scholarly journals Review of Iberia‐Eurasia plate‐boundary basins: Role of sedimentary burial and salt tectonics during rifting and continental breakup

2020 ◽  
Author(s):  
Nicolas Saspiturry ◽  
Benoit Issautier ◽  
Philippe Razin ◽  
Thierry Baudin ◽  
Riccardo Asti ◽  
...  
Keyword(s):  
Plate Boundary ◽  
Salt Tectonics ◽  
Continental Breakup

Contractional salt tectonics and role of pre-existing diapiric structures in the Southern Pyrenean foreland fold–thrust belt (Montsec and Serres Marginals)

2021 ◽  
pp. jgs2020-085 ◽  
Author(s):  
Laura Burrel ◽  
Antonio Teixell
Keyword(s):  
Cross Sections ◽  
Foreland Basin ◽  
Salt Tectonics ◽  
Structural Development ◽  
Field Observations ◽  
Content Type ◽  
Growth Strata ◽  
Structural Style ◽  
Supplementary Material

Triassic Keuper evaporites have long been recognized as the main detachment level for thrusting in the Pyrenean fold–thrust belts. The deformed Late Cretaceous–Eocene foreland basin of the Southern Pyrenees has structures and stratal geometries that can be interpreted as related to salt tectonics (e.g. unconformities, rapid thickness variations, long-lived growth fans and overturned flaps), although they have been overprinted by shortening and thrusting. Based on field observations and published maps, we build new structural cross-sections reinterpreting two classic transects of the Southern Pyrenees (Noguera Ribagorçana and Noguera Pallaresa river transects). The sequential restoration of the sections explores the variations in structural style, addressing the role of halokinesis in the tectonic and sedimentary development. In the Serres Marginals area, we propose that salt pillows and diapirs started developing locally during the Mesozoic pre-orogenic episode, evolving into a system of salt ridges and intervening synclines filled with early synorogenic sediments. Rapid amplification of folds recorded by widespread latest Cretaceous–Paleocene growth strata is taken as marking the onset of contractional folding in the area. During Pyrenean compression, folding mechanisms transitioned from dominantly halokinetic to a combination of buckling and differential sedimentary loading. Squeezing of salt diapirs and thrust welding occurred as salt ridges were unroofed. We provide new field observations that lead to a reinterpretation of the regional structural development and contribute to the debate about the role of salt tectonics in the Pyrenees.Supplementary material: Table S1, giving the thickness of the main stratigraphic units, is available at https://doi.org/10.6084/m9.figshare.c.5287737

The role of the Polochic Fault as part of the North American and Caribbean Plate boundary: Insights from the infill of the Lake Izabal Basin

2020 ◽  
Vol 32 (6) ◽  
pp. 1347-1364
Author(s):  
Jonathan Obrist‐Farner ◽  
Andreas Eckert ◽  
Marek Locmelis ◽  
James L. Crowley ◽  
Byron Mota‐Vidaure ◽  
...  
Keyword(s):  
North American ◽  
Plate Boundary ◽  
Caribbean Plate ◽  
The North

scholarly journals The role of salt tectonics and overburden in the generation of overpressure in the Dutch North Sea area

2012 ◽  
Vol 91 (4) ◽  
pp. 517-534 ◽  
Author(s):  
S. Nelskamp ◽  
J.M. Verweij ◽  
N. Witmans
Keyword(s):  
Cross Sections ◽  
Salt Tectonics ◽  
Calibration Data ◽  
Mechanical Compaction ◽  
Jurassic Rocks ◽  
Sea Area ◽  
Porosity Measurements ◽  
Sealing Layer ◽  
Early Compaction

AbstractIn this paper we study the effects of timing of salt movement and mechanical compaction on the generation of overpressures in Mesozoic rocks. To that end we apply 2D basin modelling on two N-S trending cross sections in the Dutch Central Graben and Terschelling Basin, respectively. Several overpressuring scenarios were calculated by modifying the mechanical compaction of the sealing layer, the rate of sedimentation, and the timing of salt movement. Pressure and porosity measurements from several wells along the cross sections were used as calibration data. The results show that rapid sedimentation and early compaction of Pliocene to Quaternary mudstones explain most of the overpressures in the Cretaceous and Jurassic rocks. The modifications of the mechanical compaction of the Upper Cretaceous Chalk Group performed in this study could not explain the overpressure anomalies in the southern part of the Dutch Central Graben. Processes such as chemical compaction are probably more important in this respect. Overpressures in the Triassic are mainly controlled by the timing of salt movement and the closure of lateral seals. This study has lead to a better understanding of the processes that generate overpressures and those that are involved in their lateral distribution. The integration of modelling scenarios and information on the timing of seal formation enables to define new play concepts and is important for the assessment of possible drilling hazards as well.

Guidance of commissural growth cones at the floor plate in embryonic rat spinal cord

Development ◽  
1990 ◽  
Vol 109 (2) ◽  
pp. 435-447 ◽  
Author(s):  
P. Bovolenta ◽  
J. Dodd
Keyword(s):  
Spinal Cord ◽  
Axon Guidance ◽  
Plate Boundary ◽  
Growth Cones ◽  
Floor Plate ◽  
Morphological Properties ◽  
Rat Spinal Cord ◽  
Commissural Axons ◽  
Carbocyanine Dye

The floor plate of the embryonic rat spinal cord has been proposed to act as an intermediate target that plays a role in the pattern of extension of commissural axons. To begin to examine the role of the floor plate in axon guidance at the midline, we have studied the precision of the commissural axon projection to and across the floor plate during development. To delineate the pathway, the fluorescent carbocyanine dye, Di-I, has been used as a probe. We show that commissural axons traverse the floor plate and turn rostrally at its contralateral border with remarkable precision. Axons were not observed to turn ipsilaterally and turned only upon reaching the contralateral edge of the floor plate. Virtually all commissural axons follow this route. The morphology of commissural growth cones was also examined. As they encountered the floor plate, commissural growth cones became larger and increased in complexity. The reorientation of axons in register with the floor plate boundary and the change in the morphological properties of commissural growth cones as they traverse the midline suggest that the floor plate may act as a guidepost with functions similar to cells that have been implicated in axon guidance in invertebrates.

Incipient faulting near Lake Pillsbury, California, and the role of accessory faults in plate boundary evolution

Geology ◽  
2013 ◽  
Vol 41 (10) ◽  
pp. 1119-1122 ◽  
Author(s):  
Amanda M. Thomas ◽  
Roland Bürgmann ◽  
Douglas S. Dreger
Keyword(s):  
Plate Boundary

Influence of Salt Tectonics On Fault Displacements and Submarine Slope Failures from Algeria To Sardinia

2019 ◽  
Vol 25 (4) ◽  
pp. 318-330 ◽  
Author(s):  
Julia A. Yeakley ◽  
Abdul Shakoor ◽  
William Johnson
Keyword(s):  
Debris Flows ◽  
Average Rate ◽  
Plate Boundary ◽  
Western Mediterranean ◽  
Turbidity Currents ◽  
Salt Tectonics ◽  
Slope Failures ◽  
Submarine Slope ◽  
Lateral Extent ◽  
Pipeline Route

ABSTRACT We used previously obtained marine geophysical and geotechnical data for the proposed Galsi pipeline route from Algeria to Sardinia to analyze the buried salt distribution, rates of fault displacements, and frequency and lateral extent of submarine slope failures. Crossing the convergent African/Nubian–European plate boundary, the southern section of the pipeline route traverses continental shelves and slopes of Algeria and Sardinia as well as the Algerian abyssal plain of the western Mediterranean. Deeply buried Messinian-aged salt is present throughout this area. Being less dense and more buoyant than the overburden sediment, the salt tends to flow upward to form diapiric structures that, in turn, result in the formation of faults and landslides in the overlying sediment. Measured offsets from seismic profiles of different resolutions were compared with predicted sediment age at depth of each offset, yielding an average rate of fault displacement of 1.5 cm/kiloyear (ky). The highest rates of displacement are along the Cagliari slope near Sardinia (2.5-2.7 cm/ky) and near the convergent plate boundary (2.3 cm/ky). Utilizing the same geophysical data, the frequency and lateral extent of submarine slope failures in the study area can also be linked to the distribution of salt and the influence of salt tectonics. Turbidity currents and hyperpycnal flows are present within the Algerian basin, whereas local debris flows, landslide runouts, and channelized debris flows are present along the Sardinian slope. The low sedimentation rates, determined in this study, suggest that the most recent slope failures related to salt tectonics occurred more than 12,000 years ago.

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