title: The Early Cambrian bimodal magmatism in the northeastern Siberian Craton
metadata.name: dc.contributor.author
metadata.value: Худолей, Андрей Константинович
metadata.lang: -
metadata.name: dc.date.accessioned
metadata.value: 2020-09-08T15:43:40Z
metadata.lang: -
metadata.name: dc.date.available
metadata.value: 2020-09-08T15:43:40Z
metadata.lang: -
metadata.name: dc.date.issued
metadata.value: 2016
metadata.lang: -
metadata.name: dc.identifier.uri
metadata.value: http://hdl.handle.net/11701/19263
metadata.lang: -
metadata.name: dc.description.abstract
metadata.value: We present new data on geochemistry, isotopic geochemistry, and geochronology of the Early Cambrian igneous rocks of the northeastern
  Siberian Craton (Kharaulakh anticlinorium, contact between the Siberian Platform and the West Verkhoyansk sector of the Verkhoyansk
  fold-and-thrust belt united into an Early Cambrian bimodal complex. This complex comprises trachyrhyolites forming pebbles in conglomerates
  near the base of the Cambrian succession, overlying trachybasalts, and mafic sills and dikes cutting Neoproterozoic strata. According to
  chemical composition, the felsic rocks are high-alkali rhyolites and correspond to A-type granites. The high contents of Ta, Nb, Hf, Tb, and
  Zr in these rocks suggest the presence of enriched mantle material in their magmatic sources. The mafic volcanics are high-Ti trachybasalts
  and trachydolerites with similar geochemical characteristics corresponding to alkali basalts or OIB. The high (Tb/Yb)PM ratios in these volcanics
  evidence that their magmatic source was the garnet peridotite mantle located at depths more than 90 km and characterized by a low degree
  of melting. However, the rhyolites, trachybasalts, and trachydolerites show high positive εNd(T) values (4.2–4.7, 7.5–8.9, and 7.2–8.2,
  respectively) indicating a depleted mantle source and no crustal contamination. The high (Nb/Yb)PM ratio points to the mixing of magmas
  from enriched and depleted mantle sources. Mafic magmas might have been generated from a heterogeneous source or interacted with the
  depleted mantle before intrusion. Both the felsic and the mafic rocks formed in within-plate environments. U–Pb zircon dating yielded
  concordant ages of 525.6 ± 3.9 and 537.0 ± 4.2 Ma, corresponding to the Early Cambrian age of the rhyolites. The date of 546.0 ± 7.7 Ma
  obtained for one sample points (with regard to the error) to the Late Vendian–Early Cambrian age. Thus, at the Vendian–Early Cambrian
  boundary, the northeastern Siberian Platform was subjected to continental rifting accompanied by bimodal magmatism of antidrome evolution.
  According to paleotectonic reconstructions, this part of the Siberian Craton might have been connected with the eastern margin of Laurentia
  in the Late Neoproterozoic (Late Riphean–Late Vendian), and continental rifting that started at the Vendian–Cambrian boundary led to their
  separation. The obtained isotope-geochronological data suggest that the studied bimodal complex began to form at the Vendian–Cambrian
  boundary and this process terminated no earlier than the end of the Terreneuvian (Tommