 Ophir Chasma based onTHEMIS mosaic | |
| Coordinates | 4°00′S72°30′W / 4°S 72.5°W /-4; -72.5 |
|---|---|
Ophir Chasma/ˈoʊfərˈkæzmə/ is a canyon in theCoprates quadrangle ofMars at 4° south latitude and 72.5° west longitude. It is about 317 km long and was named afterOphir, a land mentioned in the Bible.[1][2] In the Bible it was the land which King Solomon sent an expedition that returned with gold.[3] It is aclassical albedo feature name.[1]
Ophir Chasma is part of the largest canyon system in the solar system; this great canyon would go almost all the way across the United States. The name for the whole system of canyons is Valles Marineris. Starting at the west withNoctis Labyrinthus in thePhoenicis Lacus quadrangle, the canyon system ends in theMargaritifer Sinus quadrangle with Capri Chasma andEos Chasma (in the south). The wordchasma has been designated by the International Astronomical Union to refer to an elongate, steep-sided depression. Valles Marineris was discovered by and named for theMariner 9 mission. Moving east from Noctis Labyrinthus, the canyon splits into two parallel troughs,Tithonium Chasma to the North andIus Chasma to the south. In the middle of the system are very wide valleys of Ophir Chasma (north),Candor Chasma, andMelas Chasma (south). Going farther to the east, one comes to Coprates Chasma. At the end of Coprates Chasma, the valley gets wider to form Capri Chasma in the north andEos Chasma in the south. The walls of the canyons often contain many layers. The floors of some of the canyons contain large deposits of layered materials. Some researchers believe that the layers were formed when water once filled the canyons. The canyons are deep as well as long. In places they are 8-10 kilometers deep. In comparison, Earth'sGrand Canyon is 1.6 kilometers deep.[4]
Images of rocks in the canyon walls almost always show layers. Some layers appear tougher than others. In the image below of Ganges Chasma Layers, as seen by HiRISE, one can see that the upper, light-toned deposits are eroding much faster than the lower darker layers. Some cliffs on Mars show a few darker layers standing out and often breaking into large pieces; these are thought to be hard volcanic rock instead of soft ash deposits. Because of its closeness to the Tharsis volcanic region, the rock layers may be made of layer after layer oflava flows, probably mixed with deposits of volcanic ash that fell out of the air following big eruptions. It is likely the rock strata in the walls preserve a long geological history of Mars.[5] Dark layers may be due to dark lava flows. The dark volcanic rockbasalt is common on Mars. However, light-toned deposits may have resulted from rivers, lakes, volcanic ash, or wind blown deposits of sand or dust.[6] The Mars Rovers found light-toned rocks to contain sulfates. Probably having been formed in water, sulfate deposits are of great interest to scientists because they may contain traces of ancient life.[7]
 Synthetic oblique view of Ophir Chasma fromViking orbiter images. |
On August 19, 2015 ISRO released the3D portrayals[dead link] of Ophir Chasma taken by Mars Orbiter Mission.
