asfengems.blogg.se - Meteorite rock types

the measurement of the concentration of 26Mg, the product of the breakdown of the short-lived 26Al.īoth systems indicate that CAIs began forming roughly two million years prior to chondrules (at roughly 4.571 ga).

Several radiometric systems can be used on CAIs, including: If they originated in older solar systems, there would be no reason to expect them to have similar ages.

They are so refractory, so maybe they are pre-solar grains - fragments formed in older solar systems that found their way into the protocolar nebula), but never vaporized.įortunately, meteorite geochemistry enables us to choose the more reasonable hypothesis: If CAIs formed during the first condensation of the early Solar Nebula, we would expect their ages to be similar and uniform.

But were they ever really in a vapor state?

Their highly refractory composition is what we would expect of the first materials to condense in a condensations sequence, so they represent the first material to condense from vapor in the Solar Nebula.

How did they form? There are two hypotheses: The Allende meteorite, among others, contains Calcium-aluminum-rich inclusion - CAIs - little giblets of refractory material that are not chondrules. What were the first solid objects to condense? The first condensation: Recall that as the protosolar nebula first formed, much (if not all) of its material was vaporized, then recondensed from that vapor. Meteorites as forensic evidence for the early Solar SystemĬonsider some examples of the application of different methods of geochemistry to meteorites to help us answer questions about the Solar System's history: Remember from early in the semester that the relative concentrations of refractory elements in type CI chondrites are the "chondritic concentrations" that are the standard against which we compare other objects using spidergrams. These are type CI carbonaceous chondrites. Primitive meteorites: By primitive we mean "unaltered since the beginning of the Solar System." The most primitive meteorites are those whose elemental concentrations most closely resemble those of the Sun. Type C asteroids resemble carbonaceous chondrites, but not ordinary ones. Sound familiar? These chondrite types largely match up with asteroid types described previously, but not entirely. (Indeed, analyses of Messenger data is converging on the idea that Mercury may have formed primarily from enstatite chondritic material. Note: the Rosetta spacecraft's observations of the asteroid 21 Lutetia indicate that it is made of CE material.

This should have formed in the inner Solar Ssytem. Type CE - Enstatite Chondrites: Containing significant quantities of Enstatite (a pyroxene mineral).An enstatite chondrite from The Worlds of David Darling