Paleomagnetic correlation of Late Quaternary lava flows in the lower east rift zone of Kilauea Volcano, Hawaii

Abstract

Paleomagnetic data reflecting paleosecular variation (PSV) of the geomagnetic field are used to correlate individual lava flows in the lower east rift zone of Kilauea Volcano. This area has been recently mapped based on petrography, stratigraphy, soil development, and degree of weathering of the flows; eight 14C dates also provide a framework for the relative age assignments. Site‐mean directions of remanent magnetization for historic flows in this region indicate that local magnetic anomalies do not mask the PSV signal, that within‐flow angular differences are generally <5°, and that temporal resolution of the paleomagnetic directions is of the order of 100 years. The paleomagnetic correlations do not conflict with the observed stratigraphic relationships, and PSV reference curves from dated lava flows and lake sediments have also been used to help determine the sequence of directional groups. Paleomagnetic grouping of flows into eruptive events indicates a different and perhaps more refined eruptive history for the lower east rift zone than implied by the geologic mapping alone. The number of individual flows based on petrographic distinctions is likely the same, but the frequency of events (including petrographically distinct flows) is apparently lower than previously thought. Flows from ridge crest vents bifurcated by the rift indicate formation of the central graben in this region after ∼300 years ago, possibly related to the 1790 eruptions along dual fractures.

Geomagnetic field inclinations for the past 400 kyr from the 1‐km core of the Hawaii Scientific Drilling Project

“…These uncertainties were added in a root-meansquare fashion to the within-flow dispersion inherent in the paleomagnetic data. The resulting 1σ error for all 195 lava flows has a mean value of 4.96°, which is consistent with the estimate of ~5° for intraffow variations by Hagstrum and Champion [1994]. Some flows with high dispersion may actually be compound flows composed of distinct subunits.…”

“…This is the case for flow unit 15, which we subsequently divided into two flows for this study. While uncertainties of this magnitude may be significant for highly detailed secular variation studies for short time periods [e.g., Holcomb et al, 1986;Hagstrum and Champion, 1994] …”

“…Paleomagnetic studies on the island of Hawaii (known as the "Big Island," Figure 1) have established that Hawaiian basalts record the ambient field direction extremely well [Doell andCox, 1963, 1965;Hagstrum and Champion, 1994] and that all flows exposed on the surface were deposited during the Brunhes normal polarity chron [Doell and Cox, 1965]. In addition, detailed studies of hundreds of lava flows [Doell and Cox, 1971;Doell, 1972;McWilliams et al, 1982;Holcomb et al, 1986;Mankinen and Champion, 1993;Hagstrum and Champion, 1994] and lake sediments [Peng and King, 1992] have produced paleosecular variation records as far back as 13,000 years.…”

“…In addition, detailed studies of hundreds of lava flows [Doell and Cox, 1971;Doell, 1972;McWilliams et al, 1982;Holcomb et al, 1986;Mankinen and Champion, 1993;Hagstrum and Champion, 1994] and lake sediments [Peng and King, 1992] have produced paleosecular variation records as far back as 13,000 years. These records show that the subdued nature of the present Copyright 1996 by the American Geophysical Union.…”

Precision of the paleomagnetic method: An example from the Quaternary Eifel volcanics (Germany)

“…The question of paleomagnetic data dispersion has recently been addressed by Hagstrum and Champion (1994), who studied 10 historic lava flows of Kilauea Volcano (Hawaii), each at 5 to 12 sites. Angular distances between site-mean directions varied from 0.2…”