TY - JOUR
T1 - The geology of the Marcia quadrangle of asteroid Vesta
T2 - Assessing the effects of large, young craters
AU - Williams, David A.
AU - Denevi, Brett W.
AU - Mittlefehldt, David W.
AU - Mest, Scott C.
AU - Schenk, Paul M.
AU - Yingst, R. Aileen
AU - Buczkowski, Debra L.
AU - Scully, Jennifer E.C.
AU - Garry, W. Brent
AU - McCord, Thomas B.
AU - Combe, Jean Phillipe
AU - Jaumann, Ralf
AU - Pieters, Carle M.
AU - Nathues, Andreas
AU - Le Corre, Lucille
AU - Hoffmann, Martin
AU - Reddy, Vishnu
AU - Schäfer, Michael
AU - Roatsch, Thomas
AU - Preusker, Frank
AU - Marchi, Simone
AU - Kneissl, Thomas
AU - Schmedemann, Nico
AU - Neukum, Gerhard
AU - Hiesinger, Harald
AU - De Sanctis, Maria Cristina
AU - Ammannito, Eleonora
AU - Frigeri, Alessandro
AU - Prettyman, Thomas H.
AU - Russell, Christopher T.
AU - Raymond, Carol A.
N1 - Funding Information:
The authors thank James Skinner, Wesley Patterson, and editor David Blewett for productive and helpful reviews. The authors also thank the NASA Dawn Science and Flight Teams at the Jet Propulsion Laboratory for their tireless work that enabled the successful Vesta encounter, and the instrument teams at the Max Planck Institute, the German Aerospace Center (DLR), the Italian National Institute of Astrophysics (INAF), and the Planetary Science Institute for collecting and processing the data that enabled this study. DAW was funded through Grant No. NNX10AR24G from the NASA Dawn at Vesta Participating Scientists Program . The VIR Team is funded by the Italian Space Agency (ASI) through Grant No. I/004/12/0 .
Publisher Copyright:
© 2014 Elsevier Inc.
PY - 2014/12/1
Y1 - 2014/12/1
N2 - We used Dawn spacecraft data to identify and delineate geological units and landforms in the Marcia quadrangle of Vesta as a means to assess the role of the large, relatively young impact craters Marcia (~63. km diam.) and Calpurnia (~53. km diam.) and their surrounding ejecta field on the local geology. We also investigated a local topographic high with a dark-rayed crater named Aricia Tholus, and the impact crater Octavia that is surrounded by a distinctive diffuse mantle. Crater counts and stratigraphic relations suggest that Marcia is the youngest large crater on Vesta, in which a putative impact melt on the crater floor ranges in age between ~40 and 60. Ma (depending upon choice of chronology system), and Marcia's ejecta blanket ranges in age between ~120 and 390. Ma (depending upon choice of chronology system). We interpret the geologic units in and around Marcia crater to mark a major vestan time-stratigraphic event, and that the Marcia Formation is one of the geologically youngest formations on Vesta. Marcia crater reveals pristine bright and dark material in its walls and smooth and pitted terrains on its floor. The smooth unit we interpret as evidence of flow of impact melts and (for the pitted terrain) release of volatiles during or after the impact process. The distinctive dark ejecta surrounding craters Marcia and Calpurnia is enriched in OH- or H-bearing phases and has a variable morphology, suggestive of a complex mixture of impact ejecta and impact melts including dark materials possibly derived from carbonaceous chondrite-rich material. Aricia Tholus, which was originally interpreted as a putative vestan volcanic edifice based on lower resolution observations, appears to be a fragment of an ancient impact basin rim topped by a dark-rayed impact crater. Octavia crater has a cratering model formation age of ~280-990. Ma based on counts of its ejecta field (depending upon choice of chronology system), and its ejecta field is the second oldest unit in this quadrangle. The relatively young craters and their related ejecta materials in this quadrangle are in stark contrast to the surrounding heavily cratered units that are related to the billion years old or older Rheasilvia and Veneneia impact basins and Vesta's ancient crust preserved on Vestalia Terra.
AB - We used Dawn spacecraft data to identify and delineate geological units and landforms in the Marcia quadrangle of Vesta as a means to assess the role of the large, relatively young impact craters Marcia (~63. km diam.) and Calpurnia (~53. km diam.) and their surrounding ejecta field on the local geology. We also investigated a local topographic high with a dark-rayed crater named Aricia Tholus, and the impact crater Octavia that is surrounded by a distinctive diffuse mantle. Crater counts and stratigraphic relations suggest that Marcia is the youngest large crater on Vesta, in which a putative impact melt on the crater floor ranges in age between ~40 and 60. Ma (depending upon choice of chronology system), and Marcia's ejecta blanket ranges in age between ~120 and 390. Ma (depending upon choice of chronology system). We interpret the geologic units in and around Marcia crater to mark a major vestan time-stratigraphic event, and that the Marcia Formation is one of the geologically youngest formations on Vesta. Marcia crater reveals pristine bright and dark material in its walls and smooth and pitted terrains on its floor. The smooth unit we interpret as evidence of flow of impact melts and (for the pitted terrain) release of volatiles during or after the impact process. The distinctive dark ejecta surrounding craters Marcia and Calpurnia is enriched in OH- or H-bearing phases and has a variable morphology, suggestive of a complex mixture of impact ejecta and impact melts including dark materials possibly derived from carbonaceous chondrite-rich material. Aricia Tholus, which was originally interpreted as a putative vestan volcanic edifice based on lower resolution observations, appears to be a fragment of an ancient impact basin rim topped by a dark-rayed impact crater. Octavia crater has a cratering model formation age of ~280-990. Ma based on counts of its ejecta field (depending upon choice of chronology system), and its ejecta field is the second oldest unit in this quadrangle. The relatively young craters and their related ejecta materials in this quadrangle are in stark contrast to the surrounding heavily cratered units that are related to the billion years old or older Rheasilvia and Veneneia impact basins and Vesta's ancient crust preserved on Vestalia Terra.
KW - Asteroid Vesta
KW - Geological processes
KW - Impact processes
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U2 - 10.1016/j.icarus.2014.01.033
DO - 10.1016/j.icarus.2014.01.033
M3 - Article
AN - SCOPUS:84909595872
SN - 0019-1035
VL - 244
SP - 74
EP - 88
JO - Icarus
JF - Icarus
ER -