Hans Arne Nakrem

Hans Arne Nakrem
University of Oslo · Natural History Museum

MSc, PhD

About

106
Publications
24,986
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,392
Citations
Additional affiliations
January 1999 - present
Natural History Museum, Norway
Position
  • Professor (Full)
June 1988 - present
University of Oslo
Position
  • Professor (Full)

Publications

Publications (106)
Article
The late Paleozoic was characterized by a series of continental collisions and ice ages. Despite the drastic environmental changes, sparse sulfur isotope data hinder our understanding of the late Paleozoic biogeochemical sulfur cycle, especially during the Early Permian. To overcome this potential bias, we present a high-resolution sulfur isotope r...
Article
The Capitanian (Middle Permian) mass extinction event, prior to and separate from the end-Permian mass extinction, has been suggested as a severe biotic crisis comparable to the big five mass extinctions of the Phanerozoic. However, there is still controversy about its global significance. In particular , this purportedly disastrous event in the Ca...
Article
Full-text available
Rock specimens and contained fossils collected in 1976 from a submarine tunnel driven between Herøya and Rafnes in the Skien–Langesund area of southern Norway, have been restudied. The contained fossils include olenid and agnostoid trilobites, graptolites and brachiopods, groups described in detail for the first time from the area and documenting a...
Article
Full-text available
This study reports diverse spiriferellid brachiopods from the Permian rocks of Svalbard and adjacent areas (Arctic Canada and Subpolar Urals of Russia) located at the northern margin of Pangaea. In total, 11 brachiopod species in four genera are recognized and described in detail, including two new species (Spiriferella protodraschei and Arcullina?...
Article
Full-text available
In the Mesozoic seas, the apex predators were reptiles. From the Arctic archipelago of Svalbard, the Spitsbergen Mesozoic Research Group has excavated numerous well preserved marine reptile skeletons in order to understand the biology of these animals and the environment they lived in. The work of eleven field seasons has made this one of the large...
Article
Five hydrocarbon seep carbonate structures in the upper part of the Slottsmøya Member (Agardhfjellet Formation) in central Spitsbergen have been sampled and processed for foraminifera. The carbonates have been found to contain excellently preserved agglutinated assemblages, in contrast to the diagenetically deformed assemblages in the adjacent shal...
Article
Full-text available
We report on a newly excavated Spathian (Lower Triassic) bonebed on Marmierfjellet, Central Spitsbergen. The bonebed contains a varied material of bones and teeth from marine vertebrates along with conodont elements. The fauna of the bonebed could prove interesting in a global context of recovery and speciation after the Late Permian mass extinctio...
Article
Full-text available
Nine samples from the Alum Shale of Slemmestad, Oslo Region, were processed for conodonts. The limestone-rich interval extending from the mid Cambrian Paradoxides paradoxissimus trilobite Zone to the Lower Ordovician Boeckaspis trilobite Zone yielded a sparse conodont fauna. The fauna is dominated by the protoconodont species Phakelodus elongatus (...
Article
Full-text available
The possible macrofossil Telemarkites enigmaticus from the Mesoproterozoic Gjuve Formation, Telemark supracrustals, southern Norway, was described by Dons in 1959. We here present finds of similar, but larger structures from the somewhat older Åmot Formation (c. 1150–1250 Ma). The elongated, strongly oriented, nodular structures are up to 25 cm lon...
Article
Eleven gastropod species from seven latest Jurassic–earliest Cretaceous hydrocarbon seep deposits from central Spitsbergen, Svalbard are described and illustrated. Six new species and one new genus are introduced. Sassenfjordia gen. nov. is tentatively classified as a naticoid and is characterized by a naticiform gross teleoconch morphology and a l...
Article
The Oslo area has a rich geodiversity, a long history of scientific investigations, and several protected geosites. Many of the protected geosites were protected some 30 years ago and have until recently not been followed up with monitoring and systematic management. This paper presents a work where 35 protected geosites have been assessed regardin...
Article
Here we describe a Paleocene-aged methane seep locality and an associated layer of sunken wood, from Fossildalen on Spitsbergen, Svalbard, hosted in offshore to prodelta siltstones of the Basilika Formation, Van Mijenfjorden Group. The fossiliferous seep carbonates were first identified in museum collections from expeditions in the 1920s and 1970s,...
