chondrules


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chondrules

(kon -droolz) Near-spherical bodies composed chiefly of silicates, with sizes between 0.2 mm and 4 mm, found embedded in chondrites. They are usually aggregates of olivine, (Mg,Fe)2 SiO4, and pyroxene (Mg,Fe)SiO3. They may also be single crystals, wholly glass, or crystal and glass, in a wide range of proportions. They appear to have been free fluid drops made spherical by surface tension and then solidified and crystallized. There is a possibility that these silicate drops were produced by lightning discharges in the dusty primitive solar nebula or that they are crystallized droplets of impact melt produced when two asteroids collided. Chondrulelike bodies have been found in lunar soils.
References in periodicals archive ?
Showing that chondrules are as old as CAIs addresses a long-standing question of why chondrule formation should be delayed by up to 2 million years after CAIs.
Most stony meteorites contain chondrules. Using a jeweler's loupe that magnifies at least 10 x , one can usually spot these tiny spherical inclusions on a chondrite's surface.
Benton reveals a sequence of events that reflect a complex history: (1) chondrule formation and initial assembly; (2) brecciation; (3) thermal metamorphism and (4) shock veining.
They derive their name from their main component -- chondrules, which formed as molten droplets floating in space.
This technique enabled the researchers to study the orientation and position of individual micrometre-sized grain particles that had coalesced around the chondrule.
Chondrules themselves formed through quick melting events in the dusty gas cloud -- the solar nebula -- that surrounded the young sun.
"With their high precision measurements, they are able to date formation times for chondrules very precisely," he said.
Achondrites (which lack chondrules) are prized by scientists and collectors alike because they come from the Moon, Mars, the asteroid Vesta, and other geologically differentiated bodies.
These findings suggest that chondrules formed from 2 million to 5 million years after inclusions appeared.
Thirdly, I will establish a chronology for the mixing of the pre-solar material within the nebula, by dating individual meteorite components (chondrules) using absolute Pb and relative 26Al-26Mg approaches and analysing the same aliquots for their mass-independent isotopic compositions.
The early family tree of our solar system's rocky planets features tiny glassy spheres called chondrules, found today inside ancient meteorites.
In the equivalent of nine pages, you get a fast-forward account of how the solar system came to be, and in the process you are introduced to such terms as refractory inclusions, chondrules, and devolatilized.