scholarly journals Supplemental Material: Widespread glacial erosion on the Scandinavian passive margin

2021 ◽  
Author(s):  
Vivi Pedersen ◽  
et al.
Keyword(s):  
Sea Level ◽  
Passive Margin ◽  
Dynamic Topography ◽  
Glacial Erosion ◽  
Source To Sink ◽  
Effective Elastic Thickness ◽  
Wedge Volume

Table S1 (source to sink analysis), and the influence of dynamic topography (Fig. S1), effective elastic thickness (Fig. S2), and paleo sea level Fig. S3) on shelf wedge volume and bedrock deflection.<br>

scholarly journals Supplemental Material: Widespread glacial erosion on the Scandinavian passive margin

2021 ◽  
Author(s):  
Vivi Pedersen ◽  
et al.
Keyword(s):  
Sea Level ◽  
Passive Margin ◽  
Dynamic Topography ◽  
Glacial Erosion ◽  
Source To Sink ◽  
Effective Elastic Thickness ◽  
Wedge Volume

Table S1 (source to sink analysis), and the influence of dynamic topography (Fig. S1), effective elastic thickness (Fig. S2), and paleo sea level Fig. S3) on shelf wedge volume and bedrock deflection.<br>

scholarly journals Quantitative stratigraphic analysis in a source-to-sink numerical framework

2018 ◽  
Author(s):  
Xuesong Ding ◽  
Tristan Salles ◽  
Nicolas Flament ◽  
Patrice Rey
Keyword(s):  
Sea Level ◽  
Trajectory Analysis ◽  
Rate Of Change ◽  
Sediment Supply ◽  
Passive Margin ◽  
Shelf Edge ◽  
Analysis Method ◽  
Source To Sink ◽  
Sedimentary Architecture ◽  
Thermal Subsidence

Abstract. The sedimentary architecture at continental margins reflects the interplay between the rate of change of accommodation creation (δA) and the rate of change of sediment supply (δS). As a result, stratigraphic interpretation increasingly focuses on understanding the link between deposition patterns and changes in δA/δS. Here, we use the landscape modelling framework pyBadlands to assess the respective performance of two well-established stratigraphic interpretation techniques: the trajectory analysis method and the accommodation succession method. In contrast to most Stratigraphic Forward Models (SFMs), pyBadlands provides self-consistent sediment supply to basin margins as it simulates erosion, sediment transport and deposition in a source-to-sink context. We present a landscape evolution that takes into account periodic sea level variations and passive margin thermal subsidence over 30 million years, under uniform rainfall. We implement the two aforementioned approaches to interpret the resulting depositional cycles at the continental margin. We first apply both the trajectory analysis and the accommodation succession methods to manually map key stratigraphic surfaces and define stratigraphic units from shelf-edge (or offlap break) trajectories, stratal terminations and stratal geometries. We then design a set of post-processing numerical tools to calculate shoreline and shelf-edge trajectories, the temporal evolution of changes in accommodation and sedimentation, and automatically produce stratigraphic interpretations. Comparing manual and automatic stratigraphic interpretations reveals that the results of the trajectory analysis method depend on time-dependent processes such as thermal subsidence whereas the accommodation succession method does not. In addition to reconstructing stratal stacking patterns, the tools we introduce here make it possible to quickly extract Wheeler diagrams and synthetic cores at any location within the simulated domain. Our work provides an efficient and flexible quantitative sequence stratigraphic framework to evaluate the main drivers (climate, sea level and tectonics) controlling sedimentary architectures and investigate their respective roles in sedimentary basins development.

Differential uplift of three Pliocene sea level indicator sites in southern Argentina driven by upwelling asthenosphere through the Patagonian slab window 

2021 ◽  
Author(s):  
Andrew Hollyday ◽  
Jacqueline Austermann ◽  
Andrew Lloyd ◽  
Mark Hoggard ◽  
Fred Richards ◽  
...  
Keyword(s):  
Sea Level ◽  
Thermal Structure ◽  
Passive Margin ◽  
Earth Model ◽  
Temperature Structure ◽  
Dynamic Topography ◽  
Level Indicator ◽  
Isostatic Adjustment ◽  
Global Mean ◽  
Slab Window

