High-level landscapes along the margin of southern East Greenland—A record of tectonic uplift and incision after breakup in the NE Atlantic

Bonow, Johan M.; Japsen, Peter; Nielsen, Thorkild

doi:10.1016/j.gloplacha.2014.01.010

Cited by 42 publications

(76 citation statements)

References 74 publications

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“…The connection of offshore unconformities to onshore counterparts remains hampered by our fundamental inability to either accurately determine the age of formation of Scandinavia's paleosurfaces or to correlate between them. Similar highelevation surfaces do cross-cut Cenozoic volcanic rocks that were originally extruded at or just below sea level in East Greenland (Bonow et al, 2014), recording beyond doubt similar events of post-breakup uplift and erosion of Scandinavia's conjugate margin. Nevertheless, there is little geological consensus as to how post-breakup mountains can rise on a rifted margin.…”

Section: Discussionmentioning

confidence: 66%

Some remarks on the earthquakes of Fennoscandia: A conceptual seismological model drawn from the perspective of hyperextension

Redfield¹,

Osmundsen²

2015

NJG

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To a first order, patterns of Fennoscandia's seismicity reflect the benchmark domain boundaries of its Mesozoic rifted margin. Three distinct belts of earthquakes strike sub-parallel to the generalized line of breakup. The outermost seismic belt (SB1) marks the Taper Break (TB), or the zone of flexural coupling/decoupling between the distal (seaward) and proximal/necking (landward) domains. A coastal belt (SB2) follows the Innermost Limit of Extension, defined as the onset of 39 km-thick crystalline continental crust. An interior belt (SB3) follows the Hinterland Break in Slope, or the landward limit of the Scandinavian rifted margin. Between each belt, large portions of the necking, proximal, and hinterland domains are seismically quiescent. Evaluation of the 'Cumulative Seismic Moment' (CSM w ) per unit area indicates that the release of seismic energy is asymmetric. Although some of Fennoscandia's largest seismic events occur in the dominantly Proterozoic to Archean lithosphere of the eastern craton, 80% of Fennoscandian CSM w maps to the domain boundaries of the western rifted margin. CSM w energy tends to be highest at the TB and decreases system atically towards the continental interior.As proposed by many previous studies, a first-order spatial correlation between Scandinavia's offshore earthquake belt and voluminous, geo logically rapid, sedimentary loading during the Neogene period is evident. However, the presence of thinned, faulted crystalline basement is also a very important factor behind Scandinavia's offshore seismicity. Where the Neogene deposits are at their thickest the underlying crust is dominantly oceanic; CSM w is lower per unit area there than where lesser Plio-Pleistocene loading impacts continental crust that was fully prepared by Mesozoic necking and hyperextension. CSM w data suggest that the 'strength' of the TB and the continental margin's distal domain is significantly less than that of relatively young (ca. 54 Ma) oceanic lithosphere. Our data imply that ridge push does not contribute significantly to Fennoscandia's seismicity. Rather, we find that thin-plate bending stresses stemming from offshore depositional loading conspire with unbuttressed Gravitational Potential Energy (GPE), onshore erosion, and post-glacial isostatic rebound to generate Fennoscandia's earthquakes.We present a conceptual seismological model for Fennoscadia that is consistent with modern hypotheses of extended margin evolution, including post-breakup reactivation by footwall uplift in regions adjacent to sharp crustal taper. Illustrated by simple concepts of elastic thin-plate theory, the model honors our conclusion that Fennoscandian seismicity is principally the product of locally derived stress fields and that far field stress from the oceanic domain is unlikely to penetrate deeply into a hyperextended continental margin. It predicts the locations of the observed seismic belts and seismic gaps with the mathematics of thin-plate bending. It describes how the outer seismic belt will remain localized in the...

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Section: Discussionmentioning

confidence: 66%

Some remarks on the earthquakes of Fennoscandia: A conceptual seismological model drawn from the perspective of hyperextension

Redfield¹,

Osmundsen²

2015

NJG

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“…The interpretation of low-relief high-elevation surfaces as peneplains (uplifted flood plains) and offshore tilted unconformities as the result of uplift onshore has been previously presented as evidence for tectonic rejuvenation and uplift along the Scandinavian, Greenland, Canadian and British continental margins (e.g. Bonow, Japsen, & Nielsen, 2014;Chalmers, 2000;Green, Japsen, Chalmers, Bonow, & Duddy, 2018;Lidmar-Bergstr€ om, Ollier, & Sulebak, 2000;Riis, 1996;Rowberry, 2008); however, several recent studies have suggested other processes are the source of these features. Recent cosmogenic isotope studies from across West Greenland suggested the modern geomorphology is likely the result of glaciation, where warmbased glaciers focus erosion along preglacial river valleys, forming deeply incised fjords and cold-based glaciers limit erosion in highland areas, resulting in elevated low-relief surfaces Strunk et al, 2017).…”

