Provenance variability along the Early Ordovician north Gondwana margin: Paleogeographic and tectonic implications of U-Pb detrital zircon ages from the Armorican Quartzite of the Iberian Variscan belt

Shaw, J. H.; Gutiérrez-Alonso, Gabriel; Johnston, Stephen T.; Pastor‐Galán, Daniel

doi:10.1130/b30935.1

Cited by 98 publications

(92 citation statements)

References 92 publications

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“…A proximal provenance is also supported by several features of the age spectra (Fig. 8), such as: (1) the abundance of Cryogenian to Ediacaran zircon ages, which are very abundant in basement metapelites (Pereira et al, 2012a(Pereira et al, , 2012bBraid et al, 2011;Talavera et al, 2012;Shaw et al, 2014;Pérez-Cáceres et al, 2017); (2) the coincidence of the Paleozoic zircon population with magmatic events in the surrounding areas (Fernández-Suárez et al, 2000;Jesus et al, 2007;Azor et al, 2008;Rosa et al, 2009) and the detrital record of the upper Paleozoic basement rocks (Braid et al, 2011;Dinis et al, 2012;Pereira et al, 2012b;Pérez-Cáceres et al, 2017).…”

Section: Triassic (Early Fragmentation)mentioning

confidence: 85%

“…9). Zircon of Grenvillian age is scarce in the basement rocks that crop out in the vicinity of the studied basins, namely in the OMZ (Linnemann et al, 2008;Fernández-Suárez et al, 2014), in the Schist-Greywacke Complex (Pereira et al, 2012a;Talavera et al, 2012;Fernández-Suárez et al, 2014) and in the Ordovician "Armorican Quarztites" (Pereira et al, 2012a;Shaw et al, 2014), but is common in several Paleozoic units from NW Iberia (Fernández-Suárez et al, 2002;Martínez Catalán et al, 2004;Pastor-Galán et al, 2013;Shaw et al, 2014). The abundant Paleoproterozoic zircon and the occasional Archean zircons are most likely inherited from older Paleozoic to Precambrian Iberian metasedimentary successions that yield peaks of similar ages (Talavera et al, 2012;Pastor-Galán et al, 2013;Shaw et al, 2014;Rodrigues et al, 2015;Pérez-Cáceres et al, 2017).…”

Section: Main Zircon Forming Events and Sourcesmentioning

confidence: 99%

“…A discrete Ordovician peak (c. 450 Ma) is also observed in the southern sample from the Lusitanian Basin (SO). Taking into account that the basement rocks found today in the surrounding areas yield limited amounts of Cambro-Ordovician zircons (Talavera et al, 2012;Pereira et al, 2012a;Shaw et al, 2014) and the majority of these zircon grains do not display morphological features indicative of polycyclic origin, a proximal first cycle source should be considered. This sediment source unit has not yet been identified.…”

Section: Triassic (Early Fragmentation)mentioning

confidence: 99%

“…Detrital zircon geochronology has been extensively applied to the study of the provenance of Paleozoic and Precambrian sedimentary sequences on Iberia, and has helped constrain the potential contribution of these successions to Mesozoic and Cenozoic sedimentary sequences (e.g., Díez Fernández et al, 2010;Esteban et al, 2011;Pereira et al, 2012aPereira et al, , 2012bTalavera et al, 2012;Pastor-Galán et al, 2013;Fernández-Suárez et al, 2014;Shaw et al, 2014;da Silva et al, 2015;Rodrigues et al, 2015). The detrital record of syn-to post-collisional basins has provided important information on the exhumation history and the sedimentary transport systems during orogenesis (Dinis et al, 2012;Pastor-Galán et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

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The transition from Pangea amalgamation to fragmentation: Constraints from detrital zircon geochronology on West Iberia paleogeography and sediment sources

Dinis

Fernandes

Jorge

et al. 2018

Sedimentary Geology

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Detrital zircon U-Pb geochronology data from late Carboniferous to Triassic clastic sedimentary rocks in SW Iberia were used to investigate the regional paleogeography during the transition from Pangea amalgamation to breakup. The major U-Pb zircon age peaks are middle Devonian to Carboniferous (~390-300 Ma), CambrianOrdovician (~530-440 Ma), Cryogenian-Ediacaran (~750-540 Ma), Stenian-Tonian (~1.2-0.9 Ga) and Paleoproterozoic (~2.3-1.8 Ga). Rapid exhumation of Variscan crystalline rocks at the contact between the South Portuguese zone and Ossa Morena Zone, explains the abundance of late Paleozoic ages in the upper Carboniferous-lower Permian continental successions. The U-Pb zircon data constrain the maximum depositional age of the Santa Susana Basin to c. 304 Ma and the Viar Basin to c. 297 Ma. The Triassic sequences, despite being c. 100 Ma younger than the Variscan tectonothermal events, contain low proportions of late Paleozoic zircon. The major peaks in all zircon spectra closely resemble those found in the adjacent basement rocks, indicating small source areas, mainly located near the rift shoulders. Longer travelled fluvial systems are postulated for the eastern portions of the Algarve Basin, which was closer to the westward advancing Tethys Ocean than the rift basins of West Iberia. Sequences that contain significant proportions of~1.2-0.9 Ga zircon are probably recycled from post-collisional Carboniferous-Permian continental deposits that were more extensive than those found today.

