scholarly journals Episodic burial and exhumation in North-East Greenland before and after opening of the North-East Atlantic

2021 ◽  
Vol 45 (2) ◽  
Author(s):  
Peter Japsen ◽  
Paul F. Green ◽  
Johan M. Bonow ◽  
Morten Bjerager ◽  
John R. Hopper
Keyword(s):  
Sea Level ◽  
Middle Triassic ◽  
East Atlantic ◽  
East Greenland ◽  
Planation Surface ◽  
North East ◽  
The North ◽  
Stratigraphic Record ◽  
Break Up ◽  
Uplift And Erosion

The geology of North-East Greenland (70–78°N) exposes unique evidence of the basin development between the Devonian collapse of the Caledonian Orogen and the extrusion of volcanics at the Paleocene–Eocene transition during break-up of the North-East Atlantic. Here we pay special attention to unconformities in the stratigraphic record – do they represent periods of stability and non-deposition or periods of subsidence and accumulation of rocks followed by episodes of uplift and erosion? To answer that and other questions, we used apatite fission-track analysis and vitrinite reflectance data together with stratigraphic landscape analysis and observations from the stratigraphic record to study the thermo-tectonic history of North-East Greenland. Our analysis reveals eight regional stages of post-Caledonian development: (1) Late Carboniferous uplift and erosion led to formation of a sub-Permian peneplain covered by coarse siliciclastic deposits. (2) Middle Triassic exhumation led to removal of a thick cover including a considerable thickness of upper Carboniferous – Middle Triassic rocks and produced thick siliciclastic deposits in the rift system. (3) Denudation at the transition between the Early and Middle Jurassic affected most of the study area outside the Jameson Land Basin and produced a weathered surface above which Middle–Upper Jurassic sediments accumulated. (4) Earliest Cretaceous uplift and erosion along the rifted margin and further inland accompanied the Mesozoic rift climax and produced coarse-grained sedimentary infill of the rift basins. (5) Mid-Cretaceous uplift and erosion initiated removal of Cretaceous post-rift sediments that had accumulated above the Mesozoic rifts and their hinterland, leading to cooling of Mesozoic sediments from maximum palaeotemperatures. (6) End-Eocene uplift was accompanied by faulting and intrusion of magmatic bodies and resulted in extensive mass wasting on the East Greenland shelf. This event initiated the removal of a thick post-rift succession that had accumulated after break-up and produced a peneplain near sea level, the Upper Planation Surface. (7) Late Miocene uplift and erosion, evidenced by massive progradation on the shelf, resulted in the formation of the Lower Planation Surface by incision below the uplifted Upper Planation Surface. (8) Early Pliocene uplift raised the Upper and the Lower Planation Surfaces to their present elevations of about 2 and 1 km above sea level, respectively, and initiated the formation of the present-day landscape through fluvial and glacial erosion. Additional cooling episodes of more local extent, related to igneous activity in the early Eocene and in the early Miocene, primarily affected parts of northern Jameson Land. The three earliest episodes had a profound impact beyond Greenland and accompanied the fragmentation of Pangaea. Younger episodes were controlled by plate-tectonic processes, possibly including dynamic support from the Iceland Plume. Our results emphasise that gaps in the stratigraphic record often reflect episodes of kilometre-scale vertical movements that may result from both lithospheric and sub-lithospheric processes.

Central- and North-East Greenland Rifted Margin Composite Tectono-Sedimentary Element, From Onshore East Greenland to the Greenland Sea

2021 ◽  
pp. M57-2017-15
Author(s):  
Michael B. W. Fyhn ◽  
Peter Alsen ◽  
Morten Bjerager ◽  
Jørgen A. Bojesen-Koefoed ◽  
Flemming G. Christiansen ◽  
...  
Keyword(s):  
Depositional Environments ◽  
Source Rocks ◽  
Rift System ◽  
East Atlantic ◽  
Petroleum Potential ◽  
East Greenland ◽  
North East ◽  
The North ◽  
Marine Sedimentation ◽  
Uplift And Erosion

