Gunn Mangerud

Palynostratigraphy of the Permian and lowermost triassic succession, Finnmark Platform, Barents sea

A palynostratigraphic study of the Permian and lowermost Triassic succession on the Finnmark Platform in the southwestern parts of the Barents Shelf, off-shore Norway, resulted in the identification of the following palynozones: the Dyupetalum sp.-Hamiapollenites bullaeformis Assemblage Zone of Kungurian-Ufimian age, the Scutasporites sp. cf. S. unicus-Lunatisporites sp. Concurrent Range Zone of Kazanian-?Tatarian age, and the Lundbladispora obsoleta-Tympanicysta stoschiana Assemblage Zone of Griesbachian age. The ages of the zones are based on palynological correlation with similar assemblages recorded elsewhere in the present Arctic region, in particular areas where marine faunas allow dating in terms of standard marine stages.

Biostratigraphy and sequence stratigraphy of the lower and middle Triassic deposits from the Svalis Dome, Central Barents Sea, Norway

Abstract Material from shallow cores drilled through the uplifted and truncated deposits near the Svalis Dome in the Barents Sea contains Lower and Middle Triassic palynomorphs and ammonoids. Eight miospore assemblage zones have been established in this paper, and six of them are calibrated by ammonoids: Svalis‐1 is dated by ammonoids of the late Griesbachian commune Zone. The assemblage is recovered from the Havert Formation overlying the Permian limestone. Svalis‐2 is dated by ammonoids to the late Smithian tardus Zone. The deposits belong to the lower and middle parts of Klappmyss Formation. The unit represents the transgressive systems tract of a Smithian‐early Spathian T‐R Sequence. Svalis‐3 is recorded from the youngest part of Klappmyss Formation which is missing age conclusive faunal evidence. The palynological assemblage is correlated as early Spathian in age. The deposits represent the regressive systems tract of the Smithian‐early Spathian T‐R Sequence. Svalis‐4 is recovered from rocks deposite...

Upper Permian as a new play model on the mid-Norwegian continental shelf: Investigated by shallow stratigraphic drilling

A 750 m-thick, fully marine succession of sandstones, coarse-grained turbidites, shales, and reworked sabkha sediments has been cored on the eastern margin of the mid-Norwegian shelf. The succession has been dated as Upper Permian-Lower Triassic and is comparable to rocks of the same age exposed onshore East Greenland. These data demonstrate that the marine depositional basin between Greenland and Norway extended much farther east than previously thought. Reddish, shallow-marine sandstones in the lower 170 m of the cored succession probably represent reworking of older sedimentary rocks present to the east of the drill sites. This suggests that Upper Devonian-Lower Permian sediments were deposited on Caledonian basement east of the present-day limits of the basin. The cored succession also contains source rocks that can be stratigraphically correlated with the oil-prone source rocks of the Upper Permian Ravnefjeld Formation onshore East Greenland. Some of the cored sandstone intervals were stained with light, nonbiodegraded oil that most likely was sourced from Upper Permian or, alternatively, Lower Triassic mudstones. Reworked fragments of reef-building organisms in Upper Permian turbidites and Upper Permian carbonates encountered in an exploration well on the Nordland Ridge indicate that carbonate deposition and reef building occurred on structural highs on the Trondelag Platform. The observations from the cored successions are key elements in a new Paleozoic play model on the mid-Norwegian continental shelf and include the first evidence for the existence of an Upper Permian source rock in the area, with Upper Permian carbonates or sandstones or Triassic-Jurassic sandstones as reservoir. (Begin page 108)

Early Pliocene onset of modern Nordic Seas circulation related to ocean gateway changes.

The globally warm climate of the early Pliocene gradually cooled from 4 million years ago, synchronous with decreasing atmospheric CO2 concentrations. In contrast, palaeoceanographic records indicate that the Nordic Seas cooled during the earliest Pliocene, before global cooling. However, a lack of knowledge regarding the precise timing of Nordic Seas cooling has limited our understanding of the governing mechanisms. Here, using marine palynology, we show that cooling in the Nordic Seas was coincident with the first trans-Arctic migration of cool-water Pacific mollusks around 4.5 million years ago, and followed by the development of a modern-like Nordic Seas surface circulation. Nordic Seas cooling precedes global cooling by 500,000 years; as such, we propose that reconfiguration of the Bering Strait and Central American Seaway triggered the development of a modern circulation in the Nordic Seas, which is essential for North Atlantic Deep Water formation and a precursor for more widespread Greenland glaciation in the late Pliocene.

