SEGMENTED LINEAMENTS ON EUROPA: IMPLICATIONS FOR THE FORMATION OF RIDGE COMPLEXES AND BRIGHT BANDS

We describe several segmented lineaments that have been observed on the surface of Europa. These lineaments are extensive, stretching for 100s to 1000s of km, and have ridge complex or bright band morphologies. We have compared the interactions between the segmented portions of these lineaments to mechanical processes observed in association with fracture systems on Earth. These processes lead to specific geometries and, as a result, provide important information regarding the stress environment in which they formed. Analysis of four ridge complexes on Europa has indicated that they formed in a remote normal stress environment that was tensile and isotropic (or nearly so) and that these lineaments may have formed in a manner more analogous to bands on Europa than to ridges. The stress environment associated with these ridge complexes may also explain the anastomosing nature of their interior morphology. Analysis of two bright bands indicate that one formed in a remote normal stress environment that was tensile and the other was reactivated under a combination of remote tensile normal stress and remote sinistral shear stress. Aspects of the morphologies of these features also indicate that bright bands likely have complex deformation histories that can include multiple episodes of reactivation.