Geomagnetic paleointensity derived from single plagioclase crystals

We suggest a new approach for the determination of absolute geomagnetic pal eointensity that uses single plagioclase crystals to avoid problems caused by alteration during Thellier-Thellier analyses. Transmission electron micr oscope imaging and rock magnetic data indicate that plagioclase crystals fr om a recent basalt flow in Hawaii (1955 Kilauea eruption) contain pseudo-si ngle to single domain titanomagnetite inclusions. These feldspars yield pal eointensity values that agree within error with magnetic observatory data a nd paleointensity values reported from whole rock samples. These results su ggest that single plagioclase crystals from older igneous rocks may provide a viable source of paleointensity data. (C) 1999 Elsevier Science B.V. All rights reserved.