Rotationally resonant Deuterium Nuclear Magnetic Resonance spectroscopy (D MAS NMR) was applied to IOM isolated from a CR1 chondrite Grosvenor Mountains (GRO) 95577 and a CM2 chondrite (Murchison). It is shown that in IOM D strongly prefers the aliphatic hydrogen reservoir over the aromatic hydrogen reservoir. For GRO 95577, that has a bulk δD of 3303 ‰ (Alexander et al., 2010), the average δD value of the aromatic reservoir is 1740 ± 128 ‰ and the aliphatic reservoir is 4477 ± 105 ‰, i.e., D/H enrichments of 1.27 and 0.64, respectively, relative to the bulk. For Murchison IOM, that has a bulk δD of 811 ‰ (Alexander et al., 2010), the average δD of the aromatic reservoir is 512 ± 88 ‰ and the aliphatic reservoir is 1033 ± 64 ‰ i.e., D/H enrichments of 1.12 and 0.82, respectively, relative to the bulk. D-H exchange between D-enriched water and a type III kerogen reveals nearly equivalent D up take by both aromatics and aliphatics. Laboratory synthesis of IOM-like material in the presence of D2O reveals a high degree of deuteration with a strong preferential deuteration of the aliphatic hydrogen reservoir indicating that the δD of the water during IOM synthesis is the primary determinant of syn-IOM’s δD. The IOM in GRO 95577 and Murchison (FA and H/C × 100) lie on the molecular evolution line as defined by the IOM of the Tagish Lake clasts and Murchison IOM has experienced more molecular evolution relative to that exhibited by GRO 95577 IOM. A forward prediction derived from the D/H ratios for the aliphatic and aromatic hydrogen reservoirs in Murchison and GRO 95577, relative to their bulk D/H ratios, derived from D MAS NMR, is applied to explain the origin of the Tagish Lake trend of δD vs molecular evolution (H/C × 100). The results of this forward prediction suggest that the Tagish Lake isotopic trend results from a combination of molecular evolution (loss of predominantly aliphatic H and D) and partial D-H exchange with D depleted chondritic water during a short-term hydrothermal alteration event. Such events may be faithfully identified in chondritic organic solids and be a common occurrence, but not necessarily revealed in the mineralogy of type 1 and 2 carbonaceous chondrites.

中文翻译：

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关于 1 型和 2 型软骨有机固体中氘富集的起源和演化


旋转共振氘核磁共振波谱 （D MAS NMR） 应用于从 CR1 球粒陨石 Grosvenor Mountains （GRO） 95577 和 CM2 球粒陨石 （Murchison） 中分离的 IOM。结果表明，在 IOM D 中，D 强烈偏好脂肪族氢储层而不是芳香族储氢层。对于体积 δD 为 3303 ‰ 的 GRO 95577（Alexander 等人，2010 年），芳烃储层的平均 δD 值为 1740 ± 128 ‰，脂肪族储层为 4477 ± 105 ‰，即相对于本体，D/H 富集分别为 1.27 和 0.64。对于体积 δD 为 811 ‰ 的 Murchison IOM（Alexander 等人，2010 年），芳烃储层的平均 δD 为 512 ± 88 ‰，脂肪族储层为 1033 ± 64 ‰，即相对于本体，D/H 富集分别为 1.12 和 0.82。富含 D 的水和 III 型干酪根之间的 D-H 交换显示芳烃和脂肪族的 D 吸收几乎相等。在 D2O 存在下 IOM 类材料的实验室合成揭示了高度氘化，脂肪族氢储层具有很强的优先氘化作用，这表明 IOM 合成过程中水的 δD 是 syn-IOM δD 的主要决定因素。GRO 95577 和 Murchison（FA 和 H/C × 100）中的 IOM 位于 Tagish 湖碎屑的 IOM 定义的分子进化线上，而 Murchison IOM 相对于 GRO 95577 IOM 所展示的经历了更多的分子进化。根据 Murchison 和 GRO 95577 中脂肪族和芳香族氢储层的 D/H 比得出的正向预测，相对于它们从 D MAS NMR 得出的块体 D/H 比，用于解释 δD 与分子进化 （H/C × 100） 的 Tagish Lake 趋势的起源。 这一正向预测的结果表明，Tagish Lake 同位素趋势是分子进化（主要是脂肪族 H 和 D 的损失）和在短期热液蚀变事件中与 D 耗尽的软骨水的部分 D-H 交换相结合的结果。此类事件可能在软骨状有机固体中忠实地识别出来，并且很常见，但不一定在 1 型和 2 型碳质球粒陨石的矿物学中揭示出来。