Sea level response to Quartenary erosion and deposition in Scandinavia 

2021 ◽  
Author(s):  
Gustav Pallisgaard-Olesen ◽  
Vivi Kathrine Pedersen ◽  
Natalya Gomez
Keyword(s):  
Sea Level ◽  
Sea Level Changes ◽  
Glacial Cycles ◽  
Glacial Erosion ◽  
Erosion And Deposition ◽  
Late Pliocene ◽  
Glacial Origin ◽  
Sediment Deposits ◽  
Mass Redistribution ◽  
Global Sea Level

<div> <p>The landscape in western Scandinavia has undergone dramatic changes through numerous glaciations during the Quaternary. These changes in topography and in the volumes of offshore sediment deposits, have caused significant isostatic adjustments and local sea level changes, owing to erosional unloading and depositional loading of the lithosphere. Mass redistribution from erosion and deposition also has the potential to cause significant pertubations of the geoid, resulting in additional sea-level changes. The combined sea-level response from these processes, is yet to be investigated in detail for Scandinavia.</p> </div><div> <p>In this study we estimate the total sea level change from late-Pliocene- Quaternary glacial erosion and deposition in the Scandinavian region, using a gravitationally self-consistent global sea level model that includes the full viscoelastic response of the solid Earth to surface loading and unloading. In addition to the total late Pliocene-Quaternary mass redistribution, we <span>also </span>estimate transient sea level changes related specifically to the two latest glacial cycles.</p> </div><div> <p>We utilize existing observations of offshore sediment thicknesses of glacial origin, and combine these with estimates of onshore glacial erosion and estimates of erosion on the inner shelf. Based on these estimates, we can define mass redistribution and construct a preglacial landscape setting.</p> </div><div> <p>Our preliminary results show <span>perturbations of</span> the local sea level up to ∼ 200 m since<span> the</span> late-Pliocene in the Norwegian Sea, suggesting that erosion and deposition ha<span>ve</span> influenced the local paleo sea level history in Scandinavia significantly.</p> </div>

PISM paleo simulations of the Antarctic Ice Sheet over the last two glacial cycles

2020 ◽  
Author(s):  
Torsten Albrecht ◽  
Ricarda Winkelmann ◽  
Anders Levermann
Keyword(s):  
Boundary Conditions ◽  
Sea Level ◽  
Ice Sheet ◽  
Sea Level Changes ◽  
Glacial Cycles ◽  
Antarctic Ice Sheet ◽  
History Of ◽  
Global Sea Level ◽  
Glacial Time ◽  
The Antarctic

<p>Simulations of the glacial-interglacial history of the Antarctic Ice Sheet provide insights into dynamic threshold behavior and estimates of the ice sheet's contributions to global sea-level changes, for the past, present and future. However, boundary conditions are weakly constrained, in particular at the interface of the ice-sheet and the bedrock. We use the Parallel Ice Sheet Model (PISM) to investigate the dynamic effects of different choices of input data and of various parameterizations on the sea-level relevant ice volume. We evaluate the model's transient sensitivity to corresponding parameter choices and to different boundary conditions over the last two glacial cycles and provide estimates of involved uncertainties. We also present isolated and combined effects of climate and sea-level forcing on glacial time scales. </p>

scholarly journals Reconstruction of the depositional sedimentary environment of Oligocene deposits (Qom Formation) in the Qom Basin (northern Tethyan seaway), Iran

Geologos ◽  
2020 ◽  
Vol 26 (2) ◽  
pp. 93-111
Author(s):  
Amrollah Safari ◽  
Hossein Ghanbarloo ◽  
Parisa Mansoury ◽  
Mehran Mohammadian Esfahani
Keyword(s):  
Sea Level ◽  
Sedimentary Environment ◽  
Depositional Environments ◽  
Sea Level Changes ◽  
Third Order ◽  
Depositional Sequences ◽  
Qom Formation ◽  
Tethyan Seaway ◽  
Qom Basin ◽  
Global Sea Level

