Continental flood basalts are more prone to compositional modification from passage th thicker and (or) more felsic crust in comparison to their oceanic counterparts. The Steens Basalt in southeast Oregon (~17 Ma) is among the oldest and most mafic members of the Columbia River Basalt Group and provides a record of the early stages of flood basalt volcanism. We evaluate the balance of mantle sources in time during the onset of Columbia River Basalt Group magmatism and assess the effect of crustal passage using stratigraphically controlled Sr, Nd, Pb, Hf, Os, and O isotopic compositions, as well as whole rock major and trace element data.

中文翻译：

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不断变化的地幔来源和地壳通道对俄勒冈州东南部的玄武岩玄武岩的化学和同位素约束

与海洋对应物相比，大陆洪水玄武岩更容易通过变厚和（或）长英质壳形成。俄勒冈州东南部的Steens玄武岩（〜17 Ma）是哥伦比亚河玄武岩群中最古老，也是最黑手的成员之一，它提供了洪水玄武岩火山作用早期的记录。我们评估了哥伦比亚河玄武岩群岩浆活动发生时地幔源的时间平衡，并使用地层学控制的Sr，Nd，Pb，Hf，Os和O同位素组成以及整个岩石主要和地壳层，评估了地壳通过的影响。跟踪元素数据。