地下気象は大陸の安定化を促した
Jesse R Reimink1, Andrew J Smye2
1Department of Geosciences, Pennsylvania State University, University Park, PA, USA. jreimink@psu.edu.
Nature
|May 8, 2024
まとめ
新興大陸の地下気象は熱を生成する元素を集中させ,地殻の融解を促し,地球独特の大陸の地殻を安定させました. この過程はネオアルカイア期におけるクラトンの形成を説明する.
科学分野:
- 地理科学
- 惑星科学
- 地化学
背景:
- 地球の大陸地殻は シリカが豊富で 地球上の惑星の中で ユニークで 居住に不可欠です
- 古代の安定した大陸の断片であるクレートンは 地球の表面の50%を占めているが,その安定化メカニズムは十分に理解されていない.
- 異なる地殻の形成,特にウラン,トリウム,カリウムが豊富な花型岩は,30億年から25億年前に広範囲に発生しました.
研究 の 目的:
- クラトン安定化と地球の大陸地殻の分化に伴うメカニズムを調査する.
- ネオアーカイアン・グラニトイド・マグマの形成における上空の気象化の役割を明らかにする.
- ネオアルカイア期における大陸の構成の再編成について説明する.
主な方法:
- 地質学的な証拠の分析 表面下での気象変動と地殻内融解
- 熱を生成する元素の濃度のモデル化
- 大陸の出現,気象化,そして地殻の深いプロセスとの関係を調査する.
主要な成果:
- 大陸の出現に続く上空の気象は,地殻内融解とパラアルミニウム状の花岩マグマの生成を促進した.
- 熱を生成する元素 (U,Th,K) を沈殿し,深層の地殻に組み込みました.
- このプロセスは地殻の融解とクレートンの石層の安定化に必要な化学的層分化をもたらした.
結論:
- 大陸の出現とそれに続く上空の気象は,地球の地殻の最終的な分化にとって重要な要因であった.
- 気象による堆積物における放射性元素の濃度は,必然的にクレートン安定化につながった.
- この気象によるプロセスは 長期にわたる疑問を解決しています なぜ多くのクラトンは ネオアルカイア期に安定したのか 放射性熱の生成が増加した時期です
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