Structures d'écoulement dans une caisse filonienne : le mécanisme d'intrusion télescopique et le concept d'intra-épontes

Abstract

A detailed study of the internal structure of a dyke has revealed the existence of three facies, separated by magmatic discontinuities termed intrawalls. Chemical data from rocks and minerals, noteworthy for their homogeneity, point to a comagmatic identity for the different facies.Magmatic fabrics and especially intratelluric mineral distribution across the dyke width permit us to propose flow models specific for each facies. From these data it appears that, for a given facies, the flow pattern (and the consequent mechanical differentiation) must be expressed in terms of rheological characteristics of the magma during its emplacement.The data as a whole (chemical, mineralogical, structural petrology) are integrated in a dynamic emplacement model of a single magma through a pipe, according to what we define as a telescopic intrusion model.