Parent body processing, meteorites

Kojima T., Tomeoka K., and Takeda H. (1993) Unusual dark clasts in the Vigarano CV3 carbonaceous chondrite record of the parent body process. Meteoritics 28, 649-658. 

Weiler, R., Busemann, H. and Franchi, I. A. (2006) Trapping and modification processes of noble gases and nitrogen in meteorites and their parent bodies. In Meteorites and the Early Solar System II, eds. Lauretta, D. S. and McSween, H. Y., Jr. Tucson University of Arizona Press, pp. 499-517. 

Brearley, A. J. (2004) Nebular vs. parent body processing of chondritic meteorites. In Treatise on Geochemistry, Vol. 1. Meteorites, Comets, and Planets, ed. Davis, A. M. Oxford Elsevier, pp. 247-268. 

Weidenschilling S. J. (1988) Formation processes and time scales for meteorite parent bodies. In Meteorites and the Early Solar System (eds. J. F. Kerridge and M. S. Matthews). University of Arizona Press, Tucson, pp. 348-371. 

Not only do meteorites give us information on genetic and evolutionary processes of and in their parent bodies, some meteorites contain materials predating Solar System formation. Thus meteorites contain unique information on pre-Solar conditions, condensation processes within the Solar System, in the inner part where liquid water could have existed, and the present-day status of the Sun and its planets and satellites. Meteorites are unique in that they contain chronometers that allow the various genetic episodes that affected them to be dated. 

Parent body processes that occurred on the parent asteroid of the meteorite... 

Organic-rich extraterrestrial samples such as meteorites, micrometeorites, interplanetary dust particles (IDPs) and samples returned by spacecraft provide a unique record of the chemical processes in the early solar system and in the interstellar medium. In particular, detailed structural and isotopic analyses of carbonaceous meteorites have revealed a rich organic inventory and provided evidence of the synthesis of complex organic molecules in the interstellar medium and on the asteroidal parent bodies of meteorites [1,2], The organic matter in carbonaceous meteorites is present at levels of up to 5% and can be divided into solvent-soluble (l%-25%) and insoluble (75%-99%) fractions, the former characterized by considerable structural, isomeric, and isotopic diversity [2,3], and the latter characterized by a high molecular weight and complex aromatic network [4]. 

Luck, J.-M., Ben Ofhman, D., and AlbarMe, F. (2005) Zn and Cu isotopic variations in chondrites and iron meteorites early solar nebula reservoirs and parent-body processes. Geochim. Cosmochim. Acta, 69, 5351—5363. 

Brearley, A.J. Nebular versus parent-body processing. In Meteorites, Comets and Planets. Treatise on Geochemistry Davis, A.M., Ed. Elsevier Oxford, U.K. 2005 Volume 1, p. 180, pp. 247—268. 

Within each chondrite class there are petrographic grades that relate to alteration processes that occurred within the meteorite parent body. The... 

In recent years, a new source of information about stellar nucleosynthesis and the history of the elements between their ejection from stars and their incorporation into the solar system has become available. This source is the tiny dust grains that condensed from gas ejected from stars at the end of their lives and that survived unaltered to be incorporated into solar system materials. These presolar grains (Fig. 5.1) originated before the solar system formed and were part of the raw materials for the Sun, the planets, and other solar-system objects. They survived the collapse of the Sun s parent molecular cloud and the formation of the accretion disk and were incorporated essentially unchanged into the parent bodies of the chondritic meteorites. They are found in the fine-grained matrix of the least metamorphosed chondrites and in interplanetary dust particles (IDPs), materials that were not processed by high-temperature events in the solar system. 

C60 has not yet been detected in primitive meteorites, a finding that could demonstrate its existence in the early solar nebular or as a component of presolar dust. However, other allotropes of carbon, diamond and graphite, have been isolated from numerous chondritic samples. Studies of the isotopic composition and trace element content and these forms of carbon suggest that they condensed in circumstellar environments. Diamond may also have been produced in the early solar nebula and meteorite parent bodies by both low-temperature-low-pressure processes and shock events. Evidence for the occurrence of another carbon allotrope, with sp hybridized bonding, commonly known as carbyne, is presented. 

This 4.53 Gyr represents the time that has elapsed since the last high-temperature event, which determined the time t = 0. For the oldest meteorites, the formation interval can also be estimated. Short half-life (1-100 Myr) radionuclides were present in the young parent body the daughters can be detected. This is the case of 129Xe (daughter of 129I with a half-life of 16 Myr). Since 129I was frozen in the parent body matrix, this means that the accretion process took a short time (a few million years). 

---