AbstractDuring the Rupelian–Chattian, the Qom Basin (northern seaway basin) was located between the Paratethys in the north and the southern Tethyan seaway in the south. The Oligocene deposits (Qom Formation) in the Qom Basin have been interpreted for a reconstruction of environmental conditions during deposition, as well as of the influence of local fault activities and global sea level changes expressed within the basin. We have also investigated connections between the Qom Basin and adjacent basins. Seven microfacies types have been distinguished in the former. These microfacies formed within three major depositional environments, i.e., restricted lagoon, open lagoon and open marine. Strata of the Qom Formation are suggested to have been formed in an open-shelf system. In addition, the deepening and shallowing patterns noted within the microfacies suggest the presence of three third-order sequences in the Bijegan area and two third-order depositional sequences and an incomplete depositional sequence in the Naragh area. Our analysis suggests that, during the Rupelian and Chattian stages, the depositional sequences of the Qom Basin were influenced primarily by local tectonics, while global sea level changes had a greater impact on the southern Tethyan seaway and Paratethys basins. The depositional basins of the Tethyan seaway (southern Tethyan seaway, Paratethys Basin and Qom Basin) were probably related during the Burdigalian to Langhian and early Serravallian.

High Water, Low Water

2008 ◽  
Author(s):  
Jan Zalasiewicz
Keyword(s):  
Sea Level ◽  
Deep Ocean ◽  
High Water ◽  
Sea Level Changes ◽  
Flood Plains ◽  
The Face ◽  
History Of ◽  
Global Sea Level ◽  
The Waves ◽  
Rock Strata

In almost everybody’s natural lifetime, the sea is one of the great unchanging certainties of life. There is land; there is sea; and in between is that magical place, the seaside, which is sometimes knocked about a bit by the waves, but always manages to recover for that next idyllic summer. There are, one remembers, those faintly disquieting legends, about a remarkably well-organized and ecologically aware person called Noah, and about a Deluge. But these, of course, should not be taken seriously. They were a jumpy and superstitious lot, our ancestors, always prone to making up scary stories. It was a good way to keep the children in order. With a longer perspective, things seem a little different. Take any one location on the globe, for instance. Track it over millions of years. At that one location, there may be a change from deep ocean, to shallow sea, to a shoreline, and thence to terrestrial swamps and flood plains. And then, perhaps, to the absence of evidence, a horizon of absolutely no thickness at all within a succession of rock strata, in which a million years or a hundred million years—or more—may be missing, entirely unrecorded. It is that phenomenon called an unconformity, all that is left of the history of a terrestrial landscape pushed up into the erosional realm. On that eroding landscape, there may have been episodes of battle, murder, and sudden death among armoured saurians, of fire, flood, and storm, and of the humdrum day-to-day life of the vast vegetarian dinosaurs, chewing through their daily hundredweights of plants. Of this, no trace can persist. Only when that landscape is plunged again towards sea level, and begins to be silted up, can a tangible geological record resume. The Earth’s crust, as we have seen, is malleable, can be pushed downwards or thrust upwards by the forces that drive the continents across the face of the globe. Many of the sea level changes that can be read in the strata of the archives are of this sort, and mark purely local ups and downs of individual sections of crust, with no evidence that global sea level was anything other than constant.

Saltmarshes in a time of change

2002 ◽  
Vol 29 (1) ◽  
pp. 39-61 ◽  
Author(s):  
Paul Adam
Keyword(s):  
Sea Level ◽  
Native Species ◽  
Rate Of Change ◽  
Tidal Range ◽  
Direct Result ◽  
Sea Level Changes ◽  
Ecological Value ◽  
Relative Sea Level ◽  
Global Sea Level ◽  
The Tropics

