Rock magnetism and paleomagnetic stratigraphy of forearc sediments of the Japan Trench, ODP Sites 1150 and 1151 |
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| Authors: | Toshiya Kanamatsu Nobuaki Niitsuma |
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| Institution: | Deep Sea Research Department, Japan Marine Science and Technology Center, 2-15 Natsushima, Yokosuka 237-0061, Japan (email: );and Institute of Geosciences, Shizuoka University, 836 Oya, Shizuoka 422-8529, Japan |
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| Abstract: | Abstract Magnetic measurements were carried out to investigate rock magnetic properties and paleomagnetic directions of late and middle Miocene sediments recovered from the land side of the Japan Trench during the Ocean Drilling Program Leg 186. Because the low coercive component in natural remanent magnetization (NRM) normalized by anhysteretic remanent magnetization shows that the drilling‐induced magnetization is severe in the sections obtained by the advanced hydraulic piston coring method, careful analyses of demagnetization of NRM using the ‘demagnetization plane’ were carried out to decompose the direction and intensity. Magnetostratigraphic correlation down to the upper Miocene, supplemented by biostratigraphic data, revealed that the sedimentation rates are characterized by drastic changes, with the early Pliocene having the highest rate. This high sedimentation rate is related to the subsidence of the southern deep‐sea terrace of the Japan Trench. |
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| Keywords: | drilling-induced remanence Japan Trench magnetostratigraphy sedimentation rate |
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