Person:
Rojo Pérez, Esther

First Name

Esther

Last Name

Rojo Pérez

URI

https://hdl.handle.net/20.500.14352/84545

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Geológicas

Department

Mineralogía y Petrología

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Now showing 1 - 9 of 9

Exhumation of high-pressure rocks: role of late faulting (Eastern Ossa–Morena Complex, Iberian Massif)
(Geological Society Special Publications, 2024) Díez Fernández, Rubén; Novo Fernández, Irene; Moreno Martín, Diana; Arenas Martín, Ricardo; Rojo Pérez, Esther; Martín Parra, Luis Miguel; Matas, Jerónimo
Lower Cambrian magmatism in the SW Iberian sector of the African–Gondwana margin: geochemical and isotopic keys to incipient tectonic switching
(Supercontinents, Orogenesis and Magmatism, 2024) Rojo Pérez, Esther; Arenas Martín, Ricardo; Fuenlabrada Pérez, José Manuel; Novo Fernández, Irene; Sánchez Martínez, Sonia; Moreno Martín, Diana; Díez Fernández, Rubén; Nance, R. Damian; Strachan, Robin A.; Quesada Ochoa, Cecilio; Lin, S.
Aspects of the evolution of the Pan-African–Cadomian arc have been recognized in several European massifs. The Ossa–Morena Complex (SW Iberian Massif) is one of the best-preserved sections of this palaeo-Gondwana margin. In this domain, recent studies suggest that arc magmatism followed a cyclical pattern during the Upper Ediacaran and Lower Cambrian. However, its initial and more mature stages remain unclear. Upper Ediacaran magmatism (c. 602 Ma) appears to be uninterrupted and driven by slab–mantle wedge–upper plate interactions. The early Paleozoic was a period of significant change along the Gondwana margin. In the Ossa–Morena Complex, the beginning of the Cambrian (c. 541 Ma) is marked by a strong unconformity over the Ediacaran basement, which is linked to destabilization of the arc. However, subduction-related magmatism continued with increasing mantle input, driving the geochemistry to more alkaline compositions. This paper summarizes the geochemical and isotopic evolution of the peri-Gondwana arc preserved in SW Iberia during this period. These results highlight shifts in geochemistry related to a higher slab angle during each magmatic episode, suggesting a tectonic switch toward an extensional regime in this section of the Gondwana margin.
Origin and evolution of Cadomian magmatism in SW Iberia: from subduction onset and arc building to a tectonic switching
(International Geology Review, 2023) Rojo Pérez, Esther; Fuenlabrada Pérez, José Manuel; Díez Fernández, Rubén; Arenas Martín, Ricardo
The evolution of the Gondwana along the flank of the West African Craton was complex and is far from understood. Subduction-related activity along this margin spanned between c. 750 and 500 Ma. Sections close to African cratons record the earliest stages, while Autochthonous and Allochthonous domains of the Variscan Belt preserve the latest stages of the arc system, essentially between c. 540 and 500 Ma. The geochemistry of the Ediacaran-early Cambrian siliciclastic series deposited along this Cadomian active margin preserves the evolutionary history of their sources, which are related to activity in the arc and nearby continental areas. In this sense, the SW Iberian Massif (Ossa-Morena Complex) preserves a section of this Ediacaran-early Cambrian peri-Gondwanan arc. Its evolution can be tracked through the characterization of the subduction-related magmatism (including the Mérida Massif) and coeval metasedimentary record (Serie Negra Group and Malcocinado Formation) during a time interval spanning almost 100 m.y., from pre-602 Ma to at least c. 534 Ma. This study reveals that arc magmatism is closely linked with synorogenic deposition in a complex way so far unexplored. Arc recycling is revealed by the isotopic equivalence of synorogenic strata to the first magmatic event (pre-602 Ma), and by geochronological data of the arc-building pulses. The earliest magmatic pulses (c. 602–550 Ma) are characterized by significant crustal input, likely favoured by subduction erosion. Subsequently, magmatism evolved towards larger mantle involvement (c. 540–534 Ma), likely associated with progressive variation in the slab angle. These slab-mantle-upper plate interactions generated changes in the arc dynamics leading to an extensional setting with alkaline magmatism during the Cambrian. This review proposes a model of petrogenetic and geodynamic arc evolution between the Ediacaran and the Early Cambrian. The gathered data could improve the accuracy of future palaeogeographic reconstructions for the northern margin of Gondwana.
