Exhumed hydrocarbon-seep authigenic carbonates from Zakynthos Island (Greece): Concretions not archaeological remains |
| |
| Institution: | 1. School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK;2. Department of Geology and Geoenvironment, National and Kapodistrian University of Athens, GR 15784, Panepistimiopolis, Athens, Greece;3. Geochronology and Tracers Facility, NERC Isotope Geosciences Laboratory, British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK;1. College of Mathematics and Information Science, Shaanxi Normal University, Xi’an, Shaanxi 710062, People’s Republic of China;2. Institute of Mathematics and Information Science, Baoji University of Arts and Sciences, Baoji, Shaanxi 721013, People’s Republic of China;1. Université de Tours, CNRS, CEA, INSA, GREMAN UMR 7347, IUT de Blois, 15 rue de la chocolaterie, CS 2903, 41029 Blois Cedex, France;2. Bundesanstalt für Materialforschung und –prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany;1. Dep. of Biology Demography and Conservation of Long Lived Species Lab. CISSC University of Pisa, Via Volta 4, 56126, Pisa, Italy;2. Istituto Nazionale di Oceanografia e Geofisica Sperimentale, Via Grotta Gigante, 42c, Sgonico, 34010, Trieste, Italy;1. Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, 70126 Bari, Italy;2. Department of Biology, University of Bari, Via Orabona 4, 70126 Bari, Italy;1. Department of Petroleum Engineering and Applied Geophysics, Norwegian University of Science and Technology, Trondheim, Norway;2. MultiClient Geophysical, Stasjonsveien 18, 1396 Billingstad, Norway |
| |
| Abstract: | In Zakynthos Island (Greece), authigenic cementation of marine sediment has formed pipe-like, disc and doughnut-shaped concretions. The concretions are mostly composed of authigenic ferroan dolomite accompanied by pyrite. Samples with >80% dolomite, have stable isotope compositions in two groups. The more indurated concretions have δ18O around +4‰ and δ13C values between ?8 and ?29‰ indicating dolomite forming from anaerobic oxidation of thermogenic methane (hydrocarbon seep), in the sulphate-methane transition zone. The outer surfaces of some concretions, and the less-cemented concretions, typically have slightly heavier isotopic compositions and may indicate that concretion growth progressed from the outer margin in the ambient microbially-modified marine pore fluids, inward toward the central conduit where the isotopic compositions were more heavily influenced by the seep fluid. Sr isotope data suggest the concretions are fossil features, possibly of Pliocene age and represent an exhumed hydrocarbon seep plumbing system. Exposure on the modern seabed in the shallow subtidal zone has caused confusion, as concretion morphology resembles archaeological stonework of the Hellenic period. |
| |
| Keywords: | Dolomite Concretions Stable isotopes Hydrocarbon-seep Marine archaeology Zakynthos |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
