"Irregular Mare Patches as Lunar Exploration Targets. *S. E. Braden, M. S. Robinson, J. D. Stopar, S. J. Lawrence. (*sebraden@asu.edu)
Irregular Mare Patches (IMPs) are small, morphologically distinct, basaltic features within the nearside lunar maria. More than 75 separate IMPs greater than 100 m in largest dimension are known [1-4]. Several IMPs have model ages of 18-58 Ma (from crater counting) [4], which is significantly later than the last phase of lunar mare basalt volcanism (1-1.2 Ga) [e.g. 5-7]. Morphologic and stratigraphic comparisons with other young lunar features provide an additional age constraint of <100-200 Ma [4]. The existence of young IMPs suggests long-lived nearside magmatism, which is a key constraint on lunar thermal evolution. Thermal models must provide enough interior energy to allow for low volume eruptions on the surface well into the Copernican period. As potential examples of some of the youngest volcanic material, IMPs are high priority targets for future lunar exploration.
Confirmation of the young model ages through sample return would not only verify young basaltic volcanism on the lunar nearside but also provide new information on lunar magmatic evolution, while confirming methods for deriving estimated ages from crater counting on young surfaces, as well as adding to our knowledge of space weathering processes, regolith production, and the rate of erosive processes over relatively short lunar timescales (100 Ma).
A large IMP would make a scientifically rewarding and exciting landing site for robotic or human exploration. For example, Ina (18.65°N, 5.30°E, 3 km) within Lacus Felicitatis, has high-resolution LROC Narrow Angle Camera [8] digital terrain models (~2 m/pixel), which enable detailed mission planning and hazard analysis, as previously demonstrated by [9, 10]. Images from the surface documenting any exposed outcrops and flow fronts will help to clarify the processes involved in the formation of IMPs. Additionally, IMPs are visually compelling exploration targets that showcase a unique and different view of the Moon, which has the potential to significantly engage the public.
[1] Whitaker, E.A., 1972. NASA SP-289, p.25-84 to 25-85. [2] Schultz, P.H., 1976. Moon Morphology, 626 pp. [3] Stooke, P.J., 2012. LPS, 43, abstract 1011. [4] Braden, S.E., PhD Dissertation, Arizona State University, December, 2013. [5] Schultz, P.H., Spudis, P.D., 1983. Nature 302, 233-236. [6] Hiesinger H., et al., 2003. J. Geophys. Res. 108, 5065. [7] Hiesinger, H., et al., 2011. GSA Special Papers 477, 1-51. [8] Robinson, M.S., et al., 2010. Space Sci. Rev. 150, 81-124. [9] Braden, S.E., Robinson, M.S., 2011. GSA Special Papers 483, 507-518. [10] Lawrence et al. 2014 LPSC 45 2014 Abstract 2785."