The Southern Atlas Front in Tunisia and its foreland basin: Structural style and regional-scale deformation

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

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Recent geological advances in the understanding of the Torres Basin

The APPEA Journal ◽

10.1071/aj12070 ◽

2013 ◽

Vol 53 (2) ◽

pp. 459

Author(s):

Michael Swift

Keyword(s):

Cross Sections ◽

Large Scale ◽

Regional Scale ◽

Coastal Region ◽

Petroleum Potential ◽

Structural Style ◽

Time Space ◽

Australian Plate ◽

History Of ◽

Geological Section

The Torres Basin is a recently discovered Mesozoic basin in the Papuan Plateau, southeast Papua New Guinea. Newly acquired deepwater offshore seismic data and older regional data have been (re)interpreted with the view of defining structural regimes in line with the onshore geological maps and conceptual cross sections. A regional time-space plot has been developed to elucidate the breakup of the northeastern Australian Plate with a focus on the geological history of the Papuan Plateau, which holds the Torres Basin geological section. This in turn has led to a re-evaluation of the structural style and history of the southern coastal region incorporating the East Australian Early Cretaceous Island Arc; it highlights that a significant horizontal structural grain needs to be considered when evaluating the petroleum potential of the region. The southern margin is characterised as a frontal thrust system, similar to the nearby Papuan Basin. A series of regional strike lines in conjunction with the dip lines is used to divide the region into prospective and non-prospective exploration play fairways. The role of transfer faults, basement-detachments faults, regional-scale thrust faults, and recent normal faulting is discussed in the compartmentalisation of the geological section. There is basement-involved anticlinal development on a large scale and a complementary smaller-scale thin-skinned anticlinal trend. These trends are characterised as having significant strike length and breadth. Anticlinal trap fairways have been defined and have similar size and distribution as that of the Papuan Basin.

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Cross-border megasequence stratigraphy of the Northern, Central and Southern North Sea: a comparative tectono-stratigraphic synthesis

Geological Society London Special Publications ◽

10.1144/sp494-2020-228 ◽

2021 ◽

pp. SP494-2020-228

Author(s):

Stefano Patruno ◽

Henk Kombrink ◽

Stuart G. Archer

Keyword(s):

North Sea ◽

Regional Scale ◽

Foreland Basin ◽

First Order ◽

Cross Border ◽

Southern North Sea ◽

The North ◽

Lithostratigraphic Units ◽

The North Sea ◽

Basin Fill

AbstractThe Devonian-Recent tectono-stratigraphic history of the Northern, Central and Southern North Sea is here reviewed at a regional scale and four novel cross-border pseudo-Wheeler diagrams are presented to summarize the stratigraphic evolution of the cycles of basin fill and uplift/erosion. In this scheme, six first-order megasequence boundaries have been defined, characterized by extensive and long-lasting erosional hiatuses and major coastal regressions: (1) Caledonian (or Base Devonian) Unconformity; (2) Variscan-Saalian (or Base Permian) Unconformity; (3) Mid Cimmerian (or Intra-Aalenian) Unconformity; (4) Late Cimmerian (or Base Cretaceous) Unconformity; (5) Atlantean (or Near-Base Tertiary) Unconformity; (6) Eridanos (or Mid-Miocene) Unconformity. These surfaces have been linked to regional causal factors ranging from: orogenesis-related compressional uplifts, in either active plate margin settings (1) or foreland basin settings (2); intra-plate dynamically supported uplifts associated with the development of mantle plumes (3, 5 and 6); the end-of-rifting and associated widespread erosion of tilted fault block crests (4).The aforementioned megasequence boundaries punctuate the geodynamic evolution of the North Sea area and facilitate the sub-division of the entire the North Sea sedimentary basin fill into six megasequences, named here from A to F. All the lithostratigraphic units of the North Sea (formations and members) have been described within the context of this first-order tectono-stratigraphic framework. The correlation power of certain stratigraphic markers are also compared and contrasted, together with the potential cross-border equivalence of sedimentary units on different sides of the political median lines.

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Oligocene-Miocene tectonics of the SW Alps and western Apennines coupled orogenic belts, as recorded by their internal and external syn-orogenic basins

10.5194/egusphere-egu2020-17862 ◽

2020 ◽

Author(s):

Luca Barale ◽

Piana Fabrizio ◽

Bertok Carlo ◽

d'Atri Anna ◽

Irace Andrea ◽

...

Keyword(s):

Regional Scale ◽

Foreland Basin ◽

Mediterranean Area ◽

Western Alps ◽

Western Mediterranean ◽

Northern Apennines ◽

Kinematic Evolution ◽

Ligurian Alps ◽

Internal Side ◽

Miocene Tectonics

The Oligocene-Miocene evolution of the westernmost part of the Northern Apennines was constrained firstly by Oligocene E-W regional sinistral shearing and then by Early Miocene shortening and Middle to Late Miocene NW-SE dextral transpression affecting the southern termination of the Western Alps arc (Maritime and Ligurian Alps) and the substrate of the Tertiary Piemonte Basin (TPB), which started to be incorporated, in the same time span, in the Northern Apennines beltIn other words, the dynamics accommodating the different motion of the WNW-directed Adria and SW Alps with respect to the ENE-directed Ligurian-Corso-Sardinian block also controlled the evolution of TPB and its Ligurian substrate since at least the Aquitanian, when a regional conterclockwise rotation began and a deep reshaping of the basin occurred, due to predominant NE-SW shortening concomitant with the Northern Apennines thrust fronts propagation (Burdigalian). On the other side, the infilling of the SW Alps foreland basin was partially controlled also by the resedimentation of non-metamorphic Cretaceous-Paleocene Ligurian units previously deposited along the Brian&#231;onnais-Dauphinois continental margin. The subsequent Late Burdigalian to Serravallian extension in the internal side of the SW Alps allowed the creation of accomodation space and the deposition of relevant thickness of sediments in the TPB, during the coeval progressive uplifting of Alpine crystalline and metamorphic units (e.g. the Argentera Massif and Dora-Maira Unit). This Alpine process constrained the shape and evolution of the TPB syn-orogenic sub-basins and their subsequent tectonic paths within the NW Apennines belt, while it was being built. The steps of this Alps-Apennines evolution have been clearly recorded by a set of regional scale, Oligocene to Pleistocene unconformities that can be continuously traced at surface in the southern part of the Piemonte region and in the subsurface of the western Po plain.We thus remark that the evolution of the westernmost part of the Apennines can be studied largely referring to the Alpine geodynamics, since, although the Alps and the Apennines are two distinct geomorphologic and geophysical entities at the scale of the Western Mediterranean area, they share common synorogenic basins and consistent kinematic evolution in their junction zone of NW Italy.

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Magnetostratigraphic dating of the Paleogene synorogenic sediments of the NE sector of the Ebro Foreland Basin (Spanish Pyrenees)

10.5194/egusphere-egu21-14714 ◽

2021 ◽

Author(s):

Charlotte Peigney ◽

Elisabet Beamud ◽

Òscar Gratacós ◽

Eduard Roca ◽

Alberto Sáez ◽

...

Keyword(s):

Regional Scale ◽

Foreland Basin ◽

Late Eocene ◽

Tectonic Activity ◽

Orbital Eccentricity ◽

The South ◽

Drainage Pattern ◽

Ebro Basin ◽

Alluvial Deposits ◽

Thrust Sheets

In foreland settings at the front of active orogens, the aggradation/progradation of fluvial fans and sedimentary changes in lacustrine systems depends greatly on the tectonic activity and the derived drainage pattern changes in the hinterland. As a result of the emplacement and erosion of the South-Pyrenean thrust sheets, a system of N-S fluvial fans prograded into the Ebro foreland basin from late Eocene to Oligocene times. After the synorogenic deposition of the Priabonian (late Eocene) marine evaporites of the Cardona Fm, the Ebro Basin was characterized by internal drainage, with the fluvial fans grading to lacustrine systems at the center of the basin, which developed and migrated in response to subsidence changes. All these deposits were deformed by variably oriented salt-detached folds, evidencing the basinwards propagation of the deformation. In this work, we study the Solsona-Sana&#252;ja fluvial fan system by means of litostratigraphy and magnetostratigraphy aiming to determine the age of the transition from fluvial fan to lacustrine systems in the NE sector of the Ebro Basin. The precise dating of this succession reveals causal relationships between tectonic and climatic processes affecting the source-to-sink system, including changes in the depositional style linked to the evolution of the Pyrenean fold and thrust belt.Our new magnetostratigraphic study consisted in the sampling and analysis of 195 samples along a ca. 1800m thick stratigraphic section of the late Eocene-Oligocene succession in the northern limb of the NW-SE oriented Sana&#252;ja Anticline. Our results show overall Priabonian to Rupelian ages for the succession, considering an age of 36 Ma. (C16n) for the top of the Cardona Fm from previous magnetostratigraphic studies. This allows dating the end of the evaporitic sedimentation (top of the Barbastro Fm) as Priabonian and establishing a late Priabonian to early Rupelian (C13r) age for the transition from the younger lacustrine deposits (Tor&#224; Fm) to the continuous and most important fluvial fan episode of progradation in the study area. The final progradation of the fluvial fan system was coeval to a tectonically controlled reorganization of the drainage pattern of the basin responding to the emplacement of the South-Pyrenean thrust sheets. Meanwhile, smaller scale (hectometric-decametric) alternation between lacustrine and alluvial deposits was possibly driven by climatic changes related to orbital eccentricity cycles. The correlation and integration of these results with previous magnetostratigraphic studies in the area can help analyzing sedimentation patterns and architectural changes in the basin margins at a regional scale.

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Structural and Economic Analysis of Meyal Oil Field in the Northern Potwar Deformed Zone, Upper Indus Basin, Pakistan

International Journal of Economic and Environmental Geology ◽

10.46660/ijeeg.vol11.iss4.2020.521 ◽

2021 ◽

Vol 11 (4) ◽

pp. 65-71

Author(s):

Muhammad Armaghan Faisal Miraj ◽

Muhammad Yaseen ◽

Abid Ali ◽

Rana Faizan Saleem ◽

Sher Afgan ◽

...

Keyword(s):

Foreland Basin ◽

Oil Field ◽

Hydrocarbon Exploration ◽

Indus Basin ◽

Thickness Variation ◽

Borehole Data ◽

Subsurface Structures ◽

Structural Style ◽

Exploratory Wells ◽

Meyal Oil Field

Potwar sub-basin is famous for its structural style, hydrocarbon exploration and production activities from Cambrian to Pliocene rocks. Foreland basin related subsurface structures, in the presence of source and seal rocks offer a variety of traps to host hydrocarbons. Meyal Oil field, situated in the NW Potwar sub-basin, is a hydrocarbon resource for the country. Subsurface structures of Meyal area were outlined by interpreting two strike and four dip lines in IHS Kingdom suite. Borehole data of MYL-10, MYL-12 and MYL-13 exploratory wells were incorporated to improve the subsurface understanding. A total five prominent reflectors of Permian, Triassic, Jurassic, Paleocene and Eocene rocks were marked on the seismic sections. The seismic interpretation shows a post Eocene pop-up structure flanked by a back thrust and a fore thrust. Moreover, the time structure maps for Meyal area display a doubly plunging and faulted anticline as a result of south directed compression. Four isochron maps show thickness variation in Permian to Eocene sediments in the study area. The results of interpretation show favorable structural trap for economic hydrocarbon exploration.

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Regional-scale paleofluid system across the Tuscan Nappe–Umbria–Marche Apennine Ridge (northern Apennines) as revealed by mesostructural and isotopic analyses of stylolite–vein networks

Solid Earth ◽

10.5194/se-11-1617-2020 ◽

2020 ◽

Vol 11 (4) ◽

pp. 1617-1641 ◽

Cited By ~ 1

Author(s):

Nicolas E. Beaudoin ◽

Aurélie Labeur ◽

Olivier Lacombe ◽

Daniel Koehn ◽

Andrea Billi ◽

...

