This is a Magellan radar mosaic of the Lavinia region of Venus. The mosaic is centered at 45 degrees south latitude and 350 degrees longitude and covers a region 1,840 kilometers (1,100 miles) by 1,600 kilometers (970 miles). This topographically low region exhibits many diverse geologic features. The dominant structures are the tectonically deformed lineament belts which appear on this image as concentrated regions of parallel bright lines. These belts, which are slightly more elevated than the surrounding plains, consist of a series of ridges thought to be formed by the compression of the upper layer of the planet. Individual ridges within a belt are a few kilometers wide and tens of kilometers long. Small (less than 20 kilometers or 12 mile diameter) circular patches in the plains, such as those located in the upper left of the image, are believed to be small volcanic shields. The bright and dark lobes in the bottom center and middle right of the image are volcanic deposits that have flowed from source regions not seen in this image. The bottom flow complex is the northern part of Mylitta Fluctus, a region of vast outpourings of lava over 800 kilometers (480 miles) long. The northern part of this flow can be seen to surround a few ridges, suggesting that the ridge belts formed before the last eruptions.
