Feature type | Shield Volcano |
---|---|
Coordinates | 14°N 16°E / 14°N 16°E[1] |
Diameter | 475 km |
Eponym | Irnini |
Irnini Mons is a volcanic structure on the planet Venus, and is named after the Assyro-Babylonian goddess of cedar-tree mountains.[2] It has a diameter of 475 km (295 mi), a height of 1.75 km (1.09 mi), and is located in Venus' northern hemisphere.[3] More specifically, it is located in the central Eistla Regio region at (14°0′N 16°0′E / 14.000°N 16.000°E) in the V-20 quadrangle.[1] Sappho Patera, a 225 km (140 mi) diameter wide, caldera-like, depression tops the summit of Irnini Mons.[4] The primary structural features surrounding Irnini Mons are graben, seen as linear depressed sections of rock, radiating from the central magma chamber. Also, concentric, circular ridges and graben outline the Sappho Patera depression at the summit. The volcano is crossed by various rift zones, including the north-south trending Badb Linea rift, the Guor Linea rift extending to the northwest, and the Virtus Linea rift continuing to the southeast.[1]
The combination of volcanic-tectonic structures around Irnini Mons supports varying intensities of deformation and a multi-directional stress history. Although classified as a shield volcano, Irnini Mons contains many elements of the Venusian coronae, bringing speculation to its formation. If Irnini Mons was originally a corona, a shallow oval-shaped depression, it would support a thin lithosphere on Venus. On the other hand, it being a shield volcano supports the theory of a thicker lithosphere and Irnini Mons' stress history could be summarized simply as a transition from predominantly compressive forces to extensional relaxation, resulting in the observed radiating graben and concentric ridges.[3]
Irnini Mons is a significant structural feature on Venus because the preservation of the geology allows for the analysis of Venus' regional stress orientation in response to a pressurized magma chamber over time.[5]