Section: Implications For Late Cenozoic Uplift In the North Atlanticmentioning

confidence: 99%

Evolution of the central West Greenland margin and the Nuussuaq Basin: Localised basin uplift along a stable continental margin proposed from thermochronological data

2018

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The Late Cenozoic is typically considered a time of widespread episodic tectonic uplift along the West Greenland continental margin (36-2 Ma), similar to other margins across the North Atlantic, such as Norway, East Greenland and the UK. The present study re-examines and remodels onshore thermochronological data from central West Greenland and the Cretaceous Nuussuaq Basin, utilising a Bayesian modelling approach and new concepts related to radiation damage within apatite. These new thermal histories indicate that slow-protracted cooling has occurred across the southern extent of the margin during the Mesozoic and Cenozoic, whereas those from within the Nuussuaq Basin display reheating through the Late Cretaceous/Palaeogene and cooling to present. Results suggest that no significant Late Cenozoic uplift has occurred along the southern margin, while cooling in the Nuussuaq Basin is consistent with events outlined in the basin's stratigraphy and implies uplift during volcanism and an isostatic response to the unroofing of the lithosphere has elevated the modern topography. These results imply significant tectonism in the region ceased by~45 Ma, yet have wider implications regarding how low temperature thermochronology data are treated and our understanding of the postrift evolution of passive margins. K E Y W O R D Smodelling, passive margins, stratigraphy, tectonics and sedimentation, thermochronology

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“…Our computations indicate flow speeds of ~3 cm a −1 (Fig. B); a pulse that arrived beneath Iceland at 25 Ma moving laterally at that speed would have reached East Greenland ~600 km away from the Iceland plume ~5 Ma ago and could hence be the cause of recent uplift (Bonow et al ., ; Japsen et al ., ) that facilitated ice‐sheet build‐up and increased the stability of the ice sheet (Solgaard et al ., ). After the Jan Mayen microcontinent started breaking away from Greenland c .…”

Section: East Greenland Uplift Affected By a Pulsating Iceland Plumementioning

confidence: 99%

“…Recent studies show that there was no significant topography in East Greenland at 10 Ma and that much of the uplift has occurred since ~5 Ma (Bonow et al ., ; Japsen et al ., ). Glacial erosion can cause uplift of the remaining mountains, but this mechanism cannot explain the overall high topography (Medvedev et al ., ).…”

Section: Introductionmentioning

confidence: 99%

The key role of global solid‐Earth processes in preconditioning Greenland's glaciation since the Pliocene

et al. 2015

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After >500 Ma of absence, major Northern Hemisphere glaciations appeared during the Plio‐Pleistocene, with Greenland leading other northern areas. Here, we propose that three major solid‐Earth processes underpinned build‐up of the Greenland ice‐sheet. First, a mantle‐plume pulse, responsible for the North Atlantic Igneous Province at ~60 Ma, regionally thinned the lithosphere. Younger plume pulses led to uplift, which accelerated at ~5 Ma, lifting the parts of the East Greenland margin closest to Iceland to elevations of more than 3 km above sea level. Second, plate‐tectonic reconstruction shows a ~6° northward component of Greenland motion relative to the mantle since ~60 Ma. Third, a concurrent northward rotation of the entire mantle and crust towards the pole, dubbed True Polar Wander (TPW), contributed an additional ~12° change in latitude. These global geodynamic processes preconditioned Greenland to sustain long‐term glaciation, emphasizing the role of solid‐Earth processes in driving long‐term global climatic transitions.

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High-level landscapes along the margin of southern East Greenland—A record of tectonic uplift and incision after breakup in the NE Atlantic

Cited by 42 publications

References 74 publications

Some remarks on the earthquakes of Fennoscandia: A conceptual seismological model drawn from the perspective of hyperextension

Some remarks on the earthquakes of Fennoscandia: A conceptual seismological model drawn from the perspective of hyperextension

Evolution of the central West Greenland margin and the Nuussuaq Basin: Localised basin uplift along a stable continental margin proposed from thermochronological data

The key role of global solid‐Earth processes in preconditioning Greenland's glaciation since the Pliocene

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