Contrasting rotations within thrust sheets and kinematics of thrust tectonics as derived from palaeomagnetic data: an example from the Southern Pyrenees

1992 ◽  
pp. 265-275 ◽  
Author(s):  
J. Dinarès ◽  
E. McClelland ◽  
P. Santanach
Keyword(s):  
Palaeomagnetic Data ◽  
Thrust Tectonics ◽  
Thrust Sheets

Late Miocene thrust tectonics of the Latin Valley: insights from seismic lines (Central Apennines, Italy)

2020 ◽  
Author(s):  
Giuseppe Vico ◽  
Giovanni Luca Cardello
Keyword(s):  
Late Miocene ◽  
Subduction Zones ◽  
Volcanic Field ◽  
Normal Faults ◽  
Past Century ◽  
Central Apennines ◽  
Kinematic Evolution ◽  
Geothermal Fluids ◽  
Thrust Tectonics ◽  
Thrust Sheets

<p>In west-directed subduction zones, as the compression moves towards the foreland, the accretionary prism progressively expands to follow the hinge migration towards the east. Although late Miocene foreland propagation implies the shift of the thrust front, in the central Apennines, the effects of the Messinian compression can be observed on a much broader area, implying out-of-sequence thrusting in the rear.</p><p>In order to understand the Messinian involvement of the previously formed Tortonian belt-foredeep system, a regional reinterpretation is here provided. The analysis of publicly available 2D seismic reflection lines across the upper and middle Latin Valley and 10 wells enables the identification of two main seismostratigraphic units: i) the Meso-Cenozoic neritic carbonates and ii) the upper Tortonian siliciclastic pelitic and arenaceous turbiditic associations of the Frosinone Formation.</p><p>The most evident reflectors are the upper Cretaceous and upper Serravallian top paraconformities, which, due to tectonic repetition can be followed at different depths. We find that minor reflectors can be attributed to the several thrusts affecting folded Meso-Cenozoic neritic carbonates. This observation allows us, together with field and well evidences, to trace several thrust sheets characterized by a general top-to-the NE sense of shear. In a few sections from the Latin Valley (e.g. Line FR-309-80), we recognized the Meso-Cenozoic neritic carbonates being thrusted together with the Tortonian Frosinone Formation, on top of a laterally variably thick siliciclastic succession. This further syn-orogenic unit could be related to the early Messinian sandstones of the Torrice Formation, implying that out-of-sequence thrusting took place in the Latin Valley during the wedge-top sedimentation. The thin-skinned fold-and-thrust fabric is defined by en-échelon distributed thrusts, NNE- and ENE striking tear faults and minor pop-up structures often determining ideal traps for hydrocarbon and geothermal fluids. Finally, conjugated NW-striking high-angle normal faults crosscut the orogenic heritage and sets a horst and graben structure associated with continental deposition and the Volsci Volcanic Field.</p><p>The limited oil exploitation over the past century has targeted only the shallower siliciclastic traps and some evidences in the shallower neritic carbornate thrust sheets. At the light of our new interpretation, the deeper carbonate units could be a new focus for hydrocarbon accumulation and may furnish targets for geothermal and/or hydrocarbon research in the area. Future work aims at quantify the Tortonian and Messinian amount of shortening by taking into consideration the adjoining Volsci Range. Finally, our findings bear implications on geodynamic reconstructions and may represent an example of the geometry and kinematic evolution of platform derived thrust sheets and similar belts worldwide associated with W-directed subduction zones.</p>

scholarly journals Wedge equilibrium in fold-and-thrust belts: prediction of out-of-sequence thrusting based on sandbox experiments and natural examples

2000 ◽  
Vol 79 (1) ◽  
pp. 81-91 ◽  
Author(s):  
D.A. Nieuwland ◽  
J.H. Leutscher ◽  
J. Gast
Keyword(s):  
Time Lapse ◽  
In Situ Stress ◽  
Experimental Program ◽  
Critical Examination ◽  
Thrust Belt ◽  
Cross Sectional ◽  
Thrust Tectonics ◽  
Thrust Sheets ◽  
Sandbox Experiments ◽  
In Situ Stress Measurements