Spathian-Anisian (Triassic) palynology at the Svalis Dome, southwestern Barents Sea

Abstract Based on palynological and faunal evidence, two shallow cores from the Svalis Dome in the Barents Sea are interpreted to represent Upper Spathian to Middle Anisian deposits. The two palynological assemblages recognized, are correlated to assemblages M and L recorded in the Spathian-Anisian deposits of the Sassendalen Group in Svalbard. The palynofacies is characterized by high amorphous content up to the middle part of the Middle Anisian, where there is an increased input of wood, charcoal and more terrestrially dominated remains. This change in palynofacies can be related to a change from marine, dysoxic or anoxic conditions to a more oxygenated environment. A moderately humid climate is interpreted from a slight dominance of hygrophytic palynological elements.

Syn-rift evolution and resulting play models in the Snorre-H area, northern North Sea

Abstract An upper Jurassic, wedge-shaped syn-rift succession, comprising the Heather and Draupne Formations, is present in the hangingwall trough of the Snorre Fault Block. The succession is bounded to the west by the Statfjord East Fault, whereas it onlaps the snorre Fault Block to the east. It consists of a two-fold coarsening-upward sequence from shale to sandstone of shallow marine/shoreline origin. Active fault block rotation and subsidence in the Snorre-H area commenced in the Mid-Bathonian and lasted through the Ryazanian. The Heather Formation was deposited during the early rift stage (Mid-Bathonian-Early Oxfordian; 3° cumulative tilt), whereas the Draupne Formation (Late Oxfordian-Ryazanian; 9° cumulative tilt) accumulated during the main and late rift stages. The lower part of the Heather Formation was likely deposited across a submerged tilted fault block terrain, with a predominant extra-basinal sediment supply. Deposition of the upper Heather Formation, however, was governed by gradually emerging footwall islands, albeit yet without significant local erosion. As a result of increased fault/block rotation during deposition of the Draupne Formation Shale, Sequences I–II (late Early Oxfordian-early Mid-Volgian) footwall islands became firmly established, providing a predominant local sediment source to the Snorre-H sub-basin. Clay and silt were supplied from erosion of the Heather Formation on the Snorre-H hangingwall, with subordinate input of sand from the Statfjord East footwall. Subsequent deposition of the Draupne Formation, Sequences III–V (Late Mid-Volgian-Ryazanian), was governed by significant relief on the footwall islands, causing deep erosion into the Brent Group on the Snorre-H hangingwall dip-slope and leading to progradation of the Upper Draupne Sandstone shoreline complex across the Snorre-H area. Deposition of the Draupne Formation and temporal shoreline position were likely partly controlled by northwards fault-tip propagation of the Statfjord East Fault. Various syn-rift play models and depositional reservoir facies are present within the Snorre-H hangingwall basin. They include dip-slope shallow marine/shoreline sands, basin floor gravity transported sands and likely footwall talus sands enveloped in organic rich shales of the Draupne Formation. The distribution of reservoir facies is intimately linked to exposure and erosion of the middle Jurassic Brent Group below the syn-rift unconformity.

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.

Evidence for atmospheric pollution across the Permian-Triassic transition

Evidence for a cause-and-effect relationship between the emplacement of the Siberian Traps large igneous province and the Permian-Triassic marine mass extinction has been growing over the past decades. However, how the Siberian Traps volcanism affected the terrestrial vegetation is still a matter of controversy. Here, we demonstrate that a substantial part of plants’ life cycle, namely their reproductive organs, was adversely affected by environmental conditions. Effects include malformed spores and pollen grains, unseparated tetrads, and darkened walls of spores and pollen (sporoderm) from Permian-Triassic sediments from the Finnmark Platform offshore Norway. The co-occurrence of these morphological changes with the main carbon isotope excursion and the marine mass extinction may suggest that they were caused by atmospheric pollution linked to Siberian Traps emissions.

