Not logged in
PANGAEA.
Data Publisher for Earth & Environmental Science

Fehn, Udo; Lu, Zunli; Tomaru, Hitoshi (2006): Halogene concentrations and iodine isotopic composition in pore water on Hydrare Ridge, Cascadia continental margin [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.706970, Supplement to: Fehn, U et al. (2006): Data report: 129I/I ratios and halogen concentrations in pore water of Hydrate Ridge and their relevance for the origin of gas hydrates: a progress report. In: Tréhu, A.M., Bohrmann, G., Torres, M.E., Colwell, F.S. (Eds.), Proceedings of the Ocean Drilling Program, Scientific Results, 204, 1-25(online), https://doi.org/10.2973/odp.proc.sr.204.107.2006

Always quote citation above when using data! You can download the citation in several formats below.

RIS CitationBibTeX CitationShow MapGoogle Earth

Abstract:
We report iodine and bromine concentrations in a total of 256 pore water samples collected from all nine sites of Ocean Drilling Program Leg 204, Hydrate Ridge. In a subset of these samples, we also determined iodine ages in the fluids using the cosmogenic isotope 129I (T1/2 = 15.7 Ma). The presence of this cosmogenic isotope, combined with the strong association of iodine with methane, allows the identification of the organic source material responsible for iodine and methane in gas hydrates. In all cores, iodine concentrations were found to increase strongly with depth from values close to that of seawater (0.0004 mM) to concentrations >0.5 mM. Several of the cores taken from the northwest flank of the southern summit show a pronounced maximum in iodine concentrations at depths between 100 and 150 meters below seafloor in the layer just above the bottom-simulating reflector. This maximum is especially visible at Site 1245, where concentrations reach values as high as 2.3 mM, but maxima are absent in the cores taken from the slope basin sites (Sites 1251 and 1252). Bromine concentrations follow similar trends, but enrichment factors for Br are only 4-8 times that of seawater (i.e., considerably lower than those for iodine).
Iodine concentrations are sufficient to allow isotope determinations by accelerator mass spectrometry in individual pore water samples collected onboard (~5 mL). We report 129I/I ratios in a few samples from each core and a more complete profile for one flank site (Site 1245). All 129I/I ratios are below the marine input ratio (Ri = 1500x10**-15). The lowest values found at most sites are between 150 and 250x10**-15, which correspond to minimum ages between 40 and 55 Ma, respectively. These ages rule out derivation of most of the iodine (and, by association, of methane) from the sediments hosting the gas hydrates or from currently subducting sediments. The iodine maximum at Site 1245 is accompanied by an increase in 129I/I ratios, suggesting the presence of an additional source with an age younger than 10 Ma; there is indication that younger sources also contribute at other sites, but data coverage is not yet sufficient to allow a definitive identification of sources there. Likely sources for the older component are formations of early Eocene age close to the backstop in the overriding wedge, whereas the younger sources might be found in recent sediments underlying the current locations of the gas hydrates.
Project(s):
Ocean Drilling Program (ODP)
Coverage:
Median Latitude: 44.578422 * Median Longitude: -125.130240 * South-bound Latitude: 44.568600 * West-bound Longitude: -125.152517 * North-bound Latitude: 44.586233 * East-bound Longitude: -125.074000
Date/Time Start: 2002-07-12T00:00:00 * Date/Time End: 2002-09-01T00:00:00
Event(s):
204-1244 * Latitude: 44.586233 * Longitude: -125.119750 * Date/Time Start: 2002-07-12T00:00:00 * Date/Time End: 2002-08-22T00:00:00 * Elevation: -895.4 m * Penetration: 1051.2 m * Recovery: 545 m * Location: North Pacific Ocean * Campaign: Leg204 * Basis: Joides Resolution * Method/Device: Composite Core (COMPCORE) * Comment: 69 cores; 555.5 m cored; 495.7 m drilled; 98.1 % recovery
204-1245 * Latitude: 44.586133 * Longitude: -125.149050 * Date/Time Start: 2002-07-17T00:00:00 * Date/Time End: 2002-08-16T00:00:00 * Elevation: -870.7 m * Penetration: 1619.7 m * Recovery: 646.6 m * Location: North Pacific Ocean * Campaign: Leg204 * Basis: Joides Resolution * Method/Device: Composite Core (COMPCORE) * Comment: 93 cores; 761 m cored; 858.7 m drilled; 85 % recovery
204-1246 * Latitude: 44.586067 * Longitude: -125.135533 * Date/Time Start: 2002-07-18T00:00:00 * Date/Time End: 2002-08-11T00:00:00 * Elevation: -850.0 m * Penetration: 316.7 m * Recovery: 135.4 m * Location: North Pacific Ocean * Campaign: Leg204 * Basis: Joides Resolution * Method/Device: Composite Core (COMPCORE) * Comment: 16 cores; 136.7 m cored; 180 m drilled; 99 % recovery
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
18 datasets

