Geological notes on the dictyonema locality and the upper Guldal disrict in the Trondheim area
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A description is given of the Dictyonema locality from the metamorphic series of the upper Guidal district. It is further given a synopsis of the geology of this area, principally based on old unpublished observations by J. H. L.Vogt. The stratigraphy of the metamorphic series, and the position of the Dictyonema horizon, is discussed, the "Drøia series" being described, representing the lowerpart of the Gula series of Kjerulf. As to the general tectonics, a central synclinal system of the Trondheim area is suggested. Mention is made of andalusite bearing mica schists, representing a mineral facies different from the cyanite bearing facies further to the northwest, the latter being formed under higher pressure. The influence of carbonaceous matter on grain size and porphyroblast formation inmetamorphic argillaceous sediments is considered.