独特のREEパターンを持つコンドルル:高C/Oの太陽雲凝縮に及ぼす影響
Andreas Pack1, J Michael G Shelley, Herbert Palme
1Institut für Mineralogie und Geochemie, Universität Köln, Zülpicher Strasse 49b, D-50674 Köln, Germany. apack@crpg.cnrs-nancy.fr
Science (New York, N.Y.)
|February 14, 2004
まとめ
コンドルルから得られた稀土元素 (REE) のデータは,低酸素レベルでのガス/固体分離が起きたことを示唆している. これは,初期の太陽星雲の条件が,これまで考えられていたよりも酸素が少ないことを意味する.
科学分野:
- 宇宙化学 (コスモケミストリー)
- 惑星科学は惑星科学である.
- 地質化学 地質化学
背景:
- 普通のコンドライトは,初期の太陽系プロセスについての洞察を提供します.
- 稀土元素 (REEs) は,惑星の形成と分化における重要なトレーサーである.
- 以前のモデルでは,正規の太陽星雲の特定の酸素流動性を想定していた.
研究 の 目的:
- 普通のコンドライトのコンドルールにおける独特のREE異常の起源を調査する.
- REEのガス/固体分断の仮説を低酸素流動性条件下で検証する.
- 初期の太陽星雲の化学的環境を推論する.
主な方法:
- 2つの通常のコンドライトコンドルールの希土元素濃度の分析.
- コンドライトで正常化されたREEパターン分析.
- ガス/固体分断プロセスのモデリング.
主要な成果:
- コンドルルREEデータで,サマリウム,ヨーロッパウム,イテルビウムの明確な負の異常が観察されました.
- これらの異常は,低酸素流動性でのREEガス/固体分離と一致しています.
- この発見は,高濃度,超耐火性コンデンサートの組み込みを示唆している.
結論:
- 初期の太陽星雲は,かなりの酸素不足の環境を経験した可能性が高い.
- 高温凝縮プロセスは,炭素と酸素の比率が向上した条件下で発生した.
- これは,正規の太陽星雲の酸素の流動性に関する以前の仮定に異議を唱える.
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