Download Data

Download ZIP file containing all datasets as tab-delimited text — use the following character encoding:

Datasets listed in this publication series

  1. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T1) Concentrations of iodine, bromine, and chlorine in pore water of ODP Site 204-1244. https://doi.org/10.1594/PANGAEA.706952
  2. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T2) Iodine isotopic composition and minimum ages in pore water of ODP Site 204-1244. https://doi.org/10.1594/PANGAEA.706961
  3. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T1) Concentrations of iodine, bromine, and chlorine in pore water of ODP Site 204-1245. https://doi.org/10.1594/PANGAEA.706953
  4. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T2) Iodine isotopic composition and minimum ages in pore water of ODP Site 204-1245. https://doi.org/10.1594/PANGAEA.706962
  5. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T1) Concentrations of iodine, bromine, and chlorine in pore water of ODP Site 204-1246. https://doi.org/10.1594/PANGAEA.706954
  6. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T2) Iodine isotopic composition and minimum ages in pore water of ODP Hole 204-1246B. https://doi.org/10.1594/PANGAEA.706963
  7. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T1) Concentrations of iodine, bromine, and chlorine in pore water of ODP Site 204-1247. https://doi.org/10.1594/PANGAEA.706955
  8. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T2) Iodine isotopic composition and minimum ages in pore water of ODP Hole 204-1247B. https://doi.org/10.1594/PANGAEA.706964
  9. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T1) Concentrations of iodine, bromine, and chlorine in pore water of ODP Site 204-1248. https://doi.org/10.1594/PANGAEA.706956
  10. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T2) Iodine isotopic composition and minimum ages in pore water of ODP Hole 204-1248C. https://doi.org/10.1594/PANGAEA.706965
  11. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T1) Concentrations of iodine, bromine, and chlorine in pore water of ODP Site 204-1249. https://doi.org/10.1594/PANGAEA.706957
  12. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T2) Iodine isotopic composition and minimum ages in pore water of ODP Hole 204-1249C. https://doi.org/10.1594/PANGAEA.706966
  13. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T1) Concentrations of iodine, bromine, and chlorine in pore water of ODP Site 204-1250. https://doi.org/10.1594/PANGAEA.706958
  14. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T2) Iodine isotopic composition and minimum ages in pore water of ODP Hole 204-1250C. https://doi.org/10.1594/PANGAEA.706967
  15. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T1) Concentrations of iodine, bromine, and chlorine in pore water of ODP Site 204-1251. https://doi.org/10.1594/PANGAEA.706959
  16. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T2) Iodine isotopic composition and minimum ages in pore water of ODP Site 204-1251. https://doi.org/10.1594/PANGAEA.706968
  17. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T1) Concentrations of iodine, bromine, and chlorine in pore water of ODP Site 204-1252. https://doi.org/10.1594/PANGAEA.706960
  18. Fehn, U; Lu, Z; Tomaru, H (2006): (Table T2) Iodine isotopic composition and minimum ages in pore water of ODP Hole 204-1252A. https://doi.org/10.1594/PANGAEA.706969