This Magellan full-resolution mosaic of Venus centered at 60.3 degrees north, 337.5 degrees east shows the northeast portion of Danu Montes (mountains) where it borders on Lakshmi Planum (plains). Rising almost two kilometers (1.2 miles) above the adjacent plains, the mountains appear as ridges and troughs, implying crustal shortening by compressional forces. The deep gorges and valleys separate continuous ridges of the folded terrain, suggesting that an episode of expansion split apart the surface following the compression. The largest and most prominent chasm in the image spans a width of 20 kilometers (12.4 miles) with a length of 75 kilometers (46.5). There are also round and elongate pits which are thought to be areas where the surface has collapsed in -- perhaps where magma (subsurface molten rock) was emplaced close to the surface. In some instances lava flows from these depressions into channels extending more than 75 kilometers (46.5 miles) out onto the plains. A possible theory on the history of this region suggests that after the crust came together under compression, it heated up, became weaker, and slumped into the plains. Some evidence for this can be drawn from analogies on Earth such as the Himalayas where gravity has forced mountains to split apart under their own weight.
