It is practically impossible that two completely different meteorites would impact on the same coordinates of our planet, before the traces of the first one are completely erased. NO terrestrial rocks has been exposed on the planetary surface such a long time! Why not? Because here the rocks are recycled! Contrary to the Moon, the Earth has an atmosphere, a biosphere and permanent geological activity. That is enough for several consecutive impacts! This rock has been exposed on the lunar surface during approx 3000 millions of years. For this to happen, the surface must have been exposed during a LOOONG TIME. If we look carefully we see some fragments that have an other level of fragments inside them: Breccias in breccia. (other side of same slab as above, but under water, to increase the contrast) And this has happened several times.įeldspathic breccia Lunar meteorite Mauritania Then the heat and pressure from the same explosions have pasted it together again. What fragmented our moon rock are meteoritic impacts on the lunar surface. Most moon rocks are black and white, with different shades of gray. On the moon there is not a single drop of water, hence we have (practically) no iron oxides. (they are often highly decorative and used in interior of cathedrals) By which they are usually stained by iron oxides in shades of ochres and browns. We also have breccias on planet Earth, but most of them are formed in presence of water. We might now feel that the irregular clear spots in the lunar rock are not crystals rather FRAGMENTS of something that has been broken and then glued together in a darker ground mass. (I recommend to pause reading the text and look at the images for a while experience the described differences with your eyes) They exhibit complete disorder both regarding to their shapes, sizes and their distribution. The clear spots are not regular at all and they are not the slightest similar between each other. If we look back on the first pic, the lunar meteorite, we do not see any of these features. Sometime they are even more or less ordered. They are somewhat regular in their shapes (here rectangular) and more or less similar to each other in shapes and sizes. The big grains here are crystals (the white ones are felspar). With big grains (crystalized first, slowly) spread in a fine-grained ground mass (crystalized last, more quickly). Porphyry Robledo de Chavela, Community of Madrid, SpainĪ porphyry is a magmatic rock, formed by cooling of magma in several distinct rounds. For instance this one, that I have found in Robledo de Chavela near Madrid: Going step by step:įor a superficial sight, a terrestrial rock called porphyry might seem similar. A terrestrial rock can impossibly have this aspect. The essence of what we need to see is: This structure is a completely chaotic one, without any order. The task consists in perceiving several things that are NOT there, and then something that IS there, if we know what to look for. To see the exotic origin of this rock is a peculiar exercise. It will be done for a meteorite called NWA11474 from which I am fortunate to own a small slice (photo above). ![]() In this text I will answer the question: How/why can we SEE it is a rock from the moon? (if not, please seek answers in other texts) Also with why this event can happen how these meteorites differ very much from other more common ones (chondrites and irons) and the paradox that they are quite rare to find, even if the moon is the celestial body closest to us. * I assume the reader is already familiar with the possibility of having small pieces of the moon falling on earth as meteorites. The middle picture is not a meteorite, rather a seemingly similar terrestrial rock, for comparison. The first and last are two sides of a slice of the lunar meteorite NWA11474. Feldspathic breccia Lunar meteorite Mauritania Prelim comments:
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