The lunar dome site in Hortensius is one of my favourite region to study. It is found near the 7 km crater Hortensius in Mare Insularum. The area presents six very interesting domes considered by many as typical examples of lunar mare domes. Their shape is generally broad, convex and semicircular with a low topographic relief. For some reason, these domes bear no specific names other than Greek letters (Phi, Tau, Sigma, Omega, and two smaller domes that are not named).
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Mare Insularum region. Image taken on 3 May 2015 using C8 and DMK monochrome camera
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The evolution of the Hortensius domes is still poorly understood. The formation of mare domes understood to be caused by eruptions of more viscous and more silicic lava than normal mare basalts. These domes probably formed during the later stages of volcanism on the Moon, characterized at the time by a decreased rate of lava extrusion and comparably low temperature eruptions. Due to the low relief of the Hortensius domes, it is difficult to determine their exact dimensions using normal photogeologic techniques, such as shadow measurements.
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| Location of individual lunar domes near Hortensius crater (lower left) |
