To better investigate the behavior of titanium (Ti) isotopes during magmatic processes, we report high-precision Ti isotope compositions for 60 terrestrial igneous rocks from different geological settings worldwide. Based on their major element compositions and petrographic descriptions, these samples can be subdivided into two groups: Fe-Ti oxide unsaturated and Fe-Ti oxide saturated. The Fe-Ti oxide unsaturated group samples show a narrow δ 49/47 Ti (δ 49/47 Ti = [( 49 Ti/ 47 Ti) sample /( 49 Ti/ 47 Ti) OL-Ti ] × 1000) range (− 0.036 ± 0.043‰ to 0.082 ± 0.021 ‰), and no correlation between δ 49/47 Ti and the degree of differentiation is observed. By contrast, Fe-Ti oxide saturated group samples show a remarkable δ 49/47 Ti variation, ranging from 0.005 ± 0.018‰ to 1.914 ± 0.006 ‰, which are positively correlated with SiO 2 contents, and negatively correlated with MgO contents. In particular, multiple SiO 2 vs. δ 49/47 Ti trends are observed in Fe-Ti oxide saturated group, which are controlled by crystal fractionation degrees, magma SiO 2 compositions, and Fe-Ti oxide compositions during magma differentiation.

中文翻译：

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岩浆分异过程中的钛同位素分馏

为了更好地研究岩浆过程中钛 (Ti) 同位素的行为，我们报告了来自全球不同地质环境的 60 种陆地火成岩的高精度 Ti 同位素组成。根据它们的主要元素组成和岩相描述，这些样品可以细分为两组：Fe-Ti 氧化物不饱和和 Fe-Ti 氧化物饱和。Fe-Ti 氧化物不饱和基团样品显示出狭窄的 δ 49/47 Ti (δ 49/47 Ti = [( 49 Ti/ 47 Ti) 样品 /( 49 Ti/ 47 Ti) OL-Ti ] × 1000) 范围 (- 0.036 ± 0.043‰ 至 0.082 ± 0.021 ‰)，δ 49/47 Ti 与分化程度之间没有相关性。相比之下，Fe-Ti 氧化物饱和组样品显示出显着的 δ 49/47 Ti 变化，范围从 0.005 ± 0.018‰ 到 1.914 ± 0.006 ‰，与 SiO 2 含量呈正相关，与 MgO 含量呈负相关。特别地，在Fe-Ti氧化物饱和组中观察到多个SiO 2 vs. δ 49/47 Ti趋势，这受晶体分异度、岩浆SiO 2 成分和岩浆分异过程中的Fe-Ti氧化物成分控制。