Potential sources of Ediacaran strata of Iberia: a review

Pereira, M. Francisco

doi:10.1080/09853111.2014.957505

Cited by 34 publications

(21 citation statements)

References 67 publications

(117 reference statements)

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“…to the dynamics of an arc‐trench system (Eguíluz et al, ; Quesada, ). Most authors agree that Precambrian subduction gave way to a complex continental arc system rimming Gondwana from at least 650 Ma ago, although the isotopic record preserved in detrital grains extracted from younger sedimentary basins suggests an older age for the onset of subduction (~750–650 Ma; Albert, Arenas, Gerdes, Sánchez Martínez, & Marko, ; Pereira, , and references therein). Similar conclusions have been put forward for other sections of the Variscan Orogen of western Europe (Brown et al, ; Chantraine et al, ; D'Lemos et al, ; Linnemann et al, ).…”

Section: Geological Settingmentioning

confidence: 99%

Ediacaran Obduction of a Fore‐Arc Ophiolite in SW Iberia: A Turning Point in the Evolving Geodynamic Setting of Peri‐Gondwana

et al. 2019

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The Calzadilla Ophiolite is an ensemble of mafic and ultramafic rocks that represents the transition between lower crust and upper mantle of a Cadomian (peri-Gondwanan) fore arc. Mapping and structural analysis of the ophiolite demonstrates that it was obducted in latest Ediacaran times, because the Ediacaran-Early Cambrian sedimentary series (Malcocinado Formation) discordantly covers it. The ophiolite and emplacement-related structures are affected by Variscan deformation (Devonian-Carboniferous), which includes SW verging overturned folds (D 1 ) and thrusts (D 2 ), upright folds (D 3 ), extensional faults (D 4 ), and later faults (D 5 ). These phases of deformation are explained in the context of Variscan tectonics as the result of the progressive collision between Gondwana and Laurussia. Qualitative unstraining of Variscan deformation reveals the primary geometry of Ediacaran-Cambrian structures and uncovers the generation of east verging thrusts as responsible for the primary obduction of the Calzadilla Ophiolite. Restoration of planar and linear structures associated with this event indicates an Ediacaran, east directed obduction of the ophiolite, that is, emplacement of the Cadomian fore arc onto inner sections of the northern margin of Gondwana. According to regional data, the obduction separates two extension-dominated stages in the tectonic evolution of the African margin of northern Gondwana preserved in southern Europe. Preobduction extension brought about the onset and widening of fore-arc and back-arc basins in the external part of the continent, while postobduction extension facilitated the formation of extensional migmatitic domes, an oceanward migration of back-arc spreading centers across peri-Gondwana, and the eventual opening of a major basin such as the Rheic Ocean. Citation: Díez Fernández, R., Jiménez-Díaz, A., Arenas, R., Pereira, M. F., & Fernández-Suárez, J. (2019). Ediacaran obduction of a fore-arc ophiolite in SW Iberia: A turning point in the evolving geodynamic setting of peri-Gondwana. Tectonics, 38, 95-119. https://doi.

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Section: Geological Settingmentioning

confidence: 99%

Ediacaran Obduction of a Fore‐Arc Ophiolite in SW Iberia: A Turning Point in the Evolving Geodynamic Setting of Peri‐Gondwana

et al. 2019

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“…Some of the intrusives occurring just north of the Beja-Acebuches Ophiolite are characterized by a boninitic signature (Castro et al, 1996), an imprint that may be related to subduction, similarly to what is proposed for the calc-alkaline volcanism occurring near that region (Toca da Moura-Cabrela basin, Santos et al, 1990;Oliveira et al, 1991;Onézime et al, 2003). The geochemical and isotopic characteristics of some mafic to intermediate (calc-alkaline) intrusives located farther north have been explained as a combination of high heat flow and contamination by pelitic crustal material of a mafic magma chamber formed in the mid-crust (Casquet et al, 2001;Salman, 2002;Tornos et al, 2005), or as the variable combination of mantle-derived and crustal-derived magmas (Romeo et al, 2006;Moita et al, 2009;Pereira et al, 2015). The age of all this earlier magmatic event spans a range between ca.…”

Section: Sw Iberian Allochthon and Autochthonmentioning

confidence: 99%

“…The age of all this earlier magmatic event spans a range between ca. 350-335 Ma (Dallmeyer et al, 1993(Dallmeyer et al, , 1995Casquet et al, 2001;Romeo et al, 2006;Jesus et al, 2007;Pin et al, 2008;Pereira et al, 2009Pereira et al, , 2015Cambeses et al, 2015) and is coeval with volcanism, contributing to Viséan syn-orogenic sedimentary basins Pereira et al, 2012b;Oliveira et al, 2013).…”

