GLOBAL GEOLOGIC MAP OF EUROPA: USGS SCIENTIFIC INVESTIGATION MAP (SIM)

Understanding the global scale geology of Europa is essential to gaining insight into the potential habitability of this icy world. As such, work is ongoing to complete a global geological map at the scale of 1:15 million that incorporates data at all resolutions collected by the Voyager and Galileo missions. The results of this work will aid the Europa Clipper mission, now in formulation, by providing a framework for collaborative and synergistic science investigations.

Our updated geologic units include: Low Albedo Ridge Material (lam)—low albedo material that irregularly surrounds large (>20 km) ridge structures; Ridged plains (pr)—distributed over all latitudes and characterized by subparallel to cross-cutting ridges and troughs visible at high resolution (<100 m/px); Band material (b)—linear to curvilinear zones with a distinct, abrupt albedo change from the surrounding region; Crater material (c), Continuous Crater Ejecta (ce) and Discontinuous Crater Ejecta (dce)—features associated with impact craters including the site of the impact, crater material, and the fall-out debris, respectively; Low Albedo Chaos (chl), Mottled Albedo Chaos (chm) and High Albedo Chaos (chh)—disrupted terrain with a relatively uniform low albedo, patchy/variegated albedo, and uniform high albedo appearance, respectively; Knobby Chaos (chk) - disrupted terrain with rough and blocky texture occurring in the high latitudes.

In addition to the geologic units, our map also includes structural features—Ridges, Cycloids, Undifferentiated Linea, Crater Rims, Depression Margins, Dome Margins and Troughs. We also introduce a point feature (at the global scale), Microchaos, to denote small (5-20 km) patches of discontinuous chaos material. The completed map will constrain the distribution of different Europa terrains and provide a general stratigraphic framework to assess the geologic history of Europa from the regional to the global scale. We aim to submit this map to the USGS for review by mid-October, 2017.