Age and characteristics of the Loma del Aire unit (SW Iberia): Implications for the regional correlation of the Ossa-Morena Zone

Sánchez-García, Teresa; Quesada, Cecilio; Bellido, F.; Dunning, G. R.; Pin, C.; Moreno-Eirís, Elena; Perejón, Antonio

doi:10.1016/j.tecto.2016.02.043

Cited by 17 publications

(16 citation statements)

References 107 publications

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“…During most of the Ediacaran (c. 600–560 Ma), the southwestern part of the Upper Allochthon of the Ossa Morena Complex was located in the fore‐arc region of an active continental arc (Figure a). Infant subduction and extension in this section would have facilitated the generation of boninitic magmas (e.g., metagabbros from the Calzadilla Ophiolite; Arenas et al, ) and the progressive widening of a fore‐arc basin (deposition of Serie Negra fore‐arc siliciclastic sediments; Sánchez Lorda et al, ; Sánchez‐Lorda et al, ). Ongoing subduction would trigger serpentinization over the underlying mantle wedge in the fore‐arc region.…”

Section: Discussionmentioning

confidence: 99%

“…In the study area, the Loma del Aire Formation (Garrote, ) is made of slates, with some minor metasandstones, metatuffs, and sills. Lithostratigraphical complexity of this formation increases to the west, including marbles, and a Cambrian crystallization age (c. 526–505 Ma) has been obtained for some of its metaigneous rocks (U‐Pb magmatic zircon dating; Sánchez‐García et al, ).…”

Section: Geological Settingmentioning

confidence: 99%

“…The Ediacaran series, referred to as the Série Negra (Alia, ; Carvalhosa, ; Gonçalves, ), are interpreted as derived from the erosion and coeval magmatic activity in the context of a peri‐Gondwanan continental arc (Díez Fernández et al, ; Linnemann et al, ; Pereira et al, ; Pereira, Solá, et al, ). Its fore‐arc section is represented by the sequences located to the SW, whereas the intra‐arc sections are located more to the north and NE (present‐day coordinates), thus suggesting NE subduction polarity (beneath Gondwana) in Ediacaran times (Arenas et al, ; Sánchez Lorda et al, ; Sánchez‐Lorda et al, ). Cambrian strata lie discordantly over these series (Eguíluz, ; Gonçalves, ; Liñán et al, ; Quesada, ; Pereira et al, ) and are interbedded with progressively more alkaline igneous rocks (Sánchez‐García et al, ).…”

Section: Geological Settingmentioning

confidence: 99%

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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: Discussionmentioning

confidence: 99%

Section: Geological Settingmentioning

confidence: 99%

Section: Geological Settingmentioning

confidence: 99%

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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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“…Arc growth started at least ca. 630 Ma, as evidenced by igneous zircon entrained by Cadomian and Cambrian rift-related rocks (Sánchez-García et al, 2016. The Cadomian suture was somewhat reactivated during the Variscan Orogeny, and its remains are tentatively situated along the Badajoz-Córdoba (blastomylonitic) Shear Zone (BCSZ; Fig.…”

Section: Geodynamic Overview On the Cadomian Orogenymentioning

confidence: 99%

Updated stratigraphic framework and biota of the Ediacaran and Terreneuvian in the Alcudia-Toledo Mountains of the Central Iberian Zone, Spain

et al. 2019

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Se presenta en este trabajo una revisión actualizada de la estratigrafía del Ediacárico-Terranóvico del valle de Alcudia y los montes de Toledo, Zona Centroibérica. Se subdivide el Supergrupo infrayacente ediacárico del Alcudiense Inferior-Domo Extremeño en los Grupos del Guadiana (Formaciones de La Coronada y Sta. Ma de Zújar) y de Campanario (Formaciones de Botija, Monroy y Orellana). El supergrupo contiene varios acritarcos sin utilidad bioestratigráfica, así como dubiofósiles, pero su edad se ha establecido claramente a partir de zircones detríticos. Este litosoma siliciclástico aparece recubierto mediante contacto disconforme con el Grupo mixto de Ibor (Formaciones de Castañar, Villarta y Arrocampo) o la Formación siliciclástica del Cíjara. El contenido fósil del Grupo de Ibor incluye sabellidítidos, vendoténidos, macrofitas, bioacumulaciones y arrecifes con Cloudina, Sinotubulites, Protolagena y estromatolitos y trombolitos, así como una amplia variedad de icnofósiles; la Formación del Cíjara ha librado microfósiles bacterianos como Bavlinella y Palaeogomphosphaeria, y pistas fósiles simples (Gordia, Helminthoidichnites y treptícnidos). El límite Ediacárico-Cámbrico, a partir de icnofósiles, se sitúa en la parte basal de la Formación de Arrocampo y en la parte terminal de la del Cíjara. El valle del Alcudia ofrece algunas peculiaridades, lo que se refleja por el mantenimiento de una subdivisión litoestratigráfica propia: el Grupo de Ibor se divide en las Formaciones de Tamujar, Hinojosas (caracterizada por su contenido en icnofósiles, que incluye treptícnidos, Monomorphichnus, Psammichnites y Taphrelminthopsis) y Cabezarrubias (con Bergaueria y Planolites). Otra discontinuidad mayor se reconoce a techo del Grupo de Ibor y de la Formación del Cíjara, recubiertos respectivamente por la Formación de San Lorenzo y unas capas de megabrechas muy características. Las megabrechas, interpretadas como depósitos de talud y conocidas como las capas de Fuentes, Membrillar y Navalpino, se sitúan a base de la Formación del Pusa, de composición heterolítica y de edad Terranóvico a Serie cámbrica 2. Se subdivide el Pusa en tres miembros, destacando el intermedio por el registro de yacimientos de interés económico de fosfato (Capa de Fontanarejo). La Formación del Pusa contiene el fósil de cuerpo blando Beltanelliformis así como numerosos icnofósiles (Monomorphicnus y Treptichnus; miembro inferior), espículas de esponja asociadas con trombolitos (miembro intermedio) y Scenella, trilobites, arqueociatos e icnofósiles (Dactyloidites, Psammichnites, Rusophycus y Teichichnus; miembro superior). En ausencia de megabrechas, el Grupo de Ibor aparece directamente recubierto por las Formaciones de San Lorenzo y Fuentepizarra, esta última caracterizada por su contenido en calizas fosfáticas ricas en microfósiles, como Anabarella, que caracterizan la transición Fortuniense-Piso Cámbrico 2.

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“…The vulcanites of the Loma del Aire Unit do provide ages of ca. 526 and 505 Ma for the eruption/deposition (Sánchez-García et al, 2016). The ortho-derived rocks related to the Mina Afortunada (532 ± 5 Ma;Sánchez-García et al, 2008), Monesterio (532 ± 5 Ma;Montero et al, 2000), Alcaçovas (526 ± 9.9 Ma;Chichorro et al, 2008) and Santiago del Escoural orthogneises (522.3 ± 5.1 Ma;Chichorro et al, 2008) yielded similar ages.…”

Section: Paleozoic Detrital Zirconsmentioning

confidence: 73%

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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Age and characteristics of the Loma del Aire unit (SW Iberia): Implications for the regional correlation of the Ossa-Morena Zone

Cited by 17 publications

References 107 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

Updated stratigraphic framework and biota of the Ediacaran and Terreneuvian in the Alcudia-Toledo Mountains of the Central Iberian Zone, Spain

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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