Channeling of plume flow beneath mid-ocean ridges

被引:69
作者
Albers, M [1 ]
Christensen, UR [1 ]
机构
[1] Univ Gottingen, Inst Geophys, D-37075 Gottingen, Germany
关键词
mantle plumes; Mid-ocean ridges; Iceland; convection;
D O I
10.1016/S0012-821X(01)00276-X
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
We investigate the interaction of mantle plumes with mid-ocean ridges in 3-D numerical convection models. Using a finite-volume multigrid technique with local grid refinement, we are able to incorporate a much stronger temperature-dependence of viscosity than was possible in previous models. This allows lateral viscosity variations of more than six orders of magnitude, which is realistic in a ridge situation. In models of ridge-centered plumes with constant flux we determine how the shape and the along-axis width of the plume head depends on various model parameters. The plume material is significantly channeled along the axis of a slow-spreading ridge if the plume viscosity is in the order of 10(17) Pa s. The plume material spreads radially below the ridge if the spreading rate is fast or the viscosity contrast between plume and ambient mantle is small. In time-dependent calculations we investigate the temporal evolution of short-term variations of the plume flux. At slow-spreading ridges these perturbations propagate in the form of pulses along the ridge with a speed much larger than the spreading rate. Our results support the hypothesis that pulsations of the Iceland plume are the cause for V-shaped topography and gravity anomalies at the Reykjanes Ridge. (C) 2001 Elsevier Science B.V. All rights reserved.
引用
收藏
页码:207 / 220
页数:14
相关论文
共 37 条
[11]   SOLITARY WAVES ON CONDUITS OF BUOYANT FLUID IN A MORE VISCOUS-FLUID [J].
HELFRICH, KR ;
WHITEHEAD, JA .
GEOPHYSICAL AND ASTROPHYSICAL FLUID DYNAMICS, 1990, 51 (1-4) :35-52
[12]   Mantle flow, melting, and dehydration of the Iceland mantle plume [J].
Ito, G ;
Shen, Y ;
Hirth, G ;
Wolfe, CJ .
EARTH AND PLANETARY SCIENCE LETTERS, 1999, 165 (01) :81-96
[13]   Dynamics of mantle flow and melting at a ridge-centered hotspot: Iceland and the Mid-Atlantic Ridge [J].
Ito, G ;
Lin, J ;
Gable, CW .
EARTH AND PLANETARY SCIENCE LETTERS, 1996, 144 (1-2) :53-74
[14]   Interaction of mantle plumes and migrating mid-ocean ridges: Implications for the Galapagos plume-ridge system [J].
Ito, G ;
Lin, J ;
Gable, CW .
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, 1997, 102 (B7) :15403-15417
[15]   LABORATORY INVESTIGATION OF THE INTERACTION OF OFF-AXIS MANTLE PLUMES AND SPREADING CENTERS [J].
KINCAID, C ;
ITO, G ;
GABLE, C .
NATURE, 1995, 376 (6543) :758-761
[16]   SOLITARY WAVE-PROPAGATION IN A FLUID CONDUIT WITHIN A VISCOUS MATRIX [J].
OLSON, P ;
CHRISTENSEN, U .
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH AND PLANETS, 1986, 91 (B6) :6367-6374
[17]  
Patankar S.V., 1980, Numerical Heat Transfer and Fluid-Flow, DOI 10.1201/9781482234213
[18]   Viscosity structure beneath northeast Iceland [J].
Pollitz, FF ;
Sacks, IS .
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, 1996, 101 (B8) :17771-17793
[19]   THE DYNAMICS OF PLUME-RIDGE INTERACTION .1. RIDGE-CENTERED PLUMES [J].
RIBE, NM ;
CHRISTENSEN, UR ;
THEISSING, J .
EARTH AND PLANETARY SCIENCE LETTERS, 1995, 134 (1-2) :155-168
[20]   The dynamics of plume-ridge interaction .2. Off-ridge plumes [J].
Ribe, NM .
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, 1996, 101 (B7) :16195-16204