Basement inheritance affecting initiation and evolution of intracontinental rifts: Araripe Basin, northeast Brazil

2020 ◽  
Author(s):  
Pamela Richetti ◽  
Renata da Silva Schmitt ◽  
Bruno César Araújo ◽  
Maria Filipa da Gama ◽  
Marta Teixeira da Costa Soares
Keyword(s):  
Seismic Data ◽  
Shear Zones ◽  
Integrated Analysis ◽  
Rift System ◽  
Duplex System ◽  
Fault Systems ◽  
The North ◽  
Tectonic Events ◽  
Borborema Province ◽  
Formation And Evolution

<p>The structural inheritance of the basement plays an important role controlling rift formation and evolution. Here we investigate tectonic and rheological inheritance on brittle reactivation of the Precambrian basement and shear zones in the formation and evolution of the Cretaceous Araripe Basin. The basin is a part of the Northeast Brazilian Rift System, associated with the junction of the Southern and Equatorial branches of the Atlantic Rift. Its basement is part of Neoproterozoic Transversal Zone (Borborema Province), a crustal scale transpressional duplex system, related to the Brasiliano escape tectonic events. </p><p>We present here a synthesis of field observations from the Araripe Basin and its adjacent basement, combined with topographic, aeromagnetic and seismic data to propose a general overview on the tectonic framework and evaluate how it influenced the basin initiation and evolution. Our integrated analysis shows that there are three main structural trends for the basin and its surroundings: NE-SW, E-W and NW-SE. The NE-SW and E-W trends are the most expressive sets of lineaments in the topographic and aeromagnetic data, directly related to the basement framework. Integration of seismic data and filtered aeromagnetic maps confirms that NE-SW and E-W trends represent oblique fault systems.</p><p>Archean, Paleoproterozoic, Mesoproterozoic and Neoproterozoic terranes are arranged side by side in NE-SW mega sigmoid, bounded by the E-W Pernambuco (to the south) and Patos (to the north) dextral shear zones. The Araripe basin units are distributed mostly in two sub-basins, Cariri and Feira Nova, separated by a structural high, controlled by NE-SW and ESE-WNW faults. Analyzing these terranes and their link to the distribution of the depocenters and structures, we find that the NE trending Archean terrane coincides partially with the Feira Nova NE-SW single graben. On the eastern portion of the basin, the graben system is much wider and controlled by NE-SW and ESE-WNW trending fault systems. This wide graben overlies a Neoproterozoic basement terrane constituted by a supracrustal unit (Cachoeirinha Group) of phyllites, metasandstones, metavolcanics with low to medium metamorphic grade.</p><p>This evidence corroborates with the hypothesis that the rheology of the upper crust might be partially influenced by distinct lithotectonic terranes. The older Archean block sustained the narrow sub-basin, indicating a more localizing behavior, while the younger Neoproterozoic terrane, controlled a less localizing graben system with a wider sub-basin in the eastern Araripe basin.</p><p> </p><p>The authors gratefully acknowledge support from Shell Brasil Petroleo Ltda. and the strategic importance of the support given by ANP (Brazil’s National Oil, Natural Gas and Biofuels Agency) through the R&D levy regulation (Technical Cooperation #20.219-2).</p>

scholarly journals Decratonization by rifting enables orogenic reworking and transcurrent dispersal of old terranes in NE Brazil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Carlos E. Ganade ◽  
Roberto F. Weinberg ◽  
Fabricio A. Caxito ◽  
Leonardo B. L. Lopes ◽  
Lucas R. Tesser ◽  
...  
Keyword(s):  
Shear Zones ◽  
Boundary Region ◽  
The North ◽  
Pan African ◽  
Juvenile Material ◽  
Oceanic Basin ◽  
Borborema Province ◽  
Isotopic Model ◽  
Late Neoproterozoic

