The Abee enstatite chondrite breccia was studied using two methods: measurement of noble gases, and, analyses of the clast size-distribution and the overall texture of Abee. These studies were made in order to understand the formation of the Abee breccia and the formation of the enstatite chondrites. Noble gases were measured as a part of the consortium effort. Noble gases were measured in 17 samples from 10 regions within Abee. Radiogenic ages are 4.5 aeons. Cosmic ray exposure ages average 8 Myr. No evidence for pre-irradiation was found except for a chondrule which may have been neutron pre-irradiated. Abee has at least 2 iodine bearing minerals, both of which are silicate minerals. This suggests that iodine had refractory behavior in the E-chondrites. Two trapped components were found: one having planetary-type elemental and isotopic composition (termed "Kenna-type"), the second with a high argon to xenon ratio (termed "argon-rich") but isotopically similar to the first. Both components appear to be carried in silicate phases, probably enstatite. The Kenna-type component may be carried by small inclusions within silicate minerals. The argon-rich component may have originated from solar wind implantation before accretion of the E-chondrite parent body requiring an inner solar system origin or by noble gas trapping during high temperature mineral condensation requiring high nebular pressures. The clast size-distribution of Abee and 2 other meteorites from the Antarctic meteorite collection (BTNA 78004, ALHA 78113) were measured. The 3 meteorites appear to have formed during single, low energy impacts and that Abee was part of an ejecta blanket which mixed with surrounding regolith. From the textural study, a formation model for the Abee breccia is discussed. The breccia formed during a single impact. Clast metal rims were vapor deposited and partially metamorphosed during impact-generated heating. Greater heating formed dark and metal inclusions. Maximum temperatures were less than 1200 C and heating was brief. Later, the material was disturbed but not brecciated. Abee did not reside on an asteroidal regolith surface for a significant period of time due to the lack of pre-irradiation. This model suggests that the E-chondrite groups formed by metamorphic heating and metal to silicate fractionation on a single parent body.

The solid-metal/silicate-melt partition coefficient for W has been determined experimentally for the temperature and oxygen fugacity conditions at which eucritic basalts formed. The partition coefficient for W is 25 ± 5 at 1190°C and an oxygen fugacity of 10⁻¹³∙⁴. The solid-metal/silicate-melt partition coefficient for P, D(P), has been determined experimentally at 1190°C and 1300°C. The dependence of the partition coefficient on oxygen fugacity is consistent with a valence state of 5 for P in the silicate melt. The experimental partition coefficients are given by: (1) log D(P) = -1.21 log fO₂ -15.95 at 1190°C (2) log D(P) = -1.53 log fO₂ -17.73 at 1300°C The partition coefficients may be used to interpret the depletion of W/La and P/La ratios in the Earth, Moon, and eucrites relative to Cl chondrites. The depletion of the W/La ratios in the eucrites may be explained by partitioning of W into 2% to 10% solid metal assuming equilibration and separation of the metal from the silicates at low degrees of partial melting of the silicates. The depletion of P/La ratios requires an additional 5% to 25% sulfur-bearing metallic liquid. The depletion of both P/La and W/La ratios in the Moon can be explained by partitioning of P and W into liquid metal during formation of a small lunar core by metal-silicate separation at low degrees of partial melting of the silicates. The W/La ratios in the Earth and Moon are virtually indistinguishable, while P/La ratios differ by a factor of two. The concentrations of FeO also appear to be different. These observations are difficult to reconcile with the hypothesis of a terrestrial origin of the Moon following formation of the Earth's core, but are consistent with an independent formation of the Earth and Moon. In contrast to the Moon and eucrites, the depletion of P/La and W/La ratios in the Earth cannot be explained by an internally consistent model involving equilibrium between metal and silicate at low pressures.