AbstractThe Devonian to lower Eocene Central-East and NE Greenland Composite Tectono-Sedimentary Element CTSE) is a part of the North-East Atlantic rift system. East and NE Greenland geology is therefore analogues to that of the prolific basins on the conjugate Atlantic margin and in the North Sea in many respects. None the less, hydrocarbon discoveries remain. The presence of world-class source rocks, reservoirs and seals, together with large structures, may suggest an East and NE Greenland petroleum potential, however. The TSE was established through Devonian - Carboniferous, Permian - Triassic and Jurassic - Cretaceous rifting interspersed by periods of uplift and post-rift sagging. Subsequently, Paleocene - Eocene magma-rich rifting accompanied the North-East Atlantic break-up. Depositional environments through time varied in response to the changing tectonism and climate. None-marine deposition dominated until the end of the Triassic, only interrupted by marine sedimentation during Late Permian - Early Triassic times. Subsequently, marine conditions prevailed during the Jurassic and Cretaceous. Volumetric series of basalt erupted over most of the CTSE during the latest Paleocene - early Eocene following a significant latest Cretaceous - Paleocene regression, uplift and erosion event. Since the Eocene, denudation pulses have removed much of these basalts uniquely exposing the up to 17 km strata of the CTSE.

scholarly journals Peneplains and tectonics in North-East Greenland after opening of the North-East Atlantic

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Johan M. Bonow ◽  
Peter Japsen
Keyword(s):  
Sea Level ◽  
Large Scale ◽  
Continental Margins ◽  
Rift Basins ◽  
East Greenland ◽  
Planation Surface ◽  
Base Level ◽  
North East ◽  
The North ◽  
Late Neogene

Elevated plateaus with deeply incised valleys characterise elevated, passive continental margins (EPCMs) in all climate zones. These features are, however, a topic of debate regarding when and how the large-scale landscapes formed. We have investigated and mapped the partly glaciated landscape of North-East Greenland (70–78°N). The area consists of crystalline basement and Palaeozoic–Mesozoic rift basins, capped by Palaeogene basalts that erupted during the northeast Atlantic break-up. Our stratigraphic landscape analysis reveals a typical EPCM dominated by two elevated erosion surfaces, extending 200 km east–west and 900 km north–south. The low-relief Upper Planation Surface (UPS; c. 2 km above sea level) cuts across basement and Palaeogene basalts, indicating that it was graded to base level defined by the Atlantic Ocean in post-basalt times and subsequently uplifted. The UPS formed prior to the deposition of mid-Miocene lavas that rest on it, south of the study area. In the interior basement terrains, the Lower Planation Surface (LPS) forms fluvial valley benches at c. 1 km above sea level, incised below the UPS. The LPS is thus younger than the UPS, which implies that it formed post mid-Miocene. Towards the coast, the valley benches merge to form a coherent surface that defines flat-topped mountains. This shows that the LPS was graded to near sea level and was subsequently uplifted. Hence, both the UPS and the LPS formed as peneplains – erosion surfaces graded to base level. The fluvial valley benches associated with the LPS further indicates that full glacial conditions were only established after the uplift of the LPS in the early Pliocene (c. 5 Ma). The uplift of the LPS led to re-exposure of a Mesozoic etch surface. We conclude that episodes of late Neogene tectonic uplift shaped the stepped landscape and elevated topography in North-East Greenland.

scholarly journals Large-scale changes of the semidiurnal tide along North Atlantic coasts from 1846 to 2018

Ocean Science ◽  
2021 ◽  
Vol 17 (1) ◽  
pp. 17-34
Author(s):  
Lucia Pineau-Guillou ◽  
Pascal Lazure ◽  
Guy Wöppelmann
Keyword(s):  
Sea Level ◽  
North Atlantic ◽  
Large Scale ◽  
Low Frequency ◽  
Underlying Mechanism ◽  
East Atlantic ◽  
North West ◽  
North East ◽  
The North ◽  
The North Atlantic

Abstract. We investigated the long-term changes of the principal tidal component M2 along North Atlantic coasts, from 1846 to 2018. We analysed 18 tide gauges with time series starting no later than 1940. The longest is Brest with 165 years of observations. We carefully processed the data, particularly to remove the 18.6-year nodal modulation. We found that M2 variations are consistent at all the stations in the North-East Atlantic (Cuxhaven, Delfzijl, Hoek van Holland, Newlyn, Brest), whereas some discrepancies appear in the North-West Atlantic. The changes started long before the 20th century and are not linear. The secular trends in M2 amplitude vary from one station to another; most of them are positive, up to 2.5 mm/yr at Wilmington since 1910. Since 1990, the trends switch from positive to negative values in the North-East Atlantic. Concerning the possible causes of the observed changes, the similarity between the North Atlantic Oscillation and M2 variations in the North-East Atlantic suggests a possible influence of the large-scale atmospheric circulation on the tide. Our statistical analysis confirms large correlations at all the stations in the North-East Atlantic. We discuss a possible underlying mechanism. A different spatial distribution of mean sea level (corresponding to water depth) from one year to another, depending on the low-frequency sea-level pressure patterns, could impact the propagation of the tide in the North Atlantic basin. However, the hypothesis is at present unproven.

