From a bipartite Gondwanan shelf to an arcuate Variscan belt: The early Paleozoic evolution of northern Peri-Gondwana

Stephan, Tobias; Kroner, Uwe; Romer, Rolf L.; Rösel, Delia

doi:10.1016/j.earscirev.2019.03.012

Cited by 91 publications

(48 citation statements)

References 226 publications

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“…According to the Gondwana super-fan model, Saudi Arabia would lie more distal along the sediment path to the northeast. Based on a more extensive detrital zircon dataset including also peri-Gondwana units and using multivariate data analysis, Stephan et al (2019a) showed the existence of three contrasting provenance end-members in Lower Palaeozoic sedimentary rocks of the former Gondwanan shelf, namely the Avalonian, West African and East African -Arabian zircon provinces (see also Stephan et al 2019b). The East African -Arabian zircon province corresponds to the Gondwana super-fan system of Meinhold et al (2013).…”

Section: C Gondwana Super-fan System and East African -Arabian Zirmentioning

confidence: 97%

Detrital zircon provenance of north Gondwana Palaeozoic sandstones from Saudi Arabia

et al. 2020

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We present the first comprehensive detrital zircon U–Pb age dataset from Palaeozoic sandstones of Saudi Arabia, which provides new insights into the erosion history of the East African Orogen and sediment recycling in northern Gondwana. Five main age populations are present in varying amounts in the zircon age spectra, with age peaks at ~625 Ma, ~775 Ma, ~980 Ma, ~1840 Ma and ~2480 Ma. Mainly igneous rocks of the Arabian–Nubian Shield are suggested to be the most prominent sources for the Ediacaran to middle Tonian zircon grains. Palaeoproterozoic and Archaean grains may be xenocrystic zircons or they have been recycled from older terrigenous sediment. A primary derivation from Palaeoproterozoic and Archaean basement is also possible, as rocks of such age occur in the vicinity. Approximately 4 % of the detrital zircons show Palaeozoic (340–541 Ma) ages. These grains are likely derived from Palaeozoic post-orogenic and anorogenic igneous rocks of NE Africa and Arabia. A few single grains gave up to Eoarchaean (3.6–4.0 Ga) ages, which are the oldest zircons yet described from Arabia and its vicinity. Their origin, however, is yet unknown. Detrital zircons with U–Pb ages of ~1.0 Ga are present in varying amounts in all of the samples and are a feature of terrigenous sediment belonging to the Gondwana super-fan system with an East African – Arabian zircon province.

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Section: C Gondwana Super-fan System and East African -Arabian Zirmentioning

confidence: 97%

Detrital zircon provenance of north Gondwana Palaeozoic sandstones from Saudi Arabia

et al. 2020

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“…The evolution of the Indian Ocean over the past 200 Ma provides an instructive parallel for understanding the Palaeozoic geography of North Africa and southern Europe. The simple palaeogeography for the peri-Gondwanan area before the main Variscan Orogeny envisaged by Stephan et al (2018Stephan et al ( , 2019 is incorrect, even though they presented a very professional synthesis of zircon data from all of the North African and southern European peri-Gondwanan areas. However, the age spectra of detrital zircons, if interpreted critically, can only reveal their original derivation, but not their subsequent plate-tectonic and sedimentary pathways.…”

Section: Discussionmentioning

confidence: 99%

“…The publications by Kroner et al (2007), Kroner & Romer (2013) and Stephan et al (2018Stephan et al ( , 2019 have compiled the available U-Pb laser inductively coupled plasma mass spectrometry ages of detrital zircons from various parts of the European Variscides, America, northern Africa and the Middle East (late Neoproterozoic -Early Devonian). They have convincingly demonstrated that those age spectra form very uniform groupings, but from that they concluded that all the sampled areas were part of a broad, contiguous shelf fringing the north of the Gondwana craton during early Palaeozoic time before the start of the main Variscan Orogeny.…”

Section: Significance Of Detrital Zircon Agesmentioning

confidence: 99%

Detrital zircons and the interpretation of palaeogeography, with the Variscan Orogeny as an example

2019

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Analysis of the distribution of detrital zircon grains is one of the few parameters by which Precambrian palaeogeography may be interpreted. However, the break-up of Pangea and the subsequent dispersal of some of its fragments around the Indian Ocean demonstrate that zircon analysis alone may be misleading, since zircons indicate their original derivation and not their subsequent plate-tectonic pathways. Based on analysis of Precambrian–Ordovician zircon distributions, the presence of microcontinents and separating oceans in the north Gondwanan realm has been rejected in favour of an undivided pre-Variscan continental northwards extension of Africa to include Iberia, Armorica and neighbouring southern European terranes, based on analysis of Precambrian–Ordovician zircon distribution. However, contrasting views, indicating the presence of three peri-Gondwanan oceans with complete Wilson cycles, are reinforced here by a critical reappraisal of the significance of that Variscan area detrital zircon record together with a comparison of the evolution of the present-day Indian Ocean, indicating that Iberia, Armorica and other terranes were each separate from the main Gondwanan craton during the early Palaeozoic Era.