AbstractDispersion and deformation of cratonic fragments within orogens require weakening of the craton margins in a process of decratonization. The orogenic Borborema Province, in NE Brazil, is one of several Brasiliano/Pan-African late Neoproterozoic orogens that led to the amalgamation of Gondwana. A common feature of these orogens is that a period of extension and opening of narrow oceans preceded inversion and collision. For the case of the Borborema Province, the São Francisco Craton was pulled away from its other half, the Benino-Nigerian Shield, during an intermittent extension event between 1.0–0.92 and 0.9–0.82 Ga. This was followed by inversion of an embryonic and confined oceanic basin at ca. 0.60 Ga and transpressional orogeny from ca. 0.59 Ga onwards. Here we investigate the boundary region between the north São Francisco Craton and the Borborema Province and demonstrate how cratonic blocks became physically involved in the orogeny. We combine these results with a wide compilation of U–Pb and Nd-isotopic model ages to show that the Borborema Province consists of up to 65% of strongly sheared ancient rocks affiliated with the São Francisco/Benino-Nigerian Craton, separated by major transcurrent shear zones, with only ≈ 15% addition of juvenile material during the Neoproterozoic orogeny. This evolution is repeated across a number of Brasiliano/Pan-African orogens, with significant local variations, and indicate that extension weakened cratonic regions in a process of decratonization that prepared them for involvement in the orogenies, that led to the amalgamation of Gondwana.

The North Evia Gulf rift system in Central Greece: structural development and crustal inheritances from onshore fault analysis and offshore Sparker seismic data (WATER project)

2021 ◽  
Author(s):  
Frank Chanier ◽  
Fabien Caroir ◽  
Virginie Gaullier ◽  
Julien Bailleul ◽  
Agnès Maillard ◽  
...  
Keyword(s):  
Seismic Data ◽  
Tectonic Setting ◽  
Fault Analysis ◽  
North Anatolian Fault ◽  
Fault System ◽  
Rift System ◽  
Marmara Sea ◽  
Structural Development ◽  
Initial Development ◽  
The North

<p>The Sperchios - North Evia Gulf rift system is WNW-ESE directed and participates to the widespread crustal extension induced by the respectively southward and south-westward Nubian and Ionian slabs retreat, and by the extrusion of the Anatolia-Aegean microplate. This crustal stretching, active at least since the early Pliocene, is partly coeval with the North Anatolian Fault (NAF) propagation through the Marmara Sea and the North Aegean domain. At the western termination of the NAF, in the studied area, the domain is widely heterogeneous as it has been previously deformed by successive tectonic events during Hellenic orogeny, from Middle Jurassic to Paleogene times. The low elevation of the Internal Zones in respect to the External Zones of Hellenides suggest that the Frontal Thrust of the Internal Zones, that crosscut the Sperchios Rift, plays a major role in the distribution of rift systems within that area. The Sperchios-North Evia Gulf rift developed over the internal Zones and was driven by at least two major extensional episodes. The first one is characterised by a NNE-SSW extensional direction while the second, still active, is NNW-SSE to N-S. This change in direction can be associated to a modification of the tectonic setting within the Aegean Plate or can be a consequence of clockwise rotation of the whole western Aegean domain.</p><p>The WATER survey (Western Aegean Tectonic Evolution and Reactivations), conducted in July-August 2017 onboard the R/V “Téthys II”, allowed to acquire more than 1300 km of very high resolution seismic reflection profiles (Sparker 50-300 Joules) around North Evia Island (North Evia Gulf, Oreoi Channel and Skopelos Basin). The new dataset issued from this survey illustrates structural patterns that can be correlated with onland fault systems.</p><p>The interpretation of this new seismic data allowed us to precise the main trends of the North Evia Gulf rift deformation. For example, the rift bordering faults show rapid longitudinal changes in terms of offsets and of their main tilting polarity. Our structural analysis results, together with the kinematic analysis of onshore fault zones, give detailed constraints on the rift structural organisation as well as on the relative chronology of tectonic episodes.</p><p>Furthermore, these results provide important data in order to discuss the relations of some major rift structures with other crustal structures inherited from earlier deformation in the Hellenides, and also to consider the deformation patterns in the south-western prolongation of the North Anatolian Fault system during Pliocene to Quaternary times. We discuss the relations between various generations of crustal-scale structures and propose that the variations in the rift asymmetry were triggered, during its initial development, by the presence of older crustal heterogeneities.</p>

scholarly journals Decratonization by Rifting followed by Orogeny and Transcurrent Dispersal of Old Terranes in NE Brazil: A Common Feature of Gondwana Amalgamation?

