The Global Geologic Map of Ceres from Dawn

The Dawn mission to the minor planet Ceres (diameter = 950 km) began in 2014 after its successful mission to Vesta. Dawn acquired image, spectral, and topographic data during its approach to Ceres (late 2014) through two extended missions, until the Dawn mission concluded in November 2018. Global geologic mapping of Ceres began with Framing Camera images acquired during the Approach and Survey phases of the mission. Data acquired during the High Altitude Mapping Orbit (HAMO) provided a second iteration of the global geologic map of Ceres, to be generated at a spatial resolution of 140 m/pixel. Acquisition of Low Altitude Mapping Orbit (LAMO) permitted Ceres to be divided into 15 quadrangles for higher resolution geologic mapping (35 m/pixel). Lastly, following Dawn’s nominal mission to Ceres, two extended missions were approved and additional data at various altitudes (and resulting resolutions) were acquired (XM01-XM07), but not incorporated into any global geologic mapping products.

This proposed work will utilize Dawn Framing Camera (FC) images, Visible and Infrared (VIR) Mapping Spectrometer multispectral data, Gamma Ray and Neutron Detector (GRaND) data, and derived topographic data to construct a revised global geologic map of Ceres based on systematic analysis of the complete Dawn mission datasets. This proposed geologic map of Ceres will be published as a U.S. Geological Survey (USGS) Special Investigation Map (SIM) at 1:3M (equatorial) and 1:1.5M (polar). This investigation supports the science return of the Dawn mission and generates a useful digital geologic map product for the community.

We propose three main research tasks: (1) Conduct geologic mapping. We will produce a global geologic map of Ceres building on previous geologic maps of Ceres at various scales. (2) Determine relative ages and stratigraphy of mapped units and features via analysis of crater size-frequency distribution statistics and stratigraphic relations (e.g., superposition, cross-cutting). (3) Update Ceres’ chronostratigraphy and geologic time scale (as necessary). We propose to evaluate the global geology of Ceres where important spatial and temporal relationships between geologic materials and processes are preserved. Identifying and modeling surface processes requires a complete characterization and stratigraphic analysis of the resulting geologic units. We will construct a global geologic map of the surface of Ceres to address outstanding science questions regarding the nature and stratigraphy of its impact record, and other past geologic activity.