Stony meteorites Meteorites are extraterrestrial solar system and other celestial bodies from the rubble in the vast majority come from asteroids between Mars and Jupiter, and a few of the Moon (40) and Mars (40). The world has collected more than 40,000 air meteor Meteorites are extraterrestrial solar system and other celestial bodies from the rubble in the vast majority come from asteroids between Mars and Jupiter rocky meteorites Stone meteorites are the most common form of meteorites, which contains 75% -90% silicate minerals (such as olivine), and 10% -25% nickel alloy, iron and sulfur compounds. Stone meteorites are divided into two sub-categories: chondrites is chondrite. Most meteorites are chondrites, which represents about 86% of all observations meteorites. Rocky meteorites composed of silicate minerals such as olivine, pyroxene and plagioclase secondary formation also contains a small amount of iron particles glossy, sometimes up to 20 or more. Density of 3 to 3.5. Formed stone meteorite meteorite 95 total for. At 3:00 of the day after the March 8, 1976 afternoon, things Jilin 12 km, 8 km from north to south, with a total area of more than 500 square kilometers within the scope drop rare meteor shower of the world. Meteorites collected more than 200 pieces, is greater than 1 meteorite weighing 1770 kg, was ranked the best piece in the world and one of the weight meteor. Jilin meteorite surface, Black, Dark Fusion and sizes gas seal brown crust. The chemical composition of SIO2 reached 37.2, Mgo2 representing 3.19 28.43 iron. Home minerals are aquamarine, bronzite, kamacite and troilite; minor minerals are clinopyroxene, plagioclase. Located a stone meteorites up to a class of meteorites. Mainly or entirely of silicate minerals, especially iron, magnesium silicate meteorites year, in which the nickel-metal ratio is less than 30% of the iron. According rock structure without the presence of the pellets to chondrites and non-chondrites two categories; on the basis of chemical composition and generally, chondrites chondrites are divided carbonaceous, ordinary chondrites and the ball Enstatite chondrite groups. Chondrites rating is the third level, according to the chemical (mineral) formation rock (metal) high in calcium called calcium-rich achondrites low calcium called calcium poor achondrites. Meteorites are like stone formation and the emergence of ultramafic rocks, the density of 3-3.5 / g cm ^ 3 in the wild easily mistaken for ordinary terrestrial rocks, and in spite of the presence of a large number of fall, the total number of% fall of more than 92, but I found just the total number of 56.3% in the number of meteorites have been found. How to identify the meteorite Determine whether the meteorite samples can be considered from the following aspects: 1. Appearance fusion crust: meteorites fall to the ground before crossing the dense atmosphere, the meteorite during landing and friction generates heat from the atmosphere, so that the surface is melted to form a thin layer of fusion crust. Therefore, the new surface has a layer of black meteorite fell fusion crust thickness of about 1 mm. 2. Air India Surface: In addition, because of a large meteor and the interaction between the air flow, and the surface of the meteorite will be leaving a lot of gas seal, such as fingerprints finger pressed. 3. Metallic Interior: iron meteorites rock and iron meteorites interior consisting of metallic iron, nickel and iron content of these high (5-10%). Interior has also chondrite metal particles in the surface of fresh breakage can see small metal particles. 4. Magnetic: Because most of the meteorites that contain iron, so that 95% of the magnet can suck meteorites. 5. Chondrules: Most meteorites are chondrites (90% of the total), and there are a large number of these meteorites areas millimeter-sized silicate, called chondrules. In chondrite surface fresh breakage can see the pellets round. 6. gravity: the proportion of iron meteorite 8 g / CM3, is much greater than the proportion of the rocks on the planet in general. Chondrites because it contains a small amount of metal, the specific gravity is also heavier. Meteor rating Most meteorites are chondrites (91.5% of the total), of which a maximum of normal (chondrites, which represents 80% of the total). Chondrites is characterized by its interior contains a lot of mm to sub-field millimeter-sized silicate. Chondrites are the most primitive material in the solar system, not directly from the original solar nebula condensed from the product, they are representative of the average chemical composition of the chemical composition of the solar system. The biggest drop in the world meteor stone in 1976 from Jilin Province, Jilin ordinary chondrites, including one meteorite weighs about 1770 kg. Achondrites, rocky meteorites iron and iron meteorites known as meteorites segmentation, and they are made of chondrite high temperature and melt crystallization product differentiation, representing different levels within the asteroid samples. The internal structure of the asteroid with the Earth similar to three separate centers for the iron core (iron meteorites), the center stone of iron mantle mixed layer (rocky iron meteorites), the outer shell is based on the stone (non-spherical particles Stone meteorite). Largest iron meteorite Africa Namibia Hoba meteorite iron in the world, weighing 60 tons. In the Altai region qinggouzi Yinniu iron meteorite Xinjiang province of China found in the ditch, and weighs about 28 tons, is the third largest iron meteorite in the world. Recently, scientists all over the world in the desert areas south polar region in Africa to collect a large number of meteorites, including lunar meteorites and rare and precious Mars meteorite. Martian meteorite found in Antarctica (ALH84001) for US scientists in 1996 in the Martian meteorite found signs of life on Mars. Chinese Antarctic expedition team has three times the Grove Mountains in Antarctica discovered and recovered 4,480 meteorites, which has two meteorite from Mars. Stone, GRV99027 and GRV020090. GRV99027 Mars meteorite weighed 9.97 grams, melt surface covered with black thin. Shell. GRV020090 Mars meteorite weight 7.54 grams. This two Martian meteorite lherzolite is relatively rare, only six of these meteorites in the world.
Posted on: Thu, 11 Dec 2014 10:57:59 +0000
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