کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6441599 | 1639095 | 2014 | 47 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Shallow water methane-derived authigenic carbonate mounds at the Codling Fault Zone, western Irish Sea
ترجمه فارسی عنوان
تپه های کربنات اته یژنیک مشتق شده از متان در منطقه گسل نوردی، دریای ایرلند غربی
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کلمات کلیدی
MDACCFZEDSDMDSMethane-derived authigenic carbonateMAGEAOMGas seepage - اشباع گازAnaerobic oxidation of methane - اکسیداسیون بی هوازی متانIrish Sea - دریای ایرلندیdimethyl disulfide - دی متیل دی سولفیدEnergy-dispersive spectroscopy - طیف سنجی انرژی پراکندهFatty acid methyl ester - متیل استر اسید چربFAME یا fatty acid methyl esters - متیل استرهای اسید چربSEM - مدل معادلات ساختاری / میکروسکوپ الکترونی روبشیScanning electron microscopy - میکروسکوپ الکترونی روبشیX-ray diffraction - پراش اشعه ایکسXRD - پراش اشعه ایکس
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
ژئوشیمی و پترولوژی
چکیده انگلیسی
Methane-derived authigenic carbonate (MDAC) mound features at the Codling Fault Zone (CFZ), located in shallow waters (50-120 m) of the western Irish Sea were investigated and provide a comparison to deep sea MDAC settings. Carbonates consisted of aragonite as the major mineral phase, with δ13C depletion to â 50â° and δ18O enrichment to ~ 2â°. These isotope signatures, together with the co-precipitation of framboidal pyrite confirm that anaerobic oxidation of methane (AOM) is an important process mediating methane release to the water column and the atmosphere in this region. 18O-enrichment could be a result of MDAC precipitation with seawater in colder than present day conditions, or precipitation with 18O-enriched water transported from deep petroleum sources. The 13C depletion of bulk carbonate and sampled gas (â 70â°) suggests a biogenic source, but significant mixing of thermogenic gas and depletion of the original isotope signature cannot be ruled out. Active seepage was recorded from one mound and together with extensive areas of reduced sediment, confirms that seepage is ongoing. The mounds appear to be composed of stacked pavements that are largely covered by sand and extensively eroded. The CFZ mounds are colonized by abundant Sabellaria polychaetes and possible Nemertesia hydroids, which benefit indirectly from available hard substrate. In contrast to deep sea MDAC settings where seep-related macrofauna are commonly reported, seep-specialist fauna appear to be lacking at the CFZ. In addition, unlike MDAC in deep waters where organic carbon input from photosynthesis is limited, lipid biomarkers and isotope signatures related to marine planktonic production (e.g. sterols, alkanols) were most abundant. Evidence for microbes involved in AOM was limited from samples taken; possibly due to this dilution effect from organic matter derived from the photic zone, and will require further investigation.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Marine Geology - Volume 357, 1 November 2014, Pages 139-150
Journal: Marine Geology - Volume 357, 1 November 2014, Pages 139-150
نویسندگان
Shane S. O'Reilly, Krzysztof Hryniewicz, Crispin T.S. Little, Xavier Monteys, Michal T. Szpak, Brian T. Murphy, Sean F. Jordan, Christopher C.R. Allen, Brian P. Kelleher,