[1] Univ Oslo, Dept Phys, Fluid Rock Interact Grp, N-0316 Oslo, Norway
[2] Univ Oslo, Dept Geol, Fluid Rock Interact Grp, N-0316 Oslo, Norway
[3] Univ Grenoble 1, LGIT CNRS Observ, F-38041 Grenoble, France
[4] Univ Paris 11, Chim Phys Lab, F-91405 Orsay, France