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A lunar cryptomare dome near Mee H and Drebbel F |
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| Authors: | Raffaello Lena Jim Phillips Geologic Lunar Research Group |
| Institution: | a Via Cartesio 144, sc.D, 00137 Rome, Italy b Daimler AG, Group Research, Environment Perception, P.O. Box 2360, D-89013 Ulm, Germany c 101 Bull Street, Charleston, SC 29401, USA d Via Ugo la Malfa 31, 00040 Pomezia, Rome, Italy e Via Ticino 14, 00042 Anzio, Rome, Italy |
| Abstract: | In this study, we examine the lunar mare dome Mee 1 situated near the craters Mee H and Drebbel F in a region showing evidence of ancient (pre-Orientale) mare volcanism and cryptomare deposits. Regional stratigraphic relations indicate that Mee 1 was formed prior to the Orientale impact at the beginning of the Imbrian period. Based on a combined photoclinometry and shape from shading technique applied to telescopic CCD images of the dome acquired under oblique illumination, we determined a diameter of Mee 1 of 25 km, a height of 250 m, a flank slope of 1.15°, and a volume of  . Based on rheologic modelling of the dome and a viscoelastic model of the feeder dike, we obtained a magma viscosity of  , an effusion rate of  , a duration of the effusion process of 1.6 years, a magma rise speed of  , a width of the feeder dike of 32 m, and a horizontal dike length of 144 km. A comparison of Mee 1 with domes with similar morphometric properties, which are located near Milichius and inside the crater Petavius, reveals strong similarities with respect to the viscosity of the dome-forming magma and the feeder dike geometry, while the effusion rate and magma rise speed of Mee 1 are somewhat higher. The pronounced morphometric differences between Mee 1 and a smaller dome situated close to the crater Doppelmayer and characterised by a similar magma viscosity suggest that the growth of that dome was limited by exhaustion of the magma reservoir, while Mee 1 and the other larger domes display morphometric properties presumably coming closer to the cooling limit. The comparison of the ancient dome Mee 1 with the younger (Eratosthenian) edifices near Milichius and Doppelmayer suggests that the conditions in the upper mantle and the crust favoured high eruption volumes, effusion rates, and magma rise speeds, implying the occurrence of large magma reservoirs preventing the limitation of dome growth by magma exhaustion. On the other hand, we observe similar general morphometric, rheologic, and feeder dike characteristics and, thus, conclude that the formation conditions of lunar mare domes did not change fundamentally during the Imbrian period. |
| Keywords: | Moon Volcanism Image processing Spectrophotometry Geological processes |
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