Abstract We report the finding of rare eclogite-facies vugs forming millimeter- to centimeter-sized pockets in meta-ophiolites from western European Alps. Euhedral garnet crystals covering vug walls display oscillatory chemical zoning for a wide range major and trace elements, including Cr, Mn, earth elements. Thermodynamic modeling revealed that closed-system fluid production through breakdown...

Petrological data provide a new approach to an evaluation of the depth–age problem for ancient seafloor. The correlations among basalt chemical composition, axial depth and mantle temperature at current ocean ridges allow the determination of initial depth and mantle temperature for any portion of ancient seafloor that was created at a spreading center, provided the chemical composition of the ...

T h e problem of the origin of the cont inental crust can be resolved into two fundamenta l quest ions: (1) the lo­ cation and mechani sms of init ial m a n t l e extract ion of the primitive crust and (2) the processes by which this primitive crust is converted into the cont inental crust that presently exists . W e know that Archean cont inen­ tal crust is compos i t iona l ly dist inct from ...