AbstractThrust tectonics are dealt with on the basis of primarily experiments focusing on the dynamics of a developing thrust belt and on understanding and predicting normal-sequence and out-of-sequence thrusting. Field examples are presented in addition to the examples of sandbox-model experiments. The results have improved the insight into thrust-belt-forming mechanisms; the validity of the conclusions is supported by natural examples.The experimental program was aimed at examining the effect of changes in a selection of key parameters in thrust tectonics on the geometry and the successive phases in the development of thrust sheets. Sandbox experiments were used to analyse the effects of basal friction, detachment lithology, basement relief and syntectonic sedimentation. Multilayer experiments were performed to simulate the effects of ductile detachment lithologies.It was found that a thrust belt’s cross-sectional geometry is formed in a dynamic process during which the wedge may develop from subcritical through critical to supercritical and back to critical again. The process is illustrated with sandbox experiments, analysed by time-lapse computed tomography scans and in-situ stress measurements. On the basis of the sandbox-model results and the natural examples, we conclude that a critical examination of the boundary conditions of a fold-and-thrust belt and of changes in these conditions during the deformation process enables predictions about the geometry and kinematics of the thrust belt.

scholarly journals Thrust tectonics in the Wetterstein and Mieming mountains, and a new tectonic subdivision of the Northern Calcareous Alps of Western Austria and Southern Germany

2021 ◽  
Author(s):  
Hugo Ortner ◽  
Sinah Kilian
Keyword(s):  
Eastern Alps ◽  
Northern Calcareous Alps ◽  
Main Body ◽  
Thrust Belt ◽  
Southeastern Part ◽  
Thrust Sheet ◽  
Northern Calcareous ◽  
Lateral Contact ◽  
Thrust Tectonics ◽  
Thrust Sheets

AbstractWe investigate the tectonic evolution of the Wetterstein and Mieming mountains in the western Northern Calcareous Alps (NCA) of the European Eastern Alps. In-sequence NW-directed stacking of thrust sheets in this thin-skinned foreland thrust belt lasted from the Hauterivian to the Cenomanian. In the more internal NCA major E-striking intracontinental transform faults dissected the thrust belt at the Albian–Cenomanian boundary that facilitated ascent of mantle melts feeding basanitic dykes and sills. Afterwards, the NCA basement was subducted, and the NCA were transported piggy-back across the tectonically deeper Penninic units. This process was accompanied by renewed Late Cretaceous NW-directed thrusting, and folding of thrusts. During Paleogene collision, N(NE)-directed out-of-sequence thrusts developed that offset the in-sequence thrust. We use this latter observation to revise the existing tectonic subdivision of the western NCA, in which these out-of-sequence thrusts had been used to delimit nappes, locally with young-on-old contacts at the base. We define new units that represent thrust sheets having exclusively old-on-young contacts at their base. Two large thrust sheets build the western NCA: (1) the tectonically deeper Tannheim thrust sheet and (2) the tectonically higher Karwendel thrust sheet. West of the Wetterstein and Mieming mountains, the Imst part of the Karwendel thrust sheet is stacked by an out-of-sequence thrust onto the main body of the Karwendel thrust sheet, which is, in its southeastern part, in lateral contact with the latter across a tear fault.

Thrust tectonics on Brøggerhalvøya and their relationship to the Tertiary West Spitsbergen Fold-and-Thrust Belt

2002 ◽  
Vol 139 (1) ◽  
pp. 47-72 ◽  
Author(s):  
K. SAALMANN ◽  
F. THIEDIG
Keyword(s):  
Middle Eocene ◽  
Kinematic Model ◽  
Thrust Belt ◽  
Fold Belt ◽  
Kinematic Evolution ◽  
Fold And Thrust Belt ◽  
Thrust Tectonics ◽  
Tectonic Transport ◽  
Thrust Sheets ◽  
West Spitsbergen

