Spallanzani (Martian crater)
Stair-stepping mesas in interior deposit of Spallanzani Crater, as seen by THEMIS.
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| Planet | Mars |
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| Coordinates | 58°18′S 273°42′W / 58.3°S 273.7°WCoordinates: 58°18′S 273°42′W / 58.3°S 273.7°W |
| Diameter | 71.69 km |
| Eponym | Lazzaro Spallanzani, an Italian biologist (1729–1799) |
Spallanzani is a crater on Mars, located in the Hellas quadrangle at 58.3° south latitude and 273.7° west longitude. It measures approximately 72 kilometers in diameter and was named after Italian biologist Lazzaro Spallanzani (1729–1799). The name was adopted by IAU's Working Group for Planetary System Nomenclature in 1973.
Pictures from orbiting spacecraft have shown many layers on the floor of the crater.
Spallanzani Crater with layers, as seen by CTX camera (on Mars Reconnaissance Orbiter).
Layers in Spallanzani Crater, as seen by CTX camera (on Mars Reconnaissance Orbiter). Note: this is an enlargement of the northern side of previous image.
Many places on Mars show rocks arranged in layers. Rock can form layers in a variety of ways. Volcanoes, wind, or water can produce layers.
Many craters once contained lakes. Because some crater floors show deltas, we know that water had to be present for some time. Dozens of deltas have been spotted on Mars. Deltas form when sediment is washed in from a stream entering a quiet body of water. It takes a bit of time to form a delta, so the presence of a delta is exciting; it means water was there for a time, maybe for many years. Primitive organisms may have developed in such lakes; hence, some craters may be prime targets for the search for evidence of life on the Red Planet.
The density of impact craters is used to determine the surface ages of Mars and other solar system bodies. The older the surface, the more craters present. Crater shapes can reveal the presence of ground ice.
The area around craters may be rich in minerals. On Mars, heat from the impact melts ice in the ground. Water from the melting ice dissolves minerals, and then deposits them in cracks or faults that were produced with the impact. This process, called hydrothermal alteration, is a major way in which ore deposits are produced. The area around Martian craters may be rich in useful ores for the future colonization of Mars.
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