A COMPOSITIONAL AND GEOLOGICAL VIEW ONTO THE EJECTA OF SMALL FRESH IMPACT CRATERS ON ASTEROID 4 VESTA
Abstract
In order to further understand the composition of the upper as well as lower parts of Vesta’s crust, small impact crater (< 10km in diameter), which show distinct ejecta and thus represent unweathered surface areas, have been identified and their spectral properties investigated with respect to their geological and geomorphological context. The study was performed based on data acquired by the Visual and Infrared Spectrometer (VIR), which observed Vesta’s surface between 0.25 and 5.1µm with a pixel ground resolution of ~60 m/pixel. The geological and geomorphological context is provided by images acquired by the Framing Camera (FC) with a pixel ground resolution up to 20 m/pixel. The spectral variations mirror the global trend with a more diogenitic composition in the Rheasilvia basin and an eucrite-/howardite-like composition in the geologically older densely cratered equatorial region. This points to the interpretation that the bright ejecta might be related to the Rheasilvia basin whereas the darker material resembles excavated in-situ subsurface material. This interpretation is strengthend by the fact that the bright ejecta were formed only in the western part of the small impact crater in the direction of slightly higher elevation possibly representing an addional upper surface layer of former ejecta of Rheasilvia newly excavated.
- Publication:
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AAS/Division for Planetary Sciences Meeting Abstracts #45
- Pub Date:
- October 2013
- Bibcode:
- 2013DPS....4511224S