Palaeogeographic reconstruction of the pre- to syn-Iapetus rifting sediments in the Caledonides of Finnmark, N Norway

Gayer, Rod; Rice, Anthony H.

doi:10.1007/978-94-009-2549-6_11

Cited by 12 publications

(26 citation statements)

References 16 publications

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“…2). There is no stratigraphic overlap of this unit with the cover successions further south and west in the Komagfjord Antiformal Stack and, as it is lithologically distinct from the units in the Gaissa Thrust Belt and East Finnmark Autochthon, its age is uncertain, but it has been correlated with the Laksefjord Group (Pharaoh 1985;Gayer & Rice 1989;column B, Figs 2 & 4). The Burford Formation, deposited in the westernmost part of the Komagfjord Antiformal Stack (Fig.…”

Section: Lithostratigraphymentioning

confidence: 93%

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Restoration of the External Caledonides, Finnmark, North Norway

Rice

2013

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Branch line restoration of the external Finnmark Caledonides, northern Norway, gives 232 km linear displacement of the Middle Allochthon, rising to 252 km when including thrustingdirection changes. A 108 km SSE/SE-directed deformation, mostly ductile, and 144 km ENE/ ESE-directed deformation, mostly brittle, occurred. The North Varanger Region/Terrane restores to under Porsangerhalvøya, with the Trollfjorden-Komagelva Fault a possible precursor of the Kokelv Fault. Dextral offset on the Trollfjorden-Komagelva Fault was c. 207 km. Three major sediment depositional areas are recognized: Timan Basin (including Barents Sea-Løkvikfjellet, Einovskaya -Manjunnas-Digermulen and Laksefjord sub-basins); Gaissa Basin (including Finnmark Ridge and Baltica Coast); and Gaissa Promontory. The Barents Sea-Løkvikfjellet Sub-basin comprises 15.9 km of sediments of the North Varanger Terrane. The Einovskaya-ManjunnasDigermulen Sub-basin comprises 4 km of Rybachi Terrane sediments overlain by the Manjunnas Group (3 km) and then a Gaissa Basin equivalent succession (4.2 km). The 7.7 km-thick Laksefjord Group (Laksefjord Sub-basin) lies directly WNW of the Finnmark Ridge. Maximum clastic sedimentation (c. 3.7 km) in the Gaissa Basin was in the NE and maximum dolomite accumulation (235 m) in the SW, where the basin closed off. The Finnmark Ridge and Baltica Coast have condensed Gaissa Basin successions. The Gaissa Promontory lies north of the Gaissa Basin, probably with the same lithostratigraphy.

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Section: Lithostratigraphymentioning

confidence: 93%

“…In the central part of the north margin of the Alta -Kvaenangen tectonic window, dolostones correlated with the upper part of the Tanafjorden Group crop out (Talvik Dolomite; cf. Gayer & Rice 1989;Fig. 1).…”

Section: Lithostratigraphymentioning

confidence: 96%

Restoration of the External Caledonides, Finnmark, North Norway

Rice

2013

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“…If one accepts suggested correlations farther to the west, based on lithological grounds, the pericratonic succession may continue as far west as the Kv~enangsfjorden area, an additional c. 200 km along strike (e.g. Reusch 1900;Gayer & Rice 1989) (Fig. 1).…”

Section: Westward Extension Of the Neoproterozoic Successions And Sedmentioning

confidence: 98%

“…These psammitic rocks are interpreted as representing alluvial fan, braided stream and flood-plain alluvial deposits deriving from a highland area of basement gneisses to the SE (FCyn et al 1983), known as the Finnmark Ridge (Gayer et al 1987;Gayer & Rice 1989). The sandstones are succeeded by shallow to deeper marine siltstones and mudstones.…”

Section: Type II Basins In the Middle Allochthon And Lower Part Of Thmentioning

confidence: 99%

Northeastern and northwestern margins of Baltica in Neoproterozoic time: evidence from the Timanian and Caledonian Orogens

