Person:
Fuenlabrada Pérez, José Manuel

First Name

José Manuel

Last Name

Fuenlabrada Pérez

URI

https://hdl.handle.net/20.500.14352/87137

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Geológicas

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Now showing 1 - 10 of 26

Sm–Nd isotope geochemistry and tectonic setting of the metasedimentary rocks from the basal allochthonous units of NW Iberia (Variscan suture, Galicia)
(Lithos (Oslo. Print), 2012) Fuenlabrada Pérez, José Manuel; Arenas Martín, Ricardo; Díez Fernández, Rubén; Sánchez Martínez, Sonia; Abati Gómez, Jacobo; López Carmona, Alicia
The basal units of the allochthonous complexes of NW Iberia are formed by thick metasedimentary rock sequences intruded by granitoids, ranging in composition from calc-alkaline (c. 493 Ma) to minor alkaline– peralkaline massifs (c. 475–470 Ma), and mafic rocks. The granitoids were transformed into variably deformed othogneisses and the associated mafic rocks were transformed into amphibolites, blueschists and eclogites during eo-Variscan high-P metamorphism dated at c. 370 Ma. Two different superimposed metasedimentary rock sequences can be distinguished. The lower sequence (maximum depositional age at c. 560 Ma) is mainly composed of metagreywackes, while the upper sequence (maximum depositional age at c. 500 Ma) consists of mica schists and other minor types. Major and trace element geochemistry of the metagreywackes of the lower sequence suggests that they were generated in relation to a peri-Gondwanan arc system built on the thinned continental margin, although some chemical transition to passive margin greywackes is also observed. This sedimentary sequence was probably deposited in an Ediacaran–Early Cambrian back-arc setting or retro-arc setting, closer to the thinned platform of the continental margin. The geochemical features of the sedimentary rocks of the upper sequence suggest some affinity with passive margin sediments; they were probably deposited closer to the continental domain and to certain distance from the most active zones of the magmatic arc. The Nd model ages of 23 analysed samples are Paleoproterozoic and range between 1782 Ma and 2223 Ma (average value 1919 Ma). The Nd model ages are slightly younger in the upper sequence than in the lower sequence, but altogether they define a single population, and therefore the two metasedimentary rock sequences can be clearly related. Sedimentation probably took place within the same basin located in the continental platform of Gondwana, the main source areas of these sedimentary rocks did not change during the Late Neoproterozoic and Cambrian times. The Nd model ages are very old and they seem to be compatible with Paleoproterozoic or Archean source areas, with only minor participation of younger sources probably represented by intrusive Cadomian–Pan-African granitoids.
Paleogeografía geoquímica de las series metasedimentarias del Macizo Ibérico
(Geotemas, 2016) Fuenlabrada Pérez, José Manuel; Arenas Martín, Ricardo; Sánchez Martínez, Sonia; Díez Fernández, Rubén; Pieren Pidal, Agustín Pedro
Las características geoquímicas e isotópicas de las series turbidíticas del Macizo Ibérico reflejan distintos escenarios tectónicos en la periferia de Gondwana. Estos cambios se observan en el registro sedimentario de la transición Ediacarense-Cámbrico, que tuvo lugar en el contexto general de un margen continental activo. TDM jóvenes y ɛNd menos negativos resultan característicos de cuencas sedimentarias más exteriores, con una importante contribución de material juvenil derivado del sector más activo del arco volcánico (metagrauvacas culminantes de las Unidades Superiores del Complejo de Órdenes). Las cuencas sedimentarias más próximas al continente se caracterizan por mayores aportes desde dominios alejados del arco activo que dan lugar a valores de TDM más antiguos y ɛNd muy negativos (metagrauvacas de las Unidades Basales del Complejo de Malpica-Tui). Una evolución desde contextos activos hasta otros más propios de márgenes pasivos se detecta con claridad en la transición Ediacarense-Cámbrico, y debe relacionarse con una disminución de la actividad del arco volcánico y la transición hacia un margen pasivo. El diagrama de fSm/Nd vs ɛNd confirma esta variación de los escenarios tectónicos asociados al margen de Gondwana, perfectamente registrados en los metasedimentos de diferentes sectores y unidades del Macizo Ibérico.
A Peri-Gondwanan arc active in Cambrian-Ordovician times: the evidence of the uppermost terrane of NW Iberia