The Tertiary fold-and-thrust belt on Brøggerhalvøya is characterized by a NE-vergent pile of nine thrust sheets. The sole thrust of the pile is located in Precambrian phyllites and climbs up-section to the northeast. Four lower thrust sheets consisting predominantly of Upper Palaeozoic sediments are overlain by two thrust sheets in the central part of the stack which contain a kilometre-scale syncline and anticline. The fold is cut by juxtaposed thrusts giving rise to the formation of three structurally higher basement-dominated thrust sheets. A multiple-stage kinematic model is proposed including (1) in-sequence foreland-propagating formation of the lower thrust sheets in response to N–S subhorizontal bedding-parallel movements, (2) a change in tectonic transport to ENE and out-of-sequence thrusting and formation of the kilometre-scale fold-structure followed by (3) truncation of the kilometre-scale fold and stacking of the highest basement-dominated thrust sheets by hind-ward-propagating out-of-sequence thrusting. The strain of the thrust sheets is predominantly compressive with the exception of the structurally highest thrust sheets, reflecting a temporal change to a more transpressive regime. Thrusting was followed by (4) N–S extension and (5) W–E extension. Comparison of the structural geometry and kinematic evolution of Brøggerhalvøya with the data reported for the fold belt further south allows us to assume a coeval evolution with the fold belt. A latest Paleocene/Early Eocene age for the main phase of thrusting is suggested for the West Spitsbergen Fold-and-Thrust Belt; the main phases therefore pre-date the separation of Svalbard and Greenland due to right-lateral movements along the Hornsund Fault Zone. The fold belt's temporal evolution followed by the formation of the Forlandsundet Graben can be linked with the plate-kinematic framework in the span between latest Paleocene and Middle Eocene times.

Early Proterozoic thrust tectonics east of Ataa Sund, north-east Disko Bugt, West Greenland

1999 ◽  
pp. 171-179
Author(s):  
Jan C. Escher ◽  
Michael J. Ryan ◽  
Mogens Marker
Keyword(s):  
Amphibolite Facies ◽  
The West ◽  
Original Series ◽  
Early Proterozoic ◽  
West Greenland ◽  
North East ◽  
Thrust Tectonics ◽  
Thrust Sheets

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Escher, J. C., Ryan, M. J., & Marker, M. (1999). Early Proterozoic thrust tectonics east of Ataa Sund, north-east Disko Bugt, West Greenland. Geology of Greenland Survey Bulletin, 181, 171-179. https://doi.org/10.34194/ggub.v181.5124 _______________ The area east of Ataa Sund consists mainly of amphibolite facies grade Archaean gneisses, amphibolites and granites. Intense early Proterozoic deformation led to low-angle ductile imbrication of thrust sheets with movement directions to the west. Late tectonic Proterozoic basic sills with olivine-rich cumulates were intruded along the thrust sheets.

Pliocene—Quaternary sedimentation in the Northern Apennine Foredeep and related denudation

1996 ◽  
Vol 133 (3) ◽  
pp. 255-273 ◽  
Author(s):  
Carlo Bartolini ◽  
Riccardo Caputo ◽  
Marco Pieri
Keyword(s):  
Source Area ◽  
Reliable Estimate ◽  
Present Volume ◽  
Denudation Rates ◽  
Direct Measurements ◽  
Thrust Tectonics ◽  
Thrust Sheets ◽  
Quaternary Base ◽  
Alpine Rivers ◽  
Basin Area