Keyword(s):

Late Stage ◽

Regional Scale ◽

Northern Apennines ◽

Burial Depth ◽

Calcite Vein ◽

Structural Style ◽

Fluid Systems ◽

Isotopic Analyses ◽

Isotopic Characterization ◽

The Difference

Abstract. We report the results of a multiproxy study that combines structural analysis of a fracture–stylolite network and isotopic characterization of calcite vein cements and/or fault coating. Together with new paleopiezometric and radiometric constraints on burial evolution and deformation timing, these results provide a first-order picture of the regional fluid systems and pathways that were present during the main stages of contraction in the Tuscan Nappe and Umbria–Marche Apennine Ridge (northern Apennines). We reconstruct four steps of deformation at the scale of the belt: burial-related stylolitization, Apenninic-related layer-parallel shortening with a contraction trending NE–SW, local extension related to folding, and late-stage fold tightening under a contraction still striking NE–SW. We combine the paleopiezometric inversion of the roughness of sedimentary stylolites – that constrains the range of burial depth of strata prior to layer-parallel shortening – with burial models and U–Pb absolute dating of fault coatings in order to determine the timing of development of mesostructures. In the western part of the ridge, layer-parallel shortening started in Langhian time (∼15 Ma), and then folding started at Tortonian time (∼8 Ma); late-stage fold tightening started by the early Pliocene (∼5 Ma) and likely lasted until recent/modern extension occurred (∼3 Ma onward). The textural and geochemical (δ18O, δ13C, Δ47CO2 and 87Sr∕86Sr) study of calcite vein cements and fault coatings reveals that most of the fluids involved in the belt during deformation either are local or flowed laterally from the same reservoir. However, the western edge of the ridge recorded pulses of eastward migration of hydrothermal fluids (>140 ∘C), driven by the tectonic contraction and by the difference in structural style of the subsurface between the eastern Tuscan Nappe and the Umbria–Marche Apennine Ridge.

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On the syn-orogenic basins of the Alps-Apennines tectonic system in NW Italy

10.5194/egusphere-egu21-14220 ◽

2021 ◽

Author(s):

Fabrizio Piana ◽

Anna d'Atri ◽

Andrea Irace

Keyword(s):

Tectonic Evolution ◽

Middle Eocene ◽

Regional Scale ◽

Foreland Basin ◽

Mediterranean Area ◽

Western Alps ◽

Western Mediterranean ◽

Late Oligocene ◽

The Alps ◽

Nw Italy

The Alps and the westernmost part of Apennines physically join in NW Italy (Piemonte), where the Apennine thrusts interfered, since Late Oligocene, with both the inner boundary faults of the uplifting Alps axial belt and the outer fronts of the Alpine antithetic retrobelt (the Southern Alps). As the two orogenic belts had been intergrowing since the late Oligocene, coeval syn-orogenic basins developed on both, either as separate depocenters or, more frequently, to form a continuous sedimentary domain, strongly controlled by the tectonic evolution of the Alps-Apennines orogenic system.&#160; These syn-orogenic basins both recorded the main stages of the Alps (neoAlpine events) and Apennines tectonic evolution, whose evidence (mostly represented by regional-scale unconformities) can be correlated within each basin and across them. Correlations (in terms of sharing common geologic events) can be found also with the middle Eocene to lower Oligocene basal part of the Alpine foreland basin succession, which extended continuously on the external side of the Western Alps. This contribution will briefly discuss this complex matter in an integrated Alpine-Apennines perspective and in the frame of the post-Eocene evolution of the Western Mediterranean area.

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Mass-transport deposits and the onset of wedge-top basin development: An example from the Dinaric Foreland Basin, Croatia

Journal of Sedimentary Research ◽

10.2110/jsr.2019.192 ◽

2020 ◽

Vol 90 (11) ◽

pp. 1527-1548

Author(s):

Katarina Gobo ◽

Ervin Mrinjek ◽

Vlasta Ćosović

Keyword(s):

