| 不同实验条件对早新生代沉积物有机碳同位素的影响 |
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| 关键词:organic carbon isotopes conditional experiments sedimentary rock |
| 基金项目:国家973重点基础研究发展计划项目(编号: 2013CB956400, 2011CB403000);国家自然科学基金委基金(编号: 41021001, 41272128, 40920114001, 41172153);国家教育部博士点基金资助项目(编号: 20090211110021) |
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| The Influences of Different Experimental Conditions on Organic Carbon Isotopes of Early Cenozoic Sediments |
| The carbon isotope composition of organic matter has become an effective method and means in the reconstruction of paleoclimate and paleovegetation. However, because experimental methods, instruments and testing environments are different, there exists remarkable deviation between the measured δ13C values and the true values. As for the older strata sample, the factors affecting the δ13C values of organic matter are more complex, and the study of the experimental conditions is relatively insufficient, thus restricting the application of the δ13C of organic matter to the old strata. In view of such a situation, the authors took the early Cenozoic sediments as the study object and made a comparative study and analysis of the experimental materials, apparatuses and temperatures. Some conclusions have been reached: (1) PC centrifuge tube has no influence on sample δ13C values in a low temperature environment, and there exists no difference in experimental result between the use of PC centrifuge tube and the use of glass beaker. (2) The EA-IRMS δ13C values are higher than MAT-252 δ13C values by 2‰–4‰, and the difference of the instrument test environments and the oxidation temperatures seems to be the key factor causing the deviation. (3) As for the old strata samples, the oxidation temperature of 850℃ cannot cause complete oxidation, and the repeated sample results show rather poor reproducibility, implying that the oxidation fails to reach a steady state; along with the increase of temperature, the δ13C values tend to become positive; the temperature of 1020℃ can result in complete oxidation, and the repeated sample results show fairly satisfying reproducibility, suggesting arriving at a steady state. (4) When gypsum samples are tested, we must pay attention to removing water vapor, thus reducing the adverse effect of water vapor. |
| CHI Yun-ping,ZHANG Sa,WU Song,SONG Chun-hui,YAN Mao-du,MIAO Yun-fa.2012.The Influences of Different Experimental Conditions on Organic Carbon Isotopes of Early Cenozoic Sediments[J].Acta Geoscientica Sinica,33(6):967-976. |
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