Guinevere Planitia
View of pancake domes in lowlands
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| Feature type | Terra |
|---|---|
| Coordinates | 21°54′N 325°00′E / 21.9°N 325°ECoordinates: 21°54′N 325°00′E / 21.9°N 325°E |
| Diameter | 7,520 km |
Guinevere Planitia is an expansive lowland region of Venus that lies east of Beta Regio and west of Eistla Regio (quadrangle V-30). These low-lying plains, particularly in the western portion, are characterized by apparent volcanic source vents and broad regions of bright, dark, and mottled deposits. They are the only break in an equatorially connected zone of highlands and tectonic zones. The types, numbers, and patterns of mapped tectonic features and small volcanic landforms in the region provide important detail in the interpretation and evolution of venusian landscape.
By using Pioneer Venus, Goldstone, and Arecibo data, these regions have been interpreted as widespread superposed flows that originated from the source vents. Fracture zones and lineament belt segments that have been identified are said to represent the Beta-Eistla deformation zones of the region. Magellan SAR images have revealed that most of these surface units are composed of volcanic land forms. There is also Seymour crater that is associated with extensive crater outflow deposits.
The region of Guinevere Planitia gives great insight to venusian tectonics and how the planet manages its heat. The nature of these structures also provides clues to the styles of volcanism, which is related to composition, volatile content, interaction with crust during magma movement, and the structure of the crust and lithosphere. By using geomorphic properties observed in the images taken, the terrain can be categorized into three types of geologic material: ridge terrain, plains materials, and volcanoes. There are crater materials locally that include ejecta, rim, and floor deposits from nine recognized craters. These structures also exhibit prominent outflow deposits.
Complex ridge terrain in Guinevere Planitia consists of embayed remnants of material that have undergone extensive deformation. Lineated materials contain one dominant orientation of tectonic features, and complexly lineated materials contain two or more tectonic fabrics. Ridge terrain includes the oldest materials found in this region and are often referred to as tessera. The ridge terrain is generally referred to as mottled, lineated plains which are generally large expanses of rolling topography that contain a small variety of volcanic domes, shields, cones, and flows. The mottled nature of the ridges is a result of ponding of flows and flow deposits in regions of low slopes.
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