Geologic Map of the Mare Vaporum Region - Geologic Evolution and Resource Assessment

Introduction: Upcoming lunar missions aim to combine technical demonstrations with scientific outcomes. In particular, geologically diverse regions on the lunar nearside offer valuable opportunities for the development of in‑situ resource utilization (ISRU), which could reduce dependence on Earth for future lunar exploration [1].

To investigate a promising target for future missions, we produced a new geologic map of the Mare Vaporum region (13.20°N/4.09°E) at a scale of 1:125,000. Two distinct dark mantling deposits were identified that exhibit high concentrations of FeO (~15-19 wt.%) and TiO₂ (~4-8 wt.%), indicating the presence of ilmenite (FeTiO₃). Ilmenite-bearing materials may enable the extraction of oxygen and helium‑3 [2]. As a result, Mare Vaporum is well suited for future ISRU efforts and, due to its diverse geology (Figure 1), also provides an excellent opportunity to better understand the Moon’s volcanic and tectonic history.

Method: The different geologic units were distinguished based on variations in relative albedo, topography, and morphology. Datasets used include Kaguya SELenological and Engineering Explorer (SELENE) Terrain Camera (TC) images and Kaguya TC digital elevation models (DEMs), both with pixel scales of ~10 m/px [3], as well as spectral data such as the Clementine UVVIS color ratio map [4] and Kaguya Lunar Multiband Imager (MI) maps ([5], [6]). Mapping was carried out following the stratigraphic scheme of [7] and adheres to the mapping standards described in [8] and the Planetary Geologic Mapping Protocol [9].

Results: The Mare Vaporum region shows diverse geologic units with exposed materials spanning from the Nectarian period to the Copernican period.

Figure 1: Geologic map of the Mare Vaporum region, mapped at a scale of 1:125.000.

Terra material (Nt): A prominent elongated ridge in the eastern portion of the study region is interpreted as Nectarian terra material.

Basin material (Nbm, If): The rim of the Serenitatis basin forms a distinct elevated feature in the northeastern study region. Ejecta deposits from the Imbrium impact event are present in the northern and southern part of the study region and are mapped as the Fra Mauro Formation.

Dark mantling material (Id1, Id2): Two dark mantling deposits occur in the region. The underlying topography remains visible at both deposits. FeO concentrations range from ~15-19 wt.%, and the TiO₂ values range from ~4-8 wt.%. The dark mantling deposits are likely represent pyroclastic material from the Imbrian period.

Light plains material (Ilp): This unit is characterized by high albedo and flat topography and is interpreted as the result of emplacement of impact‑generated material. It occurs in the southern part of the mapping area and is Imbrian in age.

Cratered plains material (Ipc): Compared to the Fra Mauro Formation, this unit shows a lower albedo and a rougher, more heavily cratered morphology. It is located in the southeastern part of the study region and is interpreted as Imbrian in age.

Mare material (Im1-7, Em): The majority of the study area is covered with dark and smooth materials with moderate TiO₂ and high FeO concentrations. These areas are interpreted as mare basalts emplaced during the Imbrian and Eratosthenian periods.

Crater material (Ic, Ec, Cc): Materials related to impact craters were also identified, including ejecta blankets, central peaks, crater floors, and impact melt. deposits Only craters with diameters of 5 km or greater were mapped individually.

Tectonic and volcanic features: A variety of tectonic and volcanic features could be identified, includig domes, pits, irregular mare patches, wrinkle ridges, and graben. Rima Hyginus (Ir), which we mapped as separate geologic unit, is a large graben partly surrounded by dark mantling deposits. Domes, pits, and graben are interpreted as Imbrian in age, while wrinkle ridges formed between the Imbrian and the Eratosthenian periods in the study region. The age of irregular mare patches, such as Ina, remains debated, with proposed ages ranging from Imbrian [10] to Copernican [11].

Conclusion: Our new geologic map shows that Mare Vaporum is a promising region for future ISRU efforts, especially due to the presence of dark mantling deposits enriched in FeO and TiO₂. In addition, a variety of geologic units and features is present (e.g., highland and basin materials, mare material, light plains, crater material), which increases the scientific potential for future lunar missions. Domes, pits, and irregular mare patches provide evidence for past volcanism and allow reconstruction of the volcanic evolution of the region. Furthermore, slope and rock abundance analyses indicate that Mare Vaporum is suitable for safe landings.

References:

 [1] Carpenter, J. et al. (2016) Space Policy, 37, 52-57. [2] Hawke, B. R. et al. (1990) Proc. Lunar Planet. Sc. Conf. 20th, p. 249-258. [3] Haruyama, J. et al. (2008) EPS, 60, 243-255. [4] Lucey, P. G. et al. (2000) JGR: Planets, 105(E8). [5] Lemelin, M. et al. (2019) PSS, 165, 230-243. [6] Sato, H. et al. (2017) Icarus, 296, 216-238. [7] Wilhelms, D. E. et al. (1987) USGS, 1348. [8] Federal Geographic Data Committee (2006) FGDC-STD-013-2006. [9] Skinner, J. A. et al. (2022) USGS, TM11-B13. [10] Qiao, L. et al. (2017) Geology, 45(5), 455-458. [11] Braden, S. E. et al. (2014) Nature Geoscience, 7(11), 787-791.