Pyroxene chemistry and crystallization history of basaltic units in the Mare Humorum on the nearside of the Moon: Implications for the volcanic history of the region
Earth and Space Sciences
We investigated the mineralogy and chemical variations of the mare basaltic units in the Mare Humorum on the Moon’s nearside using orbital remote sensing data. Basalts of Imbrian-Eratosthenian periods occur in the Mare Humorum. Hyperspectral data from Moon Mineralogy Mapper onboard Chandrayaan-1 mission showed pigeonites and augites as the major compositions in these basaltic units. The compositional trend between pigeonites and augites point towards the differentiation of the basaltic magma while cooling. The older units crystallized from a Fe-enriched fractionated magma while the younger unit formed from an Mg and Ca-rich magma. The distinct chemical trends in the pyroxene quadrilateral revealed that multiple volcanic eruptions have occurred in the Mare Humorum. The longward and shortward shifts in the Band I and Band II centres in the younger and older basalts respectively, also indicate that the older basaltic units crystallized more Fe2+-rich, Ca-depleted pyroxenes while the younger basaltic unit was formed from a rather Ca-rich magma.The study revealed that the basaltic magmas erupted in the Mare Humorum during Imbrian and Eratosthenian periods were derived from heterogeneous source regions.
Ref: Thesniya P. M. and Rajesh V. J. 2020. Pyroxene chemistry and crystallization history of basaltic units in the Mare Humorum on the nearside Moon: Implications for the volcanic history of the region. Planetary and Space Science 193:105093. 10.1016/j.pss.2020.105093.