Detectability of subsurface interfaces in lunar maria by the LRS/SELENE sounding radar: Influence of mineralogical composition

Pommerol, Antoine; Kofman, W.; Audouard, J.; Grima, C.; Beck, Pierre; Mouginot, J.; Hérique, Alain; Kumamoto, A.; Kobayashi, Takao; Ono, Takayuki

doi:10.1029/2009gl041681

Cited by 30 publications

(24 citation statements)

References 17 publications

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“…The Lunar Radar Sounder (with 60 m wavelength) onboard the Kaguya mission also detected subsurface interfaces in Mare Serenitatis, Mare Crisium, Mare Smythii, Mare Nectaris, Mare Humorum, Mare Imbrium, and Oceanus Procellarum, which might represent the interface between the basalt flows and underlying crust. However, the thicknesses from Kaguya appear to be thinner than from the Apollo experiment, and it is uncertain if the Kaguya radar sounder detected the mare‐highland interface or just a shallower interface between two lava flows of differing ages [ Ono et al , ; Pommerol et al , ; Oshigami et al , ].…”

Section: Introductionmentioning

confidence: 99%

Thicknesses of mare basalts on the Moon from gravity and topography

et al. 2016

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A new method of determining the thickness of mare basalts on the Moon is introduced that is made possible by high‐resolution gravity data acquired from NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission. Using a localized multitaper spherical‐harmonic analysis, an effective density spectrum is calculated that provides an estimate of the average crustal density as a function of spherical harmonic degree. By comparing the observed effective density spectrum with one generated from a theoretical model, the thickness of mare basalts can be constrained. We assume that the grain density of the basalts is known from remote sensing data and petrologic considerations, we assign a constant porosity to the basalts, and we let both the thickness of the basalts and the density of the underlying crust vary. Using this method, the total thickness of basalts was estimated on the nearside hemisphere, yielding an average of 0.74 km with 1σ upper and lower bounds of 1.62 km and 100 m, respectively. The region of Marius Hills, which is a long‐lived volcanic complex, is found to have the thickest basalts, with an average of 2.86 km and 1σ limits of 3.65 and 1.02 km, respectively. The crust beneath the Mare Imbrium basalts is found to have an atypically high density of about 3000 kg m−3 that we interpret as representing a mafic, unfractured, impact melt sheet.

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Section: Introductionmentioning

confidence: 99%

Thicknesses of mare basalts on the Moon from gravity and topography

et al. 2016

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“…At present, the geological structures in the lunar maria can be directly investigated using the observation data of the Lunar Radar Sounder (LRS) onboard Kaguya (SELENE), which detected echoes from layers at depths of several hundred meters [ Ono et al ., ; Oshigami et al ., ; Pommerol et al ., ]. LRS was a chirp radar using a wavelength of ~60 m to detect echoes from subsurface discontinuities, where the permittivity changes abruptly [ Ono and Oya , ].…”

Section: Introductionmentioning

confidence: 99%

Mare volcanism: Reinterpretation based on Kaguya Lunar Radar Sounder data

Oshigami

Watanabe

Yamaguchi

et al. 2014

J. Geophys. Res. Planets

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The Lunar Radar Sounder (LRS) onboard Kaguya (SELENE) detected widespread horizontal reflectors under some nearside maria. Previous studies estimated that the depths of the subsurface reflectors were up to several hundreds of meters and suggested that the reflectors were interfaces between mare basalt units. The comparison between the reflectors detected in the LRS data and surface age maps indicating the formation age of each basalt unit allows us to discuss the lower limit volume of each basalt unit and its space and time variation. We estimated volumes of basalt units in the ages of 2.7 Ga to 3.8 Ga in the nearside maria including Mare Crisium, Mare Humorum, Mare Imbrium, Mare Nectaris, Mare Serenitatis, Mare Smythii, and Oceanus Procellarum. The lower limit volumes of the geologic units estimated in this study were on the order of 10 3 to 10 4 km 3 . This volume range is consistent with the total amount of erupted lava flows derived from numerical simulations of thermal erosion models of lunar sinuous rille formation and is also comparable to the average flow volumes of continental flood basalt units formed after the Paleozoic and calculated flow volumes of Archean komatiite flows on the Earth. The lower limits of average eruption rates estimated from the unit volumes were on the order of 10 À5 to 10 À3 km 3 /yr. The estimated volumes of the geologic mare units and average eruption rate showed clear positive correlations with their ages within the same mare basin, while they vary among different maria compared within the same age range.

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“…They also pointed out that clear subsurface echoes were well found in the old-age area; the surface ages of most of the area are older than 3.4 billion years. As for the inhomogeneity of the clear subsurface echoes, Pommerol et al (2010) made another suggestion that there was clear anticorrelation between the observation points of clear subsurface echoes and TiO 2 -rich area. Olhoeft and Strangway (1975) reported that loss tangent of the surface media depends on the abundance of ilmenite.…”

Section: Initial Results Of Radar Sounder Observationsmentioning

confidence: 97%

The Lunar Radar Sounder (LRS) Onboard the KAGUYA (SELENE) Spacecraft

et al. 2010

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The Lunar Radar Sounder (LRS) onboard the KAGUYA (SELENE) spacecraft has successfully performed radar sounder observations of the lunar subsurface structures and passive observations of natural radio and plasma waves from the lunar orbit. After the transfer of the spacecraft into the final lunar orbit and antenna deployment, the operation of LRS started on hours worth of radar sounder data and 8961 hours worth of natural radio and plasma wave data have been obtained. It was revealed through radar sounder observations that there are distinct reflectors at a depth of several hundred meters in the nearside maria, which are inferred to be buried regolith layers covered by a basalt layer with a thickness of several hundred meters. Radar sounder data were obtained not only in the nearside maria but also in other regions such as the farside highland region and polar region. LRS also performed passive observations of natural plasma waves associated with interaction processes between the solar wind plasma and the moon, and the natural waves from the Earth, the sun, and Jupiter. Natural 146 T. Ono et al. radio waves such as auroral kilometric radiation (AKR) with interference patterns caused by the lunar surface reflections, and Jovian hectometric (HOM) emissions were detected. Intense electrostatic plasma waves around 20 kHz were almost always observed at local electron plasma frequency in the solar wind, and the electron density profile, including the lunar wake boundary, was derived along the spacecraft trajectory. Broadband noises below several kHz were frequently observed in the dayside and wake boundary of the moon and it was found that a portion of them consist of bipolar pulses. The datasets obtained by LRS will make contributions for studies on the lunar geology and physical processes of natural radio and plasma wave generation and propagation.

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Detectability of subsurface interfaces in lunar maria by the LRS/SELENE sounding radar: Influence of mineralogical composition

Cited by 30 publications

References 17 publications

Thicknesses of mare basalts on the Moon from gravity and topography

Thicknesses of mare basalts on the Moon from gravity and topography

Mare volcanism: Reinterpretation based on Kaguya Lunar Radar Sounder data

The Lunar Radar Sounder (LRS) Onboard the KAGUYA (SELENE) Spacecraft

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