Ocean floor basalt, not continental gabbro: a reinterpretation of the Hoher Bogen amphibolites, Tepla-Barrandian, Bohemian massif

At its southern margin along the Hoher Bogen mountain, the Tepla-Barrandian (Bohemian massif, Central Europe) is made up of a 1- to 4-km wide belt of amphibolites. An upper amphibolite/lower granulite facies Variscan metamorp hism has brought forth coarse-grained, weakly foliated rocks with hbl+pl+/- cpx+/-opx+/-grt parageneses. Since the beginning of this century, these roc ks, together with fine-grained or mylonitized amphibolites, have been regar ded as metamorphic gabbros (gabbro amphibolites) of the Neukirchen-Kdyne ig neous complex. Relies of magmatic textures, however, cannot be found anywhe re. The amphibolites are therefore reinterpreted as metamorphic basalts. Th e Hoher Bogen amphibolites (HBA) derive from N-type MORE. The most primitiv e samples have Mg#s between 60 and 65. Locally occurring (garnet-)hornblend ites and leucodioritic mobilisates are the products of partial melting of a mphibolites during the Variscan metamorphism and do not belong to the prima ry magmatic rock association. Ultramafic rocks are tectonically emplaced be tween the HBA belt and the metapelitic rocks of the Moldanubian. At the ver y least, the metapyroxenites among them seem to have a cumulus origin. Toge ther with the ultramafic rocks, the HBA belt may be regarded as a metaophio lite, comparable to the Marianske Lazne complex. The reinterpretation of th e former "gabbro amphibolites" as a metaophiolite has consequences for the geology of the Tepla-Barrandian: the size of the Neukirchen-Kdyne igneous c omplex is reduced. The HBA belt is a piece of oceanic crust which is possib ly younger than the Precambrian metasedimentary/metavolcanic country rock o f the Neukirchen-Kdyne igneous complex.