A revised palynozonation for the Middle–Upper Triassic (Anisian–Rhaetian) Series of the Norwegian Arctic

Abstract

AbstractThe Barents Sea region of Arctic Norway preserves a thick succession of marine and deltaic Triassic strata that yield an abundant and diverse association of terrestrial and marine palynomorphs. Despite being the principal means for dating and correlation across this vast region, the Upper Triassic palynozonal resolution has remained relatively low. This is problematic due to the thickness of the Upper Triassic Series and since this corresponds to the longest of the three Triassic epochs. This paper presents a refined Middle–Upper Triassic palynozonation for the region, based on a detailed investigation of multiple localities ranging from the Svalbard Archipelago to the southern Barents Sea. The zonation comprises eleven spore-pollen zones: the Carnisporites spiniger, Triadispora obscura and Protodiploxypinus decus zones (Anisian), the Echinitosporites iliacoides Zone (Ladinian), the Semiretisporis hochulii, Podosporites vigraniae, Leschikisporis aduncus, and Protodiploxypinus spp. zones (Carnian), the Classopollis torosus, and Quadraeculina anellaeformis zones (Norian), and the Ricciisporites spp. Zone (Rhaetian). Additionally, two new dinoflagellate cyst zones are defined: the Rhaetogonyaulax arctica (upper Carnian – lower Norian) and Rhaetogonyaulax rhaetica (lower Norian) zones. Three new age-significant palynomorph taxa are described: Kyrtomisporis moerki sp. nov., Podosporites vigraniae sp. nov. and Semiretisporis hochulii sp. nov. The revised palynozonation is compared with previous palynozonal schemes for the Greater Barents Sea region, and its relationship to Triassic palaeoclimate, palaeoenvironments and sequence stratigraphy is discussed.