scholarly journals Contribution of gravity gliding in salt-bearing rift basins – a new experimental setup for simulating salt tectonics under the influence of sub-salt extension and tilting

Solid Earth ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1987-2020
Author(s):  
Michael Warsitzka ◽  
Prokop Závada ◽  
Fabian Jähne-Klingberg ◽  
Piotr Krzywiec
Keyword(s):  
Structural Evolution ◽  
Image Correlation ◽  
Salt Tectonics ◽  
Rift Basins ◽  
Downward Movement ◽  
Basin Scale ◽  
Experimental Analogue ◽  
Pure Extension ◽  
Top View ◽  
Salt Flow

Abstract. Basin-scale salt flow and the evolution of salt structures in rift basins is mainly driven by sub- and supra-salt faulting and sedimentary loading. Crustal extension is often accompanied and followed by thermal subsidence leading to tilting of the graben flanks, which might induce an additional basinward-directed driver for salt tectonics. We designed a new experimental analogue apparatus capable of integrating the processes of sub-salt graben extension and tilting of the flanks, such that the overlapping effects on the deformation of a viscous substratum and the brittle overburden can be simulated. The presented experimental study was performed to demonstrate the main functionality of the experimental procedure and setup, demonstrating the main differences in structural evolution between conditions of pure extension, pure tilting, and extension combined with tilting. Digital image correlation of top-view stereoscopic images was applied to reveal the 3D displacement and strain patterns. The results of these experiments suggest that in salt basins affected by sub-salt extension and flank inclination, the salt flow and downward movement of overburden affects the entire flanks of the basin. Supra-salt extension occurring close to the graben centre is overprinted by the downward movement; i.e. the amount of extension is reduced or extensional faults zones are shortened. At the basin margins, thin-skinned extensional faults developed as a result of gravity gliding. A comparison with natural examples reveals that such fault zones can also be observed at the margins of many salt-bearing rift basins indicating that gravity gliding played a role in these basins.

scholarly journals Contribution of gravity gliding in salt-bearing rift basins – A new experimental setup for simulating salt tectonics under the influence of sub-salt extension and tilting

2021 ◽  
Author(s):  
Michael Warsitzka ◽  
Prokop Závada ◽  
Fabian Jähne-Klingberg ◽  
Piotr Krzywiec
Keyword(s):  
Structural Evolution ◽  
Image Correlation ◽  
Salt Tectonics ◽  
Rift Basins ◽  
Downward Movement ◽  
Experimental Procedure ◽  
Basin Scale ◽  
Pure Extension ◽  
Top View ◽  
Salt Flow

Abstract. Basin-scale salt flow and the evolution of salt structures in rift basin is mainly driven by sub- and supra-salt faulting and sedimentary loading. Crustal extension is often accompanied and followed by thermal subsidence leading to tilting of the graben flanks, which might induce an additional basinward directed driver for salt tectonics. We designed a new experimental analog apparatus capable of integrating the processes of sub-salt graben extension and tilting of the flanks, such that the overlapping effects on the deformation of a viscous substratum and the brittle overburden can be simulated. The presented experimental study was performed to demonstrate the main functionality of the experimental procedure and setup demonstrating the main differences in structural evolution between conditions of pure extension, pure tilting and extension combined with tilting. Digital image correlation of top view stereoscopic images was applied to reveal the 3D displacement and strain patterns. Results of these experiments suggest that in salt basins affected by sub-salt extension and flank inclination, the salt flow and downward movement of overburden affects the entire flanks of the basin. Supra-salt extension occurring close to the graben centre is overprinted by the downward movement, i.e. amount of extension is reduced or extensional faults zones are shortened. At the basin margins, thin-skinned extensional fault developed, which resemble fault zones observed on basin flanks offset from the central graben zone.

A new experimental approach to assess the influence of gravity gliding on salt tectonics in rift basins

2021 ◽  
Author(s):  
Michael Warsitzka ◽  
Prokop Závada ◽  
Fabian Jähne-Klingberg ◽  
Piotr Krzywiec
Keyword(s):  
Cross Sections ◽  
Hanging Wall ◽  
Fault Zones ◽  
Image Correlation ◽  
Salt Tectonics ◽  
Correlation Technique ◽  
Shear Stresses ◽  
Rift Basins ◽  
Salt Flow ◽  
Extensional Structures

<p>Salt flow in rift basins is mainly driven by sub- and supra-salt extension imposing shear stresses and differential loading on the salt layer. In many rift basins, the graben flanks are tilted as a result of thermal subsidence and sediment load. Such tilt induces additional basin-ward directed stresses potentially causing downward directed salt flow and gravity gliding of the supra-salt overburden. However, sediment loading in extensional basins is usually largest in the basin centre, which would lead to an upward directed salt expulsion and might act as an effective buttress resisting downward gliding.</p><p>Our aim is to investigate the opposing influence of sub-salt extension, sedimentary loading and tilting on deformation patterns in the viscous salt and the brittle overburden. We try to assess under which geological configurations (e.g. minimum basin slope or topographic gradient) upward directed salt flow and downward directed gravity gliding are the dominating deformation processes in extensional basins. Therefore, we developed a new analogue modelling apparatus enabling to simulate the processes of tectonic extension of a graben structure and the gradual tilting of the graben flanks, acting either simultaneously or separately. Using digital image correlation technique, temporal and spatial changes of the displacement and strain patterns can be analysed. Cross sections through the final experiments enable to identify structures characteristic for specific driving processes.</p><p>Here, we present results of a preliminary experimental study in which the basic influence of flank tilting and syn-kinematic sedimentation on salt tectonics in rift basins is examined. In case that the graben flanks remain flat during extension, widespread extensional fault zones develop on the footwall sides near the graben faults. In case that the flanks are tilted simultaneously with basal extension, additional extensional fault zones evolve at the upslope basin margins resulting from downward gliding of the overburden. In the downslope basin centre, this peripheral extension is balanced by reduced amounts of extension near the graben and later by shortening above the graben bounding faults and the hanging wall graben centre. If syn-kinematic sedimentation is introduced, downslope gravity gliding is significantly reduced and extensional fault zones are rather localized. Peripheral extensional structures observed in the experiments resemble typical thin-skinned extensional structures occurring at the flanks of many salt-bearing rift basins, e.g. the Polish Basin and Norwegian-Danish Basin. Thus, such structures might serve as diagnostic indicators for the occurrence of gravity gliding in rift basins.</p>

scholarly journals Analogue experiments of salt flow and pillow growth due basement faulting and differential loading

2014 ◽  
Vol 6 (2) ◽  
pp. 1625-1686
Author(s):  
M. Warsitzka ◽  
J. Kley ◽  
N. Kukowski
Keyword(s):  
Short Pulse ◽  
Structural Evolution ◽  
Image Correlation ◽  
Extension Rate ◽  
Viscous Layer ◽  
Sand Mixture ◽  
The North ◽  
Basement Fault ◽  
Analogue Experiments ◽  
Salt Flow

Abstract. Basement faulting is widely acknowledged as a potential trigger for salt flow and the growth of salt structures in salt-bearing extensional basins. In this study, dynamically scaled analogue experiments were designed to examine the evolution of salt pillows and the kinematics of salt flow due to a short pulse of basement faulting and a long-lasting phase of successive sedimentation. Experiments performed in the framework of this study consist of viscous silicone putty to simulate ductile rock salt, and a PVC-beads-quartz sand mixture representing a brittle supra-salt layer. In order to derive 2-D incremental displacement and strain patterns, the analogue experiments were monitored by an optical image correlation system (Particle Imaging Velocimetry). By varying layer thicknesses and extension rates, the influence of these parameters on the kinematics of salt flow were tested. Model results reveal that significant strain is triggered in the viscous layer by minor basement faulting. During basement extension downward flow occurs in the viscous layer above the basement fault tip. In contrast, upward flow takes place during post-extensional sedimentation. Lateral redistribution of the viscous material during post-extensional sedimentation is associated with subsidence above the footwall block and uplift adjacent to the basement faults leading to the formation of pillow structures (primary pillows). Decoupled cover faulting and the subsidence of peripheral sinks adjacent to the primary pillow causes the formation of additional pillow structures at large distance from the basement fault (secondary pillows). Experimental results demonstrate that the development of salt pillows can be triggered by basement extension, but requires a phase of tectonic quiescence. The potential for pillow growth and the displacement rate in the viscous layer increase with increasing thickness of the viscous layer and increasing extension rate, but decrease with increasing thickness of the overburden. The experimentally obtained structures resemble those of some natural extensional basins, e.g. the North German Basin or the Mid-Polish Trough, and can help to understand the kinematics during the structural evolution.

scholarly journals Multi-Scale Digital Image Correlation Analysis of In Situ Deformation of Open-Cell UHMWPE Foam

2020 ◽  
Author(s):  
Eugene S. Statnik ◽  
Codrutza Dragu ◽  
Cyril Besnard ◽  
Alexander J.G. Lunt ◽  
Alexey I. Salimon ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
High Performance ◽  
Structural Evolution ◽  
Image Correlation ◽  
Deformation Bands ◽  
Open Cell ◽  
Polyether Ether Ketone ◽  
Structural Levels

Porous ultra-high molecular weight polyethylene (UHMWPE) is a high performance bioinert polymer used in cranio-facial reconstructive surgery in procedures where relatively low mechanical stresses arise. As an alternative to much stiffer and costly polyether-ether-ketone (PEEK) polymer, UHMWPE finds further wide application in hierarchically structured hybrids for advanced implants mimicking cartilage, cortical and trabecular bone tissues within a single component. The mechanical behaviour of open-cell UHMWPE sponges obtained through sacrificial desalination of hot compression-moulded UHMWPE-NaCl powder mixtures shows a complex dependence on the fabrication parameters and microstructural features. In particular, similarly to other porous media it displays significant inhomogeneity of strain that readily localises within deformation bands that govern the overall response. In this article, we report advances in the development of accurate experimental techniques for operando studies of the structure-performance relationship applied to the porous UHMWPE medium with pore sizes of about 250 µm that are most well-suited for live cell proliferation and fast vascularization of implants. Samples of UHMWPE sponges were subjected to in situ compression using a micromechanical testing device within Scanning Electron Microscope (SEM) chamber, allowing the acquisition of high-resolution image sequences for Digital Image Correlation (DIC) analysis. Special masking and image processing algorithms were developed and applied to reveal the evolution of pore size and aspect ratio. Key structural evolution and deformation localisation phenomena were identified at both macro- and micro-structural levels in the elastic and plastic regimes. The motion of pore walls was quantitatively described, and the presence and influence of strain localisation zones were revealed and analysed using DIC technique.

scholarly journals Stretching and Contraction of Extensional Basins With Pre-Rift Salt: A Numerical Modeling Approach

2021 ◽  
Vol 9 ◽  
Author(s):  
Pablo Granado ◽  
Jonas B. Ruh ◽  
Pablo Santolaria ◽  
Philipp Strauss ◽  
Josep Anton Muñoz
Keyword(s):  
Hanging Wall ◽  
Structural Evolution ◽  
Extension Rate ◽  
Rift Basins ◽  
Basin Inversion ◽  
Accommodation Space ◽  
Basement Faults ◽  
Original Distribution ◽  
Thrust Belts ◽  
Half Graben

We present a series of 2D thermo-mechanical numerical experiments of thick-skinned crustal extension including a pre-rift salt horizon and subsequent thin-, thick-skinned, or mixed styles of convergence accompanied by surface processes. Extension localization along steep basement faults produces half-graben structures and leads to variations in the original distribution of pre-rift salt. Thick-skinned extension rate and salt rheology control hanging wall accommodation space as well as the locus and timing of minibasin grounding. Upon shortening, extension-related basement steps hinder forward propagation of evolving shallow thrust systems; conversely, if full basin inversion takes place along every individual fault, the regional salt layer is placed back to its pre-extensional configuration, constituting a regionally continuous décollement. Continued shortening and basement involvement deform the shallow fold-thrust structures and locally breaches the shallow décollement. We aim at obtaining a series of structural, stratigraphic and kinematic templates of fold-and-thrust belts involving rift basins with an intervening pre-rift salt horizon. Numerical results are compared to natural cases of salt-related inversion tectonics to better understand their structural evolution.

Salt tectonics in salt-bearing rift basins: Progradational loading vs extension

2020 ◽  
Vol 141 ◽  
pp. 104193
Author(s):  
Luis Alberto Rojo ◽  
Hemin Koyi ◽  
Nestor Cardozo ◽  
Alejandro Escalona
Keyword(s):  
Salt Tectonics ◽  
Rift Basins

scholarly journals Global Mechanical Behavior Characterization of Uniaxially Loaded Rock Specimen Based on Its Structural Evolution

2020 ◽  
Vol 10 (21) ◽  
pp. 7647
Author(s):  
Tongzhen Xing ◽  
Haibin Zhu ◽  
Guangyan Liu ◽  
Yimin Song ◽  
Shaopeng Ma
Keyword(s):  
Mechanical Behavior ◽  
Uniaxial Compression ◽  
Structural Model ◽  
Rock Specimen ◽  
Structural Evolution ◽  
Image Correlation ◽  
Evolution Process ◽  
Deformation Localization ◽  
Characterization Model ◽  
Rock Structure

Characterizing global mechanical behavior accurately is important for a detailed understanding of the deformation mechanism of rock material. In this paper, a new characterization model of the global mechanical behavior of rock is proposed, based on the structural characteristics of rock deformation. Uniaxial compression tests were carried out using the digital image correlation method and acoustic emission to obtain the interrelationship between mechanical behavior and deformation evolution. The test results show that the appearance of deformation localization leads to non-linear evolution of global mechanical behavior in a rock specimen. Further, due to the gradual evolution of deformation localization bands, the rock specimen evolves from a complete whole to a rock structure with a “weak interlayer”. Thus, the global mechanical behavior of the rock specimen depends heavily on the structural evolution process, especially when close to failure. A simplified characterization model was established according to the deformation process. The finite element method was used to verify the rationality of the proposed structural model. The verification result showed that under uniaxial compression, the structural model can reproduce the global mechanical behavior evolution process of the rock specimen.

Facies Models at the Lake Basin Scale

2003 ◽  
Author(s):  
Andrew S. Cohen
Keyword(s):  
Lake Baikal ◽  
Large Scale ◽  
Lake Basin ◽  
Rift Basins ◽  
Sediment Delivery ◽  
Origin And Evolution ◽  
Basin Scale ◽  
African Rift ◽  
Rift Lake ◽  
Facies Models

Understanding the historical evolution of sedimentation in a lake requires not only a grounding in facies interpretation but also an understanding of the larger-scale, lakewide linkages between deposition and those factors influencing sedimentation. The facies models we examined in chapter 7 can be linked to understand the differences in deposits between lake basins. Basin-scale facies models focus on the major interactions between climate or tectonic/ volcanic activity and sedimentation, attempting to explain why particular facies types develop in particular areas or at particular times in a lake’s history. Here I will focus on a few examples from the most intensively studied depositional settings, including lake types defined by mode of origin and evolution (rifts, glacial lakes, etc.) as well as saline lakes and playas, which share chemical and climatic attributes. Large-scale facies modeling in rift lakes has been driven by a need to understand the occurrence of hydrocarbons in ancient rifts (Lambiase, 1990; Katz, 2001). This in turn spurred a rapid accumulation of seismic reflection and facies data in the East African rift lakes and Lake Baikal (Russia) during the 1980s and 1990s, as well as attempts to synthesize these data and integrate them into general models. As we saw in chapter 2, the evolution of rift basins involves the development of asymmetric half-grabens and, in larger lake systems, the linkage of these half-grabens in a linear chain. As rift basins age, progressive deformation will eventually cause extensive deformation on both sides of the basin, transforming them into asymmetric full grabens, as seen in Lake Baikal today. This pattern of tectonic development has consequences for geomorphology, sediment delivery rates and locations, and sediment composition, that also vary depending on whether the lake basin is relatively full (high-stand conditions) or empty (low-stand) (Rosendahl et al., 1986; Cohen, 1990; Scholz and Rosendahl, 1990; Tiercelin et al., 1992; Soreghan and Cohen, 1996). Large-scale depositional patterns in a rift lake therefore represent an interplay between tectonic and climatic forces, factors that operate on somewhat different time scales.

scholarly journals Thin- and thick-skinned salt tectonics in the Netherlands; a quantitative approach

2012 ◽  
Vol 91 (4) ◽  
pp. 447-464 ◽  
Author(s):  
J.H. ten Veen ◽  
S.F. van Gessel ◽  
M. den Dulk
Keyword(s):  
Thickness Distribution ◽  
A Priori ◽  
Salt Tectonics ◽  
Distribution Analysis ◽  
Burial History ◽  
Stratigraphic Sequence ◽  
The North ◽  
Structural Style ◽  
Zechstein Salt ◽  
Salt Flow

AbstractThe Zechstein salt in the Dutch part of the North Sea Basin played a key role in the generation of successful petroleum plays. This is not only because of its sealing capacity, but also because the salt occurs in structures that provide lateral and vertical traps. The structural styles of areas with thick salt and those with none- or thin salt are completely different during phases of extensional or compressional tectonics. This indicates that, indirectly, the depositional thickness of the main Zechstein salt is essential in regulating the loci of the Dutch petroleum systems. In this paper we aim at quantifying current ideas on the relationship between 1) depositional salt thicknesses; 2) structural style of the main structural elements identified in the Dutch subsurface; 3) timing of deformation; and 4) thickness of the overburden. By finalisation of TNO's subsurface mapping program (see Kombrink et al., this issue), several data products are available that allow evaluation of these relationships. The depositional thickness of the salt was estimated using iterative smoothing of the present day thickness, the results of which account both for regional thickness variations and volume preservation (99%). Fault-distribution analysis shows that faults are only able to penetrate salt with a depositional thickness of <300 m, a transition that demarcates the division between thin- and thick-skinned salt tectonics. In the southern offshore where the salt is thin or absent, the overburden shows the same fault pattern throughout the stratigraphic sequence. In the northern realm, where salt is thicker than 300 m, the salt layer acted as decollement and sub- and supra salt strain are dissimilar. A strong genetic and temporal relationship exists between periods of regional tectonism, halokinetic intensity and thickness distribution of the Zechstein overburden. This relationship is further proven by burial history analysis across two selected profiles in the northern offshore. The analysis focuses on the vertical distribution of the salt by taking into account the depositional and erosional history of the salt overburden, without a-priori defined periods of salt flow. The results corroborate the notion that platforms and highs experienced less extension during the major phases of Jurassic rifting and further suggest that the absence of a thick Jurassic overburden precludes major salt flow during this tectonic phase. Main salt flow was triggered during the Sub-Hercynian and later phases of compression resulting in salt pillow geometries. In the basinal areas, where the Jurassic succession is thickest, salt diapirs and walls formed that are almost exclusively linked to major subsalt faults. Main salt flow occurred during Late Kimmerian rifting, whereas some minor structuration occurred during Sub-Hercynian inversion.

scholarly journals Interactions between propagating rifts and linear weaknesses in the lower crust

Geosphere ◽  
2019 ◽  
Vol 15 (5) ◽  
pp. 1617-1640 ◽  
Author(s):  
Nicolas E. Molnar ◽  
Alexander R. Cruden ◽  
Peter G. Betts
Keyword(s):  
Three Dimensional ◽  
Structural Evolution ◽  
Shear Zones ◽  
Rift Basins ◽  
Significant Control ◽  
Existing Structures ◽  
Rift Propagation ◽  
Continental Rifts ◽  
Extension Direction ◽  
Changes Over Time

Abstract Pre-existing structures in the crust such as shear zones, faults, and mobile belts are known to exert a significant control on the structural evolution of continental rifts. However, the influence of such features when the extension direction progressively changes over time remains uncertain. Here we present new results from three-dimensional lithospheric-scale laboratory experiments of rotational extension that provide key insights into the temporal evolution of propagating rifts. We specifically test and characterize how rifts propagate and interact with linear crustal rheological heterogeneities oriented at variable angles with respect to the extension direction. Results show that approximately rift-parallel pre-existing heterogeneities favor the formation of long, linear faults that reach near-final lengths at early stages. Low angles between the heterogeneities and the propagating rift axis may result in strong strike-slip reactivation of the pre-existing structures if they are suitably oriented with respect to the stretching direction. When the linear heterogeneities are oriented at intermediate to high angles rift branches become laterally offset as they propagate, resulting in complex rhombic fault patterns. Rift-perpendicular crustal heterogeneities do not affect fault trends during rift propagation, but cause stalling and deepening of laterally growing rift basins. Similarities between the analogue experimental results and selected natural examples provide insights on how nature finds the preferential pathway to breakup in heterogeneous continental lithosphere.

Sign in / Sign up

Export Citation Format

Share Document