Saltmarshes are a major, widely distributed, intertidal habitat. They are dynamic systems, responding to changing environmental conditions. For centuries, saltmarshes have been subject to modification or destruction because of human activity. In this review, the range of factors influencing the survival of saltmarshes is discussed. Of critical importance are changes in relative sea level and in tidal range. Relative sea level is affected by changes in absolute sea level, changes in land level and the capacity of saltmarshes to accumulate and retain sediment. Many saltmarshes are starved of sediment because of catchment modification and coastal engineering, or exposed to erosive forces, which may be of natural origin or reflect human interference. The geographical distribution of individual saltmarsh species reflects climate, so that global climatic change will be reflected by changes in distribution and abundance of species, although the rate of change in communities dominated by perennial plants is difficult to predict. Humans have the ability to create impacts on saltmarshes at a range of scales from individual sites to globally. Pressures on the environment created by the continued increase in the human population, particularly in developing tropical countries, and the likely consequences of the enhanced greenhouse effect on both temperature and sea level give rise to particular concerns. Given the concentration of population growth and development in the coastal zone, and the potential sensitivity of saltmarsh to change in sea level, it is timely to review the present state of saltmarshes and to assess the likelihood of changes in the near (25 years) future. By 2025, global sea level rise and warming will have impacts on saltmarshes. However, the most extensive changes are likely to be the direct result of human actions at local or regional scales. Despite increasing recognition of the ecological value of saltmarsh, major projects involving loss of saltmarshes but deemed to be in the public interest will be approved. Pressures are likely to be particularly severe in the tropics, where very little is known about saltmarshes. At the local scale the cumulative impacts of activities, which individually have minor effects, may be considerable. Managers of saltmarshes will be faced with difficult choices including questions as to whether traditional uses should be retained, whether invasive alien species or native species increasing in abundance should be controlled, whether planned retreat is an appropriate response to rising relative sea level or whether measures can be taken to reduce erosion. Decisions will need to take into account social and economic as well as ecological concerns.

Sedimentary history of the western Bohai coastal plain since the late Pliocene: Implications on tectonic, climatic and sea-level changes

2012 ◽  
Vol 54-55 ◽  
pp. 192-202 ◽  
Author(s):  
Zhengquan Yao ◽  
Zhengtang Guo ◽  
Guoqiao Xiao ◽  
Qiang Wang ◽  
Xuefa Shi ◽  
...  
Keyword(s):  
Sea Level ◽  
Coastal Plain ◽  
Sea Level Changes ◽  
Late Pliocene ◽  
History Of ◽  
And Sea Level

TECTONOSTRATIGRAPHIC EVOLUTION OF THE SOUTH-EAST GIPPSLAND BASIN

1991 ◽  
Vol 31 (1) ◽  
pp. 116 ◽  
Author(s):  
B.A. Duff ◽  
N.G. Groilman ◽  
D.J. Mason ◽  
J.M. Questiaux ◽  
D.S. Ormerod ◽  
...  
Keyword(s):  
Sea Level ◽  
Normal Faults ◽  
Plate Boundaries ◽  
Sea Level Changes ◽  
The South ◽  
Seismic Sequences ◽  
Controlled Deposition ◽  
Global Sea Level ◽  
Sequence Boundaries ◽  
Gippsland Basin

Evolution of the south-east Gippsland Basin since ca. 96 Ma has been governed by the interaction of three distinct processes:re-organisation of regional plate boundaries at 96, 80 and 50 Ma, registered as major angular unconformities or megasequence boundaries;intra-basin response of cover to basement-controlled deformational phases, registered as the sequence boundaries within these megasequences; andthe more subtle balance between regressive sedimentation associated with these phases and the transgressive deposition associated with longer-term eustatic sea level rises.The Golden Beach Megasequence (seismic sequences UK1 and UK2) accumulated syntectonically in an extensional setting characterised by an orthogonal array of north-northeast trending transfer faults and associated normal faults. Major compressional tectonism at ca. 80 Ma terminated this regime, initiating a modified mosaic of stratotectonic domains which controlled deposition of the Latrobe Megasequence.The seismic sequences within this megasequence display two types of cyclicity distinguishing intra-Campanian to Top Maastrichtian sequences (UK3-UK5) from early Tertiary sequences (PL1, PL2 and EO1). The sequence boundaries are considered to be the expression of recurrent compressive deformational phases. They are demonstrable as angular unconformities in transpressional and pull-apart structures in domains within which deformation was focused over the older extensional grain.The ca. 50 Ma Top Latrobe megasequence boundary appears to mark the transition from a basement-coupled deformational style characteristic of the Latrobe Megasequence, to a basement-decoupled inversion style of deformation during deposition of the Seaspray Megasequence (post-50 Ma).Seismic sequence boundaries, at least within basins such as the Gippsland, are therefore the stratigraphic expression of deformational phases rather than signatures of global sea-level changes. Eustacy is not invariably a shorter-term process than basin tectonism, nor is it the sole or main determinant of depositional style.

