SYNTHESIZING MSL CURIOSITY ROVER OBSERVATIONS AND ORBITAL GEOLOGIC MAPPING TO BUILD A REGIONAL STRATIGRAPHY FOR AEOLIS PALUS, GALE CRATER

The Mars Science Laboratory team selected several waypoints along the ~8 km traverse from Yellowknife Bay to the base of Mt. Sharp for detailed analysis with the integrated Curiosity rover payload. These waypoints, named Darwin, Cooperstown, and Kimberley, were selected in orbital images because they contained outcrops hypothesized to provide “windows” into the stratigraphy of Aeolis Palus, the plains north of Mt. Sharp. We present an analysis and comparison of stratigraphic observations at Yellowknife Bay and the three waypoints, showing how orbiter and rover data can be integrated to test the validity of stratigraphic correlations within Gale Crater.

Two units can be identified from orbit at all four locations: a smooth, hummocky unit characterized by uniform tone and albedo and surfaces characterized by the preservation of abundant impact craters. Bright bedrock outcrops also occur at all four locations, although there are notable distinctions between these bright outcrops at each waypoint. At Yellowknife Bay, exposed outcrop mapped from orbit is bedded and exhibits meter-scale polygonal to sub-polygonal fractures. In situ rover observations show this bedded fractured unit to coincide with the mudstones and sandstones of the Sheepbed and Gillespie members, respectively. The bright outcrops at Darwin and Cooperstown do not exhibit polygonal fractures from orbit and bedding is difficult to identify. In situ observations of these units at Darwin and Cooperstown correlate generally with fine to coarse-grained cross-bedded sandstones and pebble conglomerates interpreted to represent fluvial deposition. At the Kimberley waypoint, an orbital unit characterized by northwest oriented striations is observed. In situ observations of this unit show it to be composed of generally southward-dipping sandstone clinoforms.

Comparison of orbitally defined units allow for broad, regional correlations between each location, but correlating rover-scale stratigraphy is difficult because of the fluvial setting where lateral heterogeneity can be expected. Using this synthesis of rover and orbital observations of Aeolis Palus, we present a model for the depositional environments and relative age relationships between Yellowknife Bay, Darwin, Cooperstown, and Kimberley.