&lt;div&gt; &lt;p&gt;Bivalve and gastropod shell beds deposited during the Early Pliocene (4.69-5.23 Ma) occur in uplifted outcrops (36 &amp;#8211; 180 m above sea level) along the east coast of Patagonian Argentina. These rock units provide a record of sea level during a geologic period when atmospheric CO2 and temperatures were higher than today. As such, reconstructing the elevation of global mean sea level (GMSL) during this time allows us to better understand how sensitive ice sheets are to increased past and future warming. However, reconstructing GMSL from local sea level indicators is hindered by effects such as mantle dynamic topography and glacial isostatic adjustment (GIA) that cause local sea level to deviate from the global mean. Here we use geodynamic modeling to better understand this complex dynamic setting and quantify the amount of uplift along this coastline.&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;Despite being located on a relatively stable passive margin, significant variations in the elevation of the paleo shoreline indicators imply that the underlying convecting mantle is deforming the coastline. In particular, the subduction of the Chile Rise beginning ~18 Ma beneath Patagonia has generated a slab window underneath this region through which hot asthenosphere ascends. However, the former slab is still present deeper in the mantle, which causes a complex interplay between the downwelling slab and the upwelling asthenosphere. To quantify the effects of dynamic topography change since the Pliocene, we run 3D mantle convection simulations using the code ASPECT. We initialize our global model with a composite temperature structure derived from recent tomographic studies and a calibrated parameterization of upper mantle anelasticity. Independent estimates of pressure and temperature from thermobarometric calculations of proximal Pali-Aike xenoliths agree with the thermal structure of the tomography-based Earth model. We back-advect temperature perturbations and extract the resulting change in dynamic topography. Pairing GIA models and a suite of convection simulations in which we vary the viscosity and buoyancy structure with the observed differential paleo shoreline elevations allows us to forward model the most likely scenario for uplift along this coast.&lt;/p&gt; &lt;/div&gt;

scholarly journals Widespread glacial erosion on the Scandinavian passive margin

Geology ◽  
2021 ◽  
Author(s):  
Vivi K. Pedersen ◽  
Åsne Rosseland Knutsen ◽  
Gustav Pallisgaard-Olesen ◽  
Jane Lund Andersen ◽  
Robert Moucha ◽  
...  
Keyword(s):  
High Elevation ◽  
Passive Margin ◽  
Inner Shelf ◽  
Glacial Erosion ◽  
Late Pliocene ◽  
Source To Sink

The topography in Scandinavia features enigmatic high-elevation low-relief plateau regions dissected by deep valleys and fjords. These plateau regions have long been interpreted as relict landforms of a preglacial origin, whereas recent studies suggest they have been modified significantly by glacial and periglacial denudation. We used late Pliocene–Quaternary source-to-sink analyses to untangle this scientific conundrum. We compared glacier-derived offshore sediment volumes with estimates of erosion in onshore valleys and fjords and on the inner shelf. Our results suggest that onshore valley and fjord erosion falls 61%–66% short of the offshore sink volume. Erosion on the inner shelf cannot accommodate this mismatch, implying that the entire Scandinavian landscape and adjacent shelf have experienced significant glacial erosion.

scholarly journals Evaluation of ocean circulation models in the computation of the mean dynamic topography for geodetic applications. Case study in the Greek seas

2019 ◽  
Vol 9 (1) ◽  
pp. 154-173
Author(s):  
I. Mintourakis ◽  
G. Panou ◽  
D. Paradissis
Keyword(s):  
Sea Level ◽  
Ocean Circulation ◽  
Tide Gauge ◽  
Dynamic Topography ◽  
Tide Gauge Records ◽  
Mean Dynamic Topography ◽  
Case Study Area ◽  
Extensive Evaluation ◽  
Precise Knowledge

Abstract Precise knowledge of the oceanic Mean Dynamic Topography (MDT) is crucial for a number of geodetic applications, such as vertical datum unification and marine geoid modelling. The lack of gravity surveys over many regions of the Greek seas and the incapacity of the space borne gradiometry/gravity missions to resolve the small and medium wavelengths of the geoid led to the investigation of the oceanographic approach for computing the MDT. We compute two new regional MDT surfaces after averaging, for given epochs, the periodic gridded solutions of the Dynamic Ocean Topography (DOT) provided by two ocean circulation models. These newly developed regional MDT surfaces are compared to three state-of-theart models, which represent the oceanographic, the geodetic and the mixed oceanographic/geodetic approaches in the implementation of the MDT, respectively. Based on these comparisons, we discuss the differences between the three approaches for the case study area and we present some valuable findings regarding the computation of the regional MDT. Furthermore, in order to have an estimate of the precision of the oceanographic approach, we apply extensive evaluation tests on the ability of the two regional ocean circulation models to track the sea level variations by comparing their solutions to tide gauge records and satellite altimetry Sea Level Anomalies (SLA) data. The overall findings support the claim that, for the computation of the MDT surface due to the lack of geodetic data and to limitations of the Global Geopotential Models (GGMs) in the case study area, the oceanographic approach is preferable over the geodetic or the mixed oceano-graphic/geodetic approaches.

scholarly journals Did the last sea level lowstand always lead to cross-shelf valley formation and source-to-sink sediment flux?

