Other
Scientific paper
Mar 1996
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996lpi....27..291d&link_type=abstract
Lunar and Planetary Science, volume 27, page 291
Other
2
Calcium-Aluminum-Rich Inclusions, Melilites, Partition Coefficients, Rare Earth Elements
Scientific paper
Type B CAIs are widely believed to have crystallized from melts. Beckett et al. measured melilite/liquid partition coefficients for La, Ce and Tm for a Type B CAI bulk composition cooled at 2 degrees C/hr and found that they were proportional to the gehlenite to akermanite ratio of crystallizing melilite. Davis et al. reported REE concentrations in melilite from three Allende Type B CAIs. They modeled melilite crystallization in these CAIs using REE partition coefficients and found two important discrepancies: (1) melilite in CAIs is consistently higher in REE than the amount predicted; and (2) REE patterns in CAI melilite become more steeply enriched in LREE than HREE with increasing akermanite content, whereas significant fractionation of REE from one another is not predicted. Davis et al. proposed that these differences were caused by the formation of trace element-rich boundary layers in melt adjacent to growing melilite crystals and that the fractionation of REE from one another was due to differing diffusion rates of REE in the melt, which caused slower-diffusing LREE to become more enriched in the boundary layer. In order to test for kinetic effects, we have measured melilite/liquid partition coefficients for Y and 9 REE (reported here) and Ti, Sr and Ba in synthetic Type B CAIs grown at a variety of cooling rates. We find that REE partition coefficients for melilite decrease, rather than increase, with increasing cooling rate. Cooling rates in excess of 2 degrees/hr cannot explain REE distributions in Type B CAI melilite.
Davis Aileen M.
Grossman Lawrence
Richter Frank M.
Simon Steven B.
No associations
LandOfFree
The Effect of Cooling Rate on Melilite/Liquid Partition Coefficients for Y and REE in Type B CAI Melts 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 The Effect of Cooling Rate on Melilite/Liquid Partition Coefficients for Y and REE in Type B CAI Melts, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Effect of Cooling Rate on Melilite/Liquid Partition Coefficients for Y and REE in Type B CAI Melts will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1611600