Bias Corrected Estimation of Paleointensity (BiCEP): An improved methodology for obtaining paleointensity estimates

Cych, Brendan; Morzfeld, Matthias; Tauxe, Lisa

doi:10.1002/essoar.10506403.1

Cited by 3 publications

(11 citation statements)

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“…SCAT is a Boolean value that indicates whether the data fall within 2 σ threshold of the best fit slope. Finally, CCRIT screens for non‐linearity by applying a parameter that quantifies the curvature of the NRM/pTRM data,

\vec{k}

, as suggested by Paterson (2011); curvature is associated with biased intensity estimates (Cych et al., 2021; Krása et al., 2003; Tauxe et al., 2021). In the CCRIT criteria, we use

\vert {\vec{k}}^{\prime }\vert

which calculates curvature over the portion of remanence used in the calculation (hence the requirement of a large FRAC).…”

Section: Resultsmentioning

confidence: 99%

Paleointensity Estimates From the Pleistocene of Northern Israel: Implications for Hemispheric Asymmetry in the Time‐Averaged Field

Tauxe

Asefaw

Behar

et al. 2022

Geochem Geophys Geosyst

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Twenty‐two sites, subjected to an IZZI‐modified Thellier‐Thellier experiment and strict selection criteria, recover a paleomagnetic axial dipole moment (PADM) of 62.2 ± 30.6 ZAm2 in Northern Israel over the Pleistocene (0.012–2.58 Ma). Pleistocene data from comparable studies from Antarctica, Iceland, and Hawaii, re‐analyzed using the same criteria and age range, show that the Northern Israeli data are on average slightly higher than those from Iceland (PADM = 53.8 ± 23 ZAm2, n = 51 sites) and even higher than the Antarctica average (PADM = 40.3 ± 17.3 ZAm2, n = 42 sites). Also, the data from the Hawaiian drill core, HSDP2, spanning the last half million years (PADM = 76.7 ± 21.3 ZAm2, n = 59 sites) are higher than those from Northern Israel. These results, when compared to Pleistocene results filtered from the PINT database (http://www.pintdb.org) suggest that data from the Northern hemisphere mid‐latitudes are on average higher than those from the southern hemisphere and than those from latitudes higher than 60°N. The weaker intensities found at high (northern and southern) latitudes therefore, cannot be attributed to inadequate spatiotemporal sampling of a time‐varying dipole moment or low quality data. The high fields in mid‐latitude northern hemisphere could result from long‐lived non‐axial dipole terms in the geomagnetic field with episodes of high field intensities occurring at different times in different longitudes. This hypothesis is supported by an asymmetry predicted from the Holocene, 100 kyr, and 5 million year time‐averaged geomagnetic field models.

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\vec{k}

, as suggested by Paterson (2011); curvature is associated with biased intensity estimates (Cych et al., 2021; Krása et al., 2003; Tauxe et al., 2021). In the CCRIT criteria, we use

\vert {\vec{k}}^{\prime }\vert

which calculates curvature over the portion of remanence used in the calculation (hence the requirement of a large FRAC).…”

Section: Resultsmentioning

confidence: 99%

Paleointensity Estimates From the Pleistocene of Northern Israel: Implications for Hemispheric Asymmetry in the Time‐Averaged Field

Tauxe

Asefaw

Behar

et al. 2022

Geochem Geophys Geosyst

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“…Therefore, the results from this technique are not reliable and should not be incorporated into any regional or global data compilations. Recently, a statistical method has been developed to correct for multidomain behavior in Thellier‐Thellier experiments (Cych et al., 2021). However, given the alteration that we observe in our samples during the experiments, such a method is not appropriate to apply to this data set.…”

Section: Resultsmentioning

confidence: 99%

Characterizing the Geomagnetic Field at High Southern Latitudes: Evidence From the Antarctic Peninsula

