Chondrites give geologists insights on the makeup of the early solar system. Geologists are driven by understanding how the Earth came to be what it is today. Chondrites formed at the time o
Chondrites are the most primitive rocks in the solar system. Chondrites are stony (non-metallic) meteorites that have not been modified due to melting or differentiation of the parent body. Chondrites are formed when dust and small grains that originated from the early solar system accreted to form asteroids. Chondrites represent 86% of meteorites that fall to Earth. An important diagnosing feature of chondrites is the presence of chondrules. Chondrules are millimeter sized round inclusions ...view middle of the document...
The heat for the metamorphism may also have occurred during asteroids impacting each other(). Many chondritic asteroids also contained water. This water most likely came from accretion of ice along the asteroid possibly due to the accretion of ice along with rocky material. Chondrites contain hydrous minerals, such as clays, that formed when the water interacted with the rock on the asteroid in a process known as aqueous alteration(). The net result of thermal and aqueous processes is that only a few known chondrites preserve a pristine form of the original solar system. Chondrites are the best way to comprehend the makeup of the early solar system, and understanding the petrologic history allows geologists to see what has changed from the original chondrite.
The aqueous and metamorphic alterations of chondrites are measured and given a petrologic type. Type 1 are the chondrites highly altered by water. Type 2 has been altered but not as much as type 1. Type 3 chondrites are the least altered by both water and heat. Types 4, 5, and 6 represent increasing metamorphism alterations in the chondrite. This petrologic scale of chondrites was created by Van Schmus and Wood in 1967.
There are three main groups of chondrites.
Enstatite chondrites formed void of oxygen. This means that some unusual minerals formed. Sulfide minerals found in enstatite chondrites are never found on Earth where there is plenty of oxygen. Enstatite chondrites also contain iron metal: EH chondrites have high metal contents and EL chondrites have lower metal contents. Like ordinary chondrites, enstatite chondrites were metamorphosed on their parent asteroids.
Ordinary chondrites are by far the most common type of meteorite to fall to Earth: about 80% of all meteorites and over 90% of chondrites are ordinary chondrites. They contain abundant chondrules with a sparse matrix (10–15% of the rock), limited refractory inclusions, and variable amounts of Fe-Ni...