Table 1.
Summary of published palaeosecular variation compilations and associated predictions.
| Time period | Ref. | Nlocations | Median Nsites | Model G a parameter (°) | Estimated AD/NADmedian |
|---|---|---|---|---|---|
| 0–10 Ma | 19,20 | 16a | 119 | 11.3 + 1.3/−1.1 | 11.3 + 15.0/−6.5 |
| 84–126 Ma | 20 | 19 | 24 | 10.7 + 2.2/−2.4 | 12.8 + 29.4/−8.3 |
| 127–198 Ma | 20 | 20 | 15 | 12.7 + 1.9/−2.7 | 8.7 + 18.9/−5.3 |
| 0.5–1.5 Ga | 27 | 28 | 17 | 10.1 ± 0.5 | 14.7 + 16.1/−7.6 |
| 1.5–2.9 Ga | 27 | 27 | 17 | 9.2 ± 1.1 | 18.0 + 27.0/−10.5 |
The Model G a parameter for various time periods allows estimation of AD/NADmedian from the power law shown in Fig. 2. Nlocations refers to the number of locations, where S was measured using Nsites site-mean palaeomagnetic directions. Uncertainties are reported 95% confidence limits.
aIn this study, globally distributed VGPs were grouped into 16 latitudinal bins for the purpose of fitting Model G.