page_title: Mapping of Venus
section_title: Tessera regions (t)
hierarchical_section_title: Mapping of Venus / Unit classification and mapping schemes / Stratigraphic classification scheme / Stratigraphic units / Tectonic units / Tessera regions (t)
caption_attribution_description: English: Venus - Lakshmi Planum and Maxwell Montes Original Caption Released with Image: This Magellan full resolution radar image is centered at 65 degrees north latitude, zero degrees east longitude, along the eastern edge of Lakshmi Planum and the western edge of Maxwell Montes. The plains of Lakshmi are made up of radar-dark, homogeneous, smooth lava flows. Located near the center of the image is a feature previously mapped as tessera made up of intersecting 1- to 2-km (0.6 to 1.2 miles) wide graven. The abrupt termination of dark plains against this feature indicates that it has been partially covered by lava. Additional blocks of tessera are located along the left hand edge of the image. A series of linear parallel troughs are located along the southern edge of the image. These features, 60- to 120-km (36- to 72- miles) long and 10- to 40- km (6- to 24- miles) wide are interpreted as graben. Located along the right hand part of the image is Maxwell Montes, the highest mountain on the planet, rising to an elevation of 11.5 km (7 miles) and is part of a series of mountain belts surrounding Lakshmi Planum. The western edge of Maxwell shown in this image rises sharply, 5.0 km (3.0 miles), above the adjacent plains in Lakshmi Planum. Maxwell is made up of parallel ridges 2- to 7-km (1.2- to 4.2 miles) apart and is interpreted to have formed by compressional tectonics. The image is 300 km (180 miles) wide.
context_page_description: The mapping of Venus refers to the process and results of human description of the geological features of the planet Venus. It involves surface radar images of Venus, construction of geological maps, and the identification of stratigraphic units, volumes of rock with a similar age.
  Satellite radar provides imagery of the surface morphology by using the physical properties of wave reflection. Long wavelength microwaves are used to penetrate the thick, cloudy atmosphere of Venus and reach to the surface. Different surface features reflect waves with different strengths of signal, producing images from which the maps are constructed.
  After collection of the images of the Venusian surface, scientists started to map and identify different geologic materials and units according to distinctive surface features. Different groups of scientists analysed different mapping areas, schemes and interpretation of features observed, to produce a classification of the units and comparison of their mapping.
context_section_description: Tesserae are regions of heavily deformed terrain, mostly located on highland areas (greater than 2 km in elevation) on Venus. This tectonic feature -or uni— is thought to be the oldest material on Venusian surface with highest level of tectonic deformation. It is of high topography and seen in white on the SAR images with high radar backscatter.  The materials composed tessa terrain, which was named as unit Tt in the mapping of V-17(Basilevsky, A. T.,1996).
  The intersecting of material and tectonic structures are the defined characteristic of tessera, but the sets are not always seen in the images. Due to the heavy tectonic deformation, it contains both contractional features of ridges and extensional features of graben and fractures.
  The boundaries of tessera shows embayment by other materials of other units. By this cross-cutting relationship, it provides evidence of tessera being the oldest unit within the strata.
caption: Maxwell Montes's tessera (t) terrain seen in appearing as white in SAR image
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