Mass Transport ◽

Sea Level ◽

Regional Scale ◽

Foreland Basin ◽

Combined Effect ◽

Tectonic Activity ◽

Relative Sea Level ◽

Basin Development ◽

Blind Thrust ◽

Mass Transport Deposits

ABSTRACT Mass-transport deposits (MTDs) represent resedimentation phenomena triggered by the combined effect of seismic shocks of regional scale, structural tilting, basin-floor gradient, relative sea-level fluctuations, and/or excess pore-water pressure and can be useful in the reconstruction of basin development dynamics. The present study from the Dinaric Foreland Basin in Croatia documents several limestone blocks (olistoliths), carbonate debris, and associated bipartite carbonate megabeds as MTDs of exotic origin encased in deep neritic hyperpycnites, referred to as host deposits. Detailed facies and micropaleontological analyses indicate that host deposits were sourced from a fluvio-deltaic system located in the proximity of the uplifting orogen, while the MTDs originated from gravitational collapses of late Ypresian and early Lutetian limestones that were uplifted on blind-thrust anticline ridges on the opposite side of the basin. Mass wasting-produced carbonate blocks, debris, and gravity flows were probably triggered concurrently during the middle to late Eocene, but the blocks could have travelled faster downslope due to the lubricating effect of the underlying water “cushion,” overpressured mud, and the pull of gravity. Debrisflows and co-genetic turbidity currents that contributed to the formation of bipartite megabeds were likely mobilized deeper and moved slower than the carbonate blocks and could have been partly deflected by the previously emplaced olistoliths, resulting in megabed thinning along the olistoliths' down-dip edges. Those collapses were most likely triggered by the combined effect of relative sea-level changes associated with tectonic activity and seismic shocks of regional scale. The study suggests that progressive uplift of the frontal blind-thrust anticline ridge resulted in episodic emergence and collapses of progressively older limestone units, and marked the onset of development of the wedge-top basin. Conceptual models of olistolith emplacement and onset of basin development are suggested and may be applicable to both ancient and recent settings. The insights obtained from the integration of detailed facies analysis and micropaleontology may be useful in similar areas where such a level of detail cannot be obtained by conventional field methods.

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Regional geology and tectonic framework of the Southern Indian domain, Trans-Hudson Orogen, Manitoba

Canadian Journal of Earth Sciences ◽

10.1139/cjes-2020-0142 ◽

2021 ◽

Author(s):

Tania Martins ◽

Nicole Rayner ◽

David Corrigan ◽

Paul Kremer

Keyword(s):

Regional Scale ◽

Foreland Basin ◽

Geological Mapping ◽

Metasedimentary Rocks ◽

Mafic Intrusions ◽

Plume Magmatism ◽

Tectonic Framework ◽

Lynn Lake ◽

Clastic Sedimentary ◽

Polymictic Conglomerate

The collaborative federal-provincial Southern Indian Lake project in north-central Manitoba covered an area of more than 3500 km2 of the Trans-Hudson orogen. Regional-scale geological mapping, sampling, and lithogeochemical, isotopic and geochronological studies resulted in the identification of distinct assemblages of supracrustal rocks and varied episodes of plutonism. A granodiorite gneiss dated at ca. 2520 Ma is interpreted to represent the basement of the Southern Indian domain and is considered a separate crustal domain, named the Partridge Breast block. The Churchill River assemblage is composed of juvenile pillow basalt with intervening clastic sedimentary rocks, possibly a reflection of plume magmatism related to initial rifting of the Hearne craton margin. The Pukatawakan Bay assemblage consists mainly of massive to pillowed, juvenile metabasaltic rocks and associated basinal metasedimentary rocks. The Partridge Breast Lake assemblage is dominated by continental-arc volcanic and volcaniclastic rocks associated with basinal metasedimentary rocks. The Strawberry Island assemblage, consisting of arenite and polymictic conglomerate, is interpreted to have been deposited in a foreland-basin basin or intra-orogen pull-apart basin environment. The Whyme Bay assemblage is characterized by fluvial-alluvial orogenic sediments and is temporally linked to the Sickle Group rocks in the Lynn Lake greenstone belt. Granitoid rocks, dominantly monzogranite and granodiorite, range in age from ca. 1890 to 1830 Ma and occur throughout the Southern Indian domain, and intermediate and mafic intrusions of similar ages are also present. In this paper we integrate these new data into a tectonic framework for the Southern Indian domain of the Trans-Hudson orogen in Manitoba.

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