Wind and water have shaped Schiaparelli on Mars
Many geological processes have modified the interior of the basin’s flows of lava to create the smooth plains and watery sediments.
December 15, 2010
The small crater embedded in the northwestern rim of the Schiaparelli impact basin features prominently in this new image from the European Space Agency’s (ESA) Mars Express. All around is evidence for past water and the great martian winds that periodically blow.
Schiaparelli is a large impact basin, located in the eastern Terra Meridiani region of the planet’s equator. The image shows just a small part of the basin’s northwestern rim cutting diagonally across the image (top left–bottom right) and a smaller crater embedded in its rim.
Photo by ESA/DLR/FU Berlin (G. Neukum)
Schiaparelli is a large impact basin about 285 miles (460 km) in diameter located in the eastern Terra Meridiani region of the equator of Mars. The center of the basin lies at about 3°S, 17°E, and it is named after the Italian astronomer Giovanni Schiaparelli (1835–1910). Although he also studied Mercury and Venus, he is best known for his observations of the Red Planet.
During the “Great Opposition” of 1877, when Mars passed close to Earth, Schiaparelli mapped the planet, perceiving a number of straight dark lines across the red surface. He assumed that these were natural water-filled channels and used the equivalent Italian word, “canali.”
However, other astronomers thought he meant canals, meaning artificial irrigation and transportation routes, which led to a few astronomers, and a large number of the general public, believing that they had been created by intelligent martians.
Now we know that Schiaparelli's “canali” were illusions created by the comparatively poor telescopes of the time, and there are no water-filled channels on Mars today. Nevertheless, there is evidence in this new picture that water was once present in this region of the planet, perhaps in the form of a lake.
The High-Resolution Stereo Camera of ESA’s Mars Express took this image July 15, 2010.
The scene shows a small part of the northwestern area of the Schiaparelli basin with the crater rim, the crater interior, and parts of the surrounding highlands. Evidence for water can be seen in the form of dark sediments that appear on the floor of Schiaparelli, resembling those deposited by evaporated lakes on Earth.
Multiple geological processes, including the fall of ejecta blasted upward by the initial impact, have modified the interior of Schiaparelli flows of lava to create the smooth plains and watery sediments. Also in the crater floor, smaller impact craters have been partially flooded and filled.
The sediments forming the smooth plains have been modified by erosion, either by wind, water, or both to form sharp contours. In other places, the wind has deposited material to form hills and dunes.
The prominent that rests on the inner rim of Schiaparelli is 26 miles (42 km) across. The interior of the smaller crater is filled with sediments that appear to form a terrace in the northern part and a delta-like structure near the center. The latter seems to be partially composed of rounded light-colored mounds. Dark wind-borne material has accumulated in the southern portion of the crater.