palaeomagnetism references

Biggin et al., 2011

tested palaeomagnetism of archean Barberton greenstone belt rocks with a positive fold test and conglomerate test supporting a stable geomagnetic field. does not support rapidly moving plates at 3.5Ga

Biggin et al., 2011

lacks pTRM checks, assumes high temperature components of magnetism are primary

Borlina et al., 2020

Proving tarduno et al., 2015 wrong. out of 4000 jack hills zircons, no grain records a primary magnetism so single grain analysis on magnetite in zircons is unlikely to be accurate

Borlina et al., 2020

because none of the zircons were primary records, we still cannot say whether there was a magnetic field in the hadean

Brenner et al., 2020

evidence for modern plate motion velocities at 3.2Ga. positive fold test. average latitudinal drift of >2.5cm/yr

Brenner et al., 2020

assume motion is from plates rather than polar wander. doesnt prove plates, a stagnant lid shell could be rotating.

Fu et al., 2024

proving tarduno et al., 2023 wrong. any latitudinal displacement from jack hills zircons are permitted within 95% confidence interval. 2/3rds of modern plate motion would not be resolved by zircon palaeointensities. no conclusions can be made from the data

Herro-Bervera et al., 2016

found a whole rock palaeointensity of the duffer formation of the Pilbara craton to be 6.4 microT

Herro-Bervera et al., 2016

TRM may not actually be thermal. bulk rocks can underestimate palaeointensity

Tarduno et al., 2015

single grain palaeointensity on jack hills zircons. 44 pass their test so they say there is a geodynamo at 4.2Ga

Tarduno et al., 2015

Borlina et al., 2020 prove them wrong. there are cracks in their zircons so magnetisms are unlikely to b primary. lax grain selection criteria

Tarduno et al., 2023

palaeointensity values remained constant between 3.9-3.4Ga. palaeointensity should vary as a functions of latitude suggesting earth was in stagnant lid. life persisted through stagnant lid.

Tarduno et al., 2023

Fu et al., 2024 prove them wrong. they use the bad zircons from tarduno et al., 2015. flawed statistical methods and no valid conclusions can be made from their data.

Weiss et al., 2015

use conglomerate, baked contact and fold tests to show there has been widespread remagnetisation of jack hills rocks

Evans and Tikoo, 2022

episodic weak lunar dynamo driven by sinking Ti-rich cumulate. heat flux from core to cold diapirs increases convection

Evans and Tikoo, 2022

simplifies sinking diapirs as spherical. the fields they model only last a matter of days.

Nichols et al., 2021

used photographs from the moon to determine way up direction of rocks. supports evidence for a lunar dynamo for at least 2Ga

Nichols et al., 2021

uncertain whether we have a dipole or a more complex dipole and unsure of any polar wander. assumptions that the rocks have not been moved and the way up is correct. only having 1 sample is not enough to constrain field geometry

Nichols et al., 2024

expands on evans and tikoo, 2022. magnetism is only recorded in Ti-rich basalts. melting of sinking ti diapirs drives volcanism on the surface. only rocks erupted during this time, the ti basalts, record a magnetic field

Nichols et al., 2024

unknown diapir shape and size and time period the magnetic field is accurate. correlation doesnt necessarily mean causation, maybe the ti basalts are the only ones able to record a magnetic field but its present all the time.

Tarduno et al., 2021

analysed a 2Ma glass impact sample that has a high magnetic field. analysed other ancient moon samples to show they do not have a field. field induced on impact

Tarduno et al., 2021

sample could have incorporated impactor material. saggy arai plot, and lack pTRM checks at high temperatures. impact induced magnetic fields are very transient. magnetic fields generated by impacts are directionally unstable so we would expect a nice uniform magnetisation

Tikoo et al., 2014

impacts on the moon after 3.7Ga are rare and small. the magnetic fields they would generate would last for <1 second

Tikoo et al., 2017

analysed a glassy matrix of a breccia showing the moon had a weak magnetic field between 1 - 2.5Ga. impact fields are too transient to have been recorded in this sample

Tikoo et al., 2017

hard to constrain age and potential for contamination from the impactor

Zhou et al., 2024

strong magnetism reported form apollo studies are artefacts due to non-deal recorders. magnetisations are unreliable and so the moon lacked a long lived field

Zhou et al., 2024

they say multidomain grains overestimate the field strength, but multidomains actually underestimate because they are unstable. don't show the domain state of the crystals. not robust.

