ocr: STRUCTURE Crust: 25 to 40 km thick Mantle: 1300 to 1800 km thick Core: 1500 to 2000 km in radius Composition Researchers are not certain whether Mars has acore, but they speculate that it would be iron rich and smaller than Earth's. Surrounding the core is a thick mantle, composed of silicates. The thin crust is covered by reddish oxides, which give the planet its color. Rocks on' the surface are volcanic in origin and are composed mainly of iron (18%) and silicon (45%). Traces of magnesium, sulphur, and aluminum are also present. The poles of Mars are covered with white caps of1 frozen carbon ...
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