Month: March 2015

We are undertaking a detailed structural analysis of a targeted portion of an Aphrodite fracture zone in order to understand the architectural evolution through time and space and, ultimately, to construct thermal models in order to gain insight into possible mechanisms of heat transfer on Venus. The target area (15S-20S/110E-124E), characterized by extreme density of faults and pit chains, encompasses over 700,000 km². It is part of an extensive fracture zone that overlaps with focused coronae chains to the east,and splits into regional splays to the west,cutting highland crustal plateaus. Hybrid tectono-volcanic structures,change along strike from en echelon fractures, fractures, pit-­‐chains, graben, leaky dikes, and canali. Widths range from 1 to >5 km; lengths exceed several 100 km; structure spacing ranges from 10’s of km to lineament overlapping, intersecting, or coalescing. Hybrid structures, which play a key role in transferring material to/from depth, both predate and postdate surface deposits.The fracture zone domain is the youngest regional domain in Aphrodite Terra, and extends ~2000 km in width and over 6000 km in length. The hybrid structures likely play a significant role in cooling reflecting contemporary mechanisms/processes.

 

Co-authors: David Tovar¹, J.B. Swenson¹, and I. López², ¹ University of Minnesota Duluth, ² Universidad Rey Juan Carlos.

Fissures near the south pole of Saturn’s icy moon Enceladus are observed to be erupting jets of water, which illustrates that the small moon is presently geologically active. Farther to the north, ridges, fractures, and relaxed crater topography preserve evidence for a surprisingly complex history of recent tectonic and thermal activity on the small moon. Here we demonstrate that the regions near the south pole, and along the leading and trailing hemispheres are each morphologically distinct, suggesting unique tectonic deformation events for each area. Previous researchers have demonstrated that some terrains appear to have experienced more ductile deformation, pointing to a significant amount of heat flux generated in the interior of the moon. We show that some ridged terrains, particularly on the leading and trailing hemispheres, preserve a history of apparent brittle deformation that accommodated significant contraction. This analysis of the ridge terrains seeks to constrain the recent and long-term tectonic history of Enceladus.