Geochemistry of metasedimentary rocks from the Eastern Pyrenees (Iberian Peninsula): Implications for correlation of Ediacaran terranes along the Gondwanan margin
(Precambrian Research, 2023) Rojo Pérez, Esther; Druguet, Elena; Casas, Josep M.; Proenza Fernández, Joaquin Antonio; Fuenlabrada Pérez, José Manuel; Sánchez Martínez, Sonia; Garcia Casco, Antonio; Arenas Martín, Ricardo
The North African margin of Gondwana formed by subduction and accretion during Ediacaran to Cambrian times. Sections of this active margin were incorporated during the late Paleozoic to the Variscan and Appalachian orogens. In the Variscan realm, these sections define in some regions a Cadomian basement comprising thick metasedimentary series associated with coeval subduction-related magmatic rock dated in the range 650–500 Ma. In the Cap de Creus Massif (Eastern Pyrenean domain), the Cadomian metasedimentary rocks formed from sediments derived from mixed felsic and intermediate/mafic sources, intruded by granitoid and minor mafic igneous rocks. These series were formed in a peri-Gondwanan volcanic arc setting, like other Cadomian series described in the SW of the Iberian Massif, such as Serie Negra Group of the Ossa Morena Complex. However, the Nd model ages of the Cap de Creus metasedimentary samples range from 1431 to 1620 Ma and are younger than those of their SW Iberia equivalents. This result can be interpreted as an indication of an eastern location in the Ediacaran - Cambrian peri-Gondwanan magmatic arc. Furthermore, the Cadomian series in the Central Iberian Zone have even younger Nd model ages than those of SW and NE Iberia. We present two end-member paleogeographic models consistent with reconstruction of the initial location of the Cap de Creus Massif and its relations with other domains (Ossa Morena Complex and Central Iberian Zone) in this sector of the North African Gondwanan margin.
Building and collapse of the Cadomian Orogen: A plate-scale model based on structural data from the SW Iberian Massif
(Tectonics, 2023) Moreno Martín, Diana; Díez Fernández, Rubén; Arenas Martín, Ricardo; Rojo Pérez, Esther; Novo Fernández, Irene; Sánchez Martínez, Sonia
The Cadomian Orogeny produced a subduction-related orogen along the periphery of Gondwana and configured the pre-Variscan basement of the Iberian Massif. The architecture of the Cadomian Orogen requires detailed structural analysis for reconstruction because of severe tectonic reworking during the Paleozoic (Variscan cycle). Tectonometamorphic analysis and data compilation in SW Iberia (La Serena Massif, Spain) have allowed the identification of three Cadomian deformation phases and further constrained the global architecture and large-scale processes that contributed to the Ediacaran building and early Paleozoic dismantling of the Cadomian Orogen. The first phase (DC1, prior to 573 Ma) favored tabular morphology in plutons that intruded during the building of a continental arc. The second phase (DC2, 573–535 Ma) produced an upright folding and contributed to further crustal thickening. The third phase of deformation (DC3, ranging between ∼535 and ∼480 Ma) resulted in an orogen-parallel dome with oblique extensional flow. DC1 represents the crustal growth and thickening stage. DC2 is synchronous with a period of crustal thickening that affected most of the Gondwanan periphery, from the most external sections (Cadomian fore-arc) to the inner ones (Cadomian back-arc). We explain DC2 as a consequence of flat subduction, which was followed by a period dominated by crustal extension (DC3) upon roll-back of the lower plate. The Ediacaran construction of the Cadomian Orogen (DC1 and DC2) requires ongoing subduction beneath Gondwana s.l., whereas its dismantlement during the Early Paleozoic is compatible with oblique, sinistral convergence.
Late Ediacaran-early Cambrian geochemical evolution of the peri-Gondwanan magmatic arc of the Ossa-Morena complex (SW Iberian massif)
(2023) Rojo Pérez, Esther; Fuenlabrada Pérez, José Manuel; Andonaegui Moreno, Pilar; Fernández Suarez, Javier
In the Iberian Massif, the Ossa-Morena Complex and its prolongation in the NW Iberia allochthonous complexes represent the outermost section of the North African margin of Gondwana. This margin hosted a long-lived magmatic arc active at least between c. 750 to 500 Ma. The activity of this arc can be traced by sedimentary sequences deposited along the margin and igneous rocks generated during the arc construction, as well as by deposits generated during its progressive dismantling. The dynamic evolution of the peri-Gondwanan North-African margin from the Late Ediacaran to the Early Cambrian resulted in a complex tectonic configuration involving units with continental affinity and others of oceanic/transitional nature. This PhD Thesis presents the results obtained from the study of this margin section preserved in SW Iberia and suggests a possible geodynamic and petrogenetic model based on its geochemical and isotopic evolution. This peri-Gondwanan arc section is probably one of the best well-preserved in the Variscan Orogen. The results also include the identification of previously undescribed tectonostratigraphic units, and the detailed description of a new ophiolitic unit, the Mérida Ophiolite.The methodology used includes a structural study of the units implied in this section, whole-rock and isotopic (Sr-Nd) geochemistry, and geochronology (U-Pb ) of implied rocks. The study of the Merida ophiolite further included Hf isotopes in the analyzed zircons. The results have been published in journals of impact in Earth Sciences. In this sense, this volume is presented as a compilation of publications following a chronological and thematic order...
Variability in the sources of North Gondwana Cadomian basins tracked by Nd isotopic systematics (Iberian Massif)
(Precambrian Research, 2023) Fuenlabrada Pérez, José Manuel; Arenas Martín, Ricardo; Pereira, M. Francisco; Rojo Pérez, Esther; Sánchez Martínez, Sonia; Díez Fernández, Rubén
The Cadomian Orogeny encompassed the opening and closure of oceanic domains and associated sedimentary basins in the northern margin of Gondwana from Ediacaran to Early Cambrian time. In the Iberian Massif, these Cadomian basins are included in autochthonous and allochthonous (far-travelled) terranes of the Variscan Orogen. A compilation of Nd isotope information of Ediacaran-Lower Cambrian siliciclastic series supports previous proposal for variability in the sources along the North Gondwanan margin that continued during the Early Paleozoic. Older TDM model ages ranging from 1361 to 2357 Ma of the Variscan allochthonous Ediacaran-Lower Cambrian siliciclastic series indicate proximity to Archean and Paleoproterozoic old crustal sources of the West African Craton and represent deposition on a western Cadomian basin. In turn, the autochthonous Ediacaran-Lower Cambrian siliciclastic series show relatively younger TDM values ranging from 1179 to 2114 Ma, suggesting derivation from more juvenile magmatic rocks that are well represented further east. The Ediacaran-Lower Cambrian siliciclastic series of the autochthonous terranes formed in an eastern Cadomian basin located near the Sahara Metacraton, the Trans-Saharan Orogen and the Tuareg and Arabian-Nubian shields.
Frontier of the Paleo-Tethys Ocean in the western Mediterranean: Isotopic (Sm-Nd) constraints on sources of Devonian units from Menorca Island
(Geoscience Frontiers, 2024) Arenas Martín, Ricardo; Fuenlabrada Pérez, José Manuel; Timoner, C.; Díez Fernández, Rubén; Rojo Pérez, Esther
The c. 1000-m-thick pre-orogenic Devonian mainly metapelitic sequence of North Menorca Island shows a fairly complete stratigraphic succession. The rocks of this sequence indicate gradually increasing deeper marine conditions of sedimentation towards its uppermost levels. Furthermore, the obtained sedimentary characteristics resemble those related to a deep and narrow basin-associated deposit. Thin sills of Ti-augite-bearing alkaline gabbros occur within the Devonian sequence. The intensity of Variscan deformation increases downwards through the structure. According to the characteristics of the Devonian sequence and its location within the Variscan Orogen, a correlation with similar units located in the southern sectors of the Central Iberian Zone (Iberian Massif) is suggested. The Devonian metapelitic rocks have geochemical characteristics suggesting that they represent moderately recycled mature siliciclastic sediments, generated from erosion of distant source areas belonging to an upper continental crust. The relatively narrow range of variation observed in initial 143Nd/144Nd ratios supports a similar source for the Menorcan slates (0.51165–0.51182). However, a marked trend is observed in these isotope ratios, from lower values at the base of the stratigraphic column (minimum value of 0.511941) to higher values at the top (maximum value of 0.512131). The 147Sm/144Nd ratios vary between 0.1074 and 0.1238, within the range defined for siliciclastic rocks with felsic crustal provenance. The Nd model ages define a narrow range between 1496 Ma and 1754 Ma (Late Paleoproterozoic–Early Mesoproterozoic), and they are consistently younger up-section. These data rule out a provenance from the erosion of the West Africa Craton, as they are more compatible with a provenance from regions located in the Trans-Saharan Belt or Sahara Metacraton. The characteristics of the Menorcan Devonian sequence are compatible with its deposition in a narrow and deep peri-Gondwanan transtensional basin, generated to the south of an advancing Variscan orogenic wedge. Systematic variations in the Nd isotopic composition indicate the progressive and continuous denudation of increasingly more easterly North African sectors in a collisional context between Laurussia and Gondwana with a marked dextral component. These data must be interpreted in the sense that there was not a large oceanic domain during Devonian times to the south of Iberia, able to block the arrival of detrital material from North Africa. A large tract of the Paleo-Tethys Ocean would therefore not have existed during the Devonian south of Iberia. This ocean must therefore have had limited extent in this period towards the westernmost sectors. The Devonian peri-Gondwanan shelf was apparently continuous around Iberia. This platform was progressively affected by Variscan deformation advancing from north to south and incorporated into the Variscan orogenic wedge with the same vergence.
Cadomia origins: paired Ediacaran ophiolites from the Iberian Massif, the opening and closure record of peri-Gondwanan basins
(Supercontinents, Orogenesis and Magmatism, 2024) Arenas Martín, Ricardo; Vérard, Christian; Albert Roper, Richard; Rojo Pérez, Esther; Sánchez Martínez, Sonia; Novo Fernández, Irene; Moreno Martín, Diana; Gerdes, Axel; Garcia Casco, Antonio; Díez Fernández, Rubén
The recent discovery of Ediacaran ophiolites in the SW Iberian Massif has made it possible to pinpoint the evolution of the Cadomian basement of Europe. The Calzadilla and Mérida ophiolites (gabbroic protoliths dated at c. 600 and 594 Ma, respectively) have geochemical characteristics typical of supra-subduction zone ophiolites. They are interpreted as originating during the initial opening of a forearc basin with boninitic magmatism (Calzadilla), followed by the formation of a back-arc basin with arc-tholeiites (Mérida). Widening of the back-arc led to the rifting and drifting of a section of the active continental margin (Cadomia). Closure of these oceanic domains initiated rapid contraction, culminating in the collision of Cadomia with Gondwana (c. 590–540 Ma). The application of a PANALESIS model to this palaeogeographic setting confirms the plausibility of Cadomian rifting and the likely opening of broad oceanic domains. It also confirms the final collision of Cadomia with Gondwana, although the synthetic and regional data disagree in the precise chronology of the convergence and collision of Cadomia with the West Africa Craton. This work shows that the evolution of the Cadomian basement is much more complex than traditionally considered.