Sapporo Gakuin University (SGU): Repository / 札幌学院大学学術機関リポジトリ
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Geological Sketch of the Hadean from oceanic island arc tectonics
冥王代は証拠の乏しい時代で,この時期のみに起こった固有の地質事象も,いくつか推定される。そんな特異な時代を,どのように区分し,どのように地質学的に探っていくのかを検討した。月や他の惑星(小惑星帯の天体も含む),隕石,シミュレーションなどの知見を利用して,冥王代に起こったはずの大きな地質事象(地球形成,ジャイアント・インパクト,後期重爆撃)をもとに6 つに区分した。後期重爆撃後の「海洋性島弧期」については,断片的な証拠が存在し,現在の地球にもアナロジーできる地質場(多数の海洋性島弧の形成と構造侵食による消滅)が存在する。そこから,砕屑性ジルコンの欠損と散逸の理由も見いだせてきた。The Hadean Era, which is characterized by a paucity of evidence, is thought to have been a period during which distinctive geological occurrences took place during the Earth was in the process of formation. This paper presents a discussion of the division of the Hadean Era and the exploration of its geology. A division of the Hadean era into six periods was made based on geological events, including the formation of the Earth, a giant impact, and the late heavy bombardment. This was done using data from the Moon and other planets (including objects in the asteroid belt), meteorites, and computer simulations. The last “oceanic island arc period” is inferred from the evidence of detrital zircon ages and the analogy of modern geological fields (the formation of numerous oceanic island arcs and their extinction by tectonic erosion). The reasons for the loss of Hadean rocks and the dispersal of the old detrital zircons have been elucidated.Bulletin論文Articlesdepartmental bulletin pape