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Section: Triassic (Early Fragmentation)mentioning

confidence: 85%

Section: Main Zircon Forming Events and Sourcesmentioning

confidence: 99%

Section: Triassic (Early Fragmentation)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The transition from Pangea amalgamation to fragmentation: Constraints from detrital zircon geochronology on West Iberia paleogeography and sediment sources

Dinis

Fernandes

Jorge

et al. 2018

Sedimentary Geology

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“…As a result, the obtained data provide solid information that allows us to discuss wide regional aspects, as provenance areas or the paleoposition of the study sequences; nevertheless, these data are insufficient to precise local aspects of the study sequences, as their maximum depositional age. This limitation is implied in other detrital zircon age studies, in which the paucity of youngest data is also noticeable (e.g., Pereira et al, 2012a;Shaw et al, 2014). Moreover, this can be stressed if some of the obtained ages are too young, and are in conflict with regional or stratigraphic evidences.…”

Section: Limitations Of the Detrital Zircon Datamentioning

confidence: 92%

Detrital zircons from the Ordovician rocks of the Pyrenees: Geochronological constraints and provenance

et al. 2016

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Ordovician ironstone of the Iberian margin: Coastal upwelling, ocean anoxia and Palaeozoic biodiversity

Pufahl

Squires

Murphy

et al. 2020

The Depositional Record

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Middle to Upper Ordovician ironstone and associated sedimentary rocks of the West Asturian‐Leonese and Cantabrian tectonostratigraphic zones, Spain, provide new information regarding the Palaeozoic Fe cycle and the palaeoceanography of the Rheic Ocean. Examination of drill cores and outcrops indicates the southeastern margin of this narrow seaway was a dynamic continental shelf where upwelling of ferruginous seawater and storm currents controlled lithofacies character. Parasequence composition and stacking relationships suggest ironstone accumulated during marine transgression as accommodation increased from lowstand conditions. Proximal parasequences record aggradation from deep subtidal to shoreface environments. Hummocky cross‐stratified sandstone and organic‐rich siltstone grade upwards into swaley cross‐stratified sandstone and granular Fe‐silicate‐rich ironstone capped by a flooding surface. Distal parasequences were deposited below storm wave base on the distal shelf and are composed of variably bioturbated organic‐rich siltstone with thin Fe‐chlorite and phosphorite layers. These differences in parasequence character define two different ironstone factories where Fe was concentrated and precipitated in sediment. Lithofacies associations support an emerging model for ironstone deposition where coastal upwelling delivered and stimulated the precipitation of Fe within shelf sediment. This notion provides further evidence for the development of intermittent anoxic water masses in an Ordovician ocean that was near the threshold of becoming fully ventilated. This style of Fe delivery probably represents a tipping point in the oxygenation history of the Phanerozoic oceans and is a throwback to the Precambrian when widespread anoxia allowed hydrothermal Fe to concentrate in the global ocean. New data suggest that minor extinction events punctuating the Great Ordovician Biodiversification Event may be traced to these anoxic waters, which in addition to Fe, were also enriched in biologically toxic, redox sensitive trace elements. Conversely, precipitation of upwelling‐related ironstone may have helped sequester these trace elements, providing a negative feedback response that would aid post‐extinction recovery.

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Provenance variability along the Early Ordovician north Gondwana margin: Paleogeographic and tectonic implications of U-Pb detrital zircon ages from the Armorican Quartzite of the Iberian Variscan belt

Cited by 98 publications

References 92 publications

The transition from Pangea amalgamation to fragmentation: Constraints from detrital zircon geochronology on West Iberia paleogeography and sediment sources

The transition from Pangea amalgamation to fragmentation: Constraints from detrital zircon geochronology on West Iberia paleogeography and sediment sources

Detrital zircons from the Ordovician rocks of the Pyrenees: Geochronological constraints and provenance

Ordovician ironstone of the Iberian margin: Coastal upwelling, ocean anoxia and Palaeozoic biodiversity

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