Impact craters, terrain type, and terrain ages on Venus

Impact craters, terrain type, and terrain ages on Venus

Fig. 7.25 . Impact craters (top diagram) are randomly scattered all over Venus. Most are pristine (white dots). Those modified by lava (red dots) or by faults (triangles) are concentrated in places such as Aphrodite Terra. Areas with a low density of craters (blue background) are often located in highlands. Higher crater densities (yellow background) are usually found in the lowland plains. The terrain type (middle diagram) is predominately volcanic plain (blue). Within the plains are deformed areas such as tessarae (pink) and rift zones (white), as well as volcanic features such as coronae (peach), lava floods (red) and volcanoes of various sizes (orange). Volcanoes are not concentrated in chains as they are on Earth, indicating that plate tectonics do not operate. Terrain age data (bottom diagram) indicate that volcanoes and coronae tend to clump along equatorial rift zones, which are younger (blue) than the rest of the surface of Venus (green). Tesserae, ridges and plains are older (yellow). In general, however, the surface lacks the extreme variation in age that is found on Earth and Mars. (Courtesy of NASA/Mary Beth Price.)

Copyright 2010, Professor Kenneth R. Lang, Tufts University