Basement-decoupled hyperextension rifting: The tectono-stratigraphic record of the salt-rich Pyrenean necking zone (Arzacq Basin, SW France)

2021 ◽  
Author(s):  
M. Ducoux ◽  
E. Masini ◽  
J. Tugend ◽  
J. Gómez-Romeu ◽  
S. Calassou
Keyword(s):  
Rift System ◽  
Rifted Margins ◽  
Salt Layer ◽  
Stratigraphic Architecture ◽  
Stratigraphic Record ◽  
Half Graben ◽  
Southern Side ◽  
Well Data ◽  
Stratigraphic Evolution ◽  
Sw France

Half grabens and supra-detachment basins correspond to end-member basin types of magma-poor rift settings, each of them showing a characteristic stratigraphic architecture. The occurrence of a basement-cover décollement has been shown to drastically change the stratigraphic architecture of half graben basins, however, the effect of such basement-cover décollement remains to be documented in supra-detachment basins formed during hyper-extension. We investigate the tectono-stratigraphic record of the Arzacq Basin (SW France) recording the formation of a salt-rich Cretaceous hyperextended rift system. Combining 2-D and 3-D seismic reflection calibrated from well data, we show that this basin is an asymmetric syn-rift extensional syncline growing above a pre-kinematic salt layer. By mapping the sub-salt basement, we show that the formation of this syncline is controlled by the South-Arzacq Fault (SAF), soling in the sub-salt basement. Based on crosscutting relationships and the observed southward migration of syn-rift depocenters, this N110°-striking, 20°-dipping structure accommodates >10 km of thick-skinned extension. The overlying supra-salt cover coherently glided, following the basement geometry. The 3-D segmentation of the SAF and the sub-salt stratigraphic architecture of the Arzacq Basin suggest a roughly dip-slip kinematic. A post-kinematic kilometer-scale uplift is documented on the southern side of the Arzacq Basin. It may result from the increasing lithospheric thinning and thermal support at the end of asymmetric hyperextension. As salt commonly occurs in extensional settings, we believe that our description of the tectono-stratigraphic record of a basement-decoupled supra-detachment basin has global applicability to unleash the tectono-stratigraphic evolution of worldwide hyper-extended rifted margins.

The architecture and the multi-stage evolution of the North Iberian margin (Bay of Biscay)

2020 ◽  
Author(s):  
Patricia Cadenas ◽  
Gianreto Manatschal ◽  
Gabriela Fernández-Viejo
Keyword(s):  
Rift System ◽  
Plate Boundaries ◽  
Bay Of Biscay ◽  
Velocity Models ◽  
The North ◽  
Rifted Margins ◽  
Multi Stage ◽  
Stratigraphic Architecture ◽  
Half Graben ◽  
Iberian Margin

<p>In this work, we address the problem of the formation and reactivation of multi-stage rifting based on the study of the central North Iberian margin, located at the southern Bay of Biscay triangular oceanic domain. This magma-poor rifted margin registered three major Mesozoic rift events and a subsequent Alpine compressional reactivation, representing a unique setting to study the architecture of a multi-stage rift system and its control on subsequent reactivation. Based on a dense dataset of high quality 2D seismic reflection profiles, boreholes and published velocity models, we define, describe and map structural domains, major extensional and compressional structures, and the depth and thickness of syn-rift units. We provide new structural maps showing the geometry and spatial distribution of major rift basins and bounding structures.</p><p>The analysis of the tectono-stratigraphic architecture led us to define three rift systems. A diffuse and widespread of Triassic age, with classical fault-bounded half-graben basins, a second, narrow, deep and localised Late Jurassic to Barremian transtensional system, and a third, widely distributed Aptian to Cenomanian hyperextended system, including two distinctive domains. Our results show that each rift system controlled successive rift events, and that the stacking and overlap of the three rift systems resulted in a complex and segmented 3D template that guided subsequent compressional reactivation. Compression affected on a distinctive way the three rift systems, leading to an amplification of the margin segmentation.</p><p>This work shows that unravelling the tectono-stratigraphic architecture and evolution of multi-stage rift systems can provide key insights not only to decipher the spatial and temporal evolution of divergent plate boundaries, but also to set up present-day kinematic templates to test dynamic plate deformable models of conjugate rifted margins. It will also be a keystone to constrain early stages of margin reactivation and the architecture of reactivated rifted margins now incorporated in orogenic systems.</p>

