Mantle Plumes on Venus Revisited

摘要: The Equatorial Highlands of Venus consist a series quasicircular regions high topography, rising up to about 5 km above the mean planetary radius. These highlands are strongly correlated with positive geoid anomalies, peak amplitude 120 m at Atla Regio. Shield volcanism is observed Beta, Eistla, Bell, and Regiones in Hathor Mons-Innini Mons-Ushas Mons region southern hemisphere. Volcanos have also been mapped Phoebe Regio flood Ovda Thetis Regiones. Extensional tectonism many these regions. It now widely accepted that least Atla, Bell surface expressions hot, mantel plumes. Upwelling plumes consistent both extensional anomalies topography four show considerable variation. Peak exceed 90 Beta but only 40 Eistla 24 Bell. Similarly, greater than Such range values not surprising because terrestrial hotspot swells side topographic uplifts. Kiefer Hager used cylindrical axisymmetric, steady-state convection calculations mantle can quantitatively account for shape long-wavelength Atla. In models, most due uplift by vertical normal stress associated plume. Additional may be present crustal thickening thinning rifting. Smrekar Phillips considered on Venus, they restricted themselves considering geoid-topography ratio did examine either amplitudes separately or shapes anomalies.