Tectonic control of ocean island basalt sources on São Miguel, Azores?
Tectonic control of ocean island basalt sources on São Miguel, Azores?
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亚速尔群岛圣米格尔岛海洋岛玄武岩来源的构造控制？
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
C. Beier
中科院分区：
文献类型：
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作者：
K. Haase;C. Beier
圣米格尔岛上两座同位素不同的火山 Sete Cidades 和 Agua de Pau 的破火山口相距仅 30 公里。 Sete Cidades 熔岩通常具有 87Sr/86Sr < 0.7038，而 Agua de Pau 熔岩具有 87Sr/86Sr > 0.7040。两座火山之间存在两个重叠的裂谷带，熔岩成分显示每个裂谷带都与邻近的火山相连。火山系统之间的有限混合意味着独立的上升路径和直径约为 20 公里的岩浆源。这两个火山系统的走向截然不同。 Sete Cidades 火山裂谷走向西北，与伸展的特塞拉裂谷平行，而 Agua de Pau 火山裂谷地带则走向东西向。岩浆来源和岩石圈构造的共同变化可能表明岩石圈的构造结构控制着圣米格尔岛下方的地幔上涌。
The calderas of the two isotopically distinct volcanoes Sete Cidades and Agua de Pau on São Miguel are only 30 km apart. Sete Cidades lavas generally have 87Sr/86Sr < 0.7038 while Agua de Pau lavas have 87Sr/86Sr > 0.7040. Two overlapping rift zones exist between the two volcanoes and the lava compositions show that each rift zone is connected to the neighbouring volcano. Limited mixing between the volcanic systems implies separate ascent paths and magma sources with diameters of ∼20 km. The two volcanic systems follow contrasting directions; the Sete Cidades volcanic rift strikes NW parallel to the extensional Terceira Rift, while the Agua de Pau volcanic rift zone strikes E‐W. The covariation of magma sources and lithospheric tectonics may suggest that the tectonic structure of the lithosphere controls the mantle upwelling beneath São Miguel.