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Guy A Plint - One of the best experts on this subject based on the ideXlab platform.
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allostratigraphy paleogeography and subsidence in a syn Tectonic Wedge harmon and cadotte alloformations middle albian alberta b c
2014Co-Authors: Olivia A. Henderson, Robin A. Buckley, Guy A Plint, Kristy F. TiampoAbstract:Summary Detailed subsurface correlation, linked to outcrop sections, allows both the sedimentology and regional stratal geometry of the Middle Albian Harmon and Cadotte alloformations to be determined. The mudstone-dominated Harmon alloformation forms a pronounced Wedge that thins from > 145m in the west to 5 m in the NE over ~ 300 km. The Harmon is interpreted to record a time of rapid flexural subsidence in the foredeep. In contrast, the overlying, sandstone-dominated Cadotte alloformation has a much less pronounced Wedge shape, and thins from 85 to 18 m over ~ 300 km. The more tabular geometry of the Cadotte is interpreted to record less pronounced asymmetrical flexural subsidence. In an attempt to quantify the physical controls on observed stratal geometry, the modeling program tao was employed. The tao program uses a finite-difference method to calculate the deflection of the lithosphere, and thereby allows Tectonic, eustatic and sedimentary processes to be linked at varying spatial and temporal scales.
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an allostratigraphic correlation of a mudstone dominated syn Tectonic Wedge the puskwaskau formation santonian campanian in outcrop and subsurface western canada foreland basin
Bulletin of Canadian Petroleum Geology, 2009Co-Authors: Guy A PlintAbstract:Abstract The Santonian-early Campanian Puskwaskau Formation is a prismatic Wedge 340 m thick that occupies the foredeep of the Western Canada foreland basin. It is dominated by muddy, offshore sediments deposited by storms in water probably no more than a few tens of metres deep. The Puskwaskau rocks are organized into siltier-upward and sandier-upward successions, bounded by regionally-mappable marine flooding surfaces that permit definition of 14 informal allomembers (labeled A to N in ascending order). These rocks span early Santonian to? early Campanian time and probably represent approximately 2.5 Ma. Only allomember L contains swaley-stratified sandstone bodies (correlative with the Chungo Member in outcrop) that represent at least 40 km of north-eastward shoreface progradation. The upper surface of allomember L is a major, pebble-veneered erosion surface with 15 m of relief that cuts down towards the NE, implying significant relative sea-level fall, followed by subsequent transgressive ravinement. Overlying transgressive mudstone of allomember M onlaps south-westward and appears to fill bathymetric relief cut into the top of allomember L. Allomembers A to L can be grouped into three larger stratigraphic packages, informally termed units, each inferred to represent approximately 750 ka. Each unit is typified by an overall upward-fining succession, followed by an upward-coarsening succession that is capped by a transgressive or flooding surface. Within each unit, facies and small-scale parasequence stacking patterns suggest that accommodation was generated relatively rapidly in the lower part, but accommodation rate diminished towards the top of each unit, possibly even becoming negative. Units 1, 2 and 3 fill discrete arcuate depocentres, the cores of which show abrupt lateral displacement along the orogen by 200–350 km. This is interpreted to record abrupt lateral shifts in the locus of active thrust-sheet advance in the contemporaneous fold-and-thrust belt. These discrete depocentres cannot, however, be discerned in a formation-scale isopach map. In the NW, the base of allomember L is a beveling unconformity that progressively truncates allomembers K to H from the SE towards the NW. Beveling implies gradual tilting and uplift in the NW, prior to and possibly during deposition of allomember L. The initiation of new flexural depocentres took place geologically instantaneously, across the boundaries of individual allomembers (average duration approximately 190 ka); this observation implies that thrust sheets advanced independently, and were separated by major high strain zones.
Harry Fritz - One of the best experts on this subject based on the ideXlab platform.
