まとめ
ブラックヒルズのリオリチク火山岩は,約1050万年前のものである. この発見は,火山活動がオリゴセーン時代以降の地域の新たな上昇とともに起こったことを明らかにしています.
科学分野:
- 地質学 地質学 地質学
- ジオクロノロジー (Geochronology) について
- 火山学 火山学とは
背景:
- ブラックヒルズ地域には,火山活動の歴史が知られている.
- 以前の研究では,この地域の火山岩がこれほど若い年代を特定できなかった.
研究 の 目的:
- 北部ブラックヒルズのリオリチク火山岩の年齢を決定するために.
- 火山活動と地域上昇の関係を理解する.
主な方法:
- カリウム-アルゴン同位体年代測定は,火山岩の年齢を決定するために使用されました.
主要な成果:
- ブラックヒルズの北部のリオリチク火山岩は,10.5 +/- 150万年前のカリウム-アルゴン同位体の年齢を産出しました.
- この年齢は,この地域で以前に報告された火山活動よりもかなり若い.
結論:
- オリゴセーン時代以降のブラックヒルズの新たな上昇は,火山活動に伴いました.
- この発見は,ブラックヒルズの火災発生の既知の時間枠を拡大する.
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