Geng Yang, Lian-Feng Zhao, Xiao-Bi Xie, Xi He, Lei Zhang, Zhen-Xing Yao
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引用次数: 0
Abstract
South-central Alaska features a history of massive volcanic activity. How the Denali volcanic gap (DVG) formed and why the Wrangell volcanoes are clustered remain vigorously debated. Investigating the crustal thermal structure can be crucial for understanding subsurface magmatic activity. We present a high-resolution broadband Lg-wave attenuation model to constrain crustal thermal anomalies beneath Alaska. Strong Lg attenuation is observed beneath the volcanoes in south-central Alaska, indicating thermal anomalies and possible melting in the crust. In contrast, the central Yakutat terrane (YT) and DVG are characterized by weak Lg attenuation, suggesting the existence of a cool crust that prevents hot mantle materials from invading the crust. This cool crust is likely the reason for the DVG. Quarter-toroidal crustal melting with strong attenuation is revealed around the YT. This curved zone of crustal melting, possibly driven by toroidal mantle flow, weakly connects the Wrangell and Buzzard Creek-Jumbo Dome magmatic chambers.
阿拉斯加中南部有着大规模火山活动的历史。德纳利火山间隙(DVG)是如何形成的,以及弗兰格尔火山为何聚集在一起,至今仍存在激烈的争论。研究地壳热结构对于了解地下岩浆活动至关重要。我们提出了一个高分辨率宽带 Lg 波衰减模型,用于约束阿拉斯加地下的地壳热异常。在阿拉斯加中南部的火山下方观测到强烈的 Lg 波衰减,表明地壳存在热异常和可能的熔化。与此相反,雅库特地层(YT)中部和 DVG 的 Lg 衰减较弱,这表明存在一个阻止热地幔物质侵入地壳的冷地壳。这种冷壳很可能是出现 DVG 的原因。在 YT 周围发现了具有强衰减的四分之一弧形地壳熔化。这个可能由环状地幔流驱动的弯曲地壳熔化带将弗兰格尔岩浆室和巴扎德溪-巨蛋岩浆室弱连接起来。
期刊介绍:
The Journal of Geophysical Research: Solid Earth serves as the premier publication for the breadth of solid Earth geophysics including (in alphabetical order): electromagnetic methods; exploration geophysics; geodesy and gravity; geodynamics, rheology, and plate kinematics; geomagnetism and paleomagnetism; hydrogeophysics; Instruments, techniques, and models; solid Earth interactions with the cryosphere, atmosphere, oceans, and climate; marine geology and geophysics; natural and anthropogenic hazards; near surface geophysics; petrology, geochemistry, and mineralogy; planet Earth physics and chemistry; rock mechanics and deformation; seismology; tectonophysics; and volcanology.
JGR: Solid Earth has long distinguished itself as the venue for publication of Research Articles backed solidly by data and as well as presenting theoretical and numerical developments with broad applications. Research Articles published in JGR: Solid Earth have had long-term impacts in their fields.
JGR: Solid Earth provides a venue for special issues and special themes based on conferences, workshops, and community initiatives. JGR: Solid Earth also publishes Commentaries on research and emerging trends in the field; these are commissioned by the editors, and suggestion are welcome.