 |
| Titel |
Geological Mapping of the Ac-H-2 Coniraya Quadrangle of Ceres from NASA’s Dawn Mission. |
| VerfasserIn |
Jan Hendrik Pasckert, Harald Hiesinger, David Williams, David Crown, Scott Mest, Debra Buczkowski, Jennifer Scully, Nico Schmedemann, Ralf Jaumann  , Thomas Roatsch, Frank Preusker, Andrea Nass, Andreas Nathues, Martin Hoffmann, Michael Schäfer, Maria Cristina De Sanctis, Carol Raymond, Christopher Russell |
| Konferenz |
EGU General Assembly 2016
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250127338
|
| Publikation (Nr.) |
 EGU/EGU2016-7204.pdf |
|
|
|
|
|
| Zusammenfassung |
| Dwarf planet Ceres (∼950 km) is located at ∼2.8 AU in the main asteroid belt [1], and is
currently orbited by NASA’s Dawn spacecraft. Similar to Vesta [2], the 15 quadrangles of
Ceres will be mapped on the basis of Framing Camera mosaics from Low Altitude Mapping
Orbits (LAMO) with a spatial resolution of ∼35 m/px. Here we report on our preliminary
geological map of the Ac-H-2 Coniraya Quadrangle (located between 21-66 ˚ N and 0-90 ˚
E) based on High Altitude Mapping Orbit (HAMO) data (∼120 m/px), as LAMO images are
just becoming available.
The Coniraya Quadrangle is dominated by craters of different sizes and degradation
stages. Most of the craters are highly degraded and no ejecta blankets are visible (e.g.,
Coniraya: 136 km; 65.8˚ E/40.5˚ N). Only some craters like Gaue and Ikapati seem to be
relatively fresh, and still have ejecta blankets. Such fresher impact craters could already be
mapped in detail on HAMO data, and subdivided into crater ejecta, crater wall, crater floor,
and crater central peak materials. At the crater floor and around Ikapati crater we also
identified smooth materials that fill local depressions. The formation of the smooth material
seems to be related to the formation of the impact crater, as crater densities of the smooth
materials and the ejecta blanket are similar, as are their absolute model ages (AMAs), derived
from crater size-frequency distribution (CSFD) measurements. Using the lunar
derived chronology, CSFD measurements of Ikapati’s ejecta blanket and the smooth
materials located in and around the crater show AMAs of 300 to 390 Ma. CSFD
measurements of Gaue crater show AMAs of 910-980 Ma. Both craters show background
AMAs of 3.1 to 3.5 Ga, which might be related to old large craters (e.g., Coniraya or
Kerwan).
Apart from crater related units, we identified one dome-like structure (∼65 km wide; ∼3
km high) at the crater floor of a large degraded crater at the western edge of this
quadrangle. This might be an indication for the present of volcanic activity in this
quadrangle.
A lobate flow-like deposit identified at an unnamed crater (50.5˚ E/27˚ N) and
pitted terrain on some smooth units might be an indication for ice or volatiles in the
subsurface.
References: [1] C. T. Russell, C. A. Raymond, The Dawn Mission to Minor Planets 4
Vesta and 1 Ceres, Springer (2012). [2] Williams D.A. et al. (2014), Icarus, 244, 1-12. |
|
|
|
|
|
|