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doi:10.2204/iodp.proc.314315316.215.2011

Summary

In summary, sedimentary cores recovered from Expedition 316 drill sites appear to record a stable component of magnetization with both normal and reversed inclinations after removal of the pervasive drilling-induced remagnetization. Comparison between continuous and discrete samples indicates that some of the drilling-induced magnetization may remain in long-core measurements even at the highest AF demagnetization level. Rock magnetic data on Expedition 316 samples clearly indicate that titanomagnetite is the dominant mineral and the primary remanence carrier. Several representative samples of this titanomagnetite group exhibit a Verwey transition in the vicinity of 120 K, which is in good agreement with the thermomagnetic characteristics of titanomagnetites with Curie temperatures of ~580°C that were identified. The general good magnetic stability and other properties exhibited by these rocks support the inference that the characteristic directions of magnetization isolated from the Nankai Trough drill sites were acquired during original deposition. The stable inclinations identified from these samples are therefore useful for future tectonic studies.

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