Chapter
Material of six osteolepiform genera is described, including Askerichthys n. gen., a new Late Carboniferous genus from Norway, Megalichthys Agassiz, 1835 from the Carboniferous of Great Britain, Latvius Jarvik, 1948 from the Late Devonian of Germany and Latvia, and Osteolepis Agassiz, 1835 and Gyroptychius McCoy, 1848 from the Middle Devonian of Gr...
Article
Full-text available
The Upper Jurassic–Lower Cretaceous in the Isfjorden area (central Spitsbergen), consisting mostly of dark shales, with local carbonate-seep deposits, have been analysed for marine palynomorphs and palynofacies. Two dinoflagellate cyst assemblage zones have been defined in the Slottsmøya Member (Agardhfjellet Formation). The palynostratigraphic zon...
Article
Full-text available
The first known fossil vertebrate found in the Lower Cretaceous of Spitsbergen (Svalbard, Arctic Norway) is presented and described. The specimen, a femur, was collected from the Zillerberget member of the Carolinefjellet Formation at Schönrockfjellet in 1962 and was recently re-discovered. The bone is referred to ?Avialae based on a combination of...
Article
Full-text available
This study gives the first detailed report of palynomorphs from Mesozoic cold hydrocarbon seep deposits. The organic-walled microfossils and palynodebris comprise ex situ fossil material in the seep deposits of the Upper Jurassic–Lower Cretaceous Agardhfjellet Formation, and consist of both specimens that originated during the time of deposition an...
Article
Full-text available
We re-examine a Lower Cretaceous dinosaur tracksite at Boltodden in the Kvalva°gen area, on the east coast of Spitsbergen, Svalbard. The tracks are preserved in the Helvetiafjellet Formation (Barremian). A sedimentological characterization of the site indicates that the tracks formed on a beach/margin of a lake or interdistributary bay, and were pr...
Article
The paper describes Late Jurassic–Early Cretaceous seep carbonate boulders from the Russian Arctic island of Novaya Zemlya, collected in 1875 by A.E. Nordenskiöld during his expedition to Siberia. The carbonates are significantly depleted in heavy carbon isotopes (δ13C values as low as ca. − 40‰) and show textures typical for carbonates formed unde...
Poster
Full-text available
Late Smithian (Early Triassic) ammonoids from a single carbonate concretion in the uppermost Lusitaniadalen Member (“Fish Niveau”, Vikinghøgda Formation) at Stensiöfjellet, Spitsbergen, are studied and compared with similar assemblages from other areas.
Conference Paper
Full-text available
Late Smithian (Early Triassic) ammonoids from a single carbonate concretion in the uppermost Lusitaniadalen Member (“Fish Niveau”, Vikinghøgda Formation) at Stensiöfjellet, Spitsbergen, are studied and compared with similar assemblages from other areas. Late Smithian ammonoid assemblages are characterised worldwide by low diversity and predominance...
Article
Latest Jurassic–earliest Cretaceous hydrocarbon seeps from Spitsbergen, Svalbard, are known to contain unusual fauna, lacking most of the species characteristic for roughly coeval seep deposits. This study summarizes and analyses the fauna from 16 seep carbonate bodies from Spitsbergen to explain its composition. The seeps formed in a shallow epico...
Article
Full-text available
New, extensive fossil material collected in situ from the lower Cambrian Evjevik Member in the Mjøsa type area, southern Norway, allows a reevaluation of the faunal distribution and diversity of the ‘Ornamentaspis’ linnarssoni Zone. Described taxa include three holmiid, six ellipsocephalid and one eodiscoid trilobite in addition to five helcionello...
Article
Full-text available
A stenolaemate bryozoan fauna from the lower Silurian (Wenlock) Steinsfjorden Formation of the Ringerike district, southern Norway contains 10 species (2 cystoporates, 6 trepostomes, and 2 cryptostomes). Six species are new: Heterotrypa ringerikensis sp. nov., Trematopora maculata sp. nov., Amplexopora crassiparietum sp. nov., A. evae sp. nov., Ort...
Article
Full-text available
Serpulid polychaete tubes are described from Volgian-Ryazanian sediments (?Pyrgopolon decorata (Stolley, 1912), ?Pyrgopolon aff. nodulosum (Lundgren, 1883)) and four contemporaneous hydrocarbon seep deposits (?Pyrgopolon aff. nodulosum, ?Pyrgopolon sp. A, Propomatoceros sp. A, Nogrobs aff. quadricarinata Münster in Goldfuss, 1831) from Spitsbergen,...
Article
Full-text available
The Blanknuten Member of the Botneheia Formation preserves ichthyopterygians of various body-sizes. Due to the fragmentary nature of their remains, their systematic positions are controversial. The most complete skeleton of a mixosaur from Svalbard (PMO 219.250) described in this paper adds new data to the Phalarodon-Mixosaurus controversy, which i...
Article
Full-text available
Late Jurassic–Early Cretaceous (Late Volgian–latest Ryazanian) rhynchonellate brachiopods are described from eight out of 15 hydrocarbon seep deposits in the Slottsmøya Member of the Agardhfjellet Formation in the Janusfjellet to Knorringfjellet area, central Spitsbergen, Svalbard. The fauna comprises rhynchonellides, terebratulides (terebratuloids...
Article
Full-text available
The bivalve fauna from the latest Jurassic–earliest Cretaceous hydrocarbon seep deposits from central Spitsbergen, Svalbard comprises at least 17 species, four of which belong to chemosymbiotic taxa often found at seeps. These are the solemyid Solemya (Petrasma) cf. woodwardiana; Nucinella svalbardensis sp. nov., which belongs to a group of large N...
Technical Report
Full-text available
The Oslo Region (Oslofeltet) is a geological structure that varies in width from 40 to 70 km and extends approximately 115 km both north and south of Oslo. The region is fault controlled (the Oslo Graben) and covers an area of roughly 10 000 km2. It is bordered by Precambrian rocks to the east and west, and by the Caledonian nappes to the north (Fi...
Article
Full-text available
We present δ13Corg curves for the Upper Jurassic to lowermost Cretaceous of central Spitsbergen. The three sections span the Slottsmøya Member (Agardhfjellet Formation) at Janusfjellet and Knorringfjellet in the Sassenfjorden area. The results indicate that bulk organic carbon isotope chemostratigraphy can be used as a tool for high-resolution, loc...
Article
Full-text available
A well-preserved, low-diversity assemblage of fossil echinoderms from the early Middle Volgian in the Slottsmøya Member (Agardhfjellet Formation) has been discovered at Janusfjellet, Sassenfjorden area, central Spitsbergen. Five species are recognised: the isocrinid Chariocrinus sp., the pedinoid Hemipedina sp., the forcipulate asteroid Asteriidae...
Article
Full-text available
Radiolarians were studied in silt and shale samples from the Upper Jurassic Volgian part of the Slottsmøya Member (Agardhfjellet Formation) of Central Spitsbergen, Svalbard. Identifications could only be made from thin-sections, which hinders precise species level identifications. Nevertheless the preservation is sufficient to reliably identify som...
Article
We report on the discovery of large cephalopod arm hooks (mega−onychites) from the Kimmeridgian and Volgian of Spitsbergen (Agardhfjellet Formation). This includes a largely uncompressed hook in a seep carbonate,with preservation of surface sculpture. We suggest the use of logarithmic spirals as morphological descriptors for the outer part of cepha...
Article
Full-text available
We report on the discovery of large cephalopod arm hooks (mega−onychites) from the Kimmeridgian and Volgian of Spitsbergen (Agardhfjellet Formation). This includes a largely uncompressed hook in a seep carbonate,with preservation of surface sculpture. We suggest the use of logarithmic spirals as morphological descriptors for the outer part of cepha...
Article
Full-text available
A stenolaemate bryozoan fauna from the Late Ordovician (Sandbian) Furuberget Formation of the Mjøsa district, southern Norway contains 10 species. One species belongs to the Order Cyclostomata: Corynotrypa delicatula (James, 1878). Five species belong to the Order Trepostomata: Parvohallopora ramosa (d’Orbigny, 1850), Mesotrypa orientalis Bassler,...
Article
Full-text available
A series of Upper Jurassic to Lower Cretaceous samples of hydrocarbon seep bodies from central Spitsbergen (Svalbard) were treated with acetic acid to retrieve insoluble micro and macrofossils. The Lower Cretaceous samples yielded abundant lingulid material of Lingularia similis? Biernat & Ernig 1993, represented by well preserved, but invariably f...
Article
Full-text available
This paper presents a detailed analysis of microfacies of nine of the 15 hydrocarbon seep carbonates recorded from the Sassenfjorden area, Svalbard. These Late Volgian-latest Ryazanian carbonates have been found in the black shales of the uppermost Slottsmøya Member, Agardhfjellet Formation. The interval is characterised by a low sedimentation rate...
Article
Full-text available
Paleontological fieldwork on Spitsbergen, 2004-2011, has revealed the presence of abundant plesiosaur and ichthyosaur remains, a series of 15 seep carbonate bodies, as well as a rich invertebrate fauna from the Upper Jurassic – Lower Cretaceous Slottsmøya Member of the Agardhfjellet Formation, a 70-100 metre-thick unit of dark grey to black shale a...
Article
Full-text available
Ichthyosaur diversity near the Jurassic-Cretaceous boundary, particularly from high paleolatitudes, is poorly known. Two recently collected specimens of medium- to large-bodied ichthyosaurs from the Slottsmøya Member of the Agardhfjellet, Svalbard, Norway represent two new taxa of ophthalmosaurids. The holotype specimen of Cryopterygius kristiansen...
Article
Full-text available
Mixed calcareous-agglutinated benthic foraminiferal assemblages have been obtained from five hydrocarbon seep carbonate structures in the upper Slottsmøya Member (Agardhfjellet Formation) in central Spitsbergen, Svalbard. The composition of the agglutinated component is comparable to faunas previously described from the surrounding dark shales of t...
Article
Full-text available
A stenolaemate bryozoan fauna from the Late Ordovician (Katian) Mjøsa Formation of Bergevika (Helgøya, Mjøsa), southern Norway contains nine species. Seven species belong to the Order Trepostomata: Esthoniopora subsphaerica (Bassler, 1911), Hallopora gracilens Bassler, 1927, Diazipora parva (Bassler, 1911), Hemiphragma batheri Bassler, 1911, Eridot...
Article
Full-text available
A collection of 55 well preserved ammonite specimens from hydrocarbon seep carbonate bodies from the Slottsmøya Member, Agardhfjellet Formation, in the Sassenfjorden area, Spitsbergen, is described and used as a basis for a chronostratigraphical interpretation of the seep deposits. The ammonites enable us to give a detailed biostratigraphical frame...
Conference Paper
Full-text available
Biostratigraphy of the Early Cambrian Evjevik Member, Ringstrand Formation, Mjösa Area, Norway MAGNE HØYBERGET1, JAN OVE R. EBBESTAD2, BJØRN FUNKE3 and HANS ARNE NAKREM4 The Evjevik Member of the Ringstrand Formation is restricted to the Lower Allochthon in the Mjøsa area, Norway. The unit comprises a lower bioclastic limestone (25–30 centimetres),...
Conference Paper
Full-text available
A series of palaeontological expeditions to the Svalbard archipelago in 2004-2011 have revealed abundant marine reptile remains in the Upper Jurassic to Lower Cretaceous Slottsmøya Member – a 70–100 metre-thick dark grey to black shale unit of the Agardhfjellet Formation. To date, approximately 40 individual skeletal occurrences have been mapped, o...
Article
Full-text available
Fifteen carbonate bodies, interpreted as having been formed at hydrocarbon seeps, have been found in the Sassenfjorden area of Spitsbergen, Svalbard. The bodies, up to 5 m wide, are found in the siltstones and mudstones of the uppermost Slottsmøya Member, in the Upper Jurassic to lowermost Cretaceous Agardhfjellet Formation. The age of the seeps is...
Article
Six bentonite samples from the Silurian (Wenlock) Steinsfjorden Formation collected in the Ringerike District of Norway have been mineralogically and compositionally characterised. The results are used to stratigraphically correlate three bentonites in the Ringerike District. The bentonites crop out in rocks deposited in widely varying sedimentary...
Article
Full-text available
A stenolaemate bryozoan fauna from the Late Ordovician (Katian) Mjosa Formation of Bergevika (Helgoya, Mjosa), southern Norway contains nine species. Seven species belong to the Order Trepostomata: Esthoniopora subsphaerica (Bassler, 1911), Hallopora gracilens Bassler, 1927, Diazipora parva (Bassler, 1911), Hemiphragma batheri Bassler, 1911, Eridot...
Article
In this article, we present evidence for the migration of Cretaceous or younger oil into Paleozoic strata on the islands of Novaya Zemlya, Russian Arctic, originating from the surrounding basins of the Barents Sea and the Kara Sea. We thus suggest a novel petroleum system for the greater Barents Sea and Kara Sea regions. Organic geochemical data re...