Direct Evidence for Condensation in the Early Solar System and Implications for Nebular Cooling Rates

Berg, T.; Maul, J.; Schönhense, G.; Marosits, Edit; Hoppe, P.; Ott, U.; Palme, H.

doi:10.1088/0004-637x/702/2/l172

Cited by 49 publications

(106 citation statements)

References 19 publications

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“…were in agreement with theoretical equilibrium condensation calculations for similar grains (Campbell et al, 2001), this led Berg et al (2009) to conclude that all the analysed grains were nebula condensates. However, later work by Schwander et al (2014a) on RMNs from Murchison, Allende and Leoville, show that some but not all RMNs from these residues have been affected by metamorphic oxidation and sulphidation on the 55 parent body resulting in the loss of W and Mo.…”

supporting

confidence: 85%

“…An exhaustive literature search was conducted in an attempt to produce a library of all previous RMN compositional data (Berg et al, 2009;Bischoff & Palme, 1987;Blander et al, 1980;Wark & Lovering, 1976;Wark, 1986;Palme et al, 1982;Croat et al, 2013;Schwander et al, 2014a;Palme et al, 1994;Wark & 140 Lovering, 1978;Harries et al, 2012). We also include compositions of RMNs thought to be derived from crystallisation processes (Schwander et al, 2015;Rudraswami et al, 2014).…”

Section: Condensation Model and Crystallisation Proxymentioning

confidence: 99%

“…Anders et al (1975) 45 noted that PGEs were enriched in residue samples of Allende (CV3oxA) that have been dissolved with strong acids. This observation prompted Berg et al (2009) to study similar residues from the Murchison (CM2) meteorite. Their procedure concentrated RMNs and permitted the analysis of several hundred grains rather than the < 20 analysed in situ in CAIs from previous studies.…”

mentioning

confidence: 99%

“…Their procedure concentrated RMNs and permitted the analysis of several hundred grains rather than the < 20 analysed in situ in CAIs from previous studies. Following earlier work, Berg et al (2009) proceeded with the assumption that RMNs in their residues had previously been associated with CAIs. The 50 compositions of RMNs contained within these residues from energy-dispersive x-ray spectroscopy (EDS)…”

mentioning

confidence: 99%

“…The assumption that has arisen in prior studies is that RMNs are unique to CAIs (Berg et al, 2009;Bischoff & Palme, 1987;Blander et al, 1980;Eisenhour & Buseck, 1992;El Goresy et al, 1978;Fegley 60 & Kornacki, 1984;Grossman et al, 1977;Palme & Wlotzka, 1976;Palme et al, 1982;Sylvester et al, 1990;Wark, 1986;Wark & Lovering, 1976) with one exception: recent work by Croat et al (2013) described RMNs contained within pre-solar graphite. These are the only RMNs that can be interpreted as having a pre-solar origin with relative certainty.…”

mentioning

confidence: 99%

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In situ analysis of Refractory Metal Nuggets in carbonaceous chondrites

Daly

Bland

Dyl

et al. 2017

Geochimica et Cosmochimica Acta

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Micrometre to sub-micrometre scale alloys of platinum group elements (PGEs) know as refractory metal nuggets (RMNs) have been observed in primitive meteorites. The Australian Synchrotron X-ray Fluorescence (XRF) beamline, in tandem with the Maia detector, allows rapid detection of PGEs in concentrations as low as 50-100 ppm at 2 µm resolution. Corroborating this analysis with traditional electron microscopy techniques, RMNs can be rapidly identified in situ within carbonaceous chondrites. These results dispute the assumption of previous studies: that RMNs are unique to Ca-Al-rich inclusions (CAIs). We find that RMNs (Schwander et al., 2015), host phase and host meteorite. This reveals only weak correlations between parent body processes (sulphidation) and nebular processes (condensation and crystallisation) with RMN compositions. It appears that none of these processes acting in isolation or in tandem can explain the diversity we observe in the RMN population. Our interpretation is that the Solar Nebula inherited an initially compositionally diverse population of RMNs from the giant molecular cloud; that a variety of Solar System processes have acted on that population; but none have completely homogenised it. Most RMNs have experienced disk and asteroidal processing, but some may have retained a primordial composition.RMNs have been identified in pre-solar graphite (Croat et al., 2013) grains. We anticipate that pre-solar RMNs will be present elsewhere in primitive meteorites.

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supporting

confidence: 85%