44th Lunar and Planetary Science Conference (2013) 1933.pdf

SPECTROSCOPIC ANALYSIS OF FLOODED CRATERS FROM OCEANUS PROCELLARUM. S. Besse1, M. Staid2, H. Hiesinger3, 1European Space Research and Technology Cen- ter, Noordwijk, Netherlands ([email protected]), 2Planetary Science Institute, Tucson, USA, 3Institut fur Planetologie, Munster, Germany.

Introduction: The last major phases of lunar vol- canism produced compositionally unique, high- titanium basalts that are not observed elsewhere on the Moon's surface or earlier in its history [1,2]. These volcanic deposits include some of the Moon's most extensive flows and age estimates suggest that these basalts are among the youngest [3]. These flows are concentrated in Oceanus Pro- cellarum, a very large volcanic province on the lunar near side. Investigations using the Moon Mineralogy Mapper (M3) data have shown that these basalts exhibit strong mineralogical varia- tions [4,5], with compositions strongly dominated by either low-Ca pyroxene, or high-Ca pyroxene, or olivine, and even a combination of these min- erals. Fig 1: LROC observation of the unbreached crater Marius Following the surprising high olivine content of the crater Marius [4], we examine other flooded New investigations and Results: A selection craters of the large Oceanus Procellarum (O.P.) of flooded craters has been performed to investi- province to characterize the uniquess, or not, of gate their spectral properties, Fig 2. Craters with Marius. As illustrated in Fig 1., flooded craters unbreched walls have been selected as much as are characterized by a flat floor usually composed possible in order to better constrain the origin of of volcanic lava flows that filled the craters, the volcanic flows. Preliminary results show that reaching the surface through the cracks under- few craters share the high-olivine content proper- neath when the crater is unbreched. If a large ties of Marius. The crater Billy seems to be the number of flooded craters within O.P. exhibits closest one, and to a certain extend the craters similar high-olivine content, this will help us to Plato, Hansteen and Flamsteed G (although the constrain the magmatic history of the last major later one is clearly connected to the surroundings phases of lunar volcanism. lava flows through its breached walls). More detailed analysis will be performed to Instruments and Data: The Moon Mineralogy highlights the similarities and differences of these Mapper (M3) onboard the Indian Space Research flooded craters from a spectral point of view. Organization’s (ISRO) Chandrayaan-1 Spacecraft is a hyperspectral imaging spectrometer that im- Acknowledgements: NASA funding to the aged the moon at 85 spectral channels with a authors for this research through the Lunar Ad- combination of spectral and spatial mapping, vanced Science and Exploration Research Pro- which enables spectra to be placemed in a geolog- gram is gratefully acknowledged. S. Besse inves- 3 ical context [6]. M is an infrared spectrometer tigations are supported by the ESA fellowship with a spectral range from 500 to 3000 nm, and a program. spectral resolution of 20 to 40 nm. This range al- References: [1] Pieters, C. et al., (1980) JGR, lows detailed investigations of the 1 and 2 µm 85. [2] Staid, M. et al., (2001) JGR, 108. [3] Hie- absorption bands characteristic of mafic minerals singer, H. et al. (2003) JGR, 108. [4] Besse, S. et on the lunar surface. al., (2011) JGR, 116. [5] Staid, M. et al., (2011) JGR, 116. [6] Green R. O. et al. (2011) JGR, 116, E00G19. 44th Lunar and Planetary Science Conference (2013) 1933.pdf

Fig 2: M3 color image of the Oceanus Procellarum province. R: integrated 1µm band depth; G: integrated 2µm band depth; B: reflectance at 1.5µm. Letters correspond to the craters investigated in this study and highlighted in black: Plato(P), J-HerschelF (J-H), Gambart (G), Kunowsky (K), Mercator (Me), Campanus (C), Winthrop (W), Billy (B), Hansteen (H), Flamsteed-G (FG), Damoiseau-F (DF), Hermann (He), Marius (M), Herodotus (H). Billy and Marius are similar, they share this red color that indicate a high-olivine content.