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Sequence of Thrusting Within A Thick-Skinned Tectonic Wedge: Evidence From40Ar/39Ar and Rb-Sr Ages From the Austroalpine Nappe Complex of the Eastern Alps
The Journal of Geology, 1998Co-Authors: R. David Dallmeyer, Robert Handler, Franz Neubauer, Harry FritzAbstract:The sequence of thrusting within a regional‐scale Alpine thick‐skinned Tectonic Wedge has been constrained by Rb‐Sr and 40Ar/39Ar dating of whole‐rock, constituent white mica and biotite from structural units of the Austroalpine Nappe Complex, Eastern Alps (Austria). Preservation of Variscan and pre‐Variscan isotopic signatures in pre‐Alpine basement units indicates a non‐penetrative metamorphic Alpine overprint. Alpine nappe assembly and accompanying ductile deformation occurred during maintenance of lower greenschist‐facies metamorphic conditions (c. 300°–450°C). Analyses from greenschist‐facies metamorphic mylonites and penetratively ductile deformed cover sequences display decreasing 40Ar/39Ar plateau ages structurally downward. Thrusting and accompanied ductile deformation commenced at c. 100–90 Ma in the uppermost structural levels. Footwall fault propagation effected internal deformation and out‐of‐sequence thrusting within intermediate structural levels at c. 95–80 Ma. This was contemporaneous wit...
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sequence of thrusting within a thick skinned Tectonic Wedge evidence from40ar 39ar and rb sr ages from the austroalpine nappe complex of the eastern alps
The Journal of Geology, 1998Co-Authors: David R Dallmeyer, Robert Handler, Franz Neubauer, Harry FritzAbstract:The sequence of thrusting within a regional‐scale Alpine thick‐skinned Tectonic Wedge has been constrained by Rb‐Sr and 40Ar/39Ar dating of whole‐rock, constituent white mica and biotite from structural units of the Austroalpine Nappe Complex, Eastern Alps (Austria). Preservation of Variscan and pre‐Variscan isotopic signatures in pre‐Alpine basement units indicates a non‐penetrative metamorphic Alpine overprint. Alpine nappe assembly and accompanying ductile deformation occurred during maintenance of lower greenschist‐facies metamorphic conditions (c. 300°–450°C). Analyses from greenschist‐facies metamorphic mylonites and penetratively ductile deformed cover sequences display decreasing 40Ar/39Ar plateau ages structurally downward. Thrusting and accompanied ductile deformation commenced at c. 100–90 Ma in the uppermost structural levels. Footwall fault propagation effected internal deformation and out‐of‐sequence thrusting within intermediate structural levels at c. 95–80 Ma. This was contemporaneous wit...
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Sequence of Thrusting within a Thick-Skinned Tectonic Wedge: Evidence from 40 Ar/ 39 Ar and Rb-Sr Ages from the Austroalpine Nappe Complex of
1998Co-Authors: R. David Dallmeyer, Robert Handler, Franz Neubauer, Harry FritzAbstract:ABSTRACT The sequence of thrusting within a regional-scale Alpine thick-skinned Tectonic Wedge has been constrained by Rb-Sr and 40 Ar/ 39 Ar dating of whole-rock, constituent white mica and biotite from structural units of the AustroalpineNappe Complex, Eastern Alps (Austria). Preservation of Variscan and pre-Variscan isotopic signatures in pre-Alpinebasement units indicates a non-penetrative metamorphic Alpine overprint. Alpine nappe assembly and accompany-ing ductile deformation occurred during maintenance of lower greenschist-facies metamorphic conditions(c. 300°–450°C). Analyses from greenschist-facies metamorphic mylonites and penetratively ductile deformed coversequences display decreasing 40 Ar/ 39 Ar plateau ages structurally downward. Thrusting and accompanied ductiledeformation commenced at c. 100–90 Ma in the uppermost structural levels. Footwall fault propagation effected inter-nal deformation and out-of-sequence thrusting within intermediate structural levels at c. 95–80 Ma. This was contem-poraneous with regional exhumation and cooling of deeper crustal basement units at c. 88–82 Ma and was associatedwith extension and strike-slip faulting, leading to the formation of synorogenic sedimentary basins. Additional foot-wall thrust propagation was associated with ductile deformation within lowermost structural units at c. 80–70 Ma.The structural and new geochronologic results presented herein suggest that (1) the Austroalpine Nappe Complexrepresents a forward propagating thrust complex that formed as a result of footwall propagation of a master fault andassociated piggyback transport of hangingwall structural units; (2) most parts of the Austroalpine block occupied alower-plate Tectonic setting during Cretaceous Tectonics subsequent to subduction of the Meliata-Hallstatt ocean; and(3) the Austroalpine Nappe Complex had already been formed when subduction of Penninic oceanic domains wasactive.
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sequence of thrusting within a thick skinned Tectonic Wedge evidence from 40 ar 39 ar and rb sr ages from the austroalpine nappe complex of
1998Co-Authors: David R Dallmeyer, Robert Handler, Franz Neubauer, Harry FritzAbstract:ABSTRACT The sequence of thrusting within a regional-scale Alpine thick-skinned Tectonic Wedge has been constrained by Rb-Sr and 40 Ar/ 39 Ar dating of whole-rock, constituent white mica and biotite from structural units of the AustroalpineNappe Complex, Eastern Alps (Austria). Preservation of Variscan and pre-Variscan isotopic signatures in pre-Alpinebasement units indicates a non-penetrative metamorphic Alpine overprint. Alpine nappe assembly and accompany-ing ductile deformation occurred during maintenance of lower greenschist-facies metamorphic conditions(c. 300°–450°C). Analyses from greenschist-facies metamorphic mylonites and penetratively ductile deformed coversequences display decreasing 40 Ar/ 39 Ar plateau ages structurally downward. Thrusting and accompanied ductiledeformation commenced at c. 100–90 Ma in the uppermost structural levels. Footwall fault propagation effected inter-nal deformation and out-of-sequence thrusting within intermediate structural levels at c. 95–80 Ma. This was contem-poraneous with regional exhumation and cooling of deeper crustal basement units at c. 88–82 Ma and was associatedwith extension and strike-slip faulting, leading to the formation of synorogenic sedimentary basins. Additional foot-wall thrust propagation was associated with ductile deformation within lowermost structural units at c. 80–70 Ma.The structural and new geochronologic results presented herein suggest that (1) the Austroalpine Nappe Complexrepresents a forward propagating thrust complex that formed as a result of footwall propagation of a master fault andassociated piggyback transport of hangingwall structural units; (2) most parts of the Austroalpine block occupied alower-plate Tectonic setting during Cretaceous Tectonics subsequent to subduction of the Meliata-Hallstatt ocean; and(3) the Austroalpine Nappe Complex had already been formed when subduction of Penninic oceanic domains wasactive.
Massimiliano Rinaldo Barchi - One of the best experts on this subject based on the ideXlab platform.
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K-Ar fault gouge dating of Neogene thrusting: The case of the siliciclastic deposits of the Trasimeno Tectonic Wedge (Northern Apennines, Italy)
Italian Journal of Geosciences, 2020Co-Authors: Filippo Carboni, Francesco Brozzetti, Giulio Viola, Luca Aldega, Roelant Van Der Lelij, Massimiliano Rinaldo BarchiAbstract:The Northern Apennines (NA) are a characteristic example of foreland fold-and-thrust belt progressively migrating towards its foreland. Their Tectonic evolution has been quite tightly constrained in time by microfossil biostratigraphy applied to syn-orogenic deposits within foreland basins. This makes the NA well suited to test the reliability of K-Ar illite dating of Neogene deformation affecting siliciclastic sequences. We sampled two top-to-the-ENE thrusts, whose well defined cores are defined by scaly gouge formed at the expense of the pelitic component of the host rock. X-ray diffraction (XRD) and K-Ar isotopic analysis of multiple grain-size fractions of the gouge, allowed us to discriminate between syn-kinematic and inherited illite crystals in the fault rocks. Illite age analysis (IAA) constrains fault slip along the thrusts to 15.2 ± 7.6 Ma and 15.4 ± 16.6 Ma. The results, in spite of their analytical uncertainty, are fully consistent with the local evolution of the NA as constrained by the independent biostratigraphic studies and confirm the general suitability of this geochronological approach to Neogene deformation.
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Geological and geophysical study of a thin-skinned Tectonic Wedge formed during an early collisional stage: the Trasimeno Tectonic Wedge (Northern Apennines, Italy)
Geological Magazine, 2019Co-Authors: Filippo Carboni, Francesco Brozzetti, Francesco Mirabella, Francesco Cruciani, Massimiliano Porreca, Maurizio Ercoli, Stefan Back, Massimiliano Rinaldo BarchiAbstract:The presence of a set of well-known turbidite successions, deposited in progressively E-migrating foredeep basins and subsequently piled up with east vergence, makes the Northern Apennines of Italy paradigmatic of the evolution of deepwater fold-and-thrust belts. This study focuses on the early Apenninic collisional stage, early Miocene in age, which led to the accretion of the turbidites of the Trasimeno Tectonic Wedge (TTW), in the central part of the Northern Apennines. Based on the interpretation of previously unpublished seismic reflection profiles with new surface geology data and Tectonic balancing, we present a detailed Tectonic reconstruction of the TTW. In the study area, the TTW is characterized by a W-dipping shaly basal decollement located at a depth of 1–5 km. The Tectonic Wedge is c . 5 km thick at its central-western part and tapers progressively eastwards to c . 1 km. The total shortening, balanced along a 33 km long cross-section, is c . 60 km, including 20 km (40%) of internal imbrication, c . 23 km of horizontal ENE-wards translation along the basal decollement and c . 17 km of passive translation caused by the later shortening of footwall units. Deformation balancing, constrained through upper Aquitanian – upper Burdigalian ( c . 21–16 Ma) biostratigraphy, provides an average shortening rate of c . 8.6 mm a –1 . Internal shortening of the TTW shows an average shortening rate of c . 4 mm a –1 for this period.
Filippo Carboni - One of the best experts on this subject based on the ideXlab platform.
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K-Ar fault gouge dating of Neogene thrusting: The case of the siliciclastic deposits of the Trasimeno Tectonic Wedge (Northern Apennines, Italy)
Italian Journal of Geosciences, 2020Co-Authors: Filippo Carboni, Francesco Brozzetti, Giulio Viola, Luca Aldega, Roelant Van Der Lelij, Massimiliano Rinaldo BarchiAbstract:The Northern Apennines (NA) are a characteristic example of foreland fold-and-thrust belt progressively migrating towards its foreland. Their Tectonic evolution has been quite tightly constrained in time by microfossil biostratigraphy applied to syn-orogenic deposits within foreland basins. This makes the NA well suited to test the reliability of K-Ar illite dating of Neogene deformation affecting siliciclastic sequences. We sampled two top-to-the-ENE thrusts, whose well defined cores are defined by scaly gouge formed at the expense of the pelitic component of the host rock. X-ray diffraction (XRD) and K-Ar isotopic analysis of multiple grain-size fractions of the gouge, allowed us to discriminate between syn-kinematic and inherited illite crystals in the fault rocks. Illite age analysis (IAA) constrains fault slip along the thrusts to 15.2 ± 7.6 Ma and 15.4 ± 16.6 Ma. The results, in spite of their analytical uncertainty, are fully consistent with the local evolution of the NA as constrained by the independent biostratigraphic studies and confirm the general suitability of this geochronological approach to Neogene deformation.
