Since primitive and differentiated asteroids, planetary embryos, and the Earth-Moon system represent different stages of planet formation, studies of chondritic
meteorites and samples from Vesta, Mars, the Moon, and Earth can provide constraints on the evolution of planetary volatiles from primordial to present-day compositions.
7219, the chondritic
uniform reservoir (CHUR) value.
A similar chondritic
body four or five times larger blazed through the Siberian sky in 1908, exploding with a force of 3 to 5 megatons and leveling more than 2,000 square kilometers of taiga (www.
Identification of REE fractionation in the metacarbonate rocks was carried out by normalising (Haskin et al, 1968) the concentration of the rare earth elements to average chondritic
meteorites, and the result for samples having concentrations beyond detection limits is presented as REE pattern (Figure 7).
In contrast enrichment of LIL-elements with the REE having almost flat pattern between 10X and 20X chondritic
which are typical of N-MORB.
Four syenitic samples and one metarhyolite sample show similar chondrite-normalized patterns, with light REE enrichment (200 to 400 times chondritic
values) and gently sloping heavy REE at 20 to 40 times chondritic
values, and lie in the field defined by felsic samples from the West Barneys River suite (Fig.
Adding a tiny amount of chondritic
material could explain where many present-day metals came from," says Matthias Willbold, a geochemist at the University of Bristol in England, whose team reports the findings in the Sept.
Connolly and Sweeney Smith, researching at the AMNH, recognized the inclusion inside of a chondritic
meteorite to be a very special type known as a calcium-aluminum-rich refractory inclusion, the first rocks to form in the solar system.
Previous observations of Phobos at visible and near-infrared wavelengths have been interpreted to suggest the possible presence of carbonaceous chondritic
meteorites, carbon-rich "ultra primitive" materials, commonly associated with asteroids dominant in the middle part of the asteroid belt.
The authors speculated with the possibility that this nanophase could be the iridium K-T boundary carrier and that it originated from condensation of a chondritic
vaporized impactor inside a vapour impact plume.
The mantle-normalized patterns of AUK are also characterized by near chondritic
Ti/Zr (~110) and depletion of Th, Nb and LREE (Fig.
Whole-rock isotopic data from the Riga, Marjamaa, Naissaare, Neeme, and Abja plutons indicate an approximately chondritic
source for Nd in the mafic rocks of the Riga batholith and the Abja intrusion, and a Palaeoproterozoic (Svecofennian) protolith for the felsic rocks--the [T.