Ediacaran - Earliest Cambrian arc-tholeiite and adakite associations of the Malcocinado Formation (Ossa-Morena Zone, SW Spain): Juvenile continental crust and deep crustal reworking in northern Gondwana

Sarrionandia, F.; Ábalos, B.; Errandonea-Martin, Jon; Eguíluz, Luis; Santos-Zalduegui, J.F.; Madinabeitia, Sonia García de; Carracedo-Sánchez, M.; Ibarguchi, José Ignacio Gil

doi:10.1016/j.lithos.2020.105683

Cited by 16 publications

(14 citation statements)

References 64 publications

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“…Guillot et al (2009, and references therein) suggest that tectonic associations such as those described are often related to magmatic arcs, advocating for prior warm subduction. This might also be the case for the area studied here (Sarrionandia et al, 2020).…”

Section: Tectonic Contextmentioning

confidence: 57%

“…During mature stages of the subduction, hightemperature/low-pressure metamorphism and coeval deformations took place in this active margin. These are thought of as being related to the moderate/steep (warm) subduction of relatively young ridge/transform oceanic lithosphere (Sarrionandia et al, 2020). Radiometric dating of basic-ultramafic metamorphosed protoliths and of intact calc-alkaline diorite and gabbro massifs allows for tracking the duration of plate convergence at least for 645-570 Ma (Bandrés et al, 2004;S anchez-Lorda et al, 2014S anchez-Lorda et al, , 2016, that is, along a > 120 Ma time frame.…”

Section: Geological Contextmentioning

confidence: 99%

“…Current relict segments of them show that they accommodated the southward subduction (in Ediacaran–Cambrian geographical coordinates) of an oceanic slab beneath North Gondwana at high latitudes of the southern hemisphere (Wu et al, 2020). The Ossa–Morena zone of the Iberian Massif formed part of the convergent plate margin and exposes large volumes of Cadomian meta‐igneous and meta‐sedimentary rocks (Eguíluz et al, 2000; López‐Guijarro et al, 2008; Pereira et al, 2011), including subduction‐related (forearc and arc) basic‐ultrabasic igneous rocks for which a renewed interest resulted in recent publications by Arenas et al (2018), Díez Fernández et al (2019) and Sarrionandia et al (2020). Variscan reworking (mid‐late Palaeozoic) and lithospheric‐scale lateral displacements affected the entire northern margin of Gondwana (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Polyphase tectonic reworking of serpentinites and chlorite‐tremolite‐talc rocks (SW Spain) from the subduction forearc to intracontinental emplacement

Ábalos

Puelles

Ibarguchi

2022

Journal Metamorphic Geology

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The petrostructural and geochronological study of a poorly known ultramafic unit from SW Spain (Badajoz-C ordoba belt) combined with previous structural data permits disclosure of a history of metasomatism, tectono-metamorphism, reworking and isotopic resetting related to a poly-orogenic evolution in different geodynamic scenarios. The heterogeneous ultramafic unit studied contains antigorite-serpentinites and metasomatized ultramafic rocks (chlorite-talc schists, tremolite-talc-chlorite rocks and magnesio-hornblendechlorite rocks). Mantle-wedge serpentinization was followed by Si and Al preto syn-metamorphic/tectonic metasomatism in a subduction realm. Petrofabrics of selected lithologies reveal variable syn-metamorphic crystal-plastic deformation and recrystallization (assisted by other mechanisms) under relative high pressure, concomitant with the conditions recorded by neighbouring tectonic units that were later intruded by Ordovician granites. The resultant ensemble was reworked and isotopically reset much later in an intracontinental ductile shear zone. Syn-to late-tectonic apatite from chlorite-talc schists provides an anchored Tera-Wassenburg isochron radiometric age of 342.8 ± 12.2 Ma that provides evidence for the decoupling between isotopic systems and microstructures. The results are discussed from a twofold perspective: with regard to the likely tectonic context of this ophiolite (the current analogue of the Mariana forearc) and with regard to regional geological implications.