Biasi

Kirschvink

2021

JGR Solid Earth

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Introduction The High-Latitude Geomagnetic FieldAlthough Earth's instantaneous magnetic field deviates from a geocentric axial dipole (GAD), the average geomagnetic field over >10 5 year timescales is thought to be well-approximated by the GAD model (Johnson & Constable, 1995;Johnson & McFadden, 2015;Merrill & McFadden, 2003). The idea of a GAD-like time-averaged magnetic field is supported by an abundance of directional and intensity data from mid-to low-latitudes sites (e.g.,

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“…(2021) as a different means of estimating the paleointensity and uncertainty from the 1931 CE samples. BiCEP is a Bayesian method which accounts for bias in paleointensity estimates of specimens, effectively weighting the paleointensity of different specimens using the curvature of the Arai plot as a metric of nonlinearity (where linearity is measured by the

\overrightarrow{k}

statistic) and a predictor of bias (Cych et al., 2021). Specimen paleointensity and bias are estimated using a range of selected temperature steps in the Arai plot.…”

Section: Resultsmentioning

confidence: 99%

“…The BiCEP estimation using all specimens from samples NA02‐1B and NA97‐10 generated “B‐Grade” results (Cych et al., 2021), which are shown in Figure 6. The range of individual specimen paleointensity estimates relative to the range of estimated

\overrightarrow{k}

is shown on the left plot of Figure 6.…”

Section: Resultsmentioning

confidence: 99%

“… Estimated paleointensity results of the 1931 CE eruption from the Bias Corrected Estimation of Paleointensity (BiCEP) method (Cych et al., 2021). Left plot, estimated range of individual specimen paleointensity estimates relative to the estimated

\overrightarrow{k}

; right plot, resulting estimate of 1931 CE field intensity and probability distribution.…”

Section: Resultsmentioning

confidence: 99%

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New Paleointensity Data From Aniakchak Volcano, Alaska, USA

Cromwell

Zhang

2021

Geochem Geophys Geosyst

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This study presents the first set of Holocene, high‐quality absolute paleointensity data from Alaska, USA. Existing paleointensity data for the Holocene are generally located at mid‐northern latitudes in North America, Europe, the Middle East, and eastern Asia. Relatively few data are from the Alaska region. IZZI‐modified paleointensity experiments were conducted on glassy volcanic materials from Aniakchak volcano, a mid‐ to high‐latitude composite volcano on the Alaska‐Aleutian arc. The CCRIT selection criteria were applied to the paleointensity results. A total of 30 specimens from six samples with estimated ages ranging from 1931 CE to 2,300 years before present passed all selection criteria. The sample‐mean paleointensities ranged from 49.5 to 68.0 microTesla (μT). The sample‐mean paleointensity results are comparable to modeled intensities, however all except for one sample‐mean paleointensity are lower than those predicted by geomagnetic field models. The paleointensity estimate for the historical 1931 CE eruption was about 15 μT greater than the expected field strength. This overestimate may result from unrecognized alteration or non‐ideal remanence carriers in this sample. Further evaluation of samples from the 1931 CE eruption using a Bayesian estimation method resulted in a paleointensity estimate that encompasses the historical field strength within uncertainty. These new paleointensity results are a valuable contribution to the mid‐ to high‐northern latitude paleomagnetic data set. Incorporation of these data into future geomagnetic field models will improve the predictions of geomagnetic field behavior in the Alaska region.

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Bias Corrected Estimation of Paleointensity (BiCEP): An improved methodology for obtaining paleointensity estimates

Cited by 3 publications

References 0 publications

Paleointensity Estimates From the Pleistocene of Northern Israel: Implications for Hemispheric Asymmetry in the Time‐Averaged Field

Paleointensity Estimates From the Pleistocene of Northern Israel: Implications for Hemispheric Asymmetry in the Time‐Averaged Field

Characterizing the Geomagnetic Field at High Southern Latitudes: Evidence From the Antarctic Peninsula

New Paleointensity Data From Aniakchak Volcano, Alaska, USA

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