Morphological Identification and Clustering Analysis of Domes in the Lunar Large Volcanic Complexes

Lunar volcanic domes are essential windows into the volcanic activities of the Moon. This study uses high-resolution multi-source remote sensing data to extract the morphological features and Fe-Ti contents of volcanic domes developed in the three large volcanic complexes (Marius Hills and Rümker Hills in the PKT region, and Gardner outside the PKT area) on the lunar nearside. Hierarchical clustering analysis is performed with these parameters and all domes are classified into seven dome clusters (DC1‒DC7). Comprehensive analyses of the rheology, chronology, and geological background of the three large volcanic complexes are carried out. Our results show that the Marius Hills developed a large number of volcanic domes with large height and slope, dominated by medium to high TiO₂ contents, and the representative group of the domes is DC7. The geological age of the Marius Hills has a wide time span (~2.6 Ga), indicating a long-lasting volcanic activity in this region with multiple sources and phases. The volcanic domes developed in the Rümker Hills are small in number, moderate in height and slope, and dominated by low TiO₂ contents. The representative groups of domes in this region are DC1 and DC4. Rümker Hills has a relatively concentrated geological time period (~0.8 Ga), but with multiple phases of volcanic activities. The domes developed in the Gardner and its surroundings are either radially or annularly distributed, with low height and slope, dominated by low to medium TiO₂ contents, with magmatic activity lasting about 1.0 Ga. The representative group of the domes in the Gardner region is DC6, and multiple phases and complicated volcanic activities have occurred in this region. This study suggests the complexity of the magmatic activities of the lunar volcanic complexes, which may be related to different magma sources and the existence of heat-producing elements.