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“…While Cadomian magmatism lasted until at least 520 Ma (Neubauer, 2002), the main phase is roughly synchronous or slightly younger than the Pan-African orogeny (Kröner and Stern, 2004). Hence, early Ediacaran detrital zircons are difficult to definitively link to either Pan-African or Cadomian sources, especially as they could be recycled from Paleozoic strata (e.g., Hart et al, 2016;Stephan et al, 2019a).…”

Section: Pan-african and Cadomian Orogeniesmentioning

confidence: 99%

“…based on Pfiffner (2014), McCann (2008), Krawczyk et al (2008), and Stephan et al (2019a). While uncertainties and discordance of LA-ICP-MS U-Pb ages allow for overlap between these groupings, they provide a potential and viable way to depict and estimate detrital zircon contributions from these different source regions and to identify potential provenance changes in the Molasse Basin.…”

Section: Detrital U-pb Age Groups and Associated Orogenic Cyclesmentioning

confidence: 99%

Tectonic exhumation of the Central Alps recorded by detrital zircon in the Molasse Basin, Switzerland

et al. 2020

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Abstract. Eocene to Miocene sedimentary strata of the Northern Alpine Molasse Basin in Switzerland are well studied, yet they lack robust geochronologic and geochemical analysis of detrital zircon for provenance tracing purposes. Here, we present detrital zircon U–Pb ages coupled with rare-earth and trace element geochemistry to provide insights into the sedimentary provenance and to elucidate the tectonic activity of the central Alpine Orogen from the late Eocene to mid Miocene. Between 35 and 22.5 ± 1 Ma, the detrital zircon U–Pb age signatures are dominated by age groups of 300–370, 380–490, and 500–710 Ma, with minor Proterozoic age contributions. In contrast, from 21 Ma to ∼ 13.5 Ma (youngest preserved sediments), the detrital zircon U–Pb age signatures were dominated by a 252–300 Ma age group, with a secondary abundance of the 380–490 Ma age group and only minor contributions of the 500–710 Ma age group. The Eo-Oligocene provenance signatures are consistent with interpretations that initial basin deposition primarily recorded unroofing of the Austroalpine orogenic lid and lesser contributions from underlying Penninic units (including the Lepontine dome), containing reworked detritus from Variscan, Caledonian–Sardic, Cadomian, and Pan-African orogenic cycles. In contrast, the dominant 252–300 Ma age group from early Miocene foreland deposits is indicative of the exhumation of Variscan-aged crystalline rocks from the Lepontine dome basement units. Noticeable is the lack of Alpine-aged detrital zircon in all samples with the exception of one late Eocene sample, which reflects Alpine volcanism linked to incipient continent–continent collision. In addition, detrital zircon rare-earth and trace element data, coupled with zircon morphology and U∕Th ratios, point to primarily igneous and rare metamorphic sources. The observed switch from Austroalpine to Penninic detrital provenance in the Molasse Basin at ∼ 21 Ma appears to mark the onset of synorogenic extension of the Central Alps. Synorogenic extension accommodated by the Simplon fault zone promoted updoming and exhumation the Penninic crystalline core of the Alpine Orogen. The lack of Alpine detrital zircon U–Pb ages in all Oligo-Miocene strata corroborate the interpretations that between ∼ 25 and 15 Ma, the exposed bedrock in the Lepontine dome comprised greenschist-facies rocks only, where temperatures were too low for allowing zircon rims to grow, and that the Molasse Basin drainage network did not access the prominent Alpine-age Periadriatic intrusions located in the area surrounding the Periadriatic Line.

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From a bipartite Gondwanan shelf to an arcuate Variscan belt: The early Paleozoic evolution of northern Peri-Gondwana

Cited by 91 publications

References 226 publications

Detrital zircon provenance of north Gondwana Palaeozoic sandstones from Saudi Arabia

Detrital zircon provenance of north Gondwana Palaeozoic sandstones from Saudi Arabia

Detrital zircons and the interpretation of palaeogeography, with the Variscan Orogeny as an example

Tectonic exhumation of the Central Alps recorded by detrital zircon in the Molasse Basin, Switzerland

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