Late Triassic (early Carnian–Norian) palynology of the Sentralbanken High, Norwegian Barents Sea

abstract Four stratigraphic cores (7533/2-U-1, 2-U-2, 3-U-7 and 7534/4-U-1) drilled in the Sentralbanken High provide important reference sections for the Upper Triassic succession in the northern Barents Sea. The cores span the De Geerdalen, Flatsalen and Svenskøya formations (Kapp Toscana Group), which are equivalent to the Snadd to middle Fruholmen formations of the southern Barents Sea. Only cursory palynological study of the cores has been conducted previously, and no published palynofacies data is available. We present a detailed palynostratigraphy from the cores, and describe six informal palynological assemblages. Comparison with independently dated sections from elsewhere in the region enables a revised age interpretation of early Carnian to Norian for the cored interval, thereby improving correlation between Sentralbanken, Svalbard and the southern Barents Sea. A dominance of amorphous organic matter (AOM) and marine palynomorphs indicates a distal suboxic-anoxic marine depositional environment for the lower De Geerdalen Formation, with an abrupt change to a nearshore marine environment above an erosion surface in core 7534/4-U-1. Palynofacies from the remainder of the formation are characterised by a dominance of phytoclasts and are interpreted as indicative of a delta front to coastal plain environment. The reappearance of AOM, microforaminiferal test linings and marine microphytoplankton in the Flatsalen Formation in cores 7533/2-U-1 and 2-U-2 reflects a regional transgression of early Norian age. Reworked palynomorphs, shale rip-up clasts and a transition to phytoclast-dominated palynofacies above an erosion surface at the base of the overlying Svenskøya Formation is consistent with a disconformity, which was previously identified as a possible sequence boundary on the neighbouring island of Hopen.

Peter Andreas Hochuli (1946–2018)