Supraglacial Streams and Rivers

2019 ◽  
Vol 47 (1) ◽  
pp. 421-452 ◽  
Author(s):  
Lincoln H Pitcher ◽  
Laurence C. Smith
Keyword(s):  
Sea Level ◽  
Transport Processes ◽  
Future Research ◽  
Sea Level Changes ◽  
Ice Dynamics ◽  
Surface Mass ◽  
Ice Shelves ◽  
Streams And Rivers ◽  
Ice Surface ◽  
Global Sea Level

Supraglacial meltwater channels that flow on the surfaces of glaciers, ice sheets, and ice shelves connect ice surface climatology with subglacial processes, ice dynamics, and eustatic sea level changes. Their important role in transferring water and heat across and into ice is currently absent from models of surface mass balance and runoff contributions to global sea level rise. Furthermore, relatively little is known about the genesis, evolution, hydrology, hydraulics, and morphology of supraglacial rivers, and a first synthesis and review of published research on these unusual features is lacking. To that end, we review their ( a) known geographical distribution; ( b) formation, morphology, and sediment transport processes; ( c) hydrology and hydraulics; and ( d) impact on ice sheet surface energy balance, heat exchange, basal conditions, and ice shelf stability. We conclude with a synthesis of key knowledge gaps and provide recommendations for future research. ▪ Supraglacial streams and rivers transfer water and heat on glaciers, connecting climate with subglacial hydrology, ice sliding, and global sea level. ▪ Ice surface melting may expand under a warming climate, darkening the ice surface and further increasing melt.

scholarly journals The challenge of reconstructing the Phanerozoic sea level and the Pacific Basin tectonics

Geologos ◽  
2010 ◽  
Vol 16 (4) ◽  
pp. 235-243 ◽  
Author(s):  
Dmitry Ruban ◽  
Clinton Conrad ◽  
A. van Loon
Keyword(s):  
Sea Level ◽  
Careful Examination ◽  
Pacific Basin ◽  
Plate Tectonic ◽  
Sea Level Changes ◽  
The Pacific ◽  
Major Shortcoming ◽  
Global Sea Level ◽  
Accretionary Prisms ◽  
Global Tectonics

The challenge of reconstructing the Phanerozoic sea level and the Pacific Basin tectonicsThe relationships between the interior dynamics of our planet and global sea level can be unravelled when plate-tectonic reconstructions are available for the entire Earth. A review of global tectonics reveals significant deficiencies in our understanding of the geodynamic evolution of the Pacific (Panthalassa or Proto-Pacific) during the Cambrian-Jurassic time-span. This particular, but major, shortcoming presents a true challenge for modern geoscientists, who are encouraged to produce a detailed plate-tectonic reconstruction of the Pacific for the pre-Cretaceous in order to advance our understanding of Phanerozoic sea-level change. A set of approaches, including geological/geophysical modelling, investigation of accretionary prisms, palaeobiogeographical studies, and careful examination of eustatic sea-level changes, are proposed that will help geoscientists tackle the challenge of understanding how Pacific geodynamics affected global sea level during the Phanerozoic.

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