scholarly journals The Permian to Cretaceous succession at Permpasset, Wollaston Forland: the northernmost Permian and Triassic in North–East Greenland

2021 ◽  
Vol 47 ◽  
Author(s):  
Steven D. Andrews ◽  
Henrik Nøhr-Hansen ◽  
Pierpaolo Guarnieri ◽  
Karen Dybkjær ◽  
Sofie Lindström ◽  
...  
Keyword(s):  
First Record ◽  
Upper Permian ◽  
East Atlantic ◽  
East Greenland ◽  
Fine Grained ◽  
Structural Context ◽  
North East ◽  
The North ◽  
Structural Relationships ◽  
Western Side

Permian to Triassic outcrops in East Greenland diminish significantly northwards. Understanding the northward extent, and nature, of the Permian and Triassic successions has implications for regional palaeogeographic reconstructions and exploration in adjacent offshore basins. Examining the structural relationships between the basement, Permian, Triassic, Jurassic and Cretaceous successions can further our understanding of the tectonic evolution of the region. Here, we describe a hitherto overlooked section through the Permian to Cretaceous from central Wollaston Forland and consider its structural context. The western side of Permpasset forms the upthrown eroded crest of a horst block, which provides exposure of the earliest stratigraphic intervals in the region. The fractured Caledonian basement is overlain by evaporitic marine limestone facies of the Karstryggen Formation, which are succeeded by shallow marine sandstones assigned to the Schuchert Dal Formation, both Upper Permian. The overlying unit records a period of fluvial deposition and is not possible to date. However, an Early to Middle Triassic age (Pingo Dal Group) seems most likely, given regional eustatic considerations. This is, therefore, the most northerly record of Triassic strata in North–East Greenland. West of the horst structure, fine-grained sandstones and bioturbated siltstones of the Jurassic (Oxfordian) Jakobsstigen Formation are recorded. These were downfaulted prior to a prolonged hiatus after which both the Triassic and Jurassic strata were draped by Cretaceous shales of the Fosdalen Formation. The Cretaceous succession is overlain by a thick basalt pile of Eocene age, heralding the opening of the North-East Atlantic. Glendonites overlie Oxfordian siltstones at the base of the middle Albian Fosdalen Formation. These were likely winnowed from slightly older Cretaceous strata and overlie the hiatus surface between the Jurassic and Cretaceous. This is the first record of glendonites from the Cretaceous of East Greenland and they are interpreted to record the Circum–Arctic late Aptian – early Albian cooling event.

scholarly journals Thrust–wrench interference tectonics in the Gulf of Cadiz (Africa–Iberia plate boundary in the North-East Atlantic): Insights from analog models

2011 ◽  
Vol 289 (1-4) ◽  
pp. 135-149 ◽  
Author(s):  
João C. Duarte ◽  
Filipe M. Rosas ◽  
Pedro Terrinha ◽  
Marc-André Gutscher ◽  
Jacques Malavieille ◽  
...  
Keyword(s):  
Plate Boundary ◽  
Gulf Of Cadiz ◽  
East Atlantic ◽  
North East ◽  
The North ◽  
Gulf Of Cádiz ◽  
Analog Models

Exceptional influx of oceanic species into the North Sea late 1997

1999 ◽  
Vol 79 (4) ◽  
pp. 737-739 ◽  
Author(s):  
M. Edwards ◽  
A.W.G. John ◽  
H.G. Hunt ◽  
J.A. Lindley
Keyword(s):  
North Sea ◽  
Indicator Species ◽  
Climatic Conditions ◽  
Historical Evidence ◽  
East Atlantic ◽  
North East ◽  
The North ◽  
The North Sea ◽  
Oceanic Species

Continuous Plankton Recorder records from the North Sea and north-east Atlantic from September 1997 to March 1998 indicate an exceptional influx of oceanic indicator species into the North Sea. These inflow events, according to historical evidence, have only occurred sporadically during this century. This exceptional inflow and previous inflow events are discussed in relation to their similarity in terms of their physical and climatic conditions.

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