Tessera (Venusian geography)
Tesserae are regions of heavily deformed terrain on Venus, characterized by two or more intersecting tectonic elements, high topography, and subsequent high radar backscatter. Tesserae often represent the oldest material at any given location and are among the most tectonically deformed terrains on Venus's surface. Diverse types of tessera terrain exist. It is not currently clear if this is due to a variety in the interactions of Venus's mantle with regional crustal or lithospheric stresses, or if these diverse terrains represent different locations in the timeline of crustal plateau formation and fall. Multiple models of tessera formation exist and further extensive studies of Venus's surface are necessary to fully understand this complex terrain.
Pioneer Venus Orbiter detected regions of anomalous radar properties and high backscatter. Using SAR imaging, the Venera 15 and Venera 16 orbiters revealed these regions to be chaotically tiled terrain, which Russian scientists named "parquet" (tiled floors), later known as "Tesserae". The most recent data concerning tessera terrain comes from the Magellan Mission, in which the majority of Venus's surface was mapped in high resolution (~100 m/pixel). Future missions to Venus will allow for further understanding of tessera terrain.
Tesserae are recognized as covering 7.3% of Venus's surface, approximately 33.2×106 km, and occur mostly within a few extensive provinces. They are heavily concentrated between 0°E and 150°E. These longitudes represent a large area between a crustal extension center in the Aphrodite Terra and a crustal convergence center in Ishtar Terra. Tesserae are exposed almost entirely within Venus's crustal plateaus. Tessera inliers, regions of tessera not found within current crustal plateaus are thought to represent regions of collapsed crustal plateaus. Large regions of tessera terrain are labelled based on their latitude. Regions in the equatorial and southern latitudes are labelled as "Regio" while regions in the northern latitudes are labelled as "Tesserae" .
A comprehensive list of Regiones and Tesserae can be found under List of geological features on Venus. Some well explored regions of tessera include:
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