2006 ◽  
Vol 111 (F4) ◽  
Author(s):  
Torbjörn E. Törnqvist ◽  
Santina R. Wortman ◽  
Zenon Richard P. Mateo ◽  
Glenn A. Milne ◽  
John B. Swenson
Keyword(s):  
Sea Level ◽  
Sediment Flux ◽  
Source To Sink

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

&lt;div&gt; &lt;p&gt;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.&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;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 &lt;span&gt;also &lt;/span&gt;estimate transient sea level changes related specifically to the two latest glacial cycles.&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;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.&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;Our preliminary results show &lt;span&gt;perturbations of&lt;/span&gt; the local sea level up to &amp;#8764; 200 m since&lt;span&gt; the&lt;/span&gt; late-Pliocene in the Norwegian Sea, suggesting that erosion and deposition ha&lt;span&gt;ve&lt;/span&gt; influenced the local paleo sea level history in Scandinavia significantly.&lt;/p&gt; &lt;/div&gt;

Tectonic influence of Large Igneous Provinces on source-to-sink systems, the case study of Shetland during the Palaeocene - Preliminary results

2021 ◽  
Author(s):  
Lucas Albanese Valore ◽  
Christian Haug Eide ◽  
Tor Oftedal Sømme
Keyword(s):  
North Sea ◽  
Sediment Supply ◽  
Dynamic Topography ◽  
Sedimentary Record ◽  
Mantle Dynamics ◽  
Exceptional Preservation ◽  
The North ◽  
Source To Sink ◽  
The North Sea ◽  
Forcing Mechanisms

&lt;p&gt;The source-to-sink approach to sedimentology has become an increasingly valuable approach for addressing how external and internal forcing mechanisms are tied together in time and space. Processes that are initiated deep within the lower mantle can eventually propagate and affect shallow crustal sedimentary systems. This is important to predict the presence of reservoirs in areas of little data, and to interpret the sedimentary record in terms of climate and tectonic settings during deposition. To address this issue, we will study the Early Palaeogene succession of the East Shetland Platform in the North Sea, which was deposited during the emplacement of the Icelandic Plume. The plume&amp;#8217;s activity is hypothesized to be the cause of a major uplift cycle in the continental source areas, which is coeval to a sharp increase in sedimentation rates recorded in the East Shetland Platform during the Palaeocene. However, this relationship is still in need of accurate constraints derived from data with better spatial and temporal resolution, particularly due to overlapping climatic and tectonic controls, regional-to-local variations in sediment supply systems and overall gaps in the sedimentary record. This correlation can benefit from high-quality 3D seismic data on the platform, especially due to an exceptional preservation of shelf-edge geometries that are absent elsewhere. Using different 3D and 2D seismic surveys, well data and biostratigraphic data from the Shetland Platform and the North Sea, we will quantify sediment volumes supplied through time. The observed sediment volumes will be investigated using models of dynamic topography, plume activity and paleoclimatic data to closely relate supplied volumes to changes in relief, catchment geometries, precipitation and other key forcing parameters. Ultimately, we aim to investigate the relative influence of both tectonics and climate, as both long term (mantle dynamics) and short term (Palaeocene-Eocene Thermal Maximum) have been interpreted to play an important role in this system.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

Isostasy amplifies relative sea-level change on continental-scale deltas

2021 ◽  
Author(s):  
Sara Morón ◽  
Mike Blum ◽  
Tristan Salles ◽  
Bruce Frederick ◽  
Rebecca Farrington ◽  
...  
Keyword(s):  
Sea Level ◽  
Drainage Basin ◽  
Sediment Accumulation ◽  
River Mouth ◽  
Feedback Mechanism ◽  
Landscape Dynamics ◽  
Passive Margin ◽  
Sea Level Changes ◽  
Isostatic Compensation ◽  
Continental Scale

&lt;p&gt;The nature and contribution of flexural isostatic compensation to subsidence and uplift of passive margin deltas remains poorly understood. We performed a series of simulations to investigate flexural isostatic responses to high frequency fluctuations in water and sediment load associated with climatically-driven sea-level changes. We use a parallel basin and landscape dynamics model, BADLANDS, (an acronym for BAsin anD LANdscape DynamicS) that combines erosion, sedimentation, and diffusion with flexure, where the isostatic compensation of the load is computed by flexural compensation. We model a large drainage basin that discharges to a continental margin to generate a deltaic depocenter, then prescribe synthetic and climatic-driven sea-level curves of different frequencies to assess flexural response. Results show that flexural isostatic adjustments are bidirectional over 100-1000 kyr time-scales and mirror the magnitude, frequency, and direction of sea-level fluctuations, and that isostatic adjustments play an important role in driving along-strike and cross-shelf river-mouth migration and sediment accumulation. Our findings demonstrate that climate-forced sea-level changes set up a feedback mechanism that results in self-sustaining creation of accommodation into which sediment is deposited and plays a major role in delta morphology and stratigraphic architecture.&lt;/p&gt;

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