Genesis and evolution of a syn-orogenic basin in transpression: Insights from petrography, geochemistry and Sm–Nd systematics in the Variscan Pedroches basin (Mississippian, SW Iberia)

Armendáriz, Maider; López-Guijarro, Rafael; Quesada, Cecilio; Pin, Christian; Bellido, F.

doi:10.1016/j.tecto.2008.02.007

Cited by 27 publications

(18 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The geodynamic scenario behind this transtensional and magmatic event is unclear. The geochemical signature of the early Carboniferous mafic magmatism in SW Iberia is very diverse [ Munhá , ; Quesada et al ., ; Armendáriz et al ., ; Pin et al ., ; Cambeses , ] and does not support by itself any specific tectonic setting. Some authors have proposed the influence of an anomalous sublithospheric mantle, may be a mantle plume, as the reason for this event, taking into account its broad extent all along SW Iberia [ Simancas et al ., ] and neighboring regions of Canada [ Dessureau et al ., ; Murphy and Keppie , ].…”

Section: Discussion On the Carboniferous Evolutionmentioning

confidence: 99%

The elusive nature of the Rheic Ocean suture in SW Iberia

et al. 2015

View full text Add to dashboard Cite

The Rheic Ocean suture resulted from pre-Carboniferous oceanic subduction followed by Late Devonian-Carboniferous Variscan collision. In SW Iberia, this suture has been classically located along the boundary between the Ossa-Morena and South Portuguese Zones based on the presence of three units: (i) a conspicuous metamafic unit (Beja-Acebuches) that crops out along this boundary and has been interpreted as a pre-Carboniferous Rheic Ocean ophiolite; (ii) a low-grade metasedimentary unit with minor mid-ocean ridge basalt-like lithologies (Pulo do Lobo unit), thought to represent a Rheic Ocean subduction-related accretionary prism; and (iii) the allochthonous Cubito-Moura unit that contains high-pressure and ophiolitic-like rocks. We report new structural and geochronological data that allow us to reinterpret the origin and internal structure of the Beja-Acebuches and the Pulo do Lobo units. Thus, both the Beja-Acebuches protoliths and the Pulo do Lobo metabasalts would have been formed in the context of an intracollisional extensional stage that interrupted the Variscan collision at early Carboniferous time, after the Rheic Ocean consumption, and the first continental collision. Later on, collision was resumed in an oblique left-lateral regime that gave way to coeval frontal (folds and thrusts) and lateral (shear zones and strike-slip faults) structures, with variable pressure-temperature conditions and space distribution along time. As a consequence of the superposition of transtension and complex transpression, the Rheic suture in SW Iberia has an obscure nearly cryptic appearance.

show abstract

Section: Discussion On the Carboniferous Evolutionmentioning

confidence: 99%

The elusive nature of the Rheic Ocean suture in SW Iberia

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Continental growth curves calculated using the model, the equations and the data of Allègre and Rousseau (1984). The shape of these curves critically depends on the value of the erosion parameter K used in the equations, and values ranging between 2 and 50 were chosen (Hamilton et al, 1983;O'Nions et al, 1983;Allègre and Rousseau, 1984;Frost and O'Nions, 1984;O'Nions, 1984, 1985;Davies et al, 1985;Hensel et al, 1985;Michard et al, 1985;Andre et al, 1986;Miller et al, 1986;Frost and Winston, 1987;Barovich et al, 1989;Mearns et al, 1989;Dia et al, 1990aDia et al, , 1990bYanez et al, 1991;Boher et al, 1992;Nägler et al, 1992Nägler et al, , 1995Stevenson and Turek, 1992;Alibert and McCulloch, 1993;Turner et al, 1993;Bock et al, 1994;Jahn and Condie, 1995;Stevenson, 1995;Cullers et al, 1997;Henry et al, 2000;McLennan et al, 2000;Ugidos et al, 2003;Krogstad et al, 2004;Armendariz et al, 2008; A C C E P T E D M A N U S C R I P T data (circles) was calculated for every 100 Ma step, and a regression curve was calculated (brown curve, with R 2 = 0.96). The Australian shales data used in the pioneer study of Allègre and Rousseau (1984) (diamonds) are plotted for comparison.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Continental growth seen through the sedimentary record