Siedlecka

Roberts

Nystuen

et al. 2004

Memoirs

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The Neoproterozoic depositional histories of the Timanian and Baltoscandian, orthogonal margins of Baltica show several important differences but also some similarities. The Timanian margin comprises mainly low-grade, terrigenous sedimentary successions with a distinctive, margin-parallel fault zone separating pericratonic and basinal domains. Magmatic rocks are comparatively rare on land, but are common in deep drillcores recovered from beneath the Pechora Basin. Conversion to an active margin occurred in latest Riphean time, ultimately leading to the accretionary and transpressional regime of the Vendian-age, Timanian Orogeny. Along the Baltoscandian margin, successions of low to high metamorphic grade are preserved in diverse Caledonian nappe complexes. Three main types of palaeobasin are distinguished, based largely on sedimentary facies and basin geometry. Magmatic rocks are more common than in the Timanides, ranging from mafic dyke swarms to the voluminous Seiland Igneous Province. This margin remained passive throughout the Neoproterozoic era. The Vendian-dated dyke swarms signify the onset of Iapetus/,zEgir ocean opening at precisely the time when the orthogonal Timan margin was being deformed and telescoped during the Timanian Orogeny.

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“…Paleogeographically, it lies at the border between the NNE-SSW-trending (all orientations are present day) Neoproterozoic to early Paleozoic continental margin of western Baltica, now exposed in the Caledonian nappes, and the contemporary WNW-ESE-trending Timanian basin, relicts of which are seen sparsely along the northern coast of Norway and Russia (Siedlecka, 1975;Siedlecka et al, 2004;Gayer and Rice, 1989). Structurally, it lies across the boundary between deformation associated with crustal shortening (thrusting) in the Scandinavian Caledonides in the west and the underlying autochthonous Baltic Shield (Gayer et al, 1987).…”

Section: Geological Introductionmentioning

confidence: 97%

Neoproterozoic Glacial and Associated Facies in the Tanafjord-Varangerfjord Area, Finnmark, North Norway

Rice¹,

Edwards²,

Hansen³

2012

Neoproterozoic Glacial and Associated Facies in the Tanafjord-Varangerfjord Area, Finnmark, North Norway

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This excursion guide describes the glacigenic rocks of the Smalfjord and Mortensnes Formations, and parts of the intervening Nyborg Formation, at the base of the Vestertana Group in the Tanafjord-Varangerfjord region of East Finnmark, NorthNorway. These are agreed to be either of glacial (sensu lato) origin or signifi cant to our understanding of Neoproterozoic glacial processes and events. The Smalfjord and Mortensnes Formations have been equated with the Marinoan (636.3 ± 4.9 Ma and 635.5 ± 1.2 Ma) and Gaskiers (584-582 Ma) glaciations, respectively. The rocks, which are superbly exposed, display a wide range of sedimentary lithologies/facies; lodgment, banded, deformation, fl ow, and melt-out diamictites; as well as glaciomarine, proglacial, and fl uvioglacial sediments. Diamictites derived from carbonate units showing the Trezona and Wonoka negative δ 13 C anomalies are seen.Glaciotectonic and/or soft-sediment structures described include folds, normal and thrust faults (imbricate fans), fl anking structures, shear-sense criteria (sigma clasts), striations (with paleoloess), lobate-cuspate contacts, downward intrusion of fl uidized sediments (with bridge structures), pro-and subglacial channels, nested channels, graded beds, possible iceberg dump structures, ghost clasts, dropstones and lonestones, allochthonous rafts of substrate sediments, ball-and-pillow structures, convolute laminations (pseudonodules), delta foresets, ice-crystal molds, sandstone dikes, and a possible kettle hole. The complex geometry of the sub-Smalfjord unconformity onto older Neoproterozoic sediments and the Archean Baltic Shield is documented at several scales. Marinoan cap dolostones (Maieberg negative δ 13 C anomaly), with typical sheet cracking (and "pseudostromatolites") and atypical clastic interbeds, are described from the base of the Nyborg Formation at several localities.

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Palaeogeographic reconstruction of the pre- to syn-Iapetus rifting sediments in the Caledonides of Finnmark, N Norway

Cited by 12 publications

References 16 publications

Restoration of the External Caledonides, Finnmark, North Norway

Restoration of the External Caledonides, Finnmark, North Norway

Northeastern and northwestern margins of Baltica in Neoproterozoic time: evidence from the Timanian and Caledonian Orogens

Neoproterozoic Glacial and Associated Facies in the Tanafjord-Varangerfjord Area, Finnmark, North Norway

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