(2011) Arenas Martín, Ricardo; Abati Gómez, Jacobo; Sánchez Martínez, Sonia; Andonaegui Moreno, María Del Pilar; Fuenlabrada Pérez, José Manuel; Fernández Suárez, Javier; González Cuadra, P.; Gutiérrez-Marco, Juan Carlos; Rábano, Isabel; García-Bellido, Diego
Geochemical and isotopic (SmNd) provenance of Ediacaran-Cambrian metasedimentary series from the Iberian Massif. Paleoreconstruction of the North Gondwana margin
(Earth-Science Reviews, 2020) Fuenlabrada Pérez, José Manuel; Arenas Martín, Ricardo; Sánchez Martínez, Sonia; Díez Fernández, Rubén; Pieren Pidal, Agustín Pedro; Pereira, M. Francisco; Chichorro, Martim; Silva, José B.
The geochemical and isotopic (SmNd) features of the Ediacaran-Cambrian siliciclastic series from the Central Iberian Zone and the Iberian Allochthonous Domains indicate a significant paleogeographic change at the northern margin of Gondwana, associated with the development of the Avalonian-Cadomian arc. During the Neoproterozoic, the opening of a peri-Gondwanan back-arc basin and its subsequent widening during the Cambrian led to a progressive separation of the sedimentary basins from the main focus of the probably waning Cadomian magmatic arc activity. This work presents a paleogeographic reconstruction of the distribution of the Iberian terranes along the North Gondwanan margin during Ediacaran and Cambrian times, based on the geochemical and Nd-isotope data from the Iberian Allochthonous and Autochthonous Domains. These results suggest a location close to the West Africa Craton for both the allochthonous and autochthonous terranes, but they would be distributed laterally along the northern margin of Gondwana, occupying arc- or continental-ward positions within a wide back-arc basin. In this context, the peri-Gondwanan volcanic arc acted as the main supplier of the abundant juvenile material, as reflected in positive values of εNd and young TDM model ages (720–1215 Ma) of the Middle Cambrian siliciclastic series from NW Iberia Upper Allochthonous Units. On the other hand, the rather equivalent geochemical and isotopic features of the sedimentary series of the NW and SW Iberia Basal Allochthonous Units suggest a common paleolocation for those series, yet within the back-arc basin but closer to the mainland and older isotope sources. The sedimentary series of these terranes present the oldest TDM ages (1499–2156 Ma), clearly greater than the TDM ages that characterize coeval sedimentary series of the Iberian Autochthonous Domain (1256–1334 Ma). This finding allows us to place Iberian Basal Allochthonous Units very close to the West Africa Craton, from where they received a dominant contribution of old crustal materials, whereas the Iberian Autochthonous Domain occupied a more eastern paleoposition closer to the Sahara Metacraton.
Geochemistry of the Ediacaran–Early Cambrian transition in Central Iberia: Tectonic setting and isotopic sources
(Tectonophysics, 2016) Fuenlabrada Pérez, José Manuel; Pieren Pidal, Agustín Pedro; Díez Fernández, Rubén; Sánchez Martínez, Sonia; Arenas Martín, Ricardo
A complete Ediacaran–Early Cambrian stratigraphic transition can be observed in the southern part of the Central Iberian Zone (Iberian Massif). Two different stratigraphic units, underlying Ordovician series, display geochemical and Sm–Nd isotopic features in agreement with an evolving geodynamic setting. Pusa Shales (Early Cambrian) rest unconformably on greywackes of the Lower Alcudian Formation (Late Ediacaran). Both sequences present minor compositional variations for major and trace element contents and similar REE patterns, close to those of PAAS (Post Archean Australian Shale). Trace element contents and element ratios suggest mixed sources, with intermediate to felsic igneous contributions for both units. Tectonic setting discrimination diagrams for the Ediacaran greywackes indicate that these turbiditic series were deposited in a sedimentary basin associated with a mature active margin (volcanic arc). However, the compositions of the Cambrian shales fit better with a more stable context, a back-arc or retro-arc setting. εNd(T) and TDM ages are compatible with dominance of a similar cratonic source for both sequences, probably the West Africa Craton. εNd565 values for the Ediacaran greywackes (−3.0 to −1.4) along with TDM ages (1256–1334 Ma) imply a significant contribution of juvenile material, probably derived from the erosion of the volcanic arc. However, εNd530 values in the Cambrian shales (−5.2 to −4.0) together with older TDM ages (1444–1657 Ma), suggest a higher contribution of cratonic isotopic sources, probably derived from erosion of the adjacent mainland. Coeval with the progressive cessation of arc volcanism along the peri-Gondwanan realm during the Cambrian, there was a period of more tectonic stability and increasing arrival of sediments from cratonic areas. The geochemistry of the Ediacaran–Cambrian transition in Central Iberia documents a tectonic switch in the periphery of Gondwana, from an active margin to a more stable context related to the onset of a passive margin.