scholarly journals Stratigraphic revision and reconstruction of the deep-sea fan of the Voirons Flysch (Voirons Nappe, Chablais Prealps)

2021 ◽  
Vol 114 (1) ◽  
Author(s):  
Jérémy Ragusa ◽  
Lina Maria Ospina-Ostios ◽  
Pascal Kindler ◽  
Mario Sartori
Keyword(s):  
Deep Sea ◽  
Distal Part ◽  
Accretionary Prism ◽  
Proximal Part ◽  
Late Eocene ◽  
Lithostratigraphic Units ◽  
Stratigraphic Record ◽  
Sea Fan ◽  
Stratigraphic Evolution ◽  
Depositional Setting

AbstractThe Voirons Flysch (Caron in Eclogae Geologicae Helvetiae 69:297–308, 1976), is a flysch sequence aggregated into the sedimentary accretionary prism of the Chablais and Swiss Prealps. Its palaeogeographic location is still debated (South Piemont or Valais realm). We herein present a stratigraphic revision of the westernmost unit of the former Gurnigel Nappe sensu Caron (Eclogae Geologicae Helvetiae 69:297–308, 1976): the Voirons Flysch. This flysch is subdivided into three lithostratigraphic units at the formation level (the Voirons Sandstone, the Vouan Conglomerate, the Boëge Marl), with an additional unit (Bruant Sandstone) of uncertain attribution, ranging from the early Eocene to probably the late Eocene. We further propose a new model of the depositional setting of the deep-sea of the Voirons Flysch based on palaeocurrent directions, the overall geometry and sedimentary features. This model depicts an eastward deflected deep-sea fan. The stratigraphic record of the proximal part of this fan is fairly complete in the Voirons area, whereas its most distal part is only represented by one small exposure of thinly bedded sandstones in the Fenalet quarry. The stratigraphic evolution of the Voirons Flysch shows two major disruptions of the detrital sedimentation at the transition between Voirons Sandstone—Vouan Conglomerate and Vouan Conglomerate—Boëge Marl. The cause of these disturbances has to be constrained in the framework of the palaeogeographic location of the Voirons Flysch.

Synrift evaporite deposition and structural characterization of the onshore Alagoas subbasin

2019 ◽  
Vol 7 (4) ◽  
pp. SH19-SH31
Author(s):  
Gabriela Salomão Martins ◽  
Webster Ueipass Mohriak ◽  
Nivaldo Destro
Keyword(s):  
Structural Characterization ◽  
Oil And Gas ◽  
Hanging Wall ◽  
Structural Evolution ◽  
Gas Production ◽  
North East ◽  
The North ◽  
Half Graben ◽  
Well Data

The Sergipe-Alagoas Basin, situated in the north-east Brazilian margin, has a long tradition of oil and gas production and the presence and distribution of evaporites play an important role in petroleum systems in the basin. However, little research has focused on the structural evolution of the older, synrift evaporitic sections of the basin. We have focused explicitly in the detailed subsurface structural characterization of the rift in the Alagoas subbasin and the distribution of the Early Aptian evaporites. To accomplish this objective, we interpreted selected 2D and 3D seismic and well data located in two areas known as the Varela Low (VL) and Fazenda Guindaste Low (FGL). We identified diverse deformation styles in those two basin depocenters. Our interpretation indicates that VL consists of a half-graben with a significant rollover structure, controlled by two listric northeast–southwest border faults. The deformation in the hanging wall is also accommodated by release faults and minor antithetic faults. In this depocenter, we mapped in the seismic and the well data an older evaporitic sequence within the Coqueiro Seco Fm., known as Horizonte Salt. This evaporitic section occurs in the internal part of the VL half graben, where it is limited by release and antithetic faults. Significant salt strata growing toward the antithetic fault is observed. Whereas, the FGL represents a graben elongated along the north-east direction and is controlled by several types of structures. We recognized normal synthetic and antithetic faults, transfer zones, release faults, and rollover anticlines in the seismic throughout this depocenter. We mapped an evaporitic section within the Maceió Fm., known as Paripueira Salt, which consists of disconnected salt bodies, restricted to the hanging walls of synrift faults.

