气候变化领域集成服务门户(CCPortal): Thermo-Mechanical State of Ultraslow-Spreading Ridges With a Transient Magma Supply

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DOI	10.1029/2020JB020557
	Thermo-Mechanical State of Ultraslow-Spreading Ridges With a Transient Magma Supply
	Fan Q.; Olive J.-A.; Cannat M.
发表日期	2021
ISSN	21699313
卷号	126 期号:4
英文摘要	The thermal structure of mid-ocean ridge axes is a critical control on the mechanical properties of young lithosphere and modulates the faulting styles that shape the Earth's seafloor. Models that balance a steady input of magmatic heat with a vigorous hydrothermal output are generally successful at explaining the thermal state of magmatically robust mid-ocean ridges. However, the magma supply of ultraslow spreading ridges is often subdued and highly episodic, and the depth-extent and vigor of hydrothermal circulation in these settings remain poorly known, requiring modifications to the standard magmatic-hydrothermal paradigm. We develop models that couple repeated magmatic intrusions with hydrothermal convection in a permeable domain whose boundaries are controlled by the extent of grain-scale thermal cracking. Our simulations reveal decreasing trends of venting temperatures with increasing intrusion periodicity, as well as with increasing permeability. Our model explains the seismically inferred depth (∼10 km) to the brittle-ductile transition and the depth of MORB crystallization at the Mid-Cayman Spreading Center by invoking repeated intrusion of sills every 20–50 kyrs, depending on their size. Doubling this periodicity predicts a thicker (∼15 km) seismogenic layer and lower-temperature venting, as observed at the Southwest Indian Ridge (SWIR) at 64˚E. However, if fluid convection is not possible below ∼6 km, our model requires that high-temperature venting at ultraslow ridges (e.g., Longqi at SWIR 49.7˚E) be fueled by shallow episodic magma intrusions into the long-term convective region, which maintain high-output circulation for at most a few tens of kyrs. © 2021. American Geophysical Union. All Rights Reserved.
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187218
作者单位	Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing, China; Laboratoire de Géologie, Ecole Normale Supérieure / CNRS UMR 8538, PSL Research University, Paris, France; Marine Geosciences, Institut de Physique du Globe de Paris, UMR 7154 - CNRS, Université de Paris, France
推荐引用方式 GB/T 7714	Fan Q.,Olive J.-A.,Cannat M.. Thermo-Mechanical State of Ultraslow-Spreading Ridges With a Transient Magma Supply[J],2021,126(4).
APA	Fan Q.,Olive J.-A.,&Cannat M..(2021).Thermo-Mechanical State of Ultraslow-Spreading Ridges With a Transient Magma Supply.Journal of Geophysical Research: Solid Earth,126(4).
MLA	Fan Q.,et al."Thermo-Mechanical State of Ultraslow-Spreading Ridges With a Transient Magma Supply".Journal of Geophysical Research: Solid Earth 126.4(2021).