Focused Mid-Crustal Magma Intrusion During Continental Break-Up in Ethiopia
Focused Mid-Crustal Magma Intrusion During Continental Break-Up in Ethiopia
复制标题
埃塞俄比亚大陆破裂期间集中地壳中岩浆侵入
DOI：
10.1029/2023gl103257
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发表时间：
2023
影响因子：
5.2
通讯作者：
Wong K
中科院分区：
文献类型：
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作者：
Wong K
在大陆分裂期间，大量的岩浆可以侵入地壳，通过改变地壳的热机械结构及其对拉伸应力的反应来影响裂谷演化。裂谷岩浆还补充了地表火山活动，可能是全球构造二氧化碳排放的重要来源。要了解岩浆活动如何影响裂谷的发展，就需要了解地壳中岩浆侵入的深度。在这里，使用来自橄榄石托管熔融包裹体的数据，我们研究了埃塞俄比亚主裂谷（MER）中玄武岩侵入体的岩浆动力学。我们在MER上-下地壳边界（10-15公里深）发现了空间集中的岩浆侵入区的证据，与地球物理数据集一致。我们认为，MER中的上升熔体侵入了这个深度范围，作为离散的岩床，可能会产生一个机械薄弱的中地壳层。我们的研究结果有重要意义的岩浆添加如何影响地壳流变学在一个成熟的大陆裂谷。
Significant volumes of magma can be intruded into the crust during continental break‐up, influencing rift evolution by altering the thermo‐mechanical structure of the crust and its response to extensional stresses. Rift magmas additionally feed surface volcanic activity and can be globally significant sources of tectonic CO2emissions. Understanding how magmatism may affect rift development requires knowledge on magma intrusion depths in the crust. Here, using data from olivine‐hosted melt inclusions, we investigate magma dynamics for basaltic intrusions in the Main Ethiopian Rift (MER). We find evidence for a spatially focused zone of magma intrusion at the MER upper‐lower crustal boundary (10–15 km depth), consistent with geophysical datasets. We propose that ascending melts in the MER are intruded over this depth range as discrete sills, likely creating a mechanically weak mid‐crustal layer. Our results have important implications for how magma addition can influence crustal rheology in a maturing continental rift.