AbstractThe deposits of the Pliocene—Quaternary foredeep of the Northern Apennine cover at present an area of 103000 km2. The original boundaries of the basin are not known, since marginal deposits have been eroded, in particular those of the inner, southwestern border. During Pliocene times the basin area was reduced by thrust tectonics and the amount of shortening may be tentatively estimated.The present volume of Pliocene and Quaternary sediments may be inferred with good approximation from the maps of the base of the Pliocene and of the Quaternary (base of the Hyalinea balthica Zone) successions. The Pliocene volume has been corrected adding the estimate of the underthrust sediments, while no correction has been attempted for the eroded marginal deposits. The estimates of 97000 and 95000km3. reflecting the present volume of the Pliocene and Quaternary deposits, are therefore significantly less than the volumes originally deposited.Present volumes have been transformed in ‘net’ (0% porosity) volumes, in order to obtain the relative net supply rates: 0.021 (Pliocene) and 0.047 (Quaternary) km3/a. Other unmeasurable factors (volume variations due to the weathering of silicates, loss of leached carbonates) may induce a probably unimportant underestimate of the supply rates.Available data allow an approximate estimate of the range of the net volume of the Holocene sediments deposited during the last 6000 a BP (221–276km3) and of the relative net supply rate (0.037–0.046km3/a), that is not significantly different from the Quaternary one. Applying a porosity correction, these supply rates may be related to the Quaternary source area (128000km2) to obtain the relative denudation rates: 0.41–0.46mm/a (Quaternary) and 0.36–0.51 mm/a (Holocene). Present supply and denudation rates, deduced from the direct measurements of the bed load and suspended load of the apenninic and alpine rivers, do not differ significantly from the Quaternary and Holocene ones.Available data do not allow a reliable estimate of the Pliocene source area, and consequently of the Pliocene denudation rate. However, a minimum of 160000–177 000 km3 has been eroded during Pliocene and Quaternary times. Assuming, as a working hypothesis, that the Pliocene source area did not significantly differ from the present one, an average thickness of 1240–1390 m could have been eroded since the beginning of Pliocene. This estimate is in agreement with the values obtained from the measurements of coalification of vegetal organic matter in the outcrops, and suggests that post-orogenic successions and ‘higher’ thrust sheets may have been completely removed in vast areas.

Modelling of structural complexity in sedimentary basins: The role of pre-existing faults in thrust tectonics

1993 ◽  
Vol 226 (1-4) ◽  
pp. 97-112 ◽  
Author(s):  
W. Sassi ◽  
B. Colletta ◽  
P. Balé ◽  
T. Paquereau
Keyword(s):  
Structural Complexity ◽  
Sedimentary Basins ◽  
Thrust Tectonics

scholarly journals Kinematic and tectonic significance of microstructures and crystallographic fabrics within quartz mylonites from the Assynt and Eriboll regions of the Moine thrust zone, NW Scotland

1986 ◽  
Vol 77 (2) ◽  
pp. 99-125 ◽  
Author(s):  
R. D. Law ◽  
M. Casey ◽  
R. J. Knipe
Keyword(s):  
Strain Path ◽  
Extensional Flow ◽  
Crystallographic Preferred Orientation ◽  
X Ray ◽  
Tectonic Significance ◽  
Thrust Zone ◽  
Thrust Sheets ◽  
Strain Paths ◽  
Tectonic Loading ◽  
Microstructural Studies

ABSTRACTUsing a combination of optical microscopy and X-ray texture goniometry, an integrated microstructural and crystallographic fabric study has been made of quartz mylonites from thrust sheets located beneath, but immediately adjacent to, the Moine thrust in the Assynt and Eriboll regions of NW Scotland. A correlation is established between shape fabric symmetry and pattern of crystallographic preferred orientation, a particularly clear relationship being observed between shape fabric variation and quartza-axis fabrics.Coaxial strain paths dominate the internal parts of the thrust sheets and are indicated by quartzc- anda-axis fabrics which are symmetrical with respect to foliation and lineation. Non-coaxial strain paths are indicated within the more intensely deformed quartzites located near the boundaries of the sheets by asymmetricalc- anda-axis fabrics. These kinematic interpretations are supported by microstructural studies. At the Stack of Glencoul in the northern part of the Assynt region, the transition zone between these kinematic (strain path) domains is located at approximately 20 cm beneath the Moine thrust and is marked by a progression from symmetrical cross-girdlec-axis fabrics (30cm beneath the thrust), through asymmetrical cross-girdlec-axis fabrics to asymmetrical single girdlec-axis fabrics (0·5 cm beneath the thrust).Tectonic models (incorporating processes such as extensional flow, gravity spreading and tectonic loading) which may account for the presence of strain path domains within the thrust sheets are considered, and their compatibility with local thrust sheet geometries assessed.

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