Graph, based on a dataset of paleomagnetic data from a Swedish lake binned in 150-year intervals, showing the classical uncertainty measure plotted against the new proposed uncertainty measure that takes propagated measurement uncertainty into account.
The classical uncertainty measure (α95 in °) of paleomagnetic data binned in 150 year intervals (each interval is represented by a dot) from a Swedish lake paleosecular variation study (original data from Snowball et al., 2013) plotted versus the uncertainty measure proposed that takes propagated measurement uncertainty into account (α95* in °). It is clear that α95* is always larger than α95 (all data points are above the dashed line indicating the 1:1 ratio) but the differences between α95 and α95* are sometimes notably large. Uncertainty propagation enables to pick up ‘good’ and ‘less good’ measurements something which is not possible in the classic approach. Ultimately this leads to a more truthful appreciation of paleomagnetic information. Credit: Heslop and Roberts [2020], Figure 2
Source: Journal of Geophysical Research: Solid Earth

Paleomagnetic data processing involves a hierarchical chain. Classically, uncertainties are being calculated at a single level only, which is then taken to represent the entire chain. Justification for doing so is that the secular variation of the field is larger than the measurement uncertainty. Clearly more formal error propagation would lead to more robustly constrained interpretations, which would be so important for paleogeographic reconstructions, for example. However, this is more insidious than one would like as a required transformation inherently distorts the data distribution. Heslop and Roberts [2020] have now formulated a rather straightforward solution to this problem that importantly can also be applied in retrospect to legacy data.

Citation: Heslop, D., & Roberts, A. P. [2020]. Uncertainty propagation in hierarchical paleomagnetic reconstructions. Journal of Geophysical Research: Solid Earth, 125, e2020JB019488.

—Mark J. Dekkers, Associate Editor, JGR: Solid Earth

Text © 2020. The authors. CC BY-NC-ND 3.0
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