Origin of Linear Deformation Patterns in the Fortuna and Itzpapalotl Tesserae, Venus

Abstract

Tesserae are unique surface features identified by linear deformation in multiple crossing directions. They are found on Venus and are assumed to comprise the oldest known crust of the planet. This study focuses on tessera lineations in order to identify similarities regarding their formation. Two tesserae, the Fortuna Tessera and Itzpapalotl Tessera, located in the northern polar region (V1), are compared. The goal of this work is to determine if tesserae formed in isolated events or if they were formed by the same or similar events. This could help understandings in the processes that form tesserae and how they relate to each other. This study tests the hypothesis that lineations within the tesserae will differ enough in orientation to conclude that individual tesserae were formed in unique isolated events.
This study presents bearing measurements taken of the lineations within the chosen tesserae. Each tessera has two distinct sets of linear features which cross at near perpendicular angles. Using GIS, 400 lineations were mapped at a scale of 1:1,000,000 and their bearings calculated. The bearing measurements were then plotted against each other to determine if the sets of lineations had significant similarity in their orientations. Preliminary results show that there is a general northeast and northwest trend for the two sets of lineations, respectively, on each of the observed tesserae. This refutes the hypothesis that individual tessera experienced deformation during unique, local deformation events and instead suggests that tessera may record widespread, global deformation.