Deformation of salt structures by ice-sheet loading: insights into the controlling parameters from numerical modelling

Lang, Jörg; Hampel, Andrea

doi:10.1007/s00531-023-02295-5

Cited by 4 publications

(5 citation statements)

References 66 publications

(159 reference statements)

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“…As stated before, we assume that the results might differ if the domes were closer to the load margin. However, the scenarios that resulted in the most significant displacement rates in our physical models, i.e., partly loaded irregularly-shaped pillows, were not implemented in the numerical models documented in Lang et al (2014) and Lang & Hampel (2023). Our model results show that three-dimensional effects between both load margin and salt structure geometry are crucial factors that need to be included in the analyses.…”

Section: Comparison To Numerical Modeling Studiesmentioning

confidence: 93%

“…As a result, downward displacement of the salt structures during the loading phase and an upward displacement during the unloading phase could be confirmed by the models. However, the derived absolute amounts of displacement were relatively low, ranging from -37m to +4m (Lang et al, 2014) and -11 to +3.6m (Lang and Hampel, 2023), depending on the model parameters. Thus, although the physical principle was confirmed by Lang et al (2014) and Lang and Hampel (2023), the authors questioned a significant influence of ice-sheet induced salt movements on the surface topography, in contrast to previous findings by other authors (Hardt et al, 2021;Sirocko et al, 2008;Sirocko et al, 2002;Stackebrandt, 2005).…”

Section: Introduction and Rationalementioning

confidence: 92%

“…In the 2D numerical models of Lang et al (2014) and Lang & Hampel (2023), the salt domes (or in one example the salt wall) were either completely transgressed by the ice sheet, or the ice marginal position was located 1000 m "north" of the salt domes.…”

Section: Comparison To Numerical Modeling Studiesmentioning

confidence: 99%

“…In addition to the shape, also the size of the salt structure matters: the bigger the structure the bigger the potential volume of salt that can be expelled from the loaded parts of the structure. Based on their model results, Lang & Hampel (2023) questioned the impact of ice sheet induced salt movements on the landscape.…”

Section: Comparison To Numerical Modeling Studiesmentioning

confidence: 99%

“…1). Lang et al (2014) used numerical 2D models to simulate loading-and unloading effects of an ice sheet on salt structures (salt domes and salt walls) and the associated possible deformations (Lang and Hampel, 2023). As a result, downward displacement of the salt structures during the loading phase and an upward displacement during the unloading phase could be confirmed by the models.…”

Section: Introduction and Rationalementioning

confidence: 99%

See 4 more Smart Citations

Physical modeling of ice-sheet-induced salt movements using the example of northern Germany

Hardt,

Dooley,

Hudec

2023

Preprint

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Abstract. Salt structures and their surroundings can play an important role in the energy transition related to a number of storage and energy applications. Thus, it is important to assess the current and future stability of salt bodies in their specific geological settings. We investigate the influence of glacial loading and unloading on subsurface salt structures using physical models, based on the example of the Scandinavian Ice Sheet in northern Germany. Apparent spatial correlations between subsurface salt structures in northern Germany and Weichselian ice marginal positions have been observed before and the topic is a matter of ongoing debate. Recently described geomorphological features – termed surface cracks – have been interpreted as a direct result of ice sheet induced salt movement resulting in surface expansion. The spatial clustering and orientation of these surface cracks was so far not well understood, owing to only a limited number of available studies dealing with the related salt tectonic processes. Thus, we use four increasingly complex physical models to test the basic loading and unloading principle, to analyze flow patterns within the source-layer salt and within salt structures, and to examine the influence of the shape and orientation of salt structures with respect to a lobate ice margin in a three-dimensional laboratory environment. Three salt structures of the northern German basin were selected as examples that were replicated in the laboratory. Salt structures were initially grown by differential loading, and buried before loading. The ice load was simulated by a weight that was temporarily placed on a portion of the surface of the models. The replicated salt structures were either completely covered by the load, partly covered by the load, or were situated outside the load extent. In all scenarios, a dynamic response of the system to the load could be observed: while the load was applied, the structures outside the load margin started to rise, with a decreasing tendency with distance from the load margin and, at the same time, the structures under load subsided. After the load was removed, a flow reversal set in and previously loaded structures started to rise, whereas the structures outside the former load margin began to subside. The vertical displacements during the unloading stage were not as strong as during the load stage, and thus the system did not return to its pre-glaciation status. Modeled salt domes that were located at distance from the load margin showed a comparably weak reaction. A more extreme response was shown by modeled salt pillows whose margins varied from sub- parallel to sub-perpendicular to the load margin, and were partly covered by the load. Under these conditions, the structures showed a strong reaction in terms of strain and vertical displacement. The observed strain patterns at the surface were influenced by the shape of the load margin and the shape of the salt structure at depth, resulting in complex deformation patterns. These physical modeling results provide more evidence for a possible interplay between ice sheets and subsurface salt structures, highlighting the significance of three-dimensional effects in dynamic geological settings. Our results lead to a better understanding of spatial patterns of the surface cracks that were mapped at the surface above salt structures.

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Section: Comparison To Numerical Modeling Studiesmentioning

confidence: 93%

Section: Introduction and Rationalementioning

confidence: 92%

Section: Comparison To Numerical Modeling Studiesmentioning

confidence: 99%

Section: Comparison To Numerical Modeling Studiesmentioning

confidence: 99%

Section: Introduction and Rationalementioning

confidence: 99%

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Physical modeling of ice-sheet-induced salt movements using the example of northern Germany

Hardt,

Dooley,

Hudec

2023

Preprint

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Structure of Salt Diapirs in the Western Siberian Basin and Yenisei‒Khatanga Trough Based on Seismic Data

Sobornov

2024

Geotektonika

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Interpretation of regional seismic profiles characterizing the structure of the West Siberian basin and the Yenisei-Khatanga Trough to depths of 10‒20 km suggests that salt diapirs played an important role in the structure of this region. Salt diapirs have the following features: (i) large height (up to 5 km or more); (ii) seismic transparency; (iii) presence of growth layers on the flanks of inferred salt rises; (iv) existence of radial fault systems in overlying sediments; (v) isometric shapes of uplifts; (vi) reduced values of the gravity field. Salt deformation explains the origin of widespread ring inversion structures in Jurassic-Cretaceous sediments. Such ring structures probably originated above long-lived salt diapirs. The salts in them are presumably of Early Paleozoic age. The formation of salt strata took place in a large area of salt accumulation at the periphery of the Siberian Platform. The western boundary of the zone of evaporitic sediments distribution is the Trans-Eurasian fault zone, which separated the folded Uralides from the Siberian Platform and tectonic blocks amalgamated with it. The presence of the evaporitic Paleozoic deposits in the northeast of the West Siberian Basin and the Yenisei-Khatanga Trough facilitated the development of large oil and gas pools. Salt cryptodiapirs focused the migration of hydrocarbons from deeply buried, thermally mature Paleozoic sediments into the Jurassic-Cretaceous section, which explains the predominance of gas deposits in these areas, as well as the multilayer nature of the fields.

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Physical modeling of ice-sheet-induced salt movements using the example of northern Germany

Hardt,

Dooley,

Hudec

2024

Earth Surf. Dynam.

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Abstract. Salt structures and their surroundings can play an important role in the energy transition related to a number of storage and energy applications. Thus, it is important to assess the current and future stability of salt bodies in their specific geological settings. We investigate the influence of ice sheet loading and unloading on subsurface salt structures using physical models based on the geological setting of northern Germany, which was repeatedly glaciated by the Scandinavian Ice Sheet during the Pleistocene. Apparent spatial correlations between subsurface salt structures in northern Germany and Weichselian ice marginal positions have been observed before, and the topic is a matter of ongoing debate. Recently described geomorphological features – termed surface cracks – have been interpreted as a direct result of ice-sheet-induced salt movement resulting in surface expansion. The spatial clustering and orientation of these surface cracks has not been well understood so far, owing to only a limited number of available studies dealing with the related salt tectonic processes. Thus, we use four increasingly complex physical models to test the basic loading and unloading principle, to analyze flow patterns within the salt source layer and within salt structures, and to examine the influence of the shape and orientation of the salt structures with respect to a lobate ice margin in a three-dimensional laboratory environment. Three salt structures of the northern German basin were selected as examples that were replicated in the laboratory. Salt structures were initially grown by differential loading and buried before loading. The ice load was simulated by a weight that was temporarily placed on a portion of the surface of the models. The replicated salt structures were either completely covered by the load, partly covered by the load, or situated outside the load extent. In all scenarios, a dynamic response of the system to the load could be observed; while the load was applied, the structures outside the load margin started to rise, with a decreasing tendency with distance from the load margin, and, at the same time, the structures under the load subsided. After the load was removed, a flow reversal set in, and previously loaded structures started to rise, whereas the structures outside the former load margin began to subside. The vertical displacements during the unloading stage were not as strong as during the load stage, and thus the system did not return to its pre-glaciation status. Modeled salt domes that were located at distance from the load margin showed a comparably weak reaction. A more extreme response was shown by modeled salt pillows whose margins varied from sub-parallel to sub-perpendicular to the load margin and were partly covered by the load. Under these conditions, the structures showed a strong reaction in terms of strain and vertical displacement. The observed strain patterns at the surface were influenced by the shape of the load margin and the shape of the salt structure at depth, resulting in complex deformation patterns. These physical modeling results provide more evidence for a possible interplay between ice sheets and subsurface salt structures, highlighting the significance of three-dimensional effects in dynamic geological settings. Our results lead to a better understanding of spatial patterns of the surface cracks that were mapped at the surface above salt structures and offer further room for interpretation of the influence of salt movements on the present-day landscape.

show abstract

Deformation of salt structures by ice-sheet loading: insights into the controlling parameters from numerical modelling

Cited by 4 publications

References 66 publications

Physical modeling of ice-sheet-induced salt movements using the example of northern Germany

Physical modeling of ice-sheet-induced salt movements using the example of northern Germany

Structure of Salt Diapirs in the Western Siberian Basin and Yenisei‒Khatanga Trough Based on Seismic Data

Physical modeling of ice-sheet-induced salt movements using the example of northern Germany

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