Nagy et al., 2017

single vortex domain states in magnetite are more stable than single domain and can retain their recordings for billions of years

Nagy et al., 2017

focus on idea shaped grains and only look at magnetite. extrapolated to ling timescales because we cannot watch something for billions of years

Nagy et al., 2019

the transition from single vortex to multidomain in magnetite occurs at 3 microns. multidomain walls are unstable and move depending on applied fields

Nagy et al., 2019

grain size limited due to computational expense. only magnetite

Roberts et al., 2019

the day diagram is problematic because it used the PSD field as a catch all for things that aren't multidomain or single domain and it is an average of all the grains in a sample. FORC diagrams are better

Roberts et al., 2019

only test 10 alternative approaches and the effectiveness of each approach may depend on the mineral

Tauxe et al., 2021

blocking temperature at which pTRM is acquired should equal the unblocking temperature. failure of this leads to saggy arai plots. failure is more common in old or large grains because they relax overtime

Tauxe et al., 2021

doesnt quantify the timescale of aging. focuses on igneous lava samples so may be different in other rock types

williams et al., 2024

on the day diagram there is a well defined trend between SD and MD with grain size. position of the vortex grain on the day plot depends on size and shape, large and flat = close to MD; small and elongate = close to SD

Williams et al., 2024

idealised particle shapes. only looked at magnetite with no impurities

Buffet, 2016

dynamo mechanism: as the core cools, magnesium becomes supersaturated and precipitates out driving compositional convection

Buffet, 2016

different monte carlo model outcomes put magnesium precipitation at different times in earth history. assumes that magnesium can be dissolved in iron in the first place when it is normally insoluble

Livermore et al., 2016

since 2000 there have been rapid changes in the location of the geomagnetic north pole due to an accelerating an accelerating high latitude jet in the core

Livermore et al., 2016

assumption of a quasi-geostrophic flow model. less observational coverage in the southern hemisphere which may affect the interpretation of hemispheric differences

Takahashi et al., 2019

mercury's strange magnetic field is driven by bottom up crystalisation driving buoyancy convection, flow is stronger in the north making the flow asymmetric

Takashi et al., 2019

assumption of bottom up crystallisation. spacecraft measurements were biased to the north which could account for the apparent asymmetrical nature. assumes a size for the inner core even through this is unknown.

Zahnle et al., 2019

xenon is easily ionised and can escape from the atmosphere with hydrogen along polar field lines. xenon stopped being lost when hydrogen levels decreased, extending time of a hydrogen atmosphere into the archean

Zahnle et al., 2019

one dimensional models, relies on limited isotopic data. dont consider other processes that could affect xenon loss

wilson et al., 2025

classical nucleation theory predicts extreme supercooling needed for inner core nucleation. solution: 2 phase growth, initially rapid runaway growth; later slow growth governed by core cooling

wilson et al., 2025

relies on core nucleation theory which is a simplification. extrapolates low pressure experiments to high pressure

Bono et al., 2019

ediacaran magnetic field was 10 times weaker than today and palaeomagnetic directions show high angular disparity. destabilising magnetic field before inner core nucleation at 565Ma

Bono et al., 2019

few ediacaran palaeointensity datasets exist which means we dont know id this weak field was widespread and long lived. seems as though they are trying to force their data to fit a model

Zhou et al., 2022

field intensity was 5 times greater than in the ediacaran. rapid renewal of magnetic field due to inner core nucleation at ~550Ma

Zhou et al., 2022

potential overestimate due to cooling effects and assumption that the magnetism measured was primary

Zhang et al., 2022

looked at anorthosite xenoliths from the mesoproterozoic that were exceptional recorders and found palaeointensity was higher than currently measured on earth challenging the idea that the field was weakening through the proterozoic

Zhang et al., 2022

small sample set in space and time

Huguet et al., 2018

homogenous inner core nucleation requires 1000K of supercooling. heterogenous nucleation onto a metallic substrate lowers this energy barrier

Huguet et al., 2018

doesnt really explain how we get the metal substrate and whether is is possible to form solid metal in the mantle which is delivered to the core

Driscoll and davies, 2022

high thermal conductivity makes it difficult to sustain core convection and models suggest dynamo would stop before inner core nucleation. low conductivity and high radioactivity are unrealistic so propose 6000k initial core temperature

