沉积条件下白云石与伴生方解石碳氧同位素组成的差别及影响因素

李小宁; 黄思静; 黄可可; 钟怡江; 胡作维

doi:10.11781/sysydz201606828

沉积条件下白云石与伴生方解石碳氧同位素组成的差别及影响因素

doi: 10.11781/sysydz201606828

成都理工大学油气藏地质及开发工程国家重点实验室, 成都 610059

基金项目: 国家自然科学基金项目（41272130）“川渝地区早三叠世海相碳酸盐岩的碳同位素研究”资助。

详细信息

作者简介:
李小宁(1986-),女,博士生,从事沉积地球化学研究。E-mail:l-x-n@139.com。

通讯作者:
黄思静(1949-),男,教授,博士生导师,从事沉积学的教学与科研工作。E-mail:hsj@cdut.edu.cn。

中图分类号: TE122.2
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出版历程
- 收稿日期: 2016-02-06
- 修回日期: 2016-09-28
- 刊出日期: 2016-11-28

Differences and controls of carbon and oxygen isotope composition in dolomite and coexisting calcite under deposition conditions

State Key Laboratory of Oil/Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu, Sichuan 610059, China

摘要

摘要: 以岩石学为基础，运用元素、X射线衍射和碳氧同位素分析等方法，在手标本中观尺度上探讨同一样品中白云石与伴生方解石的碳氧同位素组成及影响因素。研究表明，白云石比伴生方解石具有更高的δ¹³C和δ¹⁸O值。白云石的δ¹⁸O值高于伴生方解石可能与如下2种因素有关：（1）在白云石-水和方解石-水系统中，前者的氧同位素分馏系数大于后者，因此在白云石-方解石系统中，氧同位素分馏系数大于1；（2）白云石沉淀于比方解石盐度更高、更富¹⁸O的水体中。白云石的δ¹³C值高于伴生方解石可能与如下因素有关：在白云石-CO₂和方解石-CO₂系统中，前者的碳同位素分馏系数大于后者，因而对交代过程的白云石-方解石系统而言，碳同位素分馏系数大于1。准同生白云石与伴生方解石的氧同位素组成差值较大，而热液/深埋藏白云石与伴生方解石的氧同位素组成差值较小。
- 分馏系数 /
- 碳氧同位素 /
- 伴生方解石 /
- 白云石
Abstract: We discussed the composition and factors influencing carbon and oxygen isotopes in dolomites and coexisting calcites in hand specimen mesoscale based on petrography and combined with elemental, X-ray diffraction and carbon and oxygen isotope analyses. Results indicated that dolomites have higher δ¹³C and δ¹⁸O values than coexisting calcites. Two factors may account for the higher δ¹⁸O values of dolomites. (1) The oxygen isotope fractionation factors of a dolomite-water system are higher than those of a calcite-water system. Therefore, oxygen isotope fractionation factors are greater than 1 in a dolomite-calcite system. (2) The fluids of dolomite precipitation have higher salinity and higher ¹⁸O abundance compared to coexisting calcite. In addition, the δ¹³C values of dolomites show the same trends with δ¹⁸O values. That is to say, the carbon isotope fractionation factors in a dolomite-CO₂ system are higher than those in a calcite-CO₂ system. Therefore, carbon isotope fractionation factors are greater than 1 in a dolomite-calcite system during replacement process. Oxygen isotope values varied obviously between syndepositional dolomites and coexisting calcites, while they were similar between hydrothermal/deeply burial dolomites and coexisting calcites.
- fractionation factors /
- carbon and oxygen isotope /
- coexisting calcite /
- dolomite

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参考文献(29)

