Dating recent Hawaiian lava flows using paleomagnetic secular variation
Hawaiian paleomagnetic secular variation (SV) is defined from samples at 67 sites on lava flows of known age. Paleomagnetic directions range through 40° of inclination and 30° of declination; angular dispersion within sites is commonly Dating precision is limited by dispersion of 4.5° among sites of apparently similar age. The main dispersion sources are in 14 C dates (3.0°), intra-flow deformations (2.0°), and local magnetic anomalies (1.5°). Results from 68 sites on undated flows show that 95% of Kilauea9s surface is younger than 1,000 yr. A hiatus in volcano growth 1,000–1,500 yr ago coincides with the filling of a large caldera. Averaging of available data yields an SV reference curve which is fairly reliable to ∼1,500 yr ago, contains gaps and ambiguities 1,500–3,000 yr ago, and remains highly uncertain 3,000–6,000 yr ago. The SV dating method can be precise but is limited by the need for a calibrated SV history. It can be a powerful correlation tool even if a history is unavailable.