Dhuime

Hawkesworth

Delavault

et al. 2017

Sedimentary Geology

View full text Add to dashboard Cite

International audienceSedimentary rocks and detrital minerals sample large areas of the continental crust, and they are increasingly seen as a reliable archive for its global evolution. This study presents two approaches to model the growth of the continental crust through the sedimentary archive. The first builds on the variations in U-Pb, Hf and O isotopes in global databases of detrital zircons. We show that uncertainty in the Hf isotope composition of the mantle reservoir from which new crust separated, in the 176Lu/177Hf ratio of that new crust, and in the contribution in the databases of zircons that experienced ancient Pb loss(es), adds some uncertainty to the individual Hf model ages, but not to the overall shape of the calculated continental growth curves. The second approach is based on the variation of Nd isotopes in 645 worldwide fine-grained continental sedimentary rocks with different deposition ages, which requires a correction of the bias induced by preferential erosion of younger rocks through an erosion parameter referred to as K. This dimensionless parameter relates the proportions of younger to older source rocks in the sediment, to the proportions of younger to older source rocks present in the crust from which the sediment was derived. We suggest that a Hadean/Archaean value of K = 1 (i.e., no preferential erosion), and that post-Archaean values of K = 4–6, may be reasonable for the global Earth system. Models built on the detrital zircon and the fine-grained sediment records independently suggest that at least 65% of the present volume of continental crust was established by 3 Ga. The continental crust has been generated continuously, but with a marked decrease in the growth rate at ~ 3 Ga. The period from > 4 Ga to ~ 3 Ga is characterised by relatively high net rates of continental growth (2.9–3.4 km3 yr− 1 on average), which are similar to the rates at which new crust is generated (and destroyed) at the present time. Net growth rates are much lower since 3 Ga (0.6–0.9 km3 yr− 1 on average), which can be attributed to higher rates of destruction of continental crust. The change in slope in the continental growth curve at ~ 3 Ga is taken to indicate a global change in the way bulk crust was generated and preserved, and this change has been linked to the onset of subduction-driven plate tectonics. At least 100% of the present volume of the continental crust has been destroyed and recycled back into the mantle since ~ 3 Ga, and this time marks a transition in the average composition of new continental crust. Continental crust generated before 3 Ga was on average mafic, dense, relatively thin (< 20 km) and therefore different from the calc-alkaline andesitic crust that dominates the continental record today. Continental crust that formed after 3 Ga gradually became more intermediate in composition, buoyant and thicker. The increase in crustal thickness is accompanied by increasing rates of crustal reworking and increasing input of sediment to the ocean. These changes may have been accommodated...

show abstract

“…CC BY 4.0 License. similar tectonic setting has been put forward as an explanation for differences in stratigraphy found in the Pedroches syn-orogenic basin located along the OMZ-Central Iberian Zone boundary (Armendáriz et al, 2008, and references therein) (Fig. 1).…”

Section: Provenance and Evolutionary Modelmentioning

confidence: 57%

“…10a). A factor which may explain this thermal anomaly is the subduction of an oceanic ridge beneath the OMZ (Gondwanan-side) during the initial closure of the Paleotethys Ocean in the Carboniferous, whereas other regions of the Appalachian-Variscan orogenic belt experienced oblique collision and rapid uplift (Armendáriz et al, 2008;Pereira et al, in press), but as yet there is no consensus on this (Simancas et al, 2009;Cambeses et al, 2015). A second significant finding is that detrital zircon populations from the Santa Susana Formation (samples SS-1 and SS-2) also show significant differences (Figs.…”

Section: Provenance and Evolutionary Modelmentioning

confidence: 99%

Chronostratigraphic framework and provenance of the Ossa-Morena Zone Carboniferous basins (SW Iberia)

Pereira¹,

Gama²,

Silva³

et al. 2020

Preprint

View full text Add to dashboard Cite

Abstract. Carboniferous siliciclastic and silicic magmatic rocks from the Santa Susana-São Cristovão region contain valuable information regarding the timing of synorogenic processes in SW Iberia. In this region of the Ossa-Morena Zone (OMZ), Late Carboniferous terrigenous strata (i.e. the Santa Susana Formation) unconformably overlie Early Carboniferous marine siliciclastic deposits alternating with volcanic rocks (i.e. the Toca da Moura volcano-sedimentary complex). Lying below this intra-Carboniferous unconformity, the Toca da Moura volcano-sedimentary complex is intruded and overlain by the Baleizão porphyry. Original SHRIMP and LA-ICP-MS U-Pb zircon are presented in this paper, providing chronostratigraphic and provenance constraints, since available geochronological information is scarce and only biostratigraphic ages are currently available for the Santa Susana-São Cristovão region. Our findings and the currently-available detrital zircon ages from Paleozoic terranes of SW Iberia (Pulo do Lobo Zone- PLZ, South-Portuguese Zone- SPZ, and OMZ), were jointly analyzed using the K-S test and MDS diagrams to investigate provenance. The marine deposition is constrained to the age interval of c. 335–331 Ma (Visean) by new U-Pb data for silicic tuffs from the Toca da Moura volcano-sedimentary complex. The Baleizão porphyry, intrusive in the Toca da Moura volcano-sedimentary complex, yielded a crystallization age of c. 317 Ma (Bashkirian), providing the minimum age for the overlying intra-Carboniferous unconformity. A comparison of detrital zircon populations from siliciclastic rocks of the Cabrela and Toca de Moura volcano-sedimentary complexes of the OMZ suggests that they derived from distinct sources more closely associated with the SPZ and PLZ than the OMZ. Above the intra-Carboniferous unconformity, the Santa Susana Formation is either the result of the recycling of distinct sources located in the Laurussian-side (SPZ and PLZ) and Gondwanan-side (OMZ) of the Rheic suture zone. The best estimate of the crystallization age of a granite cobble found in a conglomerate from the Santa Susana Formation yielded c. 303 Ma (Kasimovian-Gzhelian), representing the maximum depositional age for the terrestrial strata. The intra-Carboniferous unconformity seems to represent a stratigraphic gap of approximately 12–14 Ma, providing evidence of the rapid post-accretion/collision uplift of the Variscan orogenic belt in SW Iberia (i.e. the OMZ, PLZ and SPZ).

show abstract

Genesis and evolution of a syn-orogenic basin in transpression: Insights from petrography, geochemistry and Sm–Nd systematics in the Variscan Pedroches basin (Mississippian, SW Iberia)

Cited by 27 publications

References 55 publications

The elusive nature of the Rheic Ocean suture in SW Iberia

The elusive nature of the Rheic Ocean suture in SW Iberia

Continental growth seen through the sedimentary record

Chronostratigraphic framework and provenance of the Ossa-Morena Zone Carboniferous basins (SW Iberia)

Contact Info

Product

Resources

About