Publisher © Czech Geological Survey, ISSN: 2336-5757 (online), 0514-8057 (print)
Serpentinite fragments in the allochthonous crater breccia of the Moldanubicum and possible mechanisms of their emplacement
Abstract
The depth of the transient cavity of the Czech crater (Central Europe) reaches 5 kilometers (depth of 38-40 km) below the surrounding Moho level (35 km). The presupposed volume of the excavated material from the lower Crust and the upper Mantel reaches up to 5000 km3. This material was emplaced mainly via the explosive forces and transient cavity collapse into the allochthonous breccia of the Moldanubicum. The explosion energy created the free space that enabled the serpentinites to penetrate and accumulate in the form of angular fragments up to several kms in size, and in the form of pockets in the case of smaller (dm sized) ones. The protolith of the serpentinites is finely layered dunite, composed of the fine-grained olivine. This layering remains frequently preserved in spite of the strong serpentinization and anthophyllitization of rocks.
