Model of crustal plateau and tessera terrain formation after Hansen (2006). A model of formation due to mantle plumes (upwelling) was persistent for many years, however, it has since been abandoned due to its contradictory prediction of sequences of extension versus the observed cross cutting relationships. A model of formation due to a lava pond via bolide impact was put forth, although it has not currently gained much traction in the scientific community due to skepticism of the ability of a bolide impact to generate sufficient melt. Models of formation by mantle downwelling and pulsating continents are the most currently accepted models. Multiple models have been put forward to explain the formation of tessera terrain. However, the currently accepted models support regional formation. It was thought by many researches that the tesserae might form a global "onion skin" of sorts, and extended beneath Venus's regional plains. Tessera Terrain does not participate in the global resurfacing events of Venus. Tesserae represent an ancient time of globally thin lithosphere on Venus. Model of crustal plateau and tessera terrain formation via mantle downwelling after Gilmore (1998). Some well explored regions of tessera include: Regions in the equatorial and southern latitudes are labelled as "regio" while regions in the northern latitudes are labelled as "tesserae." Ī comprehensive list of regiones and tesserae can be found under List of geological features on Venus. Large regions of tessera terrain are labelled based on their latitude. Tessera inliers, regions of tessera not found within current crustal plateaus are thought to represent regions of collapsed crustal plateaus. Tesserae are exposed almost entirely within Venus's crustal plateaus. These longitudes represent a large area between a crustal extension center in the Aphrodite Terra and a crustal convergence center in Ishtar Terra. They are heavily concentrated between 0 ☎ and 150 ☎. Tesserae are recognized as covering 7.3% of Venus's surface, approximately 3.32 ×10 7 square kilometres (1.28 ×10 7 sq mi), and occur mostly within a few extensive provinces. Future missions to Venus would allow for further understanding of tessera terrain. Using SAR imaging, the Venera 15 and Venera 16 orbiters revealed these regions to be chaotically tiled terrain, which Soviet scientists named "паркет" ( parquet), 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). Pioneer Venus Orbiter detected regions of anomalous radar properties and high backscatter. Multiple models of tessera formation exist and further extensive studies of Venus's surface are necessary to fully understand this complex terrain. 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. Tesserae often represent the oldest material at any given location and are among the most tectonically deformed terrains on Venus's surface. Eastern edge of Lakshmi Planum seen in gray on the left.Ī tessera (plural tesserae) is a region of heavily deformed terrain on Venus, characterized by two or more intersecting tectonic elements, high topography, and subsequent high radar backscatter. Tessera terrain in the Maxwell Montes seen in white on the right of the image.
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