オントン・ジャワ高原のより若く伸びた位置
Peter C Davidson1, Anthony A P Koppers1, Takashi Sano2
1College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA.
まとめ
オントン・ジャワ高原
科学分野:
- 地理学,古海洋学,火山学
背景:
- オントン・ジャワ高原 (OJP) の海底火山は,海洋無酸素現象1a (OAE 1a) と関連している.
- 以前の研究では,OJPの形成の正確な年代測定が欠け,OAE 1aの接続について堆積物プロキシーに頼っていた.
研究 の 目的:
- オントン・ジャワ高原の噴火の歴史とタイミングを精査する.
- OJPの配置と海洋無酸素現象1aの因果関係を再評価する.
主な方法:
- 高精度40Ar/39Arのジオクロノロジーは,OJPの掘削と掘削現場からのサンプルで行われました.
主要な成果:
- 新しい40Ar/39Ar年代は,OJPの形成が少なくとも600万年にわたって起こったことを示しています.
- これらの年齢は,以前確立された日付より,最大1000万年若いです.
- 改訂されたタイミングは,OJPがOAE 1aの主な原因であるには若すぎることを示唆しています.
結論:
- オントン・ジャワ高原の長期形成は,OAE 1aにおけるその役割に異議を唱えるが,後のOAE 1bとの潜在的なリンクを示唆している.
- この発見は,大規模な火山地帯の位置動態を理解するための意味を持つ.
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