Meteorites come in a few different varieties. Iron-based meteoritescan often be easily distinguished from terrestrialminerals based on their highiron and nickel content. Meteorites are significantly heated when passing through theEarth’satmosphere, so the outer crust has a different structure than the interior and is oftenpunctuatedwith cavities, resulting from the rapid cooling of the molten iron-nickel alloy. (A)Meteorites from iron-nickel alloys can havestriking crystal structures(image below)called kamacite(upto ~12 wt% nickel) and taenite(higher wt% nickel). In addition to having a different composition, these form different crystal structures. Based on your understanding of crystalline metals, discuss why the crystal structure might be different in these alloys.
(B)In the meteorite image, assuming that these linear crystals have the same compositionand crystalstructure, what are thedifferentcrystal regions called?You can’t directly see it in this image, but based on youunderstanding of crystals, what differsabout the crystals that distinguishes the different regions?What is the predominate form of defect that is visible?
(C)If the crystals on the interiorof the meteorite and the exterior crusthave the same composition but different structure, what would this be called?(
D)Iron-nickel alloy meteorites aremore commonly found on Mars than on earth. This is hypothesized to be due to the different density oftheatmosphere on Mars, as well as atmospheric and planetary conditions that are low in oxygen and watercontent, so the ironalloy does not rust and erode as it does on Earth. (One reasonthat this is interesting, is we can use our understanding ofmeteoritesas a toolto learn about Mars.)Knowing that Mars has less atmospherethan Earth (and neglecting the different atmosphericcomposition), how do you expect that to effect the surface structure of the meteorites found on Earth andMars?