scholarly journals Geology of the Epicentral Area of the November 23, 1980 Earthquake (Irpinia, Italy): New Stratigraphical, Structural and Petrological Constrains

Geosciences ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 247 ◽  
Author(s):  
Fabio Matano ◽  
Silvio Di Nocera ◽  
Sara Criniti ◽  
Salvatore Critelli
Keyword(s):  
Tectonic Evolution ◽  
Foreland Basin ◽  
Structural Data ◽  
Southern Apennines ◽  
Structural Mapping ◽  
Epicentral Area ◽  
Kinematic Evolution ◽  
Stratigraphic Architecture ◽  
Stratigraphic Evolution ◽  
Basin System

The geology of the epicentral area of the 1980 earthquake (Irpinia-Lucania, Italy) is described with new stratigraphic, petrographic and structural data. Subsurface geological data have been collected during the studies for the excavation works of the Pavoncelli bis hydraulic tunnel, developing between Caposele and Conza della Campania in an area that was highly damaged during 1980 earthquake. Our approach includes geological, stratigraphic, structural studies, and petrological analyses of rock samples collected along the tunnel profile and in outcropping sections. Stratigraphic studies and detailed geological and structural mapping were carried out in about 200 km2 wide area. The main units cropping out have been studied and correlated in order to document the effects of tectonic changes during the orogenic evolution on the foreland basin systems and the sandstone detrital modes in this sector of the southern Apennines. The multi-disciplinary and updated datasets have allowed getting new insights on the tectono-stratigraphic evolution and stratigraphic architecture of the southern Apennines foreland basin system and on the structural and stratigraphic relations of Apennines tectonic units and timing of their kinematic evolution. They also allowed to better understand the relationships between internal and external basin units within the Apennine thrust belt and its tectonic evolution.

Structural interpretation of the Rukwa Rift, Tanzania

Geophysics ◽  
1988 ◽  
Vol 53 (6) ◽  
pp. 824-836 ◽  
Author(s):  
John W. Peirce ◽  
Lev Lipkov
Keyword(s):  
Gravity Data ◽  
Normal Fault ◽  
Gravity Models ◽  
Fault System ◽  
Rift System ◽  
Assistance Program ◽  
Density Control ◽  
Half Graben ◽  
Alluvial Material ◽  
Petroleum Development

The Rukwa Rift lies between Lakes Tanganyika and Malawi in the western limb of the East Africa rift system. Because little was known about the rift's structure or hydrocarbon potential, Petro‐Canada International Assistance Corporation completed a 2150 station gravity survey as part of an assistance program for the Tanzanian Petroleum Development Corporation. The survey covered an area 165 km × 375 km, which included the entire rift valley and lake plus regional control on either side. Outcrops of Carboniferous‐Triassic conglomerate, coal, and limestone, as well as Cretaceous sandstone, occur along the southwestern edge of the rift. The younger section is presumed to be dominated by alluvial material. In the absence of any density control, the gravity data were modeled using clastic sedimentary fill, which yields minimum depth estimates. Alternate models with more shale in the section have also been tried. A rift model with two shale pulses corresponding to interrift times yielded maximum depths of about 10 km. An all‐shale model failed to converge because of insufficient mass contrast. The final interpretation was based on the gravity models and aeromagnetic data acquired in an earlier survey. The Rukwa Rift is a half‐graben bounded to the northeast by a listric normal fault (strike 130 degrees) with 7 km of throw. A younger fault system forms the southwestern side of the valley and creates a major structure with 3 km of relief. The divergent strike of the younger faulting appears to be related in some way to right lateral shear in the Rukwa region. The Rukwa Rift has all the elements needed to be considered highly prospective for oil from a lacustrine source. There is strong evidence to suggest that the history of the Rukwa Rift is long and complex, providing ample opportunity for establishment of such an environment. The analogy of the Sudan rifts and the reports of oil seeps elsewhere in the western rift system support such a hypothesis. All the other elements of structure, reservoir, seal, maturation, and timing can be reasonably inferred from the available information. Of course, seismic and drilling are needed to provide firm stratigraphic control to confirm these inferences.

