The chondrite-normalised REE patterns of these rocks are depleted in most of LREE (i.e., between 10x and 18x
chondritic) and have flat HREE pattern (Fig.
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 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.sub.DM] model ages of the felsic rocks range from 2.10 to 1.89 Ga (Ramo et al.
(1978) Rare earth abundance in
chondritic meteorites.
Plots of the analyses, normalized to
chondritic values (Anders and Ebihara, 1982) are shown in Figure 9 and Figure 10.
O'Nions, "Rare-earth abundances in
chondritic meteorites," Geochimica et Cosmochimica Acta, vol.
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).
(2010) demonstrated the presence of non-reworked extraterrestrial L-type
chondritic chromite grains in the breccia, which gives further support to an impact origin.
Chondrite Normalized REE Diagrams: Chondrite normalized REE diagrams are generally prepared to determine the behavior of REE in the rocks and to constrain their source compositions, with reference to normalized
chondritic values.