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Geological and geophysical study of a thin-skinned Tectonic Wedge formed during an early collisional stage: the Trasimeno Tectonic Wedge (Northern Apennines, Italy)
Geological Magazine, 2019Co-Authors: Filippo Carboni, Francesco Brozzetti, Francesco Mirabella, Francesco Cruciani, Massimiliano Porreca, Maurizio Ercoli, Stefan Back, Massimiliano Rinaldo BarchiAbstract:The presence of a set of well-known turbidite successions, deposited in progressively E-migrating foredeep basins and subsequently piled up with east vergence, makes the Northern Apennines of Italy paradigmatic of the evolution of deepwater fold-and-thrust belts. This study focuses on the early Apenninic collisional stage, early Miocene in age, which led to the accretion of the turbidites of the Trasimeno Tectonic Wedge (TTW), in the central part of the Northern Apennines. Based on the interpretation of previously unpublished seismic reflection profiles with new surface geology data and Tectonic balancing, we present a detailed Tectonic reconstruction of the TTW. In the study area, the TTW is characterized by a W-dipping shaly basal decollement located at a depth of 1–5 km. The Tectonic Wedge is c . 5 km thick at its central-western part and tapers progressively eastwards to c . 1 km. The total shortening, balanced along a 33 km long cross-section, is c . 60 km, including 20 km (40%) of internal imbrication, c . 23 km of horizontal ENE-wards translation along the basal decollement and c . 17 km of passive translation caused by the later shortening of footwall units. Deformation balancing, constrained through upper Aquitanian – upper Burdigalian ( c . 21–16 Ma) biostratigraphy, provides an average shortening rate of c . 8.6 mm a –1 . Internal shortening of the TTW shows an average shortening rate of c . 4 mm a –1 for this period.
Patrice Baby - One of the best experts on this subject based on the ideXlab platform.
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piggyback basin development above a thin skinned thrust belt with two detachment levels as a function of interactions between Tectonic and superficial mass transfer the case of the subandean zone bolivia
Tectonophysics, 2000Co-Authors: Pascale Leturmy, Jeanlouis Mugnier, P Vinour, Patrice Baby, B Colletta, E ChabronAbstract:Abstract The Subandean fold and thrust belt of Bolivia is characterised by two major detachment levels and large piggyback basins. ‘Sand-box’ and numerical models have been used to study sedimentation and erosion control on thrust belt evolution and to study the retroactive effects of Tectonics on piggyback development in thin-skinned thrust belts with two detachment levels. Analogue models show that surface processes play a dominant role in controlling Wedge evolutions: erosion promotes fault reactivation and Tectonic delamination (passive roof duplex) while sedimentation promotes forward shifting of the frontal thrust and consequently piggyback basin development. Numerical models were used to understand the development of the Subandean fold and thrust belt of Bolivia. Numerical experiments show that the simultaneity of basement tilting and high sedimentation rates promotes the formation of a stable Tectonic Wedge. Outer and inner faults are alternately active during the beginning of deformation, a kinematic evolution that favours the development of piggyback basins between. The step-by-step history of the thrust belt predicts that each change in Tectonic location is recorded with large unconformities in basins, but these unconformities are not well preserved from progressive erosion in the final geometry.
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Development of transfer zones and location of oil and gas fields in frontal part of Bolivian Andean fold-and-thrust belt
AAPG Bulletin, 1993Co-Authors: Patrice Baby, B Colletta, M. Specht, J. Letouzey, E. Mendez, Bertrand GuillierAbstract:The frontal part of the Bolivian Andean thrust belt consists of a thick series of paleozoic to cenozoic sedimentary rocks (5 to 8 km thick) which are folded and thrusted towards the east on a sole thrust at the base of paleozoic series. The front of this Tectonic Wedge is characterized by transfer zones of various scales and geometries. The main oil and gas fields are located in these transfer zones. A study realized from YPFB (Yacimientos Petroliferos Fiscales Bolivianos) seismic data shows that in all the cases, the deformation is controlled by the geometry and thickness variations of the paleozoic basin. The most spectacular transfer zone appears at the bolivian orocline scale and corresponds to the famous bending of the andean thrust front close to Santa Cruz. More to the south (19 to 22[degrees] S) the southern foreland fold and thrust belt is characterized by a set of local right lateral offset transfer zones ([open quotes]en echellon[close quotes] folds). The difference of geometry and scale of the transfer zones seems to be related to the variation of the angle value between the shortening direction and the direction of the paleozoic basin borders. In order to test our interpretation, tomore » constrain the boundary conditions and to study the thrust propagation sequence, we performed a set of analog model experiments whose 3D visualization was analyzed by computerized X-ray tomography.« less
