269-6 Sedna Planitia, Venus: The V-18 and V-19 Quadrangles

Session: Planetary Geologic Mapping Across the Solar System (Posters)

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Abstract:

Sedna Planitia is a large area of low-lying regional plains material found to the south of Ishtar Terra, the east of Beta Regio, and north of Sif and Gula Mons. The majority of Sedna Planitia is covered by two map quadrangles: V-18 Lachesis Tessera (300^o-330^oE, 25^o-50^oN) and V-19 Sedna Planitia (330^o-360^oE, 25^o-50^oN). The V-18 Lachesis Tessera quadrangle covers the transition zone from a major area of uplift to the west (Beta Regio) to a major area of low-lying plains, making it important to the overall investigation of the evolution of the surface and lithosphere of Venus. Similarly, the V-19 Sedna Planitia quadrangle covers the transition zone from the Eistla Regio uplift to the south and Ishtar Terra in the north, divided by the low-lying Sedna Planitia.

V-18 derives its name from Lachesis, a tessera unit found in the northwestern part of the quadrangle, as well as in the neighboring V-17 Beta Regio quadrangle. Zirka, the other major tessera unit, also straddles the boundary between V-17 and V-18. Other small outcrops of tessera and tessera-like materials are identified throughout the quadrangle. Sedna and Guinevere Planitiae are the most areally extensive terrains in V-18. There are two named deformation belts –Breksta Linea and Shishimora Dorsa– as well as embayed fragments of one or two possible additional belts. Volcanic structures include three large central volcanoes, abundant small shield volcanoes with associated flow materials, and several pancake domes. There are four known coronae in the quadrangle, and a number of other corona-like features. As with most of Venus, V-18 is not heavily cratered; there are 11 named impact craters, and up to seven putative craters.

V-19 is named after Sedna Planitia, the most areally extensive terrain in the quadrangle. There are several tesserae inliers in V-19, as well as the named Manzan-Gurme Tessera. Deformation belts include Zorile Dorsa and Karra-mahte Fossae. There are two named large volcanoes (Evaki and Toci Tholi) and many hundreds of small shield volcanoes, but unlike V-18 there are no pancake domes. There are four named coronae, and 14 impact craters (12 named).

Here we present the completed geologic map of the V-18 quadrangle and outline the recently funded geologic map of the V-19 quadrangle.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-7650

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