爆発的な火山活動が極度にゆっくりと広がるガッケル山脈,北極海で起きている
Robert A Sohn1, Claire Willis, Susan Humphris
1Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA. rsohn@whoi.edu
Nature
|June 27, 2008
まとめ
爆発的な火山噴火は,以前は深海で不可能と考えられていたが,Gakkelの山脊で発見された. ピロクラスティック堆積物は,4,000mの深さで10km2以上で発見され,マグマの断片化に関する以前の仮定に異議を唱えました.
科学分野:
- 地質学 地質学 地質学
- 火山学 火山学とは
- 海洋学 海洋学とは
背景:
- 海洋殻は,地球表面の60%をカバーし,中洋の山脊の火山活動によって形成されています.
- 爆発的な噴火は,高水圧と低マグマの揮発性含有量のために3,000m以下では珍しいと考えられています.
研究 の 目的:
- 先進的な深層潜水技術を使用して,超低速に広がるガッケル山脈の火山地形を調査する.
- 海水の臨界点以下の深さでの火山活動の証拠を記録する.
主な方法:
- ガッケル山脈の写真とビデオ撮影のために,新しい深水潜水技術を活用しました.
- 北極盆地の約4,000mの水深で"ゼロエイジ"の火山地形を調査した.
主要な成果:
- バブル壁の断片を含む広範囲にわたる非統合型火力弾性堆積物が発見され,軸の谷の10km2以上を覆った.
- これらの深さでマグマの断片化のために少なくとも13.5%のCO2の必要性を特定し,以前測定された値より大幅に高くなっています.
結論:
- 大規模なピロクラスティック活動は,海中の火山系の最も深い部分で可能である.
- 発見は,爆発的な火山活動が3,000m未満の深さでは存在しないという長年の信念に挑戦しています.
- 揮発性物質の蓄積と放出メカニズムについて疑問を投げかけます.
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