The Geologically Recent Giant Impact Basins at Vesta's South Pole.

Saved in:

Bibliographic Details
Title:	The Geologically Recent Giant Impact Basins at Vesta's South Pole.
Authors:	Schenk, Paul, O'Brien, David P., Marchi, Simone, Gaskell, Robert, Preusker, Frank, Roatsch, Thomas, Jaumann, Ralf, Buczkowski, Debra, McCord, Thomas, McSween, Harry Y., Williams, David, Yingst, Aileen, Raymond, Carol, Russell, Chris
Source:	Science (pre-March 2025). 5/11/2012, Vol. 336 Issue 6082, p694-697. 4p.
Subjects:	Astrogeology, Geomorphological mapping, Impact craters, Space vehicles, Meteorites, Vesta (Asteroid)
Abstract:	Dawn's global mapping of Vesta reveals that its observed south polar depression is composed of two overlapping giant impact features. These large basins provide exceptional windows into impact processes at planetary scales. The youngest, Rheasilvia, is 500 kilometers wide and 19 kilometers deep and finds its nearest morphologic analog among large basins on low-gravity icy satettites. Extensive ejecta deposits occur, but impact melt volume is low, exposing an unusual spiral fracture pattern that is likely related to faulting during uplift and convergence of the basin floor. Rheasilvia obliterated half of another 400-kilometer-wide impact basin, Veneneia. Both basins are unexpectedly young, roughly 1 to 2 billion years, and their formation substantially reset Vestan geology and excavated sufficient volumes of older compositionally heterogeneous crustal material to have created the Vestoids and howardite—eucrite—diogenite meteorites. [ABSTRACT FROM AUTHOR]
	Copyright of Science (pre-March 2025) is the property of American Association for the Advancement of Science and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database:	Psychology and Behavioral Sciences Collection

Description
Abstract:	Dawn's global mapping of Vesta reveals that its observed south polar depression is composed of two overlapping giant impact features. These large basins provide exceptional windows into impact processes at planetary scales. The youngest, Rheasilvia, is 500 kilometers wide and 19 kilometers deep and finds its nearest morphologic analog among large basins on low-gravity icy satettites. Extensive ejecta deposits occur, but impact melt volume is low, exposing an unusual spiral fracture pattern that is likely related to faulting during uplift and convergence of the basin floor. Rheasilvia obliterated half of another 400-kilometer-wide impact basin, Veneneia. Both basins are unexpectedly young, roughly 1 to 2 billion years, and their formation substantially reset Vestan geology and excavated sufficient volumes of older compositionally heterogeneous crustal material to have created the Vestoids and howardite—eucrite—diogenite meteorites. [ABSTRACT FROM AUTHOR]
ISSN:	00368075
DOI:	10.1126/science.1223272