2020 ◽  
Author(s):  
Carlos Ganade ◽  
Roberto Weinberg ◽  
Fabricio Caxito ◽  
Leonardo Lopes ◽  
Lucas Tesser ◽  
...  
Keyword(s):  
Shear Zones ◽  
Boundary Region ◽  
The North ◽  
Juvenile Material ◽  
Borborema Province ◽  
Isotopic Model ◽  
Late Neoproterozoic

Abstract Dispersion and deformation of cratonic fragments within orogens in the periphery of cratons require weakening of the craton margins in a process of decratonization. The Borborema orogenic province, in NE Brazil, is one of several Brasiliano/Panafrican late Neoproterozoic orogens that led to the amalgamation of Gondwana. A common feature of these orogens is that a period of extension and opening of narrow oceans preceded inversion and collision. For the case of the Borborema Province, the São Francisco Craton was pulled away from its other half, the Benino-Nigerian Shield, during an extension event lasting between 1 Ga and 0.65 Ma. This was followed by inversion and a transpressional orogeny from c. 0.60 Ga onwards. Here we investigate the boundary region between the north São Francisco Craton and the Borborema Province and demonstrate how cratonic blocks became physically involved in the orogeny. We combine these results with a wide compilation of U-Pb and Nd-isotopic model ages to show that the BP consists of up to 65% of strongly sheared ancient rocks affiliated with the Sao Francisco/Benino-Nigerian Craton, separated by major transcurrent shear zones, with only ~ 15 % addition of juvenile material during the orogeny. This evolution is repeated across a number of Brasiliano/Panafrican orogens, with significant local variations, and indicate that extension weakened entire cratonic regions in a process of decratonization that prepared them for involvement in the orogenies that led to the amalgamation of Gondwana.

Multiphase oblique extension on the North West Shelf of Australia

2021 ◽  
Author(s):  
Chris Elders ◽  
Sara Moron
Keyword(s):  
Seismic Data ◽  
Lower Cretaceous ◽  
Passive Margin ◽  
Rift System ◽  
Active Deformation ◽  
North West ◽  
North East ◽  
The North ◽  
Northern Carnarvon Basin ◽  
Carnarvon Basin

<p>The North West Shelf of Australia has experienced numerous rift events during its prolonged evolution that most likely started in the Lower Palaeozoic and continued through to the formation of the present day passive margin in the Lower Cretaceous.  Carboniferous and Permian is associated with rifting of the Lhasa terrane, a phase extension in the Lower and Middle Jurassic associated with the separation of the Argo terrane Upper Jurassic to Lower Cretaceous extension culminated in the separation of Greater India and Australia.  Investigations based on interpretation of extensive, public domain seismic data, combined with numerical mechanical modelling, demonstrate that crustal structure, rheology and structural fabrics inherited from older events exert a significant control on the architecture of younger rifts.</p><p>Defining the older, more deeply buried rift episodes is challenging, but with seismic data that now images deeper structures more effectively, it is clear that NE-SW oriented Carboniferous to Permian aged rift structures control the overall geometry of the margin.  Variations in the timing, distribution and intensity of that rift may account for some of the complexity that governs the Triassic – a failed arm of the rift system might account for the accumulation of thick sequences of fluvio-delatic sediments in an apparent post-rift setting, while active deformation and igneous activity continued elsewhere on the margin.</p><p>A renewed phase of extension began in the latest Triassic in the western part of the Northern Carnarvon Basin, but became progressively younger to the NE.  High-resolution mechanical numerical experiments show that the dual mode of extension that characterises the Northern Carnarvon Basin, where both distributed and localised deformation occurs at the same time, is best explained by necking and boudinage of strong lower crust, inherited form the Permian rift event, proximal to the continental margin, and a subdued extensional strain rate across the distal extended margin.  A very clear and consistent pattern of ENE oriented extension, which interacts obliquely with the older NE-SW oriented Permian aged structures, is apparent across the whole of the Northern Carnarvon Basin and extends north east into the Roebuck and Browse Basins.  This is at odds with the NW-SE oriented extension predicted by the separation of the Argo terrane which occurs at this time.  This may be explained by the detached style of deformation that characterises the Mesozoic interval.  Alternatively, the separation of Greater India may have exerted a stronger influence on the evolution of the margin during the Jurassic than hitherto recognised.</p>

Integrated Analysis of Borehole and Surface Seismic Data to Resolve Seismic Uncertainties in the Gulf Of Suez

2014 ◽  
Author(s):  
Mohamed S El-Hateel ◽  
Parvez Ahmad ◽  
Ahmed Hesham A Ismail ◽  
Islam A M Henaish ◽  
Ahmed Ashraf
Keyword(s):  
Seismic Data ◽  
Integrated Analysis ◽  
Gulf Of Suez
Sign in / Sign up

Export Citation Format

Share Document