气候变化领域集成服务门户(CCPortal): Controls on the magmatic fraction of extension at mid-ocean ridges

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DOI	10.1016/j.epsl.2020.116541
	Controls on the magmatic fraction of extension at mid-ocean ridges
	Olive J.-A.; Dublanchet P.
发表日期	2020
ISSN	0012821X
卷号	549
英文摘要	The fraction M of plate separation accommodated by magma emplacement at mid-ocean ridges has been recognized as the main control on seafloor spreading modes, yet the factors that control M itself are poorly understood. Here we put forward a simple theoretical framework explaining M in terms of short-term cycles of earthquakes and dike intrusions interacting with one another by modulating the stress state of the ridge axis. Axial lithospheric thickness and the rate of pressure build-up in shallow, replenishing magma sills are the two main parameters controlling M in our simulations. Combined with plausible scenarios for the increase of pressure build-up rate and the decrease of lithospheric thickness with increasing spreading rate, our model appropriately brackets available measurements of M from slow, intermediate, and fast-spreading ridges. Our model further suggests that the transitions between major modes of seafloor spreading (detachment faulting, symmetric faulting, and fully-magmatic) correspond to thresholds in axial lithospheric thickness, and that the great variability in M at slow and ultraslow ridges directly reflects along-axis variability in thermal structure. More generally, this implies that the balance between bottom-up magmatic heating and top-down hydrothermal cooling fully determines the time-averaged rate of magmatic intrusions in the brittle lithosphere, and thus the modes of mid-ocean ridge faulting which shape ∼2/3 of Earth's surface. © 2020
关键词	diking mid-ocean ridge normal faults seafloor spreading submarine volcanism
英文关键词	Faulting; Hydraulic structures; Submarine geology; Detachment faulting; Lithospheric thickness; Magma emplacement; Magmatic intrusions; Pressure build up; Seafloor spreading; Seafloor spreading mode; Theoretical framework; Structural geology; dike; earthquake; emplacement; lithospheric structure; magma; mid-ocean ridge; seafloor spreading; sill
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202818
作者单位	Laboratoire de Géologie, Ecole Normale Supérieure/CNRS UMR 8538, PSL Research University, Paris, 75005, France; MINES ParisTech, PSL Research University, Centre de Géosciences, Fontainebleau, 77305, France
推荐引用方式 GB/T 7714	Olive J.-A.,Dublanchet P.. Controls on the magmatic fraction of extension at mid-ocean ridges[J],2020,549.
APA	Olive J.-A.,&Dublanchet P..(2020).Controls on the magmatic fraction of extension at mid-ocean ridges.Earth and Planetary Science Letters,549.
MLA	Olive J.-A.,et al."Controls on the magmatic fraction of extension at mid-ocean ridges".Earth and Planetary Science Letters 549(2020).