Peter Andreas Hochuli, a dedicated, eminent and highly talented palaeobotanist and palynologist with comprehensive expertise in palaeoclimatology, palaeoecology and stratigraphy, sadly died of cancer on 27 March 2018. He was only 71 years old. Peter Hochuli was born on 25 October 1946 in the small village of Unterentfelden in the Canton of Aargau, northern Switzerland. He attended primary school in Unterentfelden; however, his mother and sisters convinced him to continue his education in the boarding school at the Cistercian monastery in the nearby city of Wettingen, in the Limmat Valley, district of Baden. The monastery school stimulated and reinforced his curiosity for nature, and Peter became fascinated by all the natural sciences, especially botany. Peter collected plants in and around Aargau for his own herbarium while he was at boarding school. His herbarium encompasses 2131 sheets, largely comprising very well-preserved flowering plants together with 67 specimens of lichens. It is now part of the collection of Naturama Aargau, a museum of natural history in Aarau, the capital of the Canton of Aargau. Following graduation from school, Peter began his studies in natural sciences at the University of Z€urich. At first he focused on botany, and subsequently developed an ever-increasing interest in palaeobotany. Die Urwelt der Schweiz [The primal world of Switzerland] by Oswald Heer, a professor of botany (Heer 1883), became one of his favourite books. This impressive early magnum opus on Earth history, with chapters on palaeoclimate and the use of fossil plants as climate proxies, taught Peter well that a background in geology is essential in order to better understand the evolution of plants. In 1976 Peter completed his PhD dissertation on Cenozoic aquatic and terrestrial palynomorphs from the Alpine Molasse basin, entitled Palynological investigations of the Oligocene and the Early Miocene of the Central and Western Paratethys (Hochuli 1978). He then continued his scientific career as a postdoctoral fellow at the Swiss Federal Institute of Technology (ETH), Z€urich, which included a sabbatical at the University of Saskatchewan, Canada, to work with Bill Sarjeant. In the late 1970s, Peter began his long-standing scientific collaboration with Helmut Weissert on Cretaceous oceanic anoxic events. Together with Judy McKenzie and Helmut Weissert, Peter successfully combined carbon isotope geochemistry with micropalaeontology and palynology in order to reconstruct the palaeoclimate of the Barremian (Weissert et al. 1979). Peter Hochuli demonstrated his adaptability and versatility when he completed his habilitation on Palynostratigraphy of the Permo–Carboniferous of northeastern Switzerland in 1985 at the University of Zurich. The same year, he left university for the oil industry to work as a stratigrapher for Esso Production Research European, later Esso REP, Begles, Bordeaux, France. For 10 years at Esso, he worked as part of a team on material from the entire Phanerozoic of the northern hemisphere from northern Norway to Central Africa. In 1995 Peter moved from France back to Switzerland and rejoined academia. He was appointed senior lecturer at the universities of Fribourg and Z€urich. In addition to his university career, he continued to work as a consultant on biostratigraphy. At this time Peter and Helmut Weissert resumed their collaboration on Cretaceous palaeoclimatology and palaeoceanography, and so this long-lasting and extremely productive cooperation was reestablished. Helmut and Peter co-authored several influential articles, for example on the floral response to mid-Cretaceous oceanic anoxic events (Hochuli et al. 1999). During 2002 Peter joined Hugo Bucher’s research group at the Palaeontological Institute and Museum, University of Zurich, and in 2008 he was appointed professor. In the early 2000s, Peter worked on Cretaceous palaeoclimates and the early evolutionary history of the angiosperms, from material collected in Brazil and Portugal in collaboration with Helmut Weissert and his two PhD students Stefan Burla and Ulrich Heimhofer (e.g. Hochuli et al. 2006; Heimhofer et al. 2007, 2012; Heimhofer and Hochuli 2010). With Hugo Bucher and others, he also undertook multidisciplinary research projects on palaeoclimate and vegetational changes across the Permian–Triassic transition (e.g. Galfetti et al. 2007a, 2007b; Hochuli and Vigran 2010; Hochuli et al. 2010a; Schneebeli- Hermann et al. 2015). Peter and his co-workers, including PhD students Elke Hermann and Anna Sanson-Barrera, succeeded in demonstrating that plants responded in much more complex ways than previously thought to changing environmental conditions during mass extinctions, with shifts due largely to environmental changes rather than evolutionary phenomena and/or paced by volcanic pulses (e.g. Hermann et al. 2010, 2011; Hochuli et al. 2010b; Schneebeli- Hermann et al. 2013; Romano et al. 2013; Sanson-Barrera et al. 2015). Despite Peter’s interest in unravelling the palaeoecological aspects of plant evolution and its intimate link to palaeoenvironmental change, he never lost interest in the stratigraphical value of palynomorphs. He continued, for example, to work on material from the Barents Sea that he first examined during his time in the oil industry (Hochuli et al. 1989; Mork et al. 1990). He did this in close collaboration with Norwegian colleagues, in particularly the palynologist Jorunn Os Vigran. This work resulted in a series of pioneering publications from this region and, in one of his last research projects, he returned to the Triassic palynostratigraphy of the Barents Sea region (Vigran et al. 2014). Peter was best known for his work on terrestrially derived palynomorphs (e.g. Hochuli 1981); however, he also had significant experience with Mesozoic and Cenozoic dinoflagellate cysts (e.g. Hochuli 1978; Hochuli and Kelts 1980; Jan du Ch^ene et al. 1986; van Veen et al. 1998; Hochuli and Frank 2000). Furthermore, Peter was never afraid of presenting provocative ideas, so long as they were based on robust evidence. An example of this is his discovery, together with Susanne Feist-Burkhardt, of early angiosperm pollen grains from the Middle Triassic (Hochuliand Feist-Burkhardt 2004; Hochuli and Feist-Burkhardt 2013). Peter was one of the few scientists who managed to develop an integrated approach by combining his broad palaeobotanical expertise with his deep knowledge of geology and sedimentology. This effortless polymathy enabled him to successfully tackle some of the big questions in the evolutionary history of plants. Peter Hochuli was an outstanding scientist and research partner. One of the aspects of his character, so often missing in the world of science, was his ability to listen to others and to argue with colleagues in an utterly respectful way. Both his colleagues and his students appreciated Peter’s willingness to share his enthusiasm, experience and passion for the twin sciences of palaeobotany and palynology. In his 40 years of palynological research, Peter published over 120 articles, as well as numerous unpublished technical reports. Many of his papers are highly cited, extensively read, and published in high-profile journals. Despite his declining health, he was scientifically active right to the end of his life. Peter Hochuli will always be remembered as an extremely dedicated scientist, and an amiable, cheerful and helpful colleague. He was a dedicated and inspiring teacher and mentor with a fantastic sense of humour. Furthermore, he was always very gentle, hardworking, modest, perceptive, polite and supportive. For many younger colleagues, Peter’s scientific guidance was of outstanding value. He is deeply missed.