Isotopic ratios of carbonaceous materials incorporated in olivine crystals from the Hualalai Volcano, Hawaii. An approach to mantle carbon.
Isotopic ratios of carbonaceous materials incorporated in olivine crystals from the Hualalai Volcano, Hawaii. An approach to mantle carbon.
复制标题
夏威夷华拉莱火山橄榄石晶体中碳质材料的同位素比。
DOI：
10.2343/geochemj.17.95
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发表时间：
1983
影响因子：
0.8
通讯作者：
S. Matsuo
中科院分区：
文献类型：
--
作者：
S. Watanabe;Kazunobu Mishima;S. Matsuo
采用氧气热解法、球磨法和盐酸溶解法提取夏威夷华拉莱火山1801熔岩流中白云石结核中橄榄石晶体中的二氧化碳和石墨碳。通过对比氧化热解和球磨过程中co2的同位素比值，得出氧化热解过程中co2主要来源于流体包裹体的结论。将橄榄石晶体溶解于盐酸中，从蒸发残渣中回收石墨碳。氧化热解提取的co2平均浓度为0.87 mol /g， 613C值为-3.20/00。石墨碳为0.51 mol /g, -26 mol /g。氧化热解和球磨均未检测到橄榄石晶体中H2、H20、CH4、高碳氢化合物和H2S等含氢物质。假设所有提取的碳存在于流体包裹体在橄榄石晶体和歧化反应的CO (2 c0 _ + CO2 + C)发生在夹杂物,我们得出结论,主要含碳的物种在地幔在夏威夷群岛CO和CO2,和CO / CO2比估计的基础上约3 513 C值的实验数据和上地幔在夏威夷群岛的碳是-12%左右。一些关于日本橄榄石的额外数据表明，地幔碳的813C值可能不是整个地幔中唯一的。
Carbon dioxide and graphitic carbon in olivine crystals from dunite nodules in the 1801 lava flow of the Hualalai Volcano, Hawaii were extracted by three methods, i.e., the pyrolysis under oxygen atmo sphere, the ball-milling and the dissolution with hydrochloric acid. It is concluded that most of C02 extracted by the oxidative pyrolysis was derived from fluid inclusions , by comparing the isotopic ratios of C02 released by the oxidative pyrolysis and the ball-milling. Graphitic carbon was recovered from the evaporation residue after olivine crystals were dissolved in hydrochloric acid. The averaged concentration of C02 extracted by the oxidative pyrolysis was 0.87pmole/g and 613C value was -3.20/00. These of graphitic carbon were 0.51pmole/g and -26 .90/00, respectively, No apprecia ble amount of hydrogen-bearing species such as H2, H20, CH4, higher hydrocarbons and H2S was detected in olivine crystals by both the oxidative pyrolysis and the ball-milling. Assuming all the extracted carbon is present in fluid inclusions in olivine crystals and the disproportionation reaction of CO (2C0 _+ C02 + C) has occurred in inclusions, we conclude that the major carbon-bearing species in the mantle beneath the Hawaiian Islands are CO and C02, and the CO/CO2 ratio is estimated to be about 3 on the basis of the experimental data and that the 513C value of the carbon in upper mantle below the Hawaiian Islands is around -12%o. Some additional data on Japanese olivines suggest that the 813C value of the mantle carbon may not be unique throughout the mantle.