The Effect of Pressure and Mg‐Content on Ilmenite Rheology: Implications for Lunar Cumulate Mantle Overturn

Tokle, Leif; Hirth, Greg; Liang, Yan; Raterron, Paul; Dygert, Nick

doi:10.1029/2020je006494

Cited by 12 publications

(21 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The late fusible cumulates would sink to the lunar core-mantle boundary because of their high density ( 42 , 43 ). Thus, the addition of these components into the CE5 basalt source indicates that some late fusible domains stayed in the upper mantle ( 40 , 44 ) or rose into the upper mantle because of upwelling after overturn ( 45 , 46 ). The upward advection of fusible cumulates that had sunk during the LMO is consistent with convective overturn of the lunar mantle ( 5 , 14 , 15 ).…”

Section: Resultsmentioning

confidence: 99%

Fusible mantle cumulates trigger young mare volcanism on the cooling Moon

Yuan

Chen

et al. 2022

Sci. Adv.

View full text Add to dashboard Cite

The Chang’E-5 (CE5) mission has demonstrated that lunar volcanism was still active until two billion years ago, much younger than the previous isotopically dated lunar basalts. How the small Moon retained enough heat to drive such late volcanism is unknown, particularly as the CE5 mantle source was anhydrous and depleted in heat-producing elements. We conduct fractional crystallization and mantle melting simulations that show that mantle melting point depression by the presence of fusible, easily melted components could trigger young volcanism. Enriched in calcium oxide and titanium dioxide compared to older Apollo magmas, the young CE5 magma was, thus, sourced from the overturn of the late-stage fusible cumulates of the lunar magma ocean. Mantle melting point depression is the first mechanism to account for young volcanism on the Moon that is consistent with the newly returned CE5 basalts.

show abstract

Section: Resultsmentioning

confidence: 99%

Fusible mantle cumulates trigger young mare volcanism on the cooling Moon

Yuan

Chen

et al. 2022

Sci. Adv.

View full text Add to dashboard Cite

show abstract

“…The most likely source for this deep melt layer was proposed to be the Fe‐Ti‐rich cumulates (Khan et al., 2014; Mallik et al., 2019; Van Kan Parker et al., 2012), initially formed as the last ∼5% of the crystallizing lunar magma ocean (LMO) beneath the floating anorthositic crust. Owing to their negative buoyancy (Hess & Parmentier, 1995; Spera, 1992) and lower viscosity than that of dry olivine (Dygert et al., 2016; Tokle et al., 2021), the shallow Fe‐Ti‐rich cumulates would sink through the mantle, introducing chemical heterogeneities into the lunar interior. On their way of descending, some Fe‐Ti‐rich cumulates would melt and react with the olivine‐pyroxene mantle to form melts that might become the source for the very Fe‐Ti‐enriched Apollo lunar basalts and pristine glasses (Elkins Tanton et al., 2002; Grove & Krawczynski, 2009).…”

Section: Introductionmentioning

confidence: 99%

Experimental Evidence Supporting an Overturned Iron‐Titanium‐Rich Melt Layer in the Deep Lunar Interior

Jing

Orman

et al. 2022

Geophysical Research Letters

View full text Add to dashboard Cite

Dense Fe‐Ti‐rich cumulates, formed as the last dregs of the lunar magma ocean, are thought to have driven a large‐scale overturn of the lunar mantle over 4 Ga ago. Analysis of lunar seismic data has implied that some of the overturned bodies may have reached the lunar core‐mantle boundary and remained there until the present day as a partially molten layer. However, whether such a molten layer could be stable during >4 Ga of post‐magma‐ocean lunar history and explain lunar seismic observations remains poorly constrained. Here, we report the first sound velocity measurements on a Fe‐Ti‐rich lunar melt up to conditions of the lowermost lunar mantle. Our results suggest that a partial melt layer with at least 20% overturned Fe‐Ti‐rich melt can be trapped atop the lunar core‐mantle boundary until the present day, strongly influencing the thermochemical evolution of the lunar interior.

show abstract

“…On the other hand, Ilmenite-bearing cumulates enriched with TiO 2 may favor the existence of a partially molten layer at the lunar core-mantle boundary. Hence, we take into account the H * of the Illmenite at about [275:283] kJ/mol (Tokle et al 2021). Table 6 summarizes the parameters used for computing the Moon mantle temperature.…”

Section: On Constraining the Lunar Deep Mantle Temperaturementioning

confidence: 99%

Constraints on the lunar core viscosity from tidal deformation

Briaud¹,

Fienga²,

Melini³

et al. 2023

Preprint

View full text Add to dashboard Cite

We use the tidal deformations of the Moon induced by the Earth and the Sun as a tool for studying the inner structure of our satellite. Based on measurements of the degree-two tidal Love numbers k 2 and h 2 and dissipation coefficients from the GRAIL mission, Lunar Laser Ranging and Laser Altimetry on board of the LRO spacecraft, we perform Monte Carlo samplings for 120,000 possible combinations of thicknesses and viscosities for two classes of the lunar models. The first one includes a uniform core, a low viscosity zone (LVZ) at the core-mantle boundary, a mantle and a crust. The second one has an additional inner core. All models are consistent with the lunar total mass as well as its moment of inertia. By comparing predicted and observed parameters for the tidal deformations we find that the existence of an inner core cannot be ruled out. Furthermore, by deducing temperature profiles for the LVZ and an Earth-like mantle, we obtain stringent constraints on the radius (500 ± 1) km, viscosity, (4.5 ± 0.8) × 10 16 Pa•s and the density (3400 ± 10) kg/m 3 of the LVZ. We also infer the first estimation for the outer core viscosity, (2.07 ± 1.03) × 10 17 Pa•s, for two different possible structures: a Moon with a 70 km thick outer core and large inner core (290 km radius with a density of 6000 kg/m 3 ), and a Moon with a thicker outer core (169 km thick) but a denser and smaller inner core (219 km radius for 8000 kg/m 3 ).

show abstract

The Effect of Pressure and Mg‐Content on Ilmenite Rheology: Implications for Lunar Cumulate Mantle Overturn

Abstract: The standard thermal and chemical evolution model of the Moon involves lunar magma ocean (LMO) solidification and cumulate mantle overturn (e.g.,

Cited by 12 publications

References 61 publications

Fusible mantle cumulates trigger young mare volcanism on the cooling Moon

Fusible mantle cumulates trigger young mare volcanism on the cooling Moon

Experimental Evidence Supporting an Overturned Iron‐Titanium‐Rich Melt Layer in the Deep Lunar Interior

Constraints on the lunar core viscosity from tidal deformation

Contact Info

Product

Resources

About