blue; 0.12 T), medium- (red; 0.4 T), and high- (green; 2.9 T) coercivity components.
Previous | Close | Next | Top of page