Driscoll and davies 2022

doesnt seem realistic that the core could be this hot. a core this hot would have implications for the mantle and would lead to extreme volcanism

Marks et al., 2025

Palaeobiogeographic studies can sometimes complement palaeomagnetic reconstructions by providing independent lines of evidence for the relative positions of ancient landmasses. used brachiopods for the south china block in the early permian

Marks et al., 2025

Relies on the fundamental assumption that the degree of biogeographic similarity is correlated with geographic proximity. The accuracy of the reconstruction is also dependent on the completeness and accuracy of the fossil record and the reliability of the chosen biogeographic indices

Luo et al., 2024

a strong lunar dynamo field (up to 70 μT) existed between 4.2 and 3.5 Ga, which then decreased significantly between ~1.92 and ~0.80 Ga. Lunar crustal magnetism is heterogeneous, with strong and weak anomalies unevenly distributed, some linked to geological features. No single dynamo mechanism fully explains all observations. A combination of mechanisms throughout lunar history is likely

Luo et al., 2024

Paleomagnetic interpretations rely on the assumption that lunar samples have faithfully recorded the ancient magnetic field. Hard to reconstruct the geometry of the file due to unoriented samples

Zuo et al., 2025

lunar swirls are remnants of electrical currents that flowed through the lunar crust during periods of ancient dynamo activity. These currents could have attracted plagioclase-rich dust via electric fields and generated intense magnetic fields, leading to the observed magnetisation

Zuo et al., 2025

model relies on the assumption that impactor related magnetic fields are drivers of this

Cai et al., 2025

weak but reliable lunar field at 2Ga. Comparison of midlatitude and equatorial paleointensity data suggests that the lunar paleomagnetic field was likely not of a selenocentric axial dipole geometry during the mid- to late stage (between 3 and 1 Ga).

Cai et al., 2025

The conclusion regarding the non-dipolar field is heavily dependent on the limited number of equatorial paleointensity data points, some of which are only reported in conference abstracts

Crouzet et al., 2025

highlights that published palaeomagnetic data in the Western Alps have led to contradictory conclusions. The categorisation of the dataset based on magnetisation type and paleohorizontal knowledge is presented as crucial for assessing data reliability

Crouzet et al., 2025

The exclusion of certain data types (e.g., most volcanic data, pre-Tertiary primary magnetisations) limits the scope of the synthesis to certain types of tectonic deformations

Soderlund et al., 2025

Small differences in bulk internal properties can lead to vastly different magnetic fields. The diverse magnetic field characteristics observed across the solar system (e.g., Mercury's weak field, Uranus's tilted dipole, Jupiter's asymmetry) pose significant challenges for dynamo theory.

Soderlund et al., 2025

The review relies on the current state of knowledge in planetary science, geophysics, astrophysics, and material physics. Our understanding of the interiors of many planets, especially exoplanets, is still limited

Bologna et al., 2025

thermal current density generated by the Seebeck effect can significantly contribute to the intensity of planetary magnetic fields. The Seebeck effect is a phenomenon where a non-uniform temperature within a conducting material generates an electrical current that is proportional to the temperature gradient

Bologna et al., 2025

It provides a scaling model for the magnitude of the field but does not fully address the complex dynamo mechanisms. The analysis does not extend to Mars or Venus due to specific reasons related to their magnetic fields and interior knowledge

Brain et al., 2025

Currently, there are no unambiguous measurements of magnetic fields on exoplanets, but their existence is expected. Methods for detecting exoplanet magnetic fields largely favour gas giants. Exoplanet magnetic fields can have significant consequences for planetary evolution and habitability

Brain et al., 2025

Our understanding of exoplanet magnetic fields is primarily based on extrapolations from solar system objects and theoretical models. The detection methods have varying sensitivities and are more applicable to certain types of exoplanets.

Andrault et al., 2025

Found the thermal conductivity of pure iron at the earth’s CMB which implies a CMB cooling of 380–450 K over Earth's history and an inner core age of 1.9(4) billion years. Core size is important, large cores are bad, an so exoplanets 1.5 times denser than Earth are unlikely to have an active TDD

Andrault et al., 2025

The core is not pure iron which could have an effect on the thermal conductivity in comparison to the model. The study also assumes that a mantle cooling efficiency similar to Earth's (aEff ~ 0.09) can be applied to other Earth-like planets