A quantitative framework for global variations in arc geochemistry
A quantitative framework for global variations in arc geochemistry
复制标题
弧地球化学全球变化的定量框架
DOI：
10.1016/j.epsl.2022.117411
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发表时间：
2022
影响因子：
5.3
通讯作者：
Langmuir, Charles H.
中科院分区：
文献类型：
--
作者：
Turner, Stephen J.;Langmuir, Charles H.
弧岩浆是由俯冲沉积物和火成岩洋壳的输入改变地幔楔的部分熔融产生的。尽管这种统一的构造过程，全球弧前成层火山的成分表现出微量元素丰度，可以变化超过一个数量级。所有的不相容元素都有很好的相关性，包括那些被认为是楔源的、“流体流动的”和沉积物源的元素。有人建议，全球变化的弧微量元素丰度发生由于增加了可变板组件的耗尽地幔楔，虽然定量的全球模型，包括微量元素和同位素一直缺乏。在这里，我们提出了一个替代框架中，一个相对恒定的比例板状材料，包括熔融蚀变洋壳和沉积物，被添加到环境地幔楔，从更耗尽比MORB丰富的“EM 1”洋岛玄武岩源。改性地幔不同程度地熔融，熔融主要受上覆岩石圈厚度的控制。在大多数大陆弧中，厚的岩石圈导致石榴石稳定场中熔融程度较低。大陆弧也有富集的环境地幔，可能是因为富集的次大陆岩石圈地幔的贡献。更多贫化源的高度熔融导致海洋弧具有低不相容元素丰度。这些过程的定量模拟表明，该框架可以解释弧前成层火山所表现出的全球弧系统学，并提供了一种工具，以检查区域变化和更不寻常的岩浆成分。板坯温度和板坯输入量的变化对二阶变化和某些元素比仍然很重要。
Arc magmas are generated by partial melting of a mantle wedge modified by inputs from subducting sediment and igneous ocean crust. Despite this uniform tectonic process, global arc-front stratovolcano compositions exhibit trace element abundances that can vary by more than an order of magnitude. All incompatible elements correlate well, including those that are thought to be wedge derived, “fluid-mobile”, and sediment derived. It has been suggested that global variations in arc trace element abundances occur due to the addition of variable slab components to a depleted mantle wedge, though quantitative global models that include both trace elements and isotopes have been lacking. Here we present an alternative framework in which a relatively constant proportion of slab material, consisting of melts both of altered ocean crust and sediment, is added to ambient mantle wedge that varies from more depleted than MORB to as enriched as “EM1” ocean island basalt sources. The modified mantle melts to varying extents, with melting controlled primarily by the thickness of the overlying lithosphere. Thick lithosphere leads to lower extents of melting in the garnet stability field in most continental arcs. Continental arcs also have enriched ambient mantle, likely because of contributions from enriched sub-continental lithospheric mantle. High degrees of melting of more depleted sources cause oceanic arcs to have low incompatible element abundances. Quantitative modeling of these processes shows that this framework can account for the global arc systematics exhibited by arc-front stratovolcanoes and provides a tool to examine regional variations and more unusual magma compositions. Variations in slab temperature and amount of slab input remain important for second-order variations and certain element ratios.
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影响因子：
5
作者：
K. Heydolph;K. Hoernle;F. Hauff;P. Bogaard;M. Portnyagin;I. Bindeman;D. Garbe‐Schönberg
通讯作者：
K. Heydolph;K. Hoernle;F. Hauff;P. Bogaard;M. Portnyagin;I. Bindeman;D. Garbe‐Schönberg
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DOI：
--
发表时间：
2017
期刊：
影响因子：
--
作者：
G. Yogodzinski;P. Kelemen;K. Hoernle;Shaun T. Brown;I. Bindeman;J. Vervoort;K. Sims;M. Portnyagin;R. Werner
通讯作者：
R. Werner
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影响因子：
5
作者：
P. Wieser;S. Turner;T. Mather;D. Pyle;I. Savov;G. Orozco
通讯作者：
G. Orozco
影响因子：
5
作者：
Freymuth, Heye;Ivko, Ben;Elliott, Tim
通讯作者：
Elliott, Tim
影响因子：
5
作者：
G. Jacques;K. Hoernle;J. Gill;F. Hauff;H. Wehrmann;D. Garbe‐Schönberg;P. Bogaard;I. Bindeman
通讯作者：
G. Jacques;K. Hoernle;J. Gill;F. Hauff;H. Wehrmann;D. Garbe‐Schönberg;P. Bogaard;I. Bindeman