Section: Sw Iberian Allochthon and Autochthonmentioning

confidence: 99%

Tectonic evolution of Variscan Iberia: Gondwana–Laurussia collision revisited

Fernández

Arenas

Pereira

et al. 2016

Earth-Science Reviews

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103

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An integrated interpretation of the late Paleozoic structural and geochronological record of the Iberian Massif is presented and discussed under the perspective of a Gondwana-Laurussia collision giving way to the Variscan orogen. Compressional and extensional structures developed during the building of the Variscan orogenic crust of Iberia are linked together into major tectonic events operating at lithosphere scale. A review of the tectonometamorphic and magmatic evolution of the Iberian Massif reveals backs and forths in the overall convergence between Gondwana and Laurussia during the amalgamation of Pangea in late Paleozoic times. Stages dominated by lithosphere compression are characterized by subduction, both oceanic and continental, development of magmatic arcs, (over-and under-) thrusting of continental lithosphere, and folding. Variscan convergence resulted in the eventual transference of a large allochthonous set of peri-Gondwanan terranes, the Iberian Allochthon, onto the Gondwana mainland. The Iberian Allochthon bears the imprint of previous interaction between Gondwana and Laurussia, including their juxtaposition after the closure of the Rheic Ocean in Lower Devonian times. Stages governed by lithosphere extension are featured by the opening of two short-lived oceanic basins that dissected previous Variscan orogenic crust, first in the Lower-Middle Devonian, following the closure of the Rheic Ocean, and then in the early Carboniferous, following the emplacement of the peri-Gondwanan allochthon. An additional, major intra-orogenic extensional event in the early-middle Carboniferous dismembered the Iberian Allochthon into individual thrust stacks separated by extensional faults and domes. Lateral tectonics played an important role through the Variscan orogenesis, especially during the creation of new tectonic blocks separated by intracontinental strike-slip shear zones in the late stages of continental convergence. Units, (6) Upper Allochthonous Units, (7) Beja-Acebuches Ophiolite, and (8) South Portuguese Zone. Gathering of 4, 5, and 6 will be also referred to as Iberian Allochthon (or simply Allochthon). A simple restoration of the cross-section shown in Figure 3 (Fig. 4a) reveals two major suture zones featured with ophiolitic units with different protolith ages. The NNE-dipping suture represented by the Beja-Acebuches Ophiolite (Bard and Moine, 1979; Munhá et al., 1986; Quesada et al., 1994) cuts the suture marked by the Allochthonous Ophiolitic Units (Arenas et al., 1986) and divides the Iberian Massif in two major blocks. The northern block comprises the Cantabrian Zone, and the Iberian Autochthon, Parautochthon and Allochthon, all of which have Gondwanan affinity

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“…Fernández-Suárez et al, 2014 and references therein) and Paleozoic rocks (Gutiérrez-Alonso et al, 2015;Shaw et al, 2014) of the northern part of the CIZ. In contrast, the Neoproterozoic rocks of the southern part provide zircon populations that resemble those of the OMZ with no or minor Tonian-Stenian age zircons (Pereira, 2015;Pereira et al, 2012b).…”

Section: Constraints From the Precambrian Detrital Zirconsmentioning

confidence: 97%

U–Pb detrital zircon ages from the Paleozoic Marbella Conglomerate of the Malaguide Complex (Betic Cordilleras, Spain). Implications on Paleotethyan evolution

Esteban

Cuevas

Tubía

et al. 2017

Lithos

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The Marbella Conglomerate (Betic Cordilleras, SW Spain) is a poorly sorted and polymictic rock of vaguely constrained Late Carboniferous age interlayered within a sandy sequence. It contains variable amounts of pebbles of quartzite, gneiss, deformed granitoid, schist, aplite, dacite and other volcanic rocks among others, which makes it a potential target for detrital zircon provenance studies. In order to decipher provenance we combined U-Pb SHRIMP and LA-ICP-MS analyses on zircons obtained from single pebbles of deformed rocks (schist, granitoids) and detrital zircons from the sandy sequence, respectively. The age spectra of the detrital zircons indicates that at least the sedimentation took place soon after the start of the Permian according to the youngest detrital zircon age (≈286 Ma), and it involved the denudation of terranes with rocks bearing Paleoproterozoic, Neoproterozoic, Cambro-Ordovician, Devonian and Carboniferous zircon age clusters. In contrast with the Permian age of the detrital zircons from the sandstones, igneous (ca. 532 and 516 Ma) and metamorphic (ca. 356 Ma) U-Pb SHRIMP Concordia ages were obtained from the pebbles. The different age clusters observed could be correlated to igneous, metamorphic and detrital rocks from an already eroded terrane similar to the Ossa-Morena Zone of the Iberian Variscan Belt. Therefore, we propose that most of the sedimentation of the Marbella Conglomerate took place along the western border of the Paleotethys at the north margin of Gondwana during the dismantling of the Variscan orogenic edifice and/or the Neotethys ocean opening and the birth of the Cimmerian ribbon continent.

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Potential sources of Ediacaran strata of Iberia: a review

Cited by 34 publications

References 67 publications

Ediacaran Obduction of a Fore‐Arc Ophiolite in SW Iberia: A Turning Point in the Evolving Geodynamic Setting of Peri‐Gondwana

Ediacaran Obduction of a Fore‐Arc Ophiolite in SW Iberia: A Turning Point in the Evolving Geodynamic Setting of Peri‐Gondwana

Tectonic evolution of Variscan Iberia: Gondwana–Laurussia collision revisited

U–Pb detrital zircon ages from the Paleozoic Marbella Conglomerate of the Malaguide Complex (Betic Cordilleras, Spain). Implications on Paleotethyan evolution

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