Constraining the Decline of the Lunar Dynamo Field at ≈3.1 Ga Through Paleomagnetic Analyses of Apollo 12 Mare Basalts

Strauss, B. E.; Tikoo, S. M.; Groß, Juliane; Setera, Jacob; Turrin, B. D.

doi:10.1029/2020je006715

Cited by 11 publications

(21 citation statements)

References 74 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Whether a long‐lived lunar dynamo existed in the early Moon remains under debate. A recent study drew through paleomagnetic analyses of Apollo 12 mare basalts to estimate that the decline in the lunar dynamo field was approximately 3.10 Ga ago (Strauss et al., 2021). Additionally, impacts can impart intense signals to samples recovered from the Moon.…”

Section: Implication For the Lunar Corementioning

confidence: 99%

Electrical Resistivity of Fe and Fe‐3 wt%P at 5 GPa With Implications for the Moon's Core Conductivity and Dynamo

et al. 2022

View full text Add to dashboard Cite

To generate a self-sustained magnetic field on terrestrial planets, the convection of a metallic liquid outer core is necessary (Breuer, 2019). Liquid core convection may be driven by thermal buoyancy from superadiabatic heat flows (thermal dynamo) across the core-mantle boundary (CMB) or by compositional buoyancy from the exsolution of light elements (e.g., O, C, and Si) at the inner-core boundary (ICB) (chemical dynamo;

show abstract

Section: Implication For the Lunar Corementioning

confidence: 99%

Electrical Resistivity of Fe and Fe‐3 wt%P at 5 GPa With Implications for the Moon's Core Conductivity and Dynamo

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Paleomagnetic analyses of lunar meteorites and Apollo samples suggest that a high-intensity magnetic field of ∼10-100 μT existed ∼4.25-3.56 billion yr (Gyr) ago, followed by a weakened field of 5 μT that persisted until ∼1.9-0.8 Gyr ago (e.g., Tikoo et al 2014Tikoo et al , 2017Mighani et al 2020;Strauss et al 2021;Wieczorek et al 2022). Generation of an intrinsic magnetic field via dynamo action requires vigorous motion of an electrically conducting fluid, such as the liquid portion of a metallic core (e.g., Bullard 1949;Elsasser 1950;Bullen 1954;Glatzmaier & Roberts 1995;Kageyama et al 1995).…”

Section: Introductionmentioning

confidence: 99%

A Long-lived Lunar Magnetic Field Powered by Convection in the Core and a Basal Magma Ocean

2023

View full text Add to dashboard Cite

An internally generated magnetic field once existed on the Moon. This field reached high intensities (∼10–100 μT, perhaps intermittently) from ∼4.3 to 3.6 Gyr ago and then weakened to ≲5 μT before dissipating by ∼1.9–0.8 Gyr ago. While the Moon’s metallic core could have generated a magnetic field via a dynamo powered by vigorous convection, models of a core dynamo often fail to explain the observed characteristics of the lunar magnetic field. In particular, the core alone may not contain sufficient thermal, chemical, or radiogenic energy to sustain the high-intensity fields for >100 Myr. A recent study by Scheinberg et al. suggested that a dynamo hosted in electrically conductive, molten silicates in a basal magma ocean (BMO) may have produced a strong early field. However, that study did not fully explore the BMO’s coupled evolution with the core. Here we show that a coupled BMO–core dynamo driven primarily by inner core growth can explain the timing and staged decline of the lunar magnetic field. We compute the thermochemical evolution of the lunar core with a 1D parameterized model tied to extant simulations of mantle evolution and BMO solidification. Our models are most sensitive to four parameters: the abundances of sulfur and potassium in the core, the core’s thermal conductivity, and the present-day heat flow across the core–mantle boundary. Our models best match the Moon’s magnetic history if the bulk core contains ∼6.5–8.5 wt% sulfur, in agreement with seismic structure models.

show abstract

Section: Introductionmentioning

confidence: 99%

“…Although there is no current lunar dynamo, a global magnetic field of ∼77,000 nT previously existed until declining to a magnitude of 5,000 ± 2,000 nT by ∼3.2 Ga (Strauss et al., 2021; Tikoo et al., 2017). This lower level field has been shown to have existed until between 2.5 and 1.0 Ga (Strauss et al., 2021; Tikoo et al., 2017). This timeframe includes the period of the major basin forming events and lunar volcanism which occurred between approximately 3.9 and 2.5 Ga (Head, 1976; Hiesinger et al., 2010).…”

Section: Introductionmentioning

confidence: 99%

“…Studies have found that lunar samples can contain thermoremanent magnetization (Doell et al., 1970; Runcorn et al., 1970). Although the lunar magnetic field may have been an order of magnitude less than the Earth's current magnetic field during the period of time of the majority of lunar volcanism, the presence of a magnetic field of approximately 5,000 nT on the Moon would have provided the mechanism for the basalt forming lunar lava tubes to acquire a remanent magnetic signature during emplacement (Strauss et al., 2021; Tikoo et al., 2017).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Field Mapping and Modeling of Terrestrial Lava Tube Magnetic Anomalies as an Analog for Lunar Lava Tube Exploration and Prospecting

et al. 2022

View full text Add to dashboard Cite

Lava tubes are a commonplace feature on the terrestrial planets, and knowledge of tube size and location informs lava flow processes. Future exploration of lava tubes on the Moon can provide access to geologic environments that likely remain unaltered from their emplacement billions of years ago. Lunar lava tubes may also provide astronauts protection from thermal extremes, meteoroid impacts, and radiation. High‐resolution magnetic identification and characterization of lava tubes can be used to help inform future scientific investigations of lava tubes for human exploration and utilization. We demonstrate how magnetometry is useful for determining the geometry and extent of lava tubes on the Earth and, by proxy, the Moon, by relating the magnetic anomalies produced by lava tubes to their location and geomorphology. Using a proton‐precession total field magnetometer, we surveyed an area of more than 100,000 m2, with cross‐tube linear traverses spaced at 3–5 m, perpendicular to an approximately 1,000 m length of the Modoc Crater lava tube complex, within the Lava Beds National Monument (California, USA). The observed magnetic anomalies of the sections known as Incline, Skull, and Ship Caves are compared against synthetic predictions, and the sensitivity of the magnetic anomalies to the tube geometry used to derive a basic relationship between the two. We use our model of terrestrial lava tube magnetic anomalies and adjust for the lunar magnetic environment to predict the signature of anomalies resulting from tubes on the Moon.

show abstract

Constraining the Decline of the Lunar Dynamo Field at ≈3.1 Ga Through Paleomagnetic Analyses of Apollo 12 Mare Basalts

Abstract: Initial lunar dynamo decline spanning ≈ 370 Ma indicates two stability regimes • Grain size may control magnetic fidelity in lunar rocks

Cited by 11 publications

References 74 publications

Electrical Resistivity of Fe and Fe‐3 wt%P at 5 GPa With Implications for the Moon's Core Conductivity and Dynamo

Electrical Resistivity of Fe and Fe‐3 wt%P at 5 GPa With Implications for the Moon's Core Conductivity and Dynamo

A Long-lived Lunar Magnetic Field Powered by Convection in the Core and a Basal Magma Ocean

Field Mapping and Modeling of Terrestrial Lava Tube Magnetic Anomalies as an Analog for Lunar Lava Tube Exploration and Prospecting

Contact Info

Product

Resources

About