This image was obtained on Saturday, September 15 by the Magellan spacecraft in orbits 376 and 377. The area is centered at 36.4 degrees south latitude, 337.9 degrees east longitude, in the Lavinia Planitia region. The image is 37 kilometers (23 miles) wide, and 79 kilometers (48 miles) long. Narrow troughs, sinuous ridges and a broad arch are common in this area of otherwise smooth plains. The ridges and arches trend NNW and the arch is up to 5 kilometers (3 miles) wide. Most of the troughs trend WNW and are about 400-800 meters (1200-2500 feet) wide. The ridges and arch are similar to wrinkle ridges which are abundant in the lunar maria. Such wrinkle ridges consist of ridges and broad arches which formed in the smooth lava plains when the surface of the maria subsided and shortened. The similarity between wrinkle ridges and the ridges in this image suggests that this area has experienced a small amount of horizontal contraction. The small troughs may represent extension in the orthogonal direction. If the extension was contemporaneous with the compression, then a small amount of left-lateral shear oriented NW-SE is implied.
