These particles, or chondrules, are composed mostly of silicate minerals that appear to have been melted while they were free-floating objects in space.
32.
It seems likely that these chondrules cooled more slowly than those with radial or barred textures, however they still may have solidified in a matter of hours.
33.
Most chondrites contain both Type I and Type II chondrules mixed together, including those with both porphyritic and nonporphyritic textures, although there are exceptions to this.
34.
The tiny mass of asteroids may be partly due to inefficient chondrule formation beyond 2 AU, or less-efficient delivery of chondrules from near the protostar.
35.
The tiny mass of asteroids may be partly due to inefficient chondrule formation beyond 2 AU, or less-efficient delivery of chondrules from near the protostar.
36.
LL3, LL5, LL6 . ( Types range from 3 to 7 ) The number indicates the amount of alteration suffered by the chondrules in the meteorite.
37.
Less common types of chondrules may be dominantly composed of feldspathic material ( again either glassy or crystalline ), silica, or metallic Fe-Ni and sulfides.
38.
About 8 % of the meteorites that fall on Earth are achondrites ( meaning they do not contain chondrules ), some of which are similar to terrestrial igneous rocks.
39.
Other observed textural features that are clearly the result of very rapid cooling are dendritic and hopper-shaped olivine grains, and chondrules that are composed entirely of glass.
40.
An LL3 type is pristine with perfectly discernible chondrules, an LL7 type has been melted or altered by pressure or other force to almost completely obliterate the round chondrules.
