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Magnetic minerals and magnetic properties of the Siwalik Group sediments of the Karnali river section in Nepal
| Title: | Magnetic minerals and magnetic properties of the Siwalik Group sediments of the Karnali river section in Nepal |
| Authors: | Gautam, Pitambar Browse this author →KAKEN DB | | Hosoi, Azumi Browse this author | | Regmi, Kamal Raj Browse this author | | Khadka, Dharma Raj Browse this author | | Fujiwara, Yoshiki Browse this author |
| Issue Date: | 1-May-2000 |
| Publisher: | Terra Scientific Publishing Company |
| Journal Title: | Earth, Planets and Space |
| Volume: | 52 |
| Issue: | 5 |
| Start Page: | 337 |
| End Page: | 345 |
| Abstract: | Sandstones and siltstones collected from the Siwalik molasse sequence (~16 to 5 Ma) of the Karnali river section have been studied for their magnetic properties. Behavior of the specimens during demagnetization (of theNRMand IRM) and magnetic susceptibility vs. temperature data suggest that goethite, maghemite/magnetite, and hematite are the main magnetic minerals in the section. Goethite, carrying a recent component, is the dominant magnetic mineral in the fine-grained lithologies from the lower part. Maghemite and magnetite, which also carry a secondary remanence, occur in the sandstones from the upper part. Hematite, mainly of detrital origin, is present in the whole sequence. The magnetic fabric is defined by mainly oblate AMS ellipsoids and a low degree of anisotropy (P' < 1.20). The magnetic lineations (declinations: 75°-130° or 245°-310°; peak orientation: 290°/2.8°) are subparallel to the fold axes/bedding strikes/thrust fronts (WNW-ESE). The initial sedimentary-compactional fabric has been overprinted by a secondary tectonic fabric, which was probably induced by mild deformation active in the compressive tectonic setting. |
| Type: | article |
| URI: | http://hdl.handle.net/2115/42495 |
| Appears in Collections: | 創成研究機構 (Creative Research Institution) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: Gautam Pitambar
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