Options
Jiang, W.-T.
Loading...
Preferred name
Jiang, W.-T.
2 results
Now showing 1 - 2 of 2
- PublicationRestrictedFormation of iron sulfide nodules during anaerobic oxidation(2007)
; ; ; ; ; ; ;van Dongen, B. E.; Organic Geochemistry Unit, Bristol Biogeochemistry Research Centre, School of Chemistry, Cantock’s Close, Bristol University, Bristol BS8 1TS, United Kingdom ;Roberts, A. P.; National Oceanography Centre, University of Southampton, European Way, Southampton SO14 3ZH, United Kingdom ;Schouten, S.; Department of Marine Biogeochemistry, Royal Netherlands Institute for Sea Research, P.O. Box 59, 1790 AB Den Burg, Texel, The Netherlands ;Jiang, W-T; Department of Earth Sciences, National Cheng Kung University, Tainan 70101, Taiwan, PR China ;Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Pancost, R. D.; Organic Geochemistry Unit, Bristol Biogeochemistry Research Centre, School of Chemistry, Cantock’s Close, Bristol University, Bristol BS8 1TS, United Kingdom; ; ; ; ; The biomarker compositions of iron sulfide nodules (ISNs; upper Pliocene Valle Ricca section near Rome, Italy) that contain the ferrimagnetic mineral greigite (Fe3S4) were examined. In addition to the presence of specific terrestrial and marine biomarkers, consistent with formation in coastal marine sediments, these ISNs contain compounds thought to originate from sulfate reducing bacteria (SRB). These compounds include a variety of low-molecular-weight and branched alkanols and several non-isoprenoidal dialkyl glycerol diethers (DGDs). In addition, archaeal biomarkers, including archaeol, macrocyclic isoprenoidal DGDs and isoprenoidal glycerol dialkyl glycerol tetraethers are also present. Both SRB and archaeal lipid d13C values are depleted in 13C (d13C values are typically less than 50‰), which suggests that the SRB and archaea consumed 13C depleted methane. These biomarker and isotopic signatures are similar to those found in cold seeps and marine sediments where anaerobic oxidation of methane (AOM) occurs with sulfate serving as the terminal electron acceptor. Association of AOM with formation of greigite-containing ISNs could provide an explanation for documented remagnetization of the Valle Ricca sediments. Upward migration of methane, subsequent AOM and associated authigenic greigite formation are widespread processes in the geological record that have considerable potential to compromise paleomagnetic records. 2007 Elsevier Ltd. All rights reserved.143 19 - PublicationRestrictedAssessing the timing of greigite formation and the reliability of the Upper Olduvai polarity transition record from the Crostolo River, Italy(2005)
; ; ; ; ; ;Roberts, A. P.; Southampton Oceanography Centre, Southampton, UK ;Jiang, W.-T.; Department of Earth Sciences, National Cheng Kung University, Tainan, Taiwan ;Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Horng, C.-S.; Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan ;Laj, C.; Laboratoire des Sciences du Climat et de l’Environnement (LSCE), Gif-sur-Yvette, France; ; ; ; The Crostolo River section in Italy yielded a detailed record of the Upper Olduvai geomagnetic polarity transition that has been used to support the hypothesis of deep mantle control on the transitional geomagnetic field. The paleomagnetic record is carried by the authigenic iron sulphide, greigite, which was interpreted to have formed shortly after deposition. Our detailed scanning electron microscope investigations indicate the presence of at least 3 generations of pyrite, which usually forms with greigite as a precursor. This suggests that the total magnetization is a complex composite that produced a smoothed record of transitional field behaviour.159 21