Record details

    Influence of the load wavelength on the permeability of a viscosity interface in the mantle
Statement of responsibility
    Hana Čížková, Ondřej Čadek, Arie P. Van den Berg
    Čadek, Ondřej
    Čížková, Hana
    Van den Berg, Arie P.
Source title - serial
    Studia geophysica et geodaetica
    Roč. 41, č. 1
    s. 64-72
    4 obr., 2 s.bibl.
    Zkr. název ser.: Stud. geophys. geod. (Praha)
Subject group
    délka vlnová
Geographical name
Abstract (in english)
   Assuming a radially stratified Newtonian mantle in a steady-state approximation we demonstrate that the permeability of a viscosity interface at 660-km depth strongly depends on the wavelenght of buoyancy forces driving the flow. The flow induced by long-wavelength loads penetrates through the boundary freely even if the viscosity increases by two orders. In contrast, the boundary is practically impermeable for short-wavelength loads located in the upper mantle. Thus, a stepwise increase of viscosity is a significant obstacle for small descending features in the upper mantle, but huge upper mantle downwelling or upwelling formed in the-lower mantle can overcome it easily. This indicates that certain care is necessary in interpreting the seismic structure of the mantle by means of flow models.
   The global tomographic image includes only the first few degrees of the harmonic series and, consequently, its interpretation in terms of a present-day flow field results in a predominantly whole-mantle circulation even for extreme viscosity contrasts
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
Entered date
    28. 3. 2008
Import date
    8. 8. 2012