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.
42.
In some meteorites, together with olivine it forms the bulk of the material; it can occur in small spherical masses, or chondrules, with an internal radiated structure.
43.
However, most LL chondrites have been thermally metamorphosed to petrologic types 5 and 6, meaning that their minerals are homogeneous in composition and chondrule borders are difficult to discern.
44.
Many materials which had been presumed to be very early ( e . g . chondrules ) appear to have formed a few million years later ( Hutcheon & Hutchison ).
45.
Pyroxene-rich chondrules that contain extremely fine-grained, swirling masses of fibrous crystals only a few micrometers in size or smaller are called " cryptocrystalline " chondrules.
46.
Pyroxene-rich chondrules that contain extremely fine-grained, swirling masses of fibrous crystals only a few micrometers in size or smaller are called " cryptocrystalline " chondrules.
47.
Numbers lower than 3 are given to chondrites whose chondrules have been changed by the presence of water, down to 1, where the chondrules have been obliterated by this alteration.
48.
Numbers lower than 3 are given to chondrites whose chondrules have been changed by the presence of water, down to 1, where the chondrules have been obliterated by this alteration.
49.
He used laser resonance ionisation of xenon to measure samples with only a few thousand atoms of xenon; this enabled him to get accurate data from tiny samples, including individual chondrules.
50.
Recent research, however, indicates that larger objects such as conglomerates of chondrules may be necessary and that the concentrations produced from chondrules may instead act as the seeds of streaming instabilities.