Contrasting isotopic sources (Sm-Nd) of Late Ediacaran series in the Iberian Massif: Implications for the Central Iberian-Ossa Morena boundary
(Precambrian Research, 2019) Rojo-Pérez, Esther; Arenas Martín, Ricardo; Fuenlabrada Pérez, José Manuel; Sánchez Martínez, Sonia; Martín Parra, Luis Miguel; Matas, Jerónimo; Pieren Pidal, Agustín Pedro; Díez Fernández, Rubén
In the Iberian Massif, westernmost sector of the Variscan Orogen, the nature of the boundary between the Central Iberian Zone and the Ossa Morena Complex has been largely discussed. Peri-Gondwanan Ediacaran series similar in age (c. 565 Ma) but different in composition occur at both sides of that boundary. The Lower Alcudian Series (Central Iberian Zone) is located to the north, while the Serie Negra (Ossa-Morena Complex) can be found to the south of the boundary. Major and trace element compositions and Sm-Nd isotopic systematics of siliciclastic rocks from both series suggest a common active margin setting for their deposition, the Serie Negra likely occupying a more external (fore-arc) position within the arc-system relative to the Lower Alcudian Series, which would have been deposited within a large back-arc domain. TDM ages for these two series are notably different, yielding values of 1421–2040 Ma and 1256–1334 Ma for the Serie Negra and Lower Alcudian, respectively. These values suggest higher input from old cratonic sources in the Ossa Morena Complex, with probable participation of the West African Craton, which would be less prominent in the Central Iberia Zone. The whole data set indicate deposition of the Ediacaran series in separated basins, probably far away from each other along/across the margin of Gondwana. Current juxtaposition of these basins is explained by Variscan and probably also pre-Variscan tectonics. Similar conclusions could be also be extended to other similar boundaries in the Variscan Orogen.
A unique blueschist facies metapelite with Mg-rich chloritoid from the Badajoz-Córdoba Unit (SW Iberian Massif): correlation of Late Devonian high-pressure belts along the Variscan Orogen
(International Geology Review, 2021) Arenas Martín, Ricardo; Novo Fernández, Irene; Garcia Casco, Antonio; Díez Fernández, Rubén; Fuenlabrada Pérez, José Manuel; Pereira, Manuel Francisco; Abati Gómez, Jacobo; Sánchez Martínez, Sonia; Rubio Pascual, Francisco J.
The Badajoz-Córdoba Unit (BCU, SW Iberian Massif) is a Variscan high-P unit mainly constituted by metapelites, metagreywackes, orthogneisses, Grt-amphibolites, and retrogressed eclogites (high-P metamorphism at c. 377 Ma). Discovery of rare metapelites with well-preserved high-P mineral assemblages, including large garnets up to 1 cm in diameter with abundant inclusions, chloritoid (up to XMg = 0.32), kyanite, staurolite, chlorite, phengite (up to Si = 3.16 apfu), paragonite, margarite, and rutile, allows detailed determination of the tectonothermal evolution of the unit. Pseudosection modelling of representative samples indicates that this mineral assemblage formed in blueschist facies (near eclogite facies transition) at P conditions higher than 20 kbar at c. 525°C and that it underwent a subsequent severe exhumation and moderate heating. The lithological composition of the BCU, the age of high-P metamorphism and the characteristics of the high-P mineral assemblages are similar to those found in other high-P and low to intermediate-T units of the Variscan Orogen. All these units form part of a single blueschist-eclogite facies metamorphic belt formed during Late Devonian subduction of the external margin of Gondwana.
Provenance of the Variscan Upper Allochthon (Cabo Ortegal Complex,NW Iberian Massif)
(Gondwana Research, 2015) Albert, R.; Arenas Martín, Ricardo; Gerdes, Axel; Sánchez Martínez, Sonia; Fernández Suárez, Javier; Fuenlabrada Pérez, José Manuel