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Section: Tectonic Contextmentioning

confidence: 57%

Section: Geological Contextmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Polyphase tectonic reworking of serpentinites and chlorite‐tremolite‐talc rocks (SW Spain) from the subduction forearc to intracontinental emplacement

Ábalos

Puelles

Ibarguchi

2022

Journal Metamorphic Geology

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“…The OMZ is also characterized by an abundance of upper Ediacaran and lower-middle Cambrian to Ordovician volcanic and plutonic rocks (e.g., Simancas et al, 2004;Sarrionandia et al, 2020).…”

Section: Geological Settingmentioning

confidence: 99%

“…A bimodal volcano-sedimentary sequence with abundant associated plutonic rocks (Malcocinado Formation) unconformably overlies the Serie Negra Group. Numerous radiometric ages on the volcanic and plutonic rocks associated with this formation yielded latest Ediacaran to earliest Cambrian ages (Oschner, 1993;Ordóñez-Casado, 1998;Salman, 2004;Sarrionandia et al, 2020). The Malcocinado Formation is traditionally interpreted as representing a supra-subduction zone / Cadomian volcanic arc developed all along the northern Gondwanan continental margin (Sánchez Carretero et al, 1990;Pin et al, 2002;Simancas et al, 2004).…”

Section: Stratigraphic Frameworkmentioning

confidence: 99%

Transcurrent displacement of the Cadomian magmatic arc

Azor

Poyatos

Accotto

et al. 2021

Precambrian Research

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The oldest fossil record in the Iberian Peninsula; lower Ediacaran acritarchs of the Tentudía Formation, Ossa-Morena Zone (OMZ), Southwest Iberian Massif.

Palacios

2024

J Iber Geol

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A diverse assemblage of acritarchs, that represents the oldest fossil record of the Iberian Massif, is described from Ediacaran metasedimentary rocks of the Tentudía Formation included in the Ossa Morena Zone stratigraphy (Southwestern Iberia). The microfossils found include Assesserium pyramidalis, Cavaspina sp. A, Ceratosphaeridium sp. A, Dictyotidium sp. A, Multifronsphaeridium sp. A, Schizofusa zangwenlongii, Tanarium megaconicum Tanarium sp. A, and Tanarium ? sp. B, This assemblage is diagnostic of the mainly lower Ediacaran Doushantuo-Pertatataka acritarchs (c. 633—565 Ma.). The lithological diversity of the Tentudía Formation suggests that these Ediacaran sedimentary rocks were deposited in a diversity of environments (platform, slope and submarine fans, including mass transport deposits in a back-arc basin that extended into the southern part of the Central Iberian Zone. The mass transport deposits are represented in the Ossa-Morena Zone by the Salvaleón Olistostrome composed by turbidites including chert clast probably derived from the shelf. The migration of the mass transport deposits into the Central Iberian Zone (Orellana Formation) indicates the migration of the back-arc basin depocenter. Later inversion of the back-arc basin is marked by the deformation of the lower Ediacaran sedimentary rocks Serie Negra Group in the Ossa-Morena Zone and Domo Extremeño Group in the Central Iberian Zone. In the upper Ediacaran-Terreneuvian a carbonate platform (Ibor Group) was established in the southern part of the Central Iberian Zone unconformably overlying the previously deformed Domo Extremeño Group. The most proximal areas in the Ossa-Morena Zone are represented by the Malcocinado Formation which overlies the Serie Negra Group and the distal areas of the southern part of the Central Iberian Zone are represented by distal shelf and slope deposits of the Cijara Formation, which are overlain by mass transport deposits that include carbonate olistolites from the Ibor Group (such as the Fuentes and Membrillar olistostromes).

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Ediacaran - Earliest Cambrian arc-tholeiite and adakite associations of the Malcocinado Formation (Ossa-Morena Zone, SW Spain): Juvenile continental crust and deep crustal reworking in northern Gondwana

Cited by 16 publications

References 64 publications

Polyphase tectonic reworking of serpentinites and chlorite‐tremolite‐talc rocks (SW Spain) from the subduction forearc to intracontinental emplacement

Polyphase tectonic reworking of serpentinites and chlorite‐tremolite‐talc rocks (SW Spain) from the subduction forearc to intracontinental emplacement

Transcurrent displacement of the Cadomian magmatic arc

The oldest fossil record in the Iberian Peninsula; lower Ediacaran acritarchs of the Tentudía Formation, Ossa-Morena Zone (OMZ), Southwest Iberian Massif.

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