[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Enstatite delivery mechanism?
Jim Hurley schrieb:
> If we assume that enstatites were originally produced near the sun
> a delivery mechanism is the problem.
>
> If the enstatites were produced near the protosun in its T-Tauri phase
>
> then when the sun ignited and started hydrogen fusion, there must have
>
> been some sort of shock wave from the core.
KEIL KLAUS (1989) Enstatite meteorites and their parent bodies
(Meteoritics 24-4, 1989, 195-208) - Excerpts:
THERMAL HISTORIES OF ENSTATITE METEORITE PARENT BODIES
The EH and EL chondrites and aubrites have essentially identical oxygen
isotopic compositions (Mayeda and Clayton, 1980; Clayton and Mayeda,
1985; Clayton et al., 1984; Ivanov et al., 1987a). Thus, they probably
formed from a reservoir of similar composition, presumably in the same
region of the Solar System. [Note that their oxygen isotopic
compositions also resemble those of the Earth and the Moon. However, I
agree with Gradie and Tedesco (1982), Bell et al. (1989) and others that
regularities in the abundances of asteroids of certain taxonomic types
as a function of heliocentric distance in the asteroid belt suggest that
the parent bodies of enstatite meteorites formed in the inner regions of
the asteroidal belt and not in the immediate vicinity of the Earth-Moon
system (e.g., Wasson and Wetherill, 1989).] ...
... In either case, 26Al could not have been an effective internal heat
source.
If decay of short-lived radionuclides was not the heat source, then
unipolar dynamo induction heating by a primordial T Tauri sun (e.g.,
Sonett et al., 1968, 1970; Herbert and Sonett, 1978, 1979; Herbert et
al., 1989) appears to me to be the only viable alternative. For this
process to be effective, moderately high initial temperatures are
required to provide sufficiently high electrical conductivities of
rock-forming minerals ...
Regards, Bernd
Follow-Ups:
References: