scholarly journals The accretion of foreland basin sediments during early stages of continental collision in the European Alps and similarities to accretionary wedge tectonics

Tectonics ◽  
2016 ◽  
Vol 35 (10) ◽  
pp. 2216-2238 ◽  
Author(s):  
Armin Dielforder ◽  
Alfons Berger ◽  
Marco Herwegh
Keyword(s):  
Foreland Basin ◽  
Continental Collision ◽  
Accretionary Wedge ◽  
European Alps ◽  
Early Stages

Geodynamic evolution of the East Carpathian Foreland Basin since the Middle Miocene: Implications for sediment supply to the Black Sea and Dacian Basin

2020 ◽  
Author(s):  
Arjan de Leeuw ◽  
Stephen Vincent ◽  
Anton Matoshko ◽  
Andrei Matoshko ◽  
Marius Stoica ◽  
...  
Keyword(s):  
Black Sea ◽  
Large Scale ◽  
Drainage System ◽  
Foreland Basin ◽  
Continental Collision ◽  
Sediment Supply ◽  
The Black Sea ◽  
Accretionary Wedge ◽  
Sedimentary Architecture ◽  
The Impact

<p>The Carpathian orogen is part of the Alpine-Himalayan collision zone and formed as the result of the collision of the Tisza-Dacia and ALCAPA mega-units with the European southern margin, following a protracted phase of subduction, slab roll-back and accretionary wedge formation. The foreland basin of the East Carpathians is 800 km long and stretches out across Poland, Ukraine, Moldova and Romania. We use the results of our intensive field research to unravel the sedimentary architecture of this basin and reveal how it responded to the final phases of foreland vergent thrusting, continental collision and subsequent slab detachment. We discuss the asymmetry in the basins evolution and eventual inversion and relate this to the diachronous evolution of the Carpathian orogen. We also address the impact of changing subsidence patterns and base-level changes on connectivity with the Central and Eastern Paratethys, important for faunal exchange and patterns of endemism. We finally show that continental collision led to the establishment of a Late Miocene NW-SE prograding axial drainage system in the foreland supplying abundant sediment to the NW Black Sea, thus triggering large-scale shelf edge progradation.</p>

What slates can tell us about strain localisation and fluid flow in accretionary wedges: a microstructural analysis of deforming foreland basin sediments

2021 ◽  
Author(s):  
Ismay Vénice Akker ◽  
Christoph E. Schrank ◽  
Michael W.M. Jones ◽  
Cameron M. Kewish ◽  
Alfons Berger ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Microstructural Evolution ◽  
Microstructural Analysis ◽  
Foreland Basin ◽  
Intensity Increase ◽  
Accretionary Wedge ◽  
European Alps ◽  
Strain Localisation ◽  
Calcite Veins ◽  
Metamorphic Gradient

<p>During the accretion of foreland basin sediments into an accretionary or orogenic wedge, the sediments dehydrate and deform. Both dehydration and deformation intensity increase from the outer to the inner wedge and are a function of metamorphic processes and strain. Here, we study the microstructural evolution of slates from the exhumed Flysch units making up a paleo accretionary wedge in the European Alps. With classic SEM imaging and synchrotron X-ray fluorescence microscopy, we document the evolution of slate fabrics and calcite veins and aim at understanding the role of the evolving slate fabrics for strain localisation and fluid flow at the micro-scale.</p><p>The investigated slate samples are from a NW-SE transect covering the outer and inner wedge from 200 to 330 °C. The metamorphic gradient directly correlates with an increasing background strain gradient. With the use of the autocorrelation function, we quantify the evolution of the microfabrics along the metamorphic gradient and document deformation stages from a weakly deformed slate without foliation in the outer wedge to a strongly deformed slate with a dense spaced foliation in the inner wedge. The foliation mainly forms by dissolution-precipitation processes, which increase with increasing metamorphic gradient.</p><p>The slate matrix reveals two main sets of veins. The first vein set includes micron-scaled calcite veinlets with very high spatial densities. The second vein set includes layer parallel calcite veins that form vein-arrays (couple of metres thick) in the inner wedge. Both vein sets could have moved large amounts of fluids through the wedge. The spatial distribution of the micron-veinlets reveals that fluids were moved pervasively. In the case of the layer parallel veins forming vein-arrays, fluid flow was localized, supported by the dense spaced foliation formed in the slate matrix in the inner wedge. This way we now establish a direct link between the microstructural evolution in the slate matrix and associated dehydration, where fluids become increasingly channelled towards the inner wedge. Knowing that the vein-arrays have length dimensions in the order or hundreds of metres to kilometres, these structures are important for larger-scale fluid flow, the feeding of fluids into megathrusts and for related seismic activity in the wedge.</p>

How Himalayan collision stems from subduction

Geology ◽  
2021 ◽  
Author(s):  
M. Soret ◽  
K.P. Larson ◽  
J. Cottle ◽  
A. Ali
Keyword(s):  
Foreland Basin ◽  
Continental Collision ◽  
Ultrahigh Pressure ◽  
Metamorphic Rocks ◽  
Conductive Heat ◽  
Plate Interface ◽  
Continental Subduction ◽  
Metamorphic History ◽  
Orogenic Wedge ◽  
History Of

The mechanisms and processes active during the transition from continental subduction to continental collision at the plate interface are largely unknown. Rock records of this transition are scarce, either not exposed or obliterated during subsequent events. We examine the tectono-metamorphic history of Barrovian metamorphic rocks from the western Himalayan orogenic wedge. We demonstrate that these rocks were buried to amphibolite-facies conditions from ≤47 Ma to 39 ± 1 Ma, synchronously with the formation (46 Ma) and partial exhumation (45–40 Ma) of the ultrahigh-pressure eclogites. This association indicates that convergence during continental subduction was accommodated via development of a deep orogenic wedge built through successive underplating of continental material, including the partially exhumed eclogites, likely in response to an increase in interplate coupling. This process resulted in the heating of the subduction interface (from ~7 to ~20 °C/km) through advective and/or conductive heat transfer. Rapid cooling of the wedge from 38 Ma, coeval with the formation of a foreland basin, are interpreted to result from indentation of a promontory of thick Indian crust.

scholarly journals Control of increased sedimentation on orogenic fold-and-thrust belt structure – insights into the evolution of the Western Alps

Solid Earth ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 391-404 ◽  
Author(s):  
Zoltán Erdős ◽  
Ritske S. Huismans ◽  
Peter van der Beek
Keyword(s):  
Sedimentation Rate ◽  
Foreland Basin ◽  
Front Propagation ◽  
Western Alps ◽  
European Alps ◽  
Sudden Increase ◽  
Thrust Belt ◽  
Foreland Basins ◽  
Thrust Front ◽  
Fold And Thrust Belt

Abstract. We use two-dimensional thermomechanical models to investigate the potential role of rapid filling of foreland basins in the development of orogenic foreland fold-and-thrust belts. We focus on the extensively studied example of the Western European Alps, where a sudden increase in foreland sedimentation rate during the mid-Oligocene is well documented. Our model results indicate that such an increase in sedimentation rate will temporarily disrupt the formation of an otherwise regular, outward-propagating basement thrust-sheet sequence. The frontal basement thrust active at the time of a sudden increase in sedimentation rate remains active for a longer time and accommodates more shortening than the previous thrusts. As the propagation of deformation into the foreland fold-and-thrust belt is strongly connected to basement deformation, this transient phase appears as a period of slow migration of the distal edge of foreland deformation. The predicted pattern of foreland-basin and basement thrust-front propagation is strikingly similar to that observed in the North Alpine Foreland Basin and provides an explanation for the coeval mid-Oligocene filling of the Swiss Molasse Basin, due to increased sediment input from the Alpine orogen, and a marked decrease in thrust-front propagation rate. We also compare our results to predictions from critical-taper theory, and we conclude that they are broadly consistent even though critical-taper theory cannot be used to predict the timing and location of the formation of new basement thrusts when sedimentation is included. The evolution scenario explored here is common in orogenic foreland basins; hence, our results have broad implications for orogenic belts other than the Western Alps.

scholarly journals Large-wavelength late Miocene thrusting in the North Alpine foreland: Implications for late orogenic processes

2019 ◽  
Author(s):  
Samuel Mock ◽  
Christoph von Hagke ◽  
Fritz Schlunegger ◽  
István Dunkl ◽  
Marco Herwegh
Keyword(s):  
Late Miocene ◽  
Foreland Basin ◽  
Crustal Thickening ◽  
Tectonic Activity ◽  
Local Geometry ◽  
European Alps ◽  
The North ◽  
Nappe Tectonics ◽  
Alpine Foreland ◽  
Large Wavelength

Abstract. Additional to classical nappe tectonics, the Oligocene to mid-Miocene post-collisional evolution of the Central European Alps was characterized by vertically directed tectonics, with backthrusting along the Insubric Line and the subsequent uplift of the External Crystalline Massifs (ECMs). Thereafter, the orogen experienced axis-perpendicular growth when deformation propagated into its external parts. For the North Alpine foreland between Lake Geneva and Lake Constance, in the past, this has been kinematically and spatially linked to the uplift and exhumation of the ECMs. Based on apatite (U-Th-Sm)/He thermochronometry, we constrain thrusting in the Subalpine Molasse between 12–4 Ma, thus occurring coeval to main deformation in the Jura fold-and-thrust belt (FTB) and late stage exhumation of the ECMs. However, this pattern of tectonic activity is not restricted to areas which are bordered by ECMs, but is consistent along the northern front of the Alps between Geneva and Salzburg. Therefore, late Miocene foreland deformation is not necessarily a consequence of uplift and exhumation of the ECMs. While the local geometry of the Subalpine Molasse results from lateral variations of the mechanical stratigraphy of the foreland basin sediments, we suggest that the large-wavelength tectonic signal is the response to a shift in tectonic forces possibly caused by deep-seated geodynamic processes. This resulted in a change from dominantly vertical to horizontal tectonics and orogen-perpendicular growth of crustal thickening. We constrain the onset of this major tectonic change to ca. 12 Ma in the North Alpine foreland, resulting in thrusting and folding in the Subalpine Molasse west of Salzburg and in the Jura FTB until at least 4 Ma.

