Distribution of organic geochemical elements in differentsedimentary microfacies of tidal flats from north branch of the Yangtze River mouth
Li Lin1 Wang Zhanghua2 Wu Xuxu1 Gao Xiaoqin1
1 Department of Geography, East China Normal University, Shanghai 200062; 2 State Key Laboratory for Estuarine and Coastal Research, East China Normal University, Shanghai 200062
Abstract：We examined the spatial distribution of total organic carbon(TOC)，total nitrogen(TN)，and total sulfur(TS)in the surficial sediments of tidal flats from Beisiyaogang(SY)，Beipugang(BBG)，and Xinweicun(XW)，Chongming island at the north branch of the Yangtze River mouth.Factors controlling distribution of the organic elements were discussed and TOC/TN，TS/TOC ratios and TS-TOC relationship were analyzed to explore their potential for distinguishing different sedimentary microfacies of tidal flats in the study area.The results indicate that the content of TOC and the type of organic matter played a key role in the spatial distribution of TN and TS.In the progradational tidal flat，TOC/TN in upper tidal flat was generally larger than 10，but was smaller than 10 in middle tidal flat.The vegetation zone of the middle tidal flat had the highest average TS/TOC value of 0.063.The TS/TOC value in Spartina alterniflora zone of upper tidal flat and the bare area of middle tidal flat ranked the second(0.055 and 0.054，respectively);while in the Phragmites australis zone of upper tidal flat it showed the lowest value.The slope of TS-TOC linear regression was remarkably low in the Phragmites australis zone of upper tidal flat and gradually increased seaward.In the regradational tidal flat，TOC/TN in the whole intertidal zone exceeded 10，with higher values in mid-low tidal flat than in upper flat.However，TOC/TN was much smaller than 10 in the subtidal zone.TS/TOC increased gradually from land to sea.The slopes of TS-TOC regression lines were maximum in the middle tidal flat and minimum in the upper tidal flat.Moreover，the TS-TOC slope in regradational tidal flat was apparently lower than that in progradational tidal flat.We concluded that TOC/TN，TS/TOC and the liner regression of TS-TOC varied among different sedimentary microfacies of tidal flats in the study area，and therefore these proxies could be applied in the identification of different sedimentary microfacies of tidal flats for the Holocene core sediments.
Li Lin,Wang Zhanghua,Wu Xuxu et al. Distribution of organic geochemical elements in differentsedimentary microfacies of tidal flats from north branch of the Yangtze River mouth[J]. JOPC, 2013, 15(1): 95-104.
高晓琴，王张华，李琳，等.2012.长江口现代潮滩表层沉积物磁性特征和铁硫化物在潮滩微相的分布［J］.古地理学报，14（5）:673-684. 高占国，张利权.2006.应用间接排序识别盐沼植被的光谱特征：以崇明东滩为例［J］.植物生态学报，30（2）:252-260. 李从先，范代读.2009.全新世长江三角洲的发育及其对相邻海岸沉积体系的影响［J］.古地理学报，11（1）:115-122. 刘英俊，曹励明.1987.元素地球化学导论［M］.北京：地质出版社，253. 贺强，安渊，崔保山.2010.滨海盐沼及其植物群落的分布与多样性［J］.生态环境学报，19(3):657-664. 吴绪旭，王张华，何中发.2012.总硫总有机碳比（TS/TOC）对长江三角洲南部平原沉积环境的指示意义［J］.古地理学报，14（6）:821-828. 杨世伦，谢文辉，朱骏，等.2001.大河口潮滩地貌动力过程的研究：以长江口为例［J］.地理学与国土研究，17（3）:4-8. 战庆.2012.长江三角洲全新世早中期高精度海平面曲线重建及沉积地貌环境响应初探［D］.华东师范大学博士学位论文. Bard E，Hamelin B，Arnold M， et al.1996.Deglacial sea-level record from Tahiti corals and the timing of global meltwater discharge［J］.Nature，382（18）:241-244. Berner R A.1984.Sedimentary pyrite formation: An update［J］.Geochimica et Cosmochimica Acta，48: 605-615. Berner R A，Raiswell R.1984.C/S method for distinguishing freshwater from marine sedimentary rocks［J］.Geology，12: 365-368. Bird M Ⅰ，Austin W E N，Wurster C M， et al.2010.Punctuated eustatic sea-level rise in the early mid-Holocene［J］.Geology，38（9）:803-806. Borrego J，Lopez M，Pendon J G， et al.1998.C/S ratios in estuarine sediments of the Odiel River-mouth，S.W.Span［J］.Journal of Coastal Research，14（4）:1276-1283. Clark J A，Farrell W E，Peltier W R.1978.Global changes in postglacial sea level: A numerical calculation［J］.Quaternary Research，9: 265-287. Hanebuth T，Stattegger K，Grootes P M.2000.Rapid flooding of the Sunda Shelf: A late-glacial sea-level record［J］.Science，288（12）:1033-1035. Hasegawa T，Hibino T，Hori S.2010.Indicator of paleosalinity: Sedimentary sulfur and organic carbon in the Jurassic-Cretaceous Tetori Group，central Japan［J］.Island Arc，19: 590-604. Horton B P.1999.The distribution of contemporary intertidal foraminifera at Cowpen Marsh，Tees Estuary，UK: Implications for studies of Holocene sea-level changes［J］.Palaeogeography，Palaeoclimatology，Palaeoecology，149: 127-149. Lamb A L，Wilson G P，Leng M J.2006.A review of coastal palaeoclimate and relative sea-level reconstructions using δ13C and C/N ratios in organic material［J］.Earth-Science Reviews，75: 29-57. Lloyd J M，Shennan Ⅰ，Kirby J R， et al.1999.Holocene relative sea-level changes in the inner Solway Firth［J］.Quaternary International，60: 83-105. Meyers P A.2003.Applications of organic geochemistry to paleolimnological reconstructions: A summary of examples from the Laurentian Great Lakes［J］.Organic Geochemistry，34: 261-289. Sampei Y，Matsumoto E，Kamei T， et al.1997.Sulfur and organic carbon relationship in sediments from coastal brackish lakes in the Shimane peninsula district，southeast Japan［J］.Geochimica，31: 245-262. Szkornik K，Gehrels W R，Kirby J R.2006.Using salt-marsh diatoms to reconstruct sea-level changes in Ho Bugt western Denmark［J］.Marine Geology，235: 137-150. Wang Z H，Zhuang C C，Saito Y， et al.2012.Early mid-Holocene sea-level change and coastal environmental response on the southern Yangtze delta plain，China: Implications for the rise of Neolithic culture［J］.Quaternary Science Reviews，35: 51-62. Westrich J T，Berner R A.1984.The role of sedimentary organic matter in bacterial sulfate reduction: The G-Model tested［J］.Limnology and Oceanography，29: 236-249. Wilson G P，Lamb A L，Leng M J， et al.2005.δ13C and C/N as potentialcoastalpal aeoenvironmental indicators in the Mersey Estuary，UK［J］.Quaternary Science Reviews，24: 2015-2029. Woodroffe S A，Horton B P.2005.Holocene sea-level changes in the Indo-Pacific［J］.Journal of Asian Earth Sciences，25: 29-43. Woolfe K J，Dale P J，Brunskill G J.1995.Sedimentary C/S relationships in a large tropical estuary: Evidence for refractory carbon inputs from mangroves［J］.Geo-Marine Letters，15: 140-144. Zong Y，Horton B P.1998.Diatom zones across intertidal flats and coastal saltmarshes in Britain［J］.Diatom Research，13: 375-394.
