The paper provides a first comprehensive account of the Trollheimen volcanogenic formation, examines its structural and geological features, material composition, and age, and suggests geodynamic interpretations of its formation environments. This sedimentary-volcanic complex situated in the mountainous glacial part of Oscar II Land has been dated to the Vendian period (574–558 Ma), forming as a result of tectono-magmatic activation of the epi-Grenvillian paraplatform. The petrographic and petrogeochemical characteristics of the formation’s metabasalts, meta-andesites and metatuffs suggest their genesis through rifting. A correlation was established with the previously identified sedimentary-volcanic complex of the Chamberlandalen series (the northern part of Wedel Jarlsberg Land). The presented data support the previous reasoning for the Vendian (Baikal, Timan) intraplate activation in the archipelago and the widespread development of these complexes as part of Svalbard’s epi-Grenvillian paraplatform cover.