T146 Friends of Hoth: Episode II—Icy Bodies of the Solar System

Monday, 23 October 2017
1:30 PM - 5:30 PM
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THE HAMO-BASED GLOBAL GEOLOGIC MAP OF CERES FROM NASA’S DAWN MISSION

Paper number: T146-3
Program: Technical Sessions
Time: 2:00 PM – 2:15 PM

Authors

Abstract

We report on the progress to map the global geology of Ceres at a scale of 1:2.5M using image, spectral and topographic data derived primarily from the High Altitude Mapping Orbit (HAMO) of the Dawn mission. We are using a Dawn Framing Camera (FC) mosaic (140 m/pixel) as our primary basemap, and a global DTM (137 m/pixel) derived from FC stereo images, and FC color mosaics (0.44-0.96 µm) as supplements to help identify contacts, and provide context for map unit characterization.

Geologic mapping has defined several widespread regional units – cratered terrain, smooth material, and the units of the Urvara/Yalode system – and a number of localized units associated primarily with impact craters. Cratered terrain forms most of Ceres’ surface and contains rugged surfaces derived largely from the structures and deposits of impact features. The material of the cratered terrain includes the oldest terrains exposed on Ceres, but the geologic materials likely consist of crustal materials heavily mixed with impact materials. Smooth material forms nearly flat-lying to hummocky plains in the western equatorial hemisphere; this unit is found on the floor of, and surrounding, crater Kerwan, where it embays the cratered terrain. The geologic materials related to the Urvara and Yalode basins consist of impact materials (floor, rim, and ejecta deposits) that cover a broad part of Ceres’ eastern and southern hemispheres. Urvara ejecta consists of a rugged and a smooth facies, whereas Yalode ejecta can be distinguished by its smooth and rolling to stucco-like texture. Superposition relations show that ejecta deposits and structures from Urvara superpose Yalode.

Most local units are derived largely from impact events and include crater material, crater rim material, crater terrace material, smooth and hummocky crater floor materials, and crater central peak material. These materials are identified around many of the more fresh-appearing craters greater than ~20 km in diameter. Some morphologically fresh craters are associated with a blue to light blue color in the FC color mosaic that correlates with ejecta patterns.

In addition to mapping the global geology, we are developing the global chronostratigraphic timescale of Ceres based on the major geologic events recorded in the stratigraphic history of Ceres.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-304100

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