Evolution of topography of post-Devonian Scandinavia: Effects and rates of erosion

Medvedev, Sergei; Hartz, Ebbe H.

doi:10.1016/j.geomorph.2014.12.010

Cited by 30 publications

(28 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To contextualise the low denudation rates predicted by our model, we note that a recent compilation of apatite fission track thermochronometry suggests that the average rates of post-Devonian erosion in the Scandinavian mountains have been less than 10 m Myr −1 (Medvedev and Hartz, 2015). Such low rates are also in agreement with average millennialscale bedrock erosion rates derived from cosmogenic nuclides in many areas of the planet (Portenga and Bierman, 2011).…”

Section: The Development Of Summit Flatssupporting

confidence: 81%

The periglacial engine of mountain erosion – Part 2: Modelling large-scale landscape evolution

et al. 2015

View full text Add to dashboard Cite

Abstract. There is growing recognition of strong periglacial control on bedrock erosion in mountain landscapes, including the shaping of low-relief surfaces at high elevations (summit flats). But, as yet, the hypothesis that frost action was crucial to the assumed Late Cenozoic rise in erosion rates remains compelling and untested. Here we present a landscape evolution model incorporating two key periglacial processes -regolith production via frost cracking and sediment transport via frost creep -which together are harnessed to variations in temperature and the evolving thickness of sediment cover. Our computational experiments time-integrate the contribution of frost action to shaping mountain topography over million-year timescales, with the primary and highly reproducible outcome being the development of flattish or gently convex summit flats. A simple scaling of temperature to marine δ 18 O records spanning the past 14 Myr indicates that the highest summit flats in mid-to high-latitude mountains may have formed via frost action prior to the Quaternary. We suggest that deep cooling in the Quaternary accelerated mechanical weathering globally by significantly expanding the area subject to frost. Further, the inclusion of subglacial erosion alongside periglacial processes in our computational experiments points to alpine glaciers increasing the long-term efficiency of frost-driven erosion by steepening hillslopes.

show abstract

Section: The Development Of Summit Flatssupporting

confidence: 81%

The periglacial engine of mountain erosion – Part 2: Modelling large-scale landscape evolution

et al. 2015

View full text Add to dashboard Cite

show abstract

“…This uplift may be a continuation of updoming initiated in the Paleogene, associated with the opening of the North-east Atlantic Ocean, taking surfaces to levels nowadays at 1200 m, although it might have been initiated earlier in the Late Eocene-Early Oligocene. Consequent fluvial incision gave rise to valley incision as much as 300 m deep (Medvedev & Hartz, 2015), probably enhanced by a change to cool and wet climate in the Pliocene, and thus enhanced delivery of sediment to alluvial systems down-valley. A consequence of the uplift and climatic deterioration was increased sedimentation in the neighbouring basins beginning in the Miocene (Jordt et al, 1995).…”

Section: Neogenementioning

confidence: 99%

“…A consequence of the uplift and climatic deterioration was increased sedimentation in the neighbouring basins beginning in the Miocene (Jordt et al, 1995). Continued incision to a depth of as much as 2 km below the palaeosurfaces is attributed to further climatic deterioration in the Quaternary when fluvial and glacial erosion resulted in 0.8 km uplift of rocks and up to a 0.5 km rise of local topography according to Medvedev & Hartz (2015). This was accompanied by further increased sedimentation in surrounding basins .…”

Section: Neogenementioning

confidence: 99%

“…Discussions regarding the potential interplay of uplift and climatic deterioration of the Scandinavian mountains is still unresolved (e.g. Anell et al, 2009Anell et al, , 2012 but it is likely, given the influx of coarse clastic materials (Rundberg & Smalley, 1989), that glaciation was already established in the Norwegian mountains in Pliocene times (Ehlers et al, 2011;Medvedev & Hartz, 2015). The formation of the major elements of the preglacial landscape of Scotland, is thought to have occurred under the regime of warm to temperate humid climates during the Early Pliocene (Zanclean) Neogene (Hall & Bishop, 2002).…”

Section: Neogenementioning

confidence: 99%

See 1 more Smart Citation

Filling the North Sea Basin: Cenozoic sediment sources and river styles

Gibbard¹,

Lewin²

2016

Geol. Belg.

View full text Add to dashboard Cite

ABSTRACT. The history of the infilling of the North Sea is outlined, with particular focus on sediment sources and river inputs. In simple terms (for the detail is complex), these sources changed from domination by northwesterly sources from the Shetland area (Paleocene to Eocene), to a geographically more uniform basin-centred pattern, and then northerly input following Fennoscandian uplift (Oligocene and Neogene). Baltic inputs followed via an 'Eridanos (Baltic) River' (Miocene), with cold-climate coarser sediment inputs, and lacustrine episodes resulting from ice damming (Pleistocene). River styles in each of these phases are discussed, with the Cenozoic at first being dominated by low energy fluvial deposition (channel sands, chemically weathered clays, and organic sedimentation) in fluctuating climates. Cold climates in the latest Neogene and Quaternary are seen as major determinant of a change in fluvial style, though these are also associated with tectonic effects, as in Scandinavia. The mediating role of vegetation, relating also to temperature and precipitation, is also likely to have been significant. Narrow valley incision followed the Middle Pleistocene Transition, as well as an increasing importance of Rhine-Meuse sources that had begun earlier.

show abstract

“…Its practical effect is to augment the tensile thin-plate bending stress. The upward load may be very effective (e.g., Medvedev & Hartz, 2015). Sediments generally fill more volume than did the original crystalline bedrock; offshore Scandinavia today they displace water whereas the source that was removed has been replaced only by air.…”

Section: A Thin-plate Hypothesismentioning

confidence: 99%

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

Redfield¹,

Osmundsen²

2015

NJG

View full text Add to dashboard Cite

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...

show abstract

Evolution of topography of post-Devonian Scandinavia: Effects and rates of erosion

Cited by 30 publications

References 56 publications

The periglacial engine of mountain erosion – Part 2: Modelling large-scale landscape evolution

The periglacial engine of mountain erosion – Part 2: Modelling large-scale landscape evolution

Filling the North Sea Basin: Cenozoic sediment sources and river styles

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

Contact Info

Product

Resources

About