Løvehovden fault and Billefjorden rift basin segmentation and development, Spitsbergen, Norway

2010 ◽  
Vol 148 (1) ◽  
pp. 154-170 ◽  
Author(s):  
H. D. MAHER ◽  
A. BRAATHEN
Keyword(s):  
Normal Fault ◽  
Shear Zones ◽  
Rift Basin ◽  
The North ◽  
Structural Style ◽  
Stratigraphic Architecture ◽  
Movement Component ◽  
Half Graben ◽  
Northern Portion ◽  
Local Relief

AbstractThe Carboniferous Billefjorden rift basin is a well-known example of a suite of Carboniferous basins on the Barents Shelf and NE Greenland. The basin has a clastic, carbonate and evaporite fill with complex and disputed stratigraphic relationships, especially regarding the Ebbadalen and Minkinfjellet formations. Geometrically, the basin is considered a simple half-graben. A N–S-trending fault and monocline structure within the northern portion of the basin, the Løvehovden fault, has lithological and thickness differences across it within the Minkinfjellet and possibly Ebbadalen formations. The fault shows W-side-down movement, defining a sub-basin within the larger half-graben. Significant along-strike changes occur. Down-throw to the west is at least 150 metres and possibly 400 metres, as shown by across-fault thickness differences of Ebbadalen and/or Minkinfjellet formations. To the east of the fault, the contact between the Ebbadalen and Minkinfjellet formations is a disconformity with significant local relief, and is interpreted to represent exposure from footwall uplift, and associated near- or at-surface solution, producing basal stratiform breccias. A similar contact is not exposed west of the fault. Monoclinal deformation and thickening of the younger Wordiekammen Formation above and across the monocline constrain a later movement component. Kinematic data and the structural style clearly indicate the Løvehovden fault is a normal fault with associated tri-shear zone development, consistent with the regional Carboniferous rift setting. Earlier interpretations describe the Løvehovden fault and monocline as Tertiary contractional features. In contrast, our work advocates that they are an important architectural basin element, defining a sub-basin within the Billeforden Trough during Minkinfjellet Formation deposition, with insignificant, if any, Tertiary reactivation. The Løvehovden fault is aligned with and represents the southern termination of the Lemströmfjellet fault to the north. Thus, the Billefjorden basin changes from a narrow graben to a broader half-graben to the south. These along-strike changes have important implications for the stratigraphic architecture of the basin, and for palaeogeographic reconstructions. These results and application of 3-D models for extension related tri-shear zones may help inform interpretation of other Carboniferous basins on the Barents Shelf.

The Messinian succession of the Crotone Basin (southern Italy) I: Stratigraphic architecture reconstructed by seismic and well data

2013 ◽  
Vol 48 ◽  
pp. 455-473 ◽  
Author(s):  
Massimo Zecchin ◽  
Dario Civile ◽  
Mauro Caffau ◽  
Francesco Muto ◽  
Agata Di Stefano ◽  
...  
Keyword(s):  
Southern Italy ◽  
Stratigraphic Architecture ◽  
Well Data
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