40Ar/39Ar ラスロップウェルズ火山センターの年代,ユッカ山,ネバダ州
まとめ
古磁気年代測定とアルゴン・アルゴン年代測定は,ネバダ州ラスロップ・ウェルズ火山の中心にある2つの区別がつかない噴火イベントを明らかにし,約13万6千~14万年前に発生し,以前の年齢推定と矛盾しています.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- 火山学 火山学とは
- ジオクロノロジー (Geochronology) について
背景:
- ネバダ州にあるラスロップ・ウェルズ火山の中心は,その噴火の歴史に関する研究の対象となっている.
- 地質学と土壌プロファイルに基づく以前の解釈は,約2万年前に複数の噴火が起こったことを示唆した.
研究 の 目的:
- ラスロップ・ウェルズ火山の中心地の噴火年代を正確に決定するために.
- 火山の中心年齢と噴火頻度に関する対立する解釈を調和させるため.
主な方法:
- 火山岩の古磁気分析. 火山岩の古磁気分析. 火山岩の古磁気分析. 火山岩の古磁気分析.
- アルゴン-アルゴン (40Ar/39Ar) ジオクロノロジック年代測定.
- パレオマグネティクスとジオクロノロジックデータを地表地質単位と比較する.
主要な成果:
- ラスロップ・ウェルズ火山中心部で2つの異なる噴火が確認されました.
- これらの出来事の年代は,古磁気分析と40Ar/39Ar分析によって決定され,区別がつかない (136 ± 8年と141 ± 9千年前).
- データは,これらの2つの出来事が約100年の間隔で起こったことを示しており,地域地質年代表と一致しています.
結論:
- ラスロップ・ウェルズ火山の中心は,約13万6千~14万年前に発生した2回の噴火しか経験していない.
- これらの発見は,約2万年前の少なくとも5つの別々の噴火イベントに関する以前の仮説と矛盾しています.
- この研究は,ユッカ山脈地域の火山活動の理解を深める.
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