Other
Scientific paper
Jul 1992
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992metic..27q.279p&link_type=abstract
Meteoritics, vol. 27, no. 3, volume 27, page 279
Other
Scientific paper
Important information regarding the magmatic processes on the Eucrite Parent Body (EPB) may be recorded in the individual minerals found within the samples of eucrites and other meteorite types within the Howardite-Eucrite-Diogenite (HED) association. Trace-element data of minerals making up these samples should provide important constraints on their place within the framework of petrographic models and give us a better understanding of planetary magmatism. This study compares the trace-element mineral characteristics of two unequilibrated eucrite clasts: a "unique" eucrite clast identified in the Kapoeta howardite (1) and the Pasamonte eucrite. Here we report preliminary secondary ion mass spectrometry analyses (REE, Sr, Ti, V, Cr, Y, Zr) and offer a possible interpretation of these data. Trace-element analyses of clinopyroxene (Wo = 0.14) from Pasamonte and early clinopyroxene (Wo = 0.15) from the eucrite clast in Kapoeta are illustrated in the chondrite normalized "spider" diagram in Figure 1. The concentrations and patterns of the trace elements of both Pasamonte and the eucrite clast in Kapoeta are similar (i.e. depleted in LREE relative to HREE). Basaltic melt in equilibrium with the clinopyroxene in both eucrites were calculated using literature cpx/basaltic melt partition coefficients (2,3,4). The calculated melt patterns are slightly LREE enriched relative to HREE and show a small europium anomaly. Incompatible elements (Ti, Zr, LREE) are more depleted in the mineral compositions than in the coexisting melts, as expected. Although the abundance of the REE and to a lesser degree the shape of the REE pattern are dependent upon the appropriateness of the partition coeffecient selected for the modeling, the similarity of patterns for the clinopyroxenes and calculated melts indicate that the Kapoeta-eucrite-clast clinopyroxenes were in equilibrium with a melt similar to that which equilibrated with clinopyroxenes in Pasamonte. Modal mineralogy, petrography, and electron microprobe analyses indicate that the eucrite clast from Kapoeta has an unusual bulk chemistry with a high TiO2 content (-2 wt%), but average Mg/(Mg+Fe) ratio similar to the average eucrite (1, 5). It was suggested that this clast may have formed from a very small degree of partial melting, with eucritic compositions at or near the eutectic in the Ol-SiO2-An pseudoternary. Trace-element analyses have shown that the basaltic magmas represented by Pasamonte and the eucrite clast in Kapoeta were similar, indicating that the unusual nature of the eucrite clast in Kapoeta may be a result of sample size. Although this "unique" eucrite clast may have similar trace-element characteristics to Pasamonte, it is nevertheless unusual in its textural features. This study illustrates the usefulness of evaluating the relationship of small clasts to eucrite parent body magmatism. References: (1) Pun et al. (1992) Lunar Planet. Sci. 23rd, 1119-1120, (2) McKay, G.A. (1989) Reviews in Mineralogy, 21, 45-77, (3) Johnson et al. (1990) JGR, 95, 2661-2678, (4) Henderson, P. (1982) Inorganic Geochemistry. Pergamon, Oxford. 353 pp. (5) Pun et al. (1991) Lunar Planet. Sci. 22nd, 1105-1106.
Papike James J.
Pun Aurora
Shearer Charles K.
No associations
LandOfFree
A Comparison of the Trace Element Chemistries of Pyroxenes Between Two Unequilibrated Eucrite Clasts: A Eucrite from the Kapoeta Howardite and the Pasamonte Eucrite 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 A Comparison of the Trace Element Chemistries of Pyroxenes Between Two Unequilibrated Eucrite Clasts: A Eucrite from the Kapoeta Howardite and the Pasamonte Eucrite, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Comparison of the Trace Element Chemistries of Pyroxenes Between Two Unequilibrated Eucrite Clasts: A Eucrite from the Kapoeta Howardite and the Pasamonte Eucrite will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1209628