DOI: 10.1038/ngeo2745
论文题名: Segmentation of mid-ocean ridges attributed to oblique mantle divergence
作者: VanderBeek B.P. ; Toomey D.R. ; Hooft E.E.E. ; Wilcock W.S.D.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2016
卷: 9, 期: 8 起始页码: 636
结束页码: 642
语种: 英语
Scopus关键词: magmatism
; mantle discontinuity
; mantle process
; mid-ocean ridge
; plate tectonics
; seafloor spreading
; segmentation
; spreading center
; Juan de Fuca Ridge
; Pacific Ocean
英文摘要: The origin of mid-ocean ridge segmentation - the systematic along-axis variation in tectonic and magmatic processes - remains controversial. It is commonly assumed that mantle flow is a passive response to plate divergence and that between transform faults magma supply controls segmentation. Using seismic tomography, we constrain the geometry of mantle flow and the distribution of mantle melt beneath the intermediate-spreading Endeavour segment of the Juan de Fuca Ridge. Our results, in combination with prior studies, establish a systematic skew between the mantle-divergence and plate-spreading directions. In all three cases studied, mantle divergence is advanced with respect to recent changes in the plate-spreading direction and the extent to which the flow field is advanced increases with decreasing spreading rate. Furthermore, seismic images show that large-offset, non-transform discontinuities are regions of enhanced mantle melt retention. We propose that oblique mantle flow beneath mid-ocean ridges is a driving force for the reorientation of spreading segments and the formation of ridge-axis discontinuities. The resulting tectonic discontinuities decrease the efficiency of upward melt transport, thus defining segment-scale variations in magmatic processes. We predict that across spreading rates mid-ocean ridge segmentation is controlled by evolving patterns in asthenospheric flow and the dynamics of lithospheric rifting. © 2016 Macmillan Publishers Limited. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/105948
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: Department of Geological Sciences, University of Oregon, Eugene, OR, United States; School of Oceanography, University of Washington, Seattle, WA, United States
Recommended Citation:
VanderBeek B.P.,Toomey D.R.,Hooft E.E.E.,et al. Segmentation of mid-ocean ridges attributed to oblique mantle divergence[J]. Nature Geoscience,2016-01-01,9(8)