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The eastern Jan Mayen microcontinent volcanic margin
| Title: | The eastern Jan Mayen microcontinent volcanic margin |
| Authors: | Breivik, Asbjørn Johan Browse this author | | Mjelde, Rolf Browse this author | | Faleide, Jan Inge Browse this author | | Murai, Yoshio Browse this author →KAKEN DB |
| Keywords: | Controlled source seismology | | Continental margins: divergent | | Oceanic plateaus and microcontinents | | Large igneous provinces | | Crustal structure | | Magma genesis and partial melting |
| Issue Date: | Mar-2012 |
| Publisher: | Blackwell Publishing |
| Journal Title: | Geophysical Journal International |
| Volume: | 188 |
| Issue: | 3 |
| Start Page: | 798 |
| End Page: | 818 |
| Publisher DOI: | 10.1111/j.1365-246X.2011.05307.x |
| Abstract: | The Jan Mayen microcontinent (JMMC) in the NE Atlantic was created through two Cenozoic rift episodes. Originally part of East Greenland, the JMMC rifted from NW Europe during the Early Eocene under extensive magmatism. The eastern margin is conjugate to the Møre-Faeroes volcanic margin. The western JMMC margin underwent prolonged extension before it finally separated from East Greenland during the Late Oligocene. Here we present the modelling by forward/inverse ray tracing of two wide-angle seismic profiles acquired using Ocean Bottom Seismometers, across the northern and the southern JMMC. Early Eocene breakup magmatism at the eastern JMMC produced an igneous thickness of 7-9 km in the north, and 12-14 km in the south. While the continent is clear in the north, the southern JMMC appears to be affected by later Icelandic magmatism. Reduced seismic velocity and increased crustal thickness are compatible with continental crust adjacent to the volcanic margin in the south, but the continental presence towards the Iceland shelf is less clear. Our magnetic track off the southern JMMC gives seafloor spreading rates comparable to that of the conjugate Møre Margin. Transition to ultraslow seafloor spreading occurs at ∼43 Ma, indicating onset of major deformation of the JMMC. Calculating the igneous thickness -- mean Vp relationship at the eastern volcanic margin gives the typical positive correlation seen elsewhere on the NE Atlantic margins. The results indicate temperature driven breakup magmatism under passive mantle upwelling, with a maximum mantle temperature anomaly of ∼50℃ in the north and 90-150℃ in the south. |
| Rights: | The definitive version is available at www.blackwell-synergy.com |
| Type: | article |
| URI: | http://hdl.handle.net/2115/49141 |
| Appears in Collections: | 理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 村井 芳夫
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