[1]	Degens E T,Epstein S.Oxygen and carbon isotope ratios in coexisting calcites and dolomites from recent and ancient sediments[J].Geochimica et Cosmochimica Acta,1964,28(1):23-44.
[2]	Sheppard S M F,Schwarcz H P.Fractionation of carbon and oxygen isotopes and magnesium between coexisting metamorphic calcite and dolomite[J].Contributions to Mineralogy and Petrology,1970,26(3):161-198.
[3]	Clayton R N,Jones B F.Isotope studies of dolomite formation under sedimentary conditions[J].Geochimica et Cosmochimica Acta,1968,32(4):415-432.
[4]	Weber J N.Oxygen isotope fractionation between coexisting calcite and dolomite[J].Science,1964,145(3638):1303-1305.
[5]	Horacek M,Brandner R,Abart R.Carbon isotope record of the P/T boundary and the Lower Triassic in the southern Alps:Evidence for rapid changes in storage of organic carbon[J].Palaeogeography, Palaeoclimatology, Palaeoecology,2007,252(1/2):347-354.
[6]	Epstein S,Graf D L,Degens E T.Oxygen isotope studies on the origin of dolomites[C]//Isotopic and cosmic chemistry.Amsterdam:North-Holland Publishing Company,1964:169-180.
[7]	Northrop D A,Clayton R N.Oxygen-isotope fractionation in systems containing dolomite[J].The Journal of Geology,1966,74(2):174-196.
[8]	O'Neil J R,Epstein S.Oxygen isotope fractionation in the system dolomite-calcite-carbon dioxide[J].Science,1966,152(3719):198-201.
[9]	Clayton R A,Epstein S.The relationship between O¹⁸/O¹⁶ ratios in coexisting quartz,carbonate,and iron oxides from various geolo-gical deposits[J].The Journal of Geology,1958,66(4):352-371.
[10]	Engel A E J,Clayton R N,Epstein S.Variations in the isotopic composition of oxygen in the Leadville limestone (Mississippian,Colorado) and in its hydrothermal and metamorphic phases[J].The Journal of Geology,1958,66(4):374-393.
[11]	McKenzie J A.Holocene dolomitization of calcium carbonate sediments from the coastal Sabkhas of Abu Dhabi,U.A.E.:A stable isotope study[J].The Journal of Geology,1981,89(2):185-198.
[12]	Horita J.Oxygen and carbon isotope fractionation in the system dolomite-water-CO₂ to elevated temperatures[J].Geochimica et Cosmochimica Acta,2014,129:111-124.
[13]	Deines P.Carbon isotope effects in carbonate systems[J].Geochimica et Cosmochimica Acta,2004,68(12):2659-2679.
[14]	Jiménez-López C,Romanek C S,Huertas F J,et al.Oxygen isotope fractionation in synthetic magnesian calcite[J].Geochimica et Cosmochimica Acta,2004,68(16):3367-3377.
[15]	Mavromatis V,Schmidt M,Botz R,et al.Experimental quantification of the effect of Mg on calcite-aqueous fluid oxygen isotope fractionation[J].Chemical Geology,2012,310/311:97-105.
[16]	Chacko T,Deines P.Theoretical calculation of oxygen isotope fractionation factors in carbonate systems[J].Geochimica et Cosmochimica Acta,2008,72(15):3642-3660.
[17]	李小宁,黄思静,胡博,等.合川盐井溪嘉陵江组第二段盐溶角砾岩-次生灰岩的碳氧同位素组成[J].成都理工大学学报(自然科学版),2015,42(6):734-745. Li Xiaoning,Huang Sijing,Hu Bo,et al.Carbon and oxygen isotope composition of evaporite-solution breccia-secondary limestone of Member 2 of Triassic Jialingjiang Formation in Hechuan,eastern Sichuan Basin,China[J].Journal of Chengdu University of Technology (Science & Technology Edition),2015,42(6):734-745.
[18]	曾云贤,刘微,李西宁.川东北地区飞仙关组构造演化与油气成藏研究[J].天然气工业,2015,25(S1):21-24. Zeng Yunxian,Liu Wei,Li Xining.Research on structural evolution and oil/gas reservoiring of Feixianguan Formation in northwest Sichuan Basin[J].Natural Gas Industry,2015,25(S1):21-24.
[19]	王兴志,张帆,马青,等.四川盆地东部晚二叠世-早三叠世飞仙关组礁、滩特征与海平面变化[J].沉积学报,2002,20(2):249-254. Wang Xingzhi,Zhang Fan,Ma Qing,et al.The characteristics of reef and bank and the fluctuation of sea-level in Feixianguan period of Late Permian-Early Triassic,east Sichuan Basin[J].Acta Sedimentologia Sinica,2002,20(2):249-254.
[20]	陈琪,胡文瑄,李庆,等.川东北盘龙洞长兴组-飞仙关组白云岩化特征及成因[J].石油与天然气地质,2014,33(1):84-93. Chen Qi,Hu Wenxuan,Li Qing,et al.Characteristics and genesis of dolomitization in Changxing and Feixianguan formations in Panlongdong,northeastern Sichuan Basin[J].Oil & Gas Geo-logy,2014,33(1):84-93.
[21]	Hips K,Haas J,Poros Z,et al.Dolomitization of Triassic microbial mat deposits (Hungary):Origin of microcrystalline dolomite[J].Sedimentary Geology,2015,318:113-129.
[22]	Füchtbauer H,Goldschmidt H.Beziehungen zwischen calciumgehalt und bildungsbedingungen der dolomite[J].Geologische Rundschau,1966,55(1):29-40.
[23]	黄可可,黄思静,胡作维,等.四川盆地宣汉渡口和重庆北碚下三叠统海相碳酸盐碳同位素组成与演化[J].古地理学报,2016,18(1):101-114. Huang Keke,Huang Sijing,Hu Zuowei,et al.Carbon isotopic composition and evolution of the Lower Triassic marine carbo-nates from Dukou of Xuanhan and Beibei of Chongqing,Sichuan Basin[J].Journal of Palaeogeography,2016,18(1):101-114.
[24]	Sun Yadong,Joachimski M M,Wignall P B,et al.Lethally hot temperatures during the Early Triassic greenhouse[J].Science,2012,338(6105):366-370.
[25]	Warren J.Dolomite:Occurrence,evolution and economically important associations[J].Earth-Science Reviews,2000,52(1/3):1-81.
[26]	祝幼华,罗辉,蔡华伟,等.四川广安谢家槽海相早、中三叠世地层划分[J].地层学杂志,2012,36(4):784-791. Zhu Youhua,Luo Hui,Cai Huawei,et al.Stratigraphic division of the Early and Middle Triassic at the Xiejiacao section in Guang'an,Sichuan[J].Journal of Stratigraphy,2012,36(4):784-791.
[27]	International Commission on Stratigraphy.International chronostratigraphic chart..www.stratigraphy.org.
[28]	O'Neil J R,Clayton R N,Mayeda T K.Oxygen isotope fractionation in divalent metal carbonates[J].The Journal of Chemical Physics,1969,51(12):5547-5558.
[29]	Friedman I,O'Neil J R.Compilation of stable isotope fractionation factors of geochemical interest.Washington:United States Government Printing Office,1977:KK1-KK12.