scholarly journals Miocene high elevation in the Central Alps

Solid Earth ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 2615-2631
Author(s):  
Emilija Krsnik ◽  
Katharina Methner ◽  
Marion Campani ◽  
Svetlana Botsyun ◽  
Sebastian G. Mutz ◽  
...  
Keyword(s):  
Sea Level ◽  
Foreland Basin ◽  
European Alps ◽  
Molasse Basin ◽  
Central Alps ◽  
Pedogenic Carbonate ◽  
Northern Alpine Foreland ◽  
History Of ◽  
Alpine Foreland ◽  
Alpine Foreland Basin

Abstract. Reconstructing Oligocene–Miocene paleoelevation contributes to our understanding of the evolutionary history of the European Alps and sheds light on geodynamic and Earth surface processes involved in the development of Alpine topography. Despite being one of the most intensively explored mountain ranges worldwide, constraints on the elevation history of the European Alps remain scarce. Here we present stable and clumped isotope measurements to provide a new paleoelevation estimate for the mid-Miocene (∼14.5 Ma) European Central Alps. We apply stable isotope δ–δ paleoaltimetry to near-sea-level pedogenic carbonate oxygen isotope (δ18O) records from the Northern Alpine Foreland Basin (Swiss Molasse Basin) and high-Alpine phyllosilicate hydrogen isotope (δD) records from the Simplon Fault Zone (Swiss Alps). We further explore Miocene paleoclimate and paleoenvironmental conditions in the Swiss Molasse Basin through carbonate stable (δ18O, δ13C) and clumped (Δ47) isotope data from three foreland basin sections in different alluvial megafan settings (proximal, mid-fan, and distal). Combined pedogenic carbonate δ18O values and Δ47 temperatures (30±5 ∘C) yield a near-sea-level precipitation δ18Ow value of -5.8±1.2 ‰ and, in conjunction with the high-Alpine phyllosilicate δD value of -14.6±0.3 ‰, suggest that the region surrounding the Simplon Fault Zone attained surface elevations of >4000 m no later than the mid-Miocene. Our near-sea-level δ18Ow estimate is supported by paleoclimate (iGCM ECHAM5-wiso) modeled δ18O values, which vary between −4.2 ‰ and −7.6 ‰ for the Northern Alpine Foreland Basin.

scholarly journals Miocene high elevation and high relief in the Central Alps

2021 ◽  
Author(s):  
Emilija Krsnik ◽  
Katharina Methner ◽  
Marion Campani ◽  
Svetlana Botsyun ◽  
Sebastian G. Mutz ◽  
...  
Keyword(s):  
Sea Level ◽  
Foreland Basin ◽  
European Alps ◽  
Molasse Basin ◽  
Central Alps ◽  
Pedogenic Carbonate ◽  
Northern Alpine Foreland ◽  
History Of ◽  
Alpine Foreland ◽  
Alpine Foreland Basin

Abstract. Reconstructing Oligocene-Miocene paleoelevation contributes to our understanding of the evolutionary history of the European Alps and sheds light on geodynamic and Earth’s surface processes involved in the development of Alpine topography. Despite being one of the most intensively explored mountain ranges worldwide, constraints on the elevation history of the European Alps, however, remain scarce. Here we present stable and clumped isotope geochemistry measurements to provide a new paleoelevation estimate for the mid-Miocene (~14.5 Ma) European Central Alps. We apply stable isotope δ-δ paleoaltimetry on near sea level pedogenic carbonate oxygen isotope (δ18O) records from the Northern Alpine Foreland Basin (Swiss Molasse Basin) and high-Alpine phyllosilicate hydrogen isotope (δD) records from the Simplon Fault Zone (Swiss Alps). We further explore Miocene paleoclimate and paleoenvironmental conditions in the Swiss Molasse Basin through carbonate stable (δ18O, δ13C) and clumped (Δ47) isotope data from three foreland basin sections in different alluvial megafan settings (proximal, mid-fan, and distal). Combined pedogenic carbonate δ18O values and Δ47 temperatures (30 ± 5 °C) yield a near sea level precipitation δ18Ow value of −5.8 ± 0.2 ‰ and in conjunction with the high-Alpine phyllosilicate δD record suggest that the region surrounding the SFZ attained surface elevations of > 4000 m no later than the mid-Miocene. Our near sea level δ18Ow estimate is supported by paleoclimate (iGCM Echam5-wiso) modeled δ18O values, which vary between −4.2 and −7.6 ‰ for the Northern Alpine Foreland Basin.

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