Geologic map of Eminescu quadrangle (H-09), Mercury

As part of Mercury's global mapping initiative, started in 2016 and aiming to produce 1:3M regional geological maps of the planet, the first morpho-stratigraphic map of the Eminescu quadrangle (H-09) is now complete. Imaged only during the MESSENGER mission, the quadrangle (located between 22.5°N-22.5°S and 72°E-144°E) was first mapped in the global geologic map of Mercury by Kinczyk et al. (2019) with a scale of 1:15M. In this work, the 1:3M map for H9 provides a greater mapping detail together with a three-class craters classification and three terrain units.

The photo-geological interpretation of the morphology and stratigraphic relationships relied on the MESSENGER Mercury Dual Imaging System (MDIS) Basemap reduced Data Record monochrome basemap (up to 166 m/px). Additional insights were provided by high (HIE-HIW) and low (LOI) incidence angle basemaps, color mosaics and elevation data derived from the MESSENGER USGS global Digital Elevation Model.

The geological interpretation highlights a northeastern region significantly affected by the Caloris basin. This massive impact on Mercury resulted in a flattening of the surface with smooth terrains, interpreted as exterior volcanic plains. These plains feature exposed ridges, related to the Van Eyck Formation, interspersed by knobby and sometimes aligned deposits, correlated to the Odin Formation. The impact of the Caloris basin also resulted in the formation of numerous thrust systems, clearly visible on the smooth plains, oriented in both radial and concentric patterns around the Caloris itself. Throughout the quadrangle, several more volcanic plains, such as the Aparangi Planitia, Papsukkal Planitia and the Catuilla Planum, soften Mercury’s typically rough terrain. Explosive volcanism has been detected within the quadrangle, especially as C-shaped pits close to the center or the peak of craters, but they are rarely associated with the bright orange hues as from the MESSENGER MDIS Enhanced Color mosaic.

The Eminescu quadrangle (H-09) proves to be an interesting “slice” of Mercury, offering valuable insights into the planet's geological processes. Particularly in the perspective of the future data delivery of the BepiColombo mission (Benkhoff et al., 2010), this region will contribute significantly to our understanding of the geo-mechanical evolution of Mercury and of its subsurface stratigraphy and composition through spectral data obtained from color basemaps.

 

Acknowledgements: We acknowledge support from the Italian Space Agency (ASI) under ASI-INAF agreement 2017-47-H.0.

References: Benkhoff et al. (2010), Planetary and Space Science; Kinczyk et al. (2019), EPSC-DPS joint meeting 2019