Oxygen Fugacity Across Tectonic Settings

Here we compile published analytical data from lithologies that constrain fO2 (n=860 volcanic rocks - lavas and tephras and n=326 mantle lithologies- the majority peridotites) from ridges, back-arc basins, forearcs, arcs, and plumes. Because calculated fO2 varies with choice of activity model, we re-calculate fO2 for each dataset from compositional data, applying the same set of activity models and methodologies for each data type. Additionally, we compile trace element concentrations (e.g. vanadium) which serve as an additional fO2-proxy. The compiled data show that, on average, volcanic rocks and mantle rocks from the same tectonic setting yield similar fO2s, but mantle lithologies span a much larger range in fO2 than volcanics. Multiple Fe-based oxybarometric methods and vanadium partitioning vary with statistical significance as a function of tectonic setting, with fO2 ridges < back arcs < arcs. Plume lithologies are more nuanced to interpret, but indicate fO2s >= ridges.

本研究汇编了已发表的岩性分析数据，这些岩性数据可用于约束氧逸度(fO2)：其中包含来自洋脊、弧后盆地、前弧、岛弧及地幔柱的860件火山岩（熔岩与火山碎屑岩）样本，以及326件幔源岩性样本（多数为橄榄岩(peridotites)）。由于计算得到的氧逸度会随所选用的活度模型不同而发生变化，我们针对每个数据集基于组分数据重新计算了氧逸度，并为所有数据类型统一采用了一套相同的活度模型与计算方法。此外，我们还汇编了微量元素浓度数据（例如钒），这类数据可作为额外的氧逸度代用指标。本次汇编的数据显示，平均而言，同一构造环境下的火山岩与幔源岩的氧逸度相近，但幔源岩性的氧逸度分布范围远大于火山岩。多种基于铁的氧逸度计方法与钒分配系数均呈现出随构造环境变化的统计学显著性差异，氧逸度大小排序为：洋脊 < 弧后盆地 < 岛弧。地幔柱相关岩性的解释更为复杂微妙，但数据显示其氧逸度不低于洋脊。

搜集汇总

背景与挑战

背景概述

该数据集汇编了来自不同构造环境（如洋脊、弧后盆地、前弧、弧和地幔柱）的火山岩和地幔岩石的氧逸度(fO2)数据，共包含860个火山岩样品和326个地幔岩石样品。通过统一的计算方法和活性模型，数据集揭示了不同构造环境下氧逸度的统计显著性差异，并指出地幔岩石的氧逸度范围比火山岩更广。