This study focuses on the provenance of the uppermost unit of the Upper Allochthon of the Variscan belt with combined U–Pb and Lu–Hf zircon (LA-ICPMS) and Sm–Nd whole-rock analyses. This unit is represented in the Cabo Ortegal Complex (NW Iberia) by the metasiliciclastic Cariño Gneisses which overlap ophiolitic units that represent perigondwanan oceanic domains. The data set indicates a maximum depositional age of c. 510 Ma and a c. 1.73 Ga Sm–Nd model age, typifying a late or post Pan-African (or Cadomian) and Eburnean events, which entailed abundant input of juvenile material involving broad mixing with older crustal sources. The Mesoproterozoic activity is scarce and scattered and therefore unlikely to represent a major crust generation pulse in the source area of the siliciclastic unit. The data set also records an Archean orogenic pulse in its source area followed by a long lasting crust reworking process, where the Eburnean juvenile materials intruded. These data are interpreted asindicative of a WestAfrica Craton provenance, wherethe siliciclasticseries from whichthe Cariño Gneisses are derived were probably deposited in a back-arc type basinwhere detritus wasmostly sourced by the continent rather than the magmatic arc.
A peri-Gondwanan arc in NW Iberia I: Isotopic and geochemical constraints on the origin of the arc—A sedimentary approach
(Gondwana research, 2010) Fuenlabrada Pérez, José Manuel; Arenas Martín, Ricardo; Sánchez Martínez, Sonia; Díaz García, Florentino; Castiñeiras García, Pedro
The arc-derived upper terrane in the NW Iberia Variscan belt contains a 3000 m thick turbiditic formation at its structural top. Most of the sandstones are feldspathic greywackes with a framework of quartz and weakly altered plagioclase. Rock fragments of vitric and microgranular texture are common in polymictic conglomerates and coarse-grained greywackes, together with slates, cherts and bipyramidal volcanic quartz fragments. Although recrystallization under greenschists facies conditions (chlorite and biotite zones) and the presence of two cleavages hinder detailed textural analysis, the sandstones appear to be typically immature, first-cycle sandstones. The metagreywackes have average major and trace element compositions similar to PAAS (Post Archean Australian Shale), which is considered to reflect the composition of the upper continental crust. Their trace element composition is very consistent and records deposition within a convergent tectonic setting, probably in an intra-arc basin located in a volcanic arc built on thinned continental margin. Detrital zircon populations suggest a Middle Cambrian maximum depositional age (530–500 Ma) and a Gondwanan provenance located at the periphery of the West African Craton. Nd isotope data suggest mixing Ediacaran and Paleoproterozoic sources for the provenance of the greywackes, with TDM ranging between 720 and 1215 Ma with an average of 995 Ma (n=20)—an age range unrepresented in the detrital zircon population. The Nd model ages are similar to those exhibited by West Avalonia, Florida or the Carolina terrane, but younger than those of Cambrian and Ordovician sandstones and shales from the autochthonous realm. These data suggest a westernmost location along the Gondwanan margin for the upper terrane of NW Iberia relative to other terranes located in the footwall of the Variscan suture, consistent with several previously proposed paleogeographic models for the NW Iberia terranes.
A two-stage collision at the origin of Pangea: the allochthonous Variscan terranes
(Geotemas, 2016) Arenas Martín, Ricardo; Díez Fernández, Rubén; Sánchez Martínez, Sonia; Gerdes, Axel; Fernández Suárez, Javier; Albert, R.; Fuenlabrada Pérez, José Manuel
The Variscan suture exposed in NW Iberia contains two allochthonous terranes with Gondwanan provenance (upper and basal units), separated by ophiolites with protolith ages at c. 395 Ma. The tectonothermal evolution of the continental terranes records two consecutive events of deep subduction. The upper units record an initial high-P/ultrahigh-P metamorphic event that occurred before 400-390 Ma, while the basal units were affected by a second high-P/low-to-intermediate-T metamorphic event at c. 370 Ma. Repeated continental subduction affecting the most external margin of Gondwana occurred in a setting of dextral convergence with Laurussia. The two high-P events alternated with the opening of an ephemeral oceanic basin, probably of pull-apart type, in Early Devonian times. This ephemeral oceanic domain is suggested as the setting for the protoliths of the most common ophiolites involved in the Variscan Orogen. Current ideas for the assembly of Pangea advocate a single collisional event in Carboniferous times. However, the new evidence from the allochthonous terranes of the Variscan Orogen suggest a more complex scenario for the assembly of the supercontinent, with an interaction between the colliding continental margins that started earlier and lasted longer than previously considered.