A detailed structural mapping and geometrical analysis of distinct bedding-(sub)perpendicular and bedding-parallel quartz veins has been performed in the northeastern part of the High-Ardenne slate belt (Rursee, North Eifel, Germany), with the aim to reconstruct the local fracturing/veining history. The structural relationship of these two types of veins as well as their relationship with cleavage, folds and faults allows attributing a pre- to early-Variscan age to these veins. The first type of veins is oriented (sub)perpendicular to bedding and consists of several, mutual cross-cutting generations, which clearly predate Variscan deformation. The second type of veins, bedding-parallel veins, post-dates the bedding-(sub)perpendicular veins and reflects bedding-parallel thrusting at the onset of Variscan deformation, predating folding. Subsequently, during progressive Variscan compression both types of veins were passively folded within characteristic, NW-vergent, overturned folds. Locally, due to flexural slip folding, reactivation along the bedding-parallel veins may have taken place.
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The taxonomic affinities of fossils from theFrasnian succession of Be lgium previously described asphyllopod and phyllocarid crustacean shields are discussed.The rediscovery of the holotype of Ellipsocaris dewalquei,the type species of the genus Ellipsocaris Woodward inDewalque, 1882, allows to end the discussion on the taxo-nomic assignation of the genus Ellipsocaris. It is removedfrom the phyllopod crustaceans as interpreted originally andconsidered here as an ammonoid anaptychus. Furthermore, itis considered to be a junior synonym of the genus SidetesGiebel, 1847. Similarly, Van Straelen’s (1933) lower to middleFrasnian record Spathiocaris chagrinensis Ruedemann, 1916,is also an ammonoid anaptychus. Although ammonoids canbe relatively frequent in some Frasnian horizons of Belgium,anaptychi remain particularly scarce and the attribution to thepresent material to peculiar ammonoid species is not possible.
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RBINS Staff Publications 2017
