Time-evolving surface and subsurface signatures of Quaternary volcanism in the Cascades arc
Time-evolving surface and subsurface signatures of Quaternary volcanism in the Cascades arc
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DOI：
10.1130/geol.s.12510482.v1
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发表时间：
2020-06
期刊：
影响因子：
5.8
通讯作者：
D. O’Hara;E. al.
中科院分区：
文献类型：
--
作者：
D. O’Hara;E. al.
限制地形和地壳结构的数据分辨率的提高为评估火山下省尺度的地表-地下联系提供了新的定量方法。我们使用了一个喷口数据库，从喀斯喀特弧（北美西部）的数字高架模型（dem）中提取出具有已知时代的建筑物，得出的体积可能占第四纪喷发总量的50%。大厦体积和空间通风孔密度与各种地球物理数据相关，这些数据反映了岩浆对上地壳的影响。与火山活动相一致的地下结构变化在整个弧的第四纪喷口下是常见的，但它们与更年轻的喷口联系更紧密。喀斯喀特山脉中部和南部的地球物理岩浆特征增加，那里的喷发量最大，喷口间隔紧密。火山口和相关的地壳结构，以及空间局部和分布喷发程度的时间转变，确定了整个弧的横向范围为~ 100公里的中心，表明岩浆上升的空间聚焦是随时间演变的。
Increased resolution of data constraining topography and crustal structures provides new quantitative ways to assess province-scale surface-subsurface connections beneath volcanoes. We used a database of mapped vents to extract edifices with known epoch ages from digital elevation models (DEMs) in the Cascades arc (western North America), deriving volumes that likely represent ∼50% of total Quaternary eruptive output. Edifice volumes and spatial vent density correlate with diverse geophysical data that fingerprint magmatic influence in the upper crust. Variations in subsurface structures consistent with volcanism are common beneath Quaternary vents throughout the arc, but they are more strongly associated with younger vents. Geophysical magmatic signatures increase in the central and southern Cascade Range (Cascades), where eruptive output is largest and vents are closely spaced. Vents and correlated crustal structures, as well as temporal transitions in the degree of spatially localized versus distributed eruptions, define centers with lateral extents of ∼100 km throughout the arc, suggesting a time-evolving spatial focusing of magma ascent.