Wednesday, February 4, 2015 POSTER SESSION: EARLY SOLAR

Early Solar System Impact Bombardment III (2015)
Wednesday, February 4, 2015
5:30 p.m. Great Room
Schmedemann N. Kneissl T. Neesemann A. Michael G. Hiesinger H. Jaumann R.
Raymond C. A. Russell C. T.
The Age of the Rheasilvia Basin — How the two Geological Interpretations and Chronology Systems Differ [#3006]
We review and analyze the major disagreements in the formation age of the Rheasilvia basin on Vesta that were
published recently.
Davis C. L. Moser D. E.
U-Pb Composition and Shock Microstructures of In-Situ Accessory Phases Across the Vredefort Impact Structure,
South Africa: A Terrestrial Analogue for Dating the Lunar Surface and Other Planetary Bodies [#3028]
Accessory phases (i.e. zircon, monazite) co-exist within individual samples of the Vredefort dome, with a dichotomy
of U-Pb ages and microstructural evolution. Vredefort is a terrestrial analogue for complex craters on other
planetary bodies.
Righter K. Cosca M. A.
Ar/39Ar Age of Hornblende-Bearing R Chondrite LAP 04840 [#3022]
This unsual meteorite yields an Ar-Ar age of 4.29 Ga — evidence for post shock annealing in the R chondrite
parent body.