DOI: 10.1016/j.epsl.2020.116541
论文题名: Controls on the magmatic fraction of extension at mid-ocean ridges
作者: Olive J.-A. ; Dublanchet P.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 549 语种: 英语
中文关键词: 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
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 Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165196
Appears in Collections: 气候变化与战略
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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
Recommended Citation:
Olive J.-A.,Dublanchet P.. Controls on the magmatic fraction of extension at mid-ocean ridges[J]. Earth and Planetary Science Letters,2020-01-01,549