Mathematics – Logic
Scientific paper
Aug 1973
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1973gecoa..37.1909o&link_type=abstract
Geochimica et Cosmochimica Acta, vol. 37, Issue 8, pp.1909-1942
Mathematics
Logic
6
Scientific paper
Sequential non-destructive neutron activation analysis was used to determine the bulk abundance of Fe, Al, Na, Mn, Or, Sc, Co and Ir in approximately 300 individual chondrules from 16 chondrites representing the H (3-5), L4 and LL(3-6) compositional and petrologic classes. For some of the chondrules, Si, Ni, Ca and V were also determined. The histograms indicate that the most probable abundances for lithophilic elements, except Cr, are enriched in the chondrules, while the siderophilic elements are depleted in the chondrules compared to the whole chondrite. Some of the abundance populations, such as Al and Fe, appear to be multimodal. Systematic variations in the composition of the chondrules with increasing petrologic type were observed; most consistent are an increasing Na-Al and Cr-Al correlation, a decreasing Na-Mn correlation, increasing Na abundance and decreasing Na and Mn dispersions among chondrules. The systematic compositional variations with increasing petrologic type are consistent with an increasing approach to equilibrium between chondrules and matrix. Observed elemental correlations are generally consistent with mineralogical controls expected on the basis of geochemical affinities suggested by the mineral assemblages present in the chondrules. However, a prevalent Al-Ir correlation was observed, and is most pronounced for a group of chondrules belonging to a population high in Al. A Sc-Ir correlation was observed. Also, an anti-correlation between chondrule masses and Al (and Ir for some chondrules) content of the chondrules was observed. These correlations are attributed to a fractionation during condensation or chondrule formation and cannot be attributed to classical geochemical similarities i.e. these correlations result from a cosmochemical fractionation. From the compositional evidence, it is suggested that there may be two mechanisms for chondrule production. Some high Al chondrules which exhibit the Al-Ir correlation are believed to be remelted primitive high-temperature aggregates. The elemental composition of the chondrules from the lower Al abundance population is consistent with a preferential remelting of pre-existing silicates.
Osborn T. W.
Schmitt Roman A.
Smith Roland H.
No associations
LandOfFree
Elemental composition of individual chondrules from ordinary chondrites does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Elemental composition of individual chondrules from ordinary chondrites, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Elemental composition of individual chondrules from ordinary chondrites will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1221694