@article{oai:aue.repo.nii.ac.jp:00007374,
 author = {星, 博幸},
 issue = {10},
 journal = {地質学雑誌},
 month = {},
 note = {text, 筆者は「関東対曲構造の形成はいつ始まったか」という問題について主に地質と古地磁気の両面から最近の研究をレビューし，現状の到達点について整理した．伊豆衝突帯の櫛形山地塊の地質より，伊豆弧と本州弧の衝突は17Ma頃には始まりつつあったと考えられる．対曲構造の東西両翼から得られた古地磁気データは，対曲構造の形成が約17Maから15Maまでの間のある時期に始まった可能性が高いことを示す．地質から推定される年代と古地磁気から推定される年代が整合することから，約17Maから15Maまでの間のある時期に本州弧と伊豆弧の衝突が始まり，衝突開始と同時に対曲構造の形成も始まったと考えられる．伊豆弧衝突と対曲構造の形成開始を約15Maと考える研究者が多かったが，実際には15Maには衝突も対曲構造形成もすでに始まっていたようだ．小論では対曲構造形成に関連する検証可能な仮説についてもいくつか紹介した．, The Kanto Syntaxis in central Japan is a cuspate, convex-northward deformation structure of zonal geologic belts and belt-bounding faults, and its formation can likely be attributed to the Neogene collision of the Honshu and Izu-Ogasawara (Bonin)-Mariana (IBM) arcs. However, it remains unclear as to how and when the deformation occurred. To determine the age of onset of syntaxis formation, this review summarizes recent geological and paleomagnetic studies, published during the past 25 years, in and around the collision area. The climax of tectonic rotation of both sortheast and southwest Japan during the back-arc opening of the Japan Sea has previously been estimated at ～15 Ma, with this age potentially representing the onset of syntaxis formation. However, sedimentary records in the earliest accreted volcanic edifice indicate that arc-arc collision began at 17 Ma or shortly later .This edifice ,named the Kushigatayama (or Koma) block, originally formed on the IBM arc and is now present in the Izu collision zone. Paleomagnetic analyses, which included an orocline test that utilized early Miocene data from both limbs of the Kanto Syntaxis, suggest that it began to grow between 17 and 15 Ma. This is consistent with the age estimate of the onset of arc-arc collision inferred from the geology of the collision zone. Thus, it is concluded that the arc-arc collision ,which began between 17 and 15 Ma, caused the coeval onset of the syntaxis formation. Hypotheses relating to the development of the syntaxis are introduced, and these need to be tested in future studies.},
 pages = {805--817},
 title = {関東対曲構造の形成はいつ始まったか？},
 volume = {124},
 year = {2018}
}