Late Triassic (early Carnian) palynology of shallow stratigraphical core 7830/5-U-1, offshore Kong Karls Land, Norwegian Arctic

ABSTRACT

Palynostratigraphical and palynofacies data are presented from a shallow stratigraphical core (7830/5-U-1) drilled in the northern Barents Sea, offshore Kong Karls Land, Arctic Norway. The core spans approximately 127 m of the Snadd Formation (De Geerdalen Formation equivalent). Samples from core 7830/5-U-1 yielded a well-preserved and taxonomically diverse palynomorph association indicative of an earliest Late Triassic (Carnian) age, consistent with previously published Rhenium-Osmium (Re-Os) dates from other cores drilled in the area. The rare occurrence of angiosperm-like pollen confirms previous observations in the Triassic of the Barents Sea area. Palynofacies evidence and the occurrence of marine microplankton and macrofossils indicate that deposition occurred in an offshore marine environment which became increasingly proximal during latter stages of deposition. Variations in the relative abundance of terrestrial organic matter, rhythmic pulses in amorphous organic matter (AOM) content, and the occurrence of acritarchs and prasinophycean algae suggest episodic fluctuations along a nearshore-offshore trend. Palynomorph ecogroup (PEG) analysis reveals a dominance of spore and pollen types characteristic of coastal plain habitats. Sporadic peaks in hinterland pollen types, recorded in association with AOM, are interpreted to reflect the ‘Neves Effect’. The relatively high abundance of fern, sphenopsid and lycopsid spores is considered indicative of a humid climatic regime. A new informal palynozone termed the Podosporites cf. amicus assemblage is described, contributing to a more detailed regional palynological zonation for the Carnian of the Barents Sea region.

KEYWORDS:

• Pollen-spores
• palynofacies
• Late Triassic
• Carnian
• Svalbard
• Barents Sea
• palynomorph ecogroups

Acknowledgements

This research was funded by a FORCE industry consortium, consisting of Centrica, Chevron, ConocoPhillips, Det Norske, Dong, ENI, Lundin, Shell and Statoil. We thank Malcolm Jones of PLS PalyLab for preparation of palynological slides. The Norwegian Petroleum Directorate is thanked for providing permission to sample stratigraphical core 7830/5-U-1 and for the use of seismic data; we thank Tore Høy for interpretations of seismic data, and Bjørn Anders Lundschien for his assistance in sampling the core. The authors also acknowledge Prof. Peter Hochuli (University of Zurich) and Prof. Wolfram Kürschner (University of Oslo) for taxonomic and palynostratigraphical discussions. We are grateful to Dr Jim Riding (British Geological Survey), Dr Evelyn Kustatscher (Naturmuseum Südtirol) and one anonymous reviewer for their constructive comments on this paper.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Niall William Paterson

NIALL W. PATERSON is a postdoctoral researcher at the University of Bergen, Norway, and specialises in Palaeozoic and Mesozoic palynology. Niall began his palynological career studying Devonian and Carboniferous miospores from the Appalachian Basin, U.S.A. He gained is PhD degree from Trinity College Dublin before joining ExxonMobil Exploration Co. as a palynologist in 2009. Niall returned to academia in 2012 and is currently a co-investigator on the FORCE sponsored project ‘Middle to Late Triassic palynostratigraphy of Svalbard and the Barents Sea’. The primary aims of this work are to refine the palynological zonation and palaeoenvironmental interpretation for the Middle and Upper Triassic series in the Norwegian Arctic.

Gunn Mangerud

GUNN MANGERUD is a professor in biostratigraphy/palynology and is currently Head of the Department of Earth Science at the University of Bergen (UoB), Norway. Her main research interests are the palynology of the Triassic, Permian and Carboniferous of the Norwegian Arctic. Gunn started her career as a researcher at IKU, SINTEF in Trondheim. In 1993, Gunn moved to Bergen and started work as a geologist and a biostratigrapher at Norsk Hydro, holding different positions within the research, exploration and reservoir technology divisions. After leaving Norsk Hydro in 2004 she became CEO for the National Center Internationalization in HE. Gunn moved to her current position at UoB in 2009, allowing her to return to palynological research.

Atle Mørk

ATLE MØRK got his Can.real. thesis at University of Oslo and his Dr. Philos. at The Norwegian University of Science and Technology (NTNU), Trondheim. He has worked with Silurian rocks in the Oslo Region, but his main research is within the Arctic mainly concentrated on Triassic sedimentology, stratigraphy and sequence stratigraphy.