Geomagnetic paleointensity derived from single plagioclase crystals

We suggest a new approach for the determination of absolute geomagnetic paleointensity that uses single plagioclase crystals to avoid problems caused by alteration during Thellier–Thellier analyses. Transmission electron microscope imaging and rock magnetic data indicate that plagioclase crystals from a recent basalt flow in Hawaii (1955 Kilauea eruption) contain pseudo-single to single domain titanomagnetite inclusions. These feldspars yield paleointensity values that agree within error with magnetic observatory data and paleointensity values reported from whole rock samples. These results suggest that single plagioclase crystals from older igneous rocks may provide a viable source of paleointensity data.