The nature of seas, mascons and the lunar interior in the light of experimental studies, II

O’Hara, M. J.; Biggar, G. M.; Richardson, S. W.; Ford, C. E.; Jamieson, Brian G.

doi:10.1016/0031-9201(71)90038-0

Cited by 10 publications

(21 citation statements)

References 8 publications

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“…On the basis of experimental petrology of the lunar samples, the senior author stressed the likely importance of volatilization during lunar lava emplacement (O'Hara et al, 1970a(O'Hara et al, , 1970bO'Hara, 1972) and suggested that the Moon may have been a volatile (including water)-rich planet body at least in its early history, but this likely probability has been disregarded because it is incompatible with the "dry Moon" assumption and the LMO hypothesis, which are widely accepted by the lunar community (e.g., Wood et al, 1970). B. Io, the innermost satellite of Jupiter, is similar in size and mass to the Moon.…”

Section: Long-standing Problems In Lunar Petrogenesismentioning

confidence: 99%

“…Volatilization during lunar lava emplacement was proposed over 40 years ago (O'Hara et al, 1970a(O'Hara et al, , 1970bO'Hara, 1972O'Hara, , 2000, but the "dry moon" assumption accepted as a fact has led to the neglect of the significance of lunar magma volatilization until recently when water in lunar glasses and mineral crystals was actually measured (Saal et al, 2008;Liu et al, 2012;Hui et al, 2013).…”

Section: The Hindrance Of the Unjustifi Ed "Dry Moon" Assumptionmentioning

confidence: 99%

“…It should be noted that the NVOTM compilation fails to address the issue of selective volatilization during eruption, despite being published: (1) 34 years after the proposal and experimental demonstration (O'Hara et al, 1970a(O'Hara et al, , 1970bO'Hara, 1972); (2) after vesicles were reported in abundance in mare basalts (e.g., Keszthelyi, 2008); (3) after glass beads in the soils were identifi ed as fi re-fountain (pyroclastic) deposits driven by gas of lunar internal origin; (4) 14 years after the glasses were demonstrated to display varying S, Na, and K abundances as a result of variable volatilization during eruption (Delano and McGuire ,1992); and (5) three years after thermodynamic calculations on the importance of selective volatilization during eruption (Schaeffer and Fegley, 2004).…”

Section: The Hindrance Of the Unjustifi Ed "Dry Moon" Assumptionmentioning

confidence: 99%

“…Despite this, NVOTM indexes no references to water in the Moon. The effect of water on the melting relationships of lunar materials was explored in the early lunar program (O'Hara et al, 1970a(O'Hara et al, , 1970b in order to explain the phase equilibria. Neglect of the presence and effect of volatiles means that the "established" lunar petrogenesis model needs reconsideration.…”

Section: The Hindrance Of the Unjustifi Ed "Dry Moon" Assumptionmentioning

confidence: 99%

“…Yet no such study appears to have been done. However, there has been confi rmation of rapid alkali loss reported from molten basalt in vacuum (O'Hara et al, 1970a(O'Hara et al, , 1970bBiggar et al, 1971) by Lewis et al (1993), who reported experiments at atmospheric pressure (1300-1350 °C at the iron-wüstite oxygen fugacity buffer) on the Knippa basalt in Texas, which is an alkali olivine basalt (12.33 wt% MgO) with a high liquidus temperature of 1325 °C, 3.05 wt% Na 2 O, and 2.03 wt% K 2 O. At atmospheric pressure, the basalt liquid lost ~40% of the initial Na in 4 h, ~60% in 10 h, ~75% in 18 h, and ~95% in 72 h. In vacuum, even faster Na loss of ~85% was observed at 1330 °C in 16 h (Lewis et al, 1993).…”

Section: The Hindrance Of the Unjustifi Ed "Dry Moon" Assumptionmentioning

confidence: 99%

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Obvious problems in lunar petrogenesis and new perspectives

O’Hara¹,

Niu

Geological Society of America Special Papers

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACT Forty-six years ago saw the fi rst manned landing on the Moon and the return of the fi rst lunar samples. Since then a vast database has been accumulated with many ideas published on lunar petrogenesis, yet important problems recognized in early days remain under-addressed. In this paper, we fi rst review these problems and emphasize that these problems need resolving before genuine progress can be made. We then discuss that contrary to the prevalent view, the available data do not show the presence of a strong positive Eu anomaly (Eu/Eu* > 1) in the lunar highland crust, but a weak negative one (Eu/Eu* < 1) if any. This observation weakens the plagioclase fl otation hypothesis, which is the very foundation of the prevailing lunar magma ocean (LMO) hypothesis. Recent success in the determination of abundant water in lunar glasses and minerals confi rms the prediction in the early days of lunar research that the Moon may have been a water-rich planet and may still be so in its interior, which disfavors the dry Moon hypothesis, weakens the LMO hypothesis, and questions many related lunar petrogenesis interpretations. Volatilization (into the vacuum-like lunar "atmosphere") of lunar magmatism during its early history could have further facilitated plagioclase crystallization and feldspathic crustal formation. The important role and effect of plagioclase crystallization are best manifested by the signifi cant correlation (R 2 = 0.983 for N = 21) of Eu/Eu* (0.24-1.10) with Sr/ Sr* (0.10-1.12) defi ned by the lunar samples. Although the anorthositic lunar highlands are expected to have large positive Eu (Eu/Eu* > 1; ~1.99) and Sr (Sr/Sr* > 1; ~2.56) anomalies, their absence inferred from the global remote sensing data is best explained by the widespread but areally and volumetrically insignifi cant KREEP-like material that is enriched in K, rare earth elements, and P (hence, KREEP) as well as Gold

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Section: Long-standing Problems In Lunar Petrogenesismentioning

confidence: 99%

Section: The Hindrance Of the Unjustifi Ed "Dry Moon" Assumptionmentioning

confidence: 99%

Section: The Hindrance Of the Unjustifi Ed "Dry Moon" Assumptionmentioning

confidence: 99%

Section: The Hindrance Of the Unjustifi Ed "Dry Moon" Assumptionmentioning

confidence: 99%

Section: The Hindrance Of the Unjustifi Ed "Dry Moon" Assumptionmentioning

confidence: 99%

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Obvious problems in lunar petrogenesis and new perspectives

O’Hara¹,

Niu

Geological Society of America Special Papers

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Maria Lavas, Mascons, Layered Complexes, Achondrites and the Lunar Mantle

et al. 1972

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Lunar mascons: another model and its implications

Kunze

1974

The Moon

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A mascon model is proposed in which the mass excess of the mare basalts in the circular maria is supported isostatically by mass deficits at depth. The model predicts the observed positive gravity anomalies surrounded by negative ring anomalies and explains the absence of gravity anomalies over the irregular maria. The model implies that mare basalts were derived by partial melting of a source region at depth due to pressure relief resulting from the excavation of the circular mare basins, and that the crystalline residuum in the source region is of lower density than the original source rock. The trace element enrichment and near cotectic character of Apollo 11 and 12 lavas reported by some investigators may be caused by extensive magma fractionation enroute from an origin in the circular maria to the final, distant emplacement sites.The Moon 11 (1974) 9-17. All Rights Reserved

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The nature of seas, mascons and the lunar interior in the light of experimental studies, II

Cited by 10 publications

References 8 publications

Obvious problems in lunar petrogenesis and new perspectives

Obvious problems in lunar petrogenesis and new perspectives

Maria Lavas, Mascons, Layered Complexes, Achondrites and the Lunar Mantle

Lunar mascons: another model and its implications

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