Compositional and temporal investigation of exposed lunar basalts in the Mare Imbrium region

Volcanic history of the Imbrium basin: A close-up view from the lunar rover Yutu

“…These reflectors likely indicate buried regolith layers formed during flooding hiatus of lava flows in the northeastern Mare Imbrium. This is consistent with the presence of three main types of basalt units in Mare Imbrium, based on variation of FeO and TiO 2 contents (13,14). These basalt units were dated 3.3-3.5 Ga, 3.0 Ga, and 2-2.5 Ga (7, 12, 24).…”

“…The presence of the KREEPy materials, indicated by high concentrations of radionuclides U, Th, and K (9), around the rims of the Imbrium basin suggests that they are likely the basin-forming ejecta deposits. At least three main lava flows, dated from 3.5 Ga to 2.0-2.3 Ga (7,12), have been recognized in Mare Imbrium with distinct FeO and TiO 2 concentrations (13,14), which brought up interior information of this KREEP-rich terrain. The old and low-Ti basalt unit has been sampled by the Apollo 15 mission that landed at the eastern rim of the Imbrium basin.…”

Detectability of subsurface interfaces in lunar maria by the LRS/SELENE sounding radar: Influence of mineralogical composition

“…This is evident both at global scale ( Figure 3) and at regional scale: the example of Mare Imbrium is presented on Figures 4a and 4b. In addition, comparison with the geological map built by Bugiolacchi and Guest [2008] from geomorphologic and compositional information shows that the distinction between areas showing one unique subsurface interface and areas showing two distinct interfaces corresponds to a putative distinction between two different lower Imbrian series with very similar TiO 2 concentrations (1.4 and 1.5 wt. %).…”

“…For this purpose, we used the geologic map published by Bugiolacchi and Guest [2008], manually re-projected to fit the shaded relief map. Figure 1.…”

Extent, age, and resurfacing history of the northern smooth plains on Mercury from MESSENGER observations

“…It may be that the interval(s) between episodes of resurfacing in the NSP were not of sufficient length to allow a statistically appreciable number of craters with D P 8 km to form and contribute kinks in the cumulative SFD. For instance, an investigation in Mare Imbrium on the Moon did not show distinct kinks in the cumulative SFD for units with model age differences of less than $300-500 My (Ostrach and Robinson, 2014) despite identification of several geologic units with statistically separable model ages (Hiesinger et al, 2000;Bugiolacchi and Guest, 2008). Or, equally plausible, a latestage volcanic emplacement episode may have nearly completely resurfaced the NSP up to the largest diameters, in which case the cumulative SFD records only the post-plains craters formed since the most recent resurfacing of the region, and no kinks would be expected.…”