Tomaru, Hitoshi; Fehn, Udo (2012): Distribution of iodine concentration and (super 129) I in interstitial fluid in the Nankai Trough accretionary prism collected during IODP Expeditions 315 and 316. IODP Management International, Washington, DC, United States, In: Kinoshita, Masataka, Tobin, Harold, Ashi, J., Kimura, G., Lallemant, S., Screaton, E. J., Curewitz, D., Masago, H., Moe, K. T., Thu, Moe Kyaw, Gaillot, Philippe, Bourlange, Sylvain, Chang, Chandong, Conin, Marianne, Gulick, Sean, Jurado Rodriguez, Maria Jose Jurado, Martin, Kylara M., McNeill, Lisa, Miyakawa, Ayumu, Moore, J. Casey, Nakamura, Yasuyuki, Saito, Saneatsu, Sawyer, Dale S., Tudge, Joanne, Yamada, Yasuhiro, Masago, Hideki, Behrmann, Jan H., Boeckel, Babette, Byrne, Timothy, Calves, Gerome, Famin, Vincent, Guo Junhua, Hashimoto, Yoshitaka, Hayashi, Hiroki, Henry, Pierre, Hirono, Tetsuro, Hulme, Samuel M., Kaksonen, Anna Henriikka, Kanagawa, Kyuichi, Kanamatsu, Toshiya, Kopf, Achim, Lewis, Jonathan C., Likos, William John, Pares, Josep Maria, Saito, Hiroyuki, Schmidt-Schierhorn, Friederike, Tomaru, Hitoshi, Underwood, Michael, Zhu, Wen-Lu, Chester, Frederick, Fabbri, Olivier, Fergusson, Chris, Girault, France E., Goldsby, David, Harris, Robert, Inagaki, Fumio, Jiang, Tao, Kitamura, Yujin, Knuth, Matt, Li Chunfeng, Liljedahl, Lillemor Claesson, Louis, Laurent, Milliken, Kitty, Nicholson, Uisdean, Riedinger, Natascha, Sakaguchi, Arito, Solomon, Evan, Strasser, Michael, Xin Su, Tsutsumi, Akito, Ujiie, Kochtaro, Yamaguchi, Asuka, Zhao, Xixi, Proceedings of the Integrated Ocean Drilling Program; Nantroseize Stage 1; investigations of seismogenesis, Nankai Trough, Japan; Expeditions 314, 315, and 316 of the riser drilling platform from and to Shingu, Japan; Sites C0001-C0006, 21 September-15 November 2007; and Sites C0001 and C0002, 16 November-18 December 2007; and Sites C0004 and C0006-C0008, 19 December 2007-5 February 2008, 314/315/316, georefid:2012-016472

Abstract:

Iodine concentration and (super 129) I/I ratios were determined in interstitial fluid collected from the Nankai Trough accretionary prism during Integrated Ocean Drilling Program (IODP) Expeditions 315 and 316. Iodine concentrations increase rapidly in the uppermost 100 m below the seafloor, before concentrations reach stable values between 200 and 400 mu M, reflecting the advection of iodine released during the degradation of organic matter in deep sediments. The (super 129) I/I ratios in the interstitial fluid start just below preanthropogenic seawater values and decrease rapidly with depth to ratios approximately 400X10 (super 15) . These ratios result in ages for the potential iodine source formation between 30 and 40 Ma, which are clearly older than the host sediments and demonstrate that advection of fluids is responsible for the observed distribution of iodine at these sites. Significant increases in (super 129) I/I ratios uphole are found just above the lithologic boundary between the overlying forearc basin and older accreted sediments. This observation suggests that only limited migration of ascending deep fluids occurs beyond the lithologic boundary, where sediment porosity drops abruptly from 60% to 50%, and that fluids move preferentially along the lithologic boundary.

Coverage:

West: 136.3800 East: 136.4300 North: 33.1800 South: 33.1400

Relations:

Expedition: 314

Site: 314-C0001

Site: 314-C0002

Expedition: 315

Site: 315-C0001

Site: 315-C0002

Expedition: 326

Site: 326-C0002

Expedition: 332