Geologic evolution of southern Rusalka Planitia, Venus

Heather R. DeShon, Duncan A. Young, Vicki L. Hansen

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

Geologic mapping of southern Rusalka Planitia, Venus, reveals interactions of volcanism, tectonism, and topography. We recognize three regional plains units (prR1, prR2, and prR3) based on crosscutting structural relations, embayment patterns, radar brightness, and surface roughness data. Delineation of secondary (tectonic) structures allows us to constrain the relative temporal relations between the three material units. Unit prR1, a radar dark smooth unit exposed in local topographic highs, hosts NE trending extension fractures. Low-viscosity lava flows of prR2, the most areally extensive unit, fill local topographic lows and the NE trending fractures. A shield-sourced lava unit, prR3, overlies prR2 on the basis of embayment relations and radar brightness. NW trending wrinkle ridges deform all three plains units and record regional contraction. Locally, flood lava flows that fill NE trending fractures are structurally inverted to form short, stepped NE trending wrinkle ridges. Map patterns indicate that prR2 comprises a thin layer (<50 m thick), much thinner than previous estimates of 1-3 km. Therefore previously proposed estimates of plains flood lava flow volumes and effusion rates are much too high. The local geologic history of southern Rusalka Planitia is inconsistent with global stratigraphy models. Our study supports the view of plains evolution occurring through discrete volcanic processes working at local and regional (but not global) scales.

Original languageEnglish (US)
Article number1999JE001155
Pages (from-to)6983-6995
Number of pages13
JournalJournal of Geophysical Research E: Planets
Volume105
Issue numberE3
DOIs
StatePublished - Mar 25 2000

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