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- Bergstroem, Stig M., et al.
(author)
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The delta C-13 chemostratigraphy of the Upper Ordovician Mjosa Formation at Furuberget near Hamar, southeastern Norway: Baltic, Trans-Atlantic, and Chinese relations
- 2010
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In: Norsk Geologisk Tidsskrift. - 1502-5322. ; 90:1-2, s. 65-78
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Journal article (peer-reviewed)abstract
- Whereas no studies have previously been carried out on the delta C-13 chemostratigraphy of the Sandbian-Katian (Upper Ordovician) succession anywhere in Norway, such investigations in Sweden and the East Baltic region have made the delta C-13 chemostratigraphy of that interval well known. 1 an attempt to document for the first time the presence of the globally distributed and stratigraphically important Guttenberg Carbon Isotope Excursion (GICE), 45 samples were collected at 2 m intervals through the Furnesfjorden and Galas members of the Mjosa Formation from two sections at Furuberget in the Nes-Hamar District 70 km north of the City of Oslo. Relatively high delta C-13 values, which are interpreted to represent the GICE, were obtained throughout the Galls Member. The presence of this delta C-13 excursion in the middle part of the Mjosa Formation, combined with biostratigraphic and other evidence, are used for detailed correlations of the Mjosa Formation with other successions in Baltoscandia, North America, and on the Yangtze Platform in southern China.
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| 2. |
- Bremer, Oskar, 1985-, et al.
(author)
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Silurian vertebrate remains from the Oslo Region, Norway, and their implications for regional biostratigraphy
- 2019
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In: Norsk Geologisk Tidsskrift. - : GEOLOGICAL SOC NORWAY. - 0029-196X .- 1502-5322. ; 99:1, s. 129-155
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Journal article (peer-reviewed)abstract
- Several vertebrate assemblages are described from the Silurian of the Oslo Region, Norway, based on the review and revision of previous reports of microremains, as well as unpublished material from museum collections. Articulated thelodont specimens from the Rudstangen Fauna, Ringerike Group, are also described here for the first time, revealing a seemingly monogeneric loganelliid assemblage. The oldest assemblage (mid-Llandovery) only contains the thelodont Loganellia cf. aldridgei, while a single sample from upper Llandovery strata produced four Thelodus sp. scales. These scales share features with those from younger Thelodus taxa and give additional support to an early appearance of this genus. The mid-Wenlock faunas consist of thelodonts Loganellia grossi, Loganellia einari and Thelodus laevis. These are joined by the thelodont Paralogania martinssoni, anaspids Rhyncholepis parvula and cf. Pterygolepis nitida, as well as the osteostracans cf. Tyriaspis whitei and Osteostraci gen. et sp. indet. in late Wenlock and earliest Ludlow faunas. These complement the previously described anaspids and osteostracans of the Rudstangen Fauna based on articulated specimens. The faunas of a number of calcarenite samples collectively contain the thelodonts L. grossi, L. einari, P. martinssoni and T. laevis, and are most likely of early Ludlow age. When the vertebrate-producing samples are put in the proposed stratigraphical framework for the Oslo Region that has been refined in recent decades, the faunas fit well into the vertebrate biozonation established for the Silurian, contrary to previous claims. The earliest faunas in the area show similarities to the Llandovery of Britain, whereas thelodonts and anaspids, but not osteostracans, from late Wenlock and early Ludlow are more closely related to Baltic forms. Additional sampling of the area may assist in refining the biostratigraphy and provide insights into Silurian vertebrate distributions in Norway and related regions.
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| 3. |
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| 4. |
- Hall, Adrian M.
(author)
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The last glaciation of Shetland : local ice cap or invasive ice sheet?
- 2013
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In: Norsk Geologisk Tidsskrift. - 0029-196X .- 1502-5322. ; 93:3-4, s. 229-242
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Journal article (peer-reviewed)abstract
- The question of whether the Shetland Islands were covered by an ice cap or by an ice sheet during the last glacial cycle (40-10 ka) remains unresolved. This paper addresses this problem using existing and new data on glacial erratic carry, striae, glacial lineaments and roche moutonnee asymmetry. Its focus is on eastern Shetland, where ice-cap and ice-sheet glaciation would lead to opposed ice-flow directions, towards and away from the North Sea. Evidence cited in support of ice-sheet glaciation of Shetland is questioned. The primary survey of striae correctly identified striae orientation but the direction of ice flow from striae on eastern Shetland was misinterpreted: it was not from, but towards the North Sea. Glacial lineaments interpolated to cross the spine of Shetland instead are discontinuous and diverge away from an axial ice-shed zone that lacks lineaments. Glacitectonic structures cited recently as evidence for westward flow of an ice sheet across eastern Shetland have been partly misinterpreted and other ice-flow indicators in the vicinity of key sites indicate former eastward ice flow towards the North Sea. Westward carry of erratics over short distances in N and S Shetland may be partly accounted for by shifts in ice sheds during ice-cap deglaciation. Collectively, the evidence for movement of the Fennoscandian ice sheet across Shetland is weak. Any ice-sheet incursion over Shetland occurred before the last glacial cycle. The cleansed ice-flow directional data for Shetland show a simple pattern of divergent ice flow from an axial ice-shed zone beneath an ice cap. The deglaciation sequence for the ice cap is evident from sea-bed moraine systems. The Shetland ice cap at the Last Glacial Maximum was substantial, attaining a thickness of 1 km and a diameter of >160 km. The ice cap was of sufficient size to restrain the Fennoscandian ice sheet on the western edge of the Norwegian Channel and to divert the British ice sheet over Orkney. Glacial landscapes on Shetland indicate that ice-cap glaciation has been the dominant mode of glaciation during the Pleistocene.
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| 5. |
- Holmer, Lars E., et al.
(author)
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The lingulid brachiopod Lingularia from lowermost Cretaceous hydrocarbon seep bodies, Sassenfjorden area, central Spitsbergen, Svalbard
- 2012
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In: Norsk Geologisk Tidsskrift. - 0029-196X .- 1502-5322. ; 92:2-3, s. 167-174
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Journal article (peer-reviewed)abstract
- 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 & Emig 1993, represented by well preserved, but invariably fragmented shells. They provide the first critical ultrastructural information for this important extinct member of the extant Lingulidae.
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| 6. |
- Högström, Anette E. S., et al.
(author)
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New information on the Ediacaran-Cambrian transition in the Vestertana Group, Finnmark, northern Norway, from trace fossils and organic-walled microfossils
- 2013
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In: Norsk Geologisk Tidsskrift. - 0029-196X .- 1502-5322. ; 93:2, s. 95-106
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Journal article (peer-reviewed)abstract
- The Vestertana Group on the Digermul Peninsula, Finnmark, northern Norway, presents one of the few, potentially continuous Ediacaran-Cambrian sections in Scandinavia. Trace fossils provide the main age constraint, with the boundary traditionally placed at the base of the Breidvika Formation. Here, we provide trace-fossil evidence to show that this boundary is at least as low as the third cycle of the Manndraperelva Member, Stahpogieddi Formation, where Treptichnus pedum is associated with trilobed trace fossils. Organic-walled microfossils from the same stratigraphic interval include Granomarginata prima and the first report from Scandinavia of Cochleatina. The second cycle of the Manndraperelva Member contains trace fossils, including treptichnids and ?Cochlichnus isp. tentatively interpreted as latest Ediacaran. Reports of palaeopascichnids suggest a late Ediacaran age for the first cycle. The age of lower parts of the Stahpogieddi Formation is poorly constrained but discoidal Ediacara-type fossils, vendotaenids, and possible simple trace fossils, suggest that the middle part of the Innerelva Member is younger than c. 560 Ma.
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| 7. |
- Høyberget, Magne, et al.
(author)
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Re-evaluation of the stratigraphically important olenellid trilobite Holmia cf. mobergi from the Cambrian Series 2, Stage 3 and its implications for the lower Cambrian stratigraphy in the Mjøsa area, Norway
- 2019
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In: Norsk Geologisk Tidsskrift. - : Geological Society of Norway. - 0029-196X .- 1502-5322. ; 99:1, s. 63-92
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Journal article (peer-reviewed)abstract
- The olenellid trilobite Holmia cf. mobergi, known from a single cephalon in the upper lower Cambrian strata from a river section in Flagstadelva, Hamar, has played a significant stratigraphic role in interpreting the lower Cambrian informal Series 2, Stage 3 in the Mjøsa area, Norway, sinceits discovery in the early 1950s. It was considered one of the oldest trilobite taxa in the lower Cambrian of Scandinavia, but the stratigraphic leveland biozonation of the cephalon were problematic and a matter of discussion for decades. Moreover, organic-walled microfossil biostratigraphyquestioned the supposed age of the trilobite. New specimens of this taxon collected from the type locality show that the species occurs at a differentstratigraphic level than first reported, prompting a new description of the species and a re-evaluation of the taxon’s biostratigraphic significance.Holmia cf. mobergi is compared with new and well-preserved topotype material of Holmia inusitata, a very rare taxon hitherto known from onesingle outcrop in an autochthonous setting in Norway. Holmia cf. mobergi and Holmia inusitata are here considered conspecific.
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| 10. |
- Lindström, Sofie
(author)
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Carboniferous palynology of the Loppa High Barents Sea, Norway
- 2003
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In: Norsk Geologisk Tidsskrift. - 1502-5322. ; 83:4, s. 333-349
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Journal article (peer-reviewed)abstract
- Nine palynological intervals, A-I in ascending order, are recognised in the Carboniferous succession of the well 7120/2-1 on the Loppa High in the western Barents Sea. Within the Billefjorden Group intervals A-E are correlated with the early Visean to Serpukhovian Pu to TK Miospore Zones of western Europe. The known sedimentation break between the Billefjorden and Gipsdalen groups occurred in the Serpukhovian, as interval G of the lower part of the Gipsdalen Group is equivalent to the late Serpukhovian SO Miospore Zone. Lycospora pusilla and Densosporites spp. dominate these assemblages, indicating humid conditions. The topmost interval I correlates with early Moscovian palynofloras of the Arctic. It is at the oldest equivalent with the NJ Miospore Zone. Assemblages within this interval are dominated by the monosaccate pollen Florinites and Potonieisporites, with abundant taeniate and non-taeniate bisaccate pollen, indicating deposition under a dry climatic regime.
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