Pervasive Crustal Volcanic Mush in the Highly Stretched Sunda Plate Margin of Northern Sumatra
Pervasive Crustal Volcanic Mush in the Highly Stretched Sunda Plate Margin of Northern Sumatra
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DOI：
10.1029/2023gl104391
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发表时间：
2023-11
影响因子：
5.2
通讯作者：
Mingye Feng;S. Wei;Ling Chen;U. Muksin;K. Lythgoe;Tuo Wang;Z. Wu
中科院分区：
文献类型：
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作者：
Mingye Feng;S. Wei;Ling Chen;U. Muksin;K. Lythgoe;Tuo Wang;Z. Wu
在苏门答腊岛西北部，人们对弧火山作用、地壳形变及其相互作用知之甚少。传统的接收函数H-κ叠加研究局限于火山岩带地壳厚度和波速比的变化，但很少估计熔体分数。在这里，我们提出了一种H-Φ叠加方法，它是H-κ叠加方法的一种变体，并将其应用于来自苏门答腊岛北部亚齐的密集节点阵列数据，以估计地壳厚度、Vp/Vs比和熔体分数。大多数结果显示相当高的Vp/Vs比值(∼1.98)和熔体分数(高达19%)，表明地壳岩浆混杂作用普遍存在。亚齐地壳的西北边缘比全球伸展地壳薄得多(∼22公里)，反映了由于控制安达曼海开放的构造过程而高度拉伸的地壳。这种薄的地壳和高熔体分数解释了布格重力异常，也部分解释了第四纪火山岩的北移。
Arc volcanism, crustal deformation, and their interplay are poorly understood in northwestern Sumatra. Traditional receiver function H‐κ stacking studies constrain the variations in crustal thickness and Vp/Vs ratio in volcanic zones but rarely estimate the melt fractions. Here, we propose a H‐Φ stacking method, a variant of the H‐κ stacking method, and apply it to the dense nodal array data from Aceh, northern Sumatra, to estimate crustal thickness, Vp/Vs ratio, and melt fraction. Most results show considerably high Vp/Vs ratios (∼1.98) and melt fractions (up to 19%), indicating pervasive crustal magmatic mush. The northwestern edge of the Aceh crust is much thinner (∼22 km) than extended crust globally, reflecting a highly stretched crust due to tectonic processes governing the opening of the Andaman Sea. This thin crust and high melt fractions explain the Bouguer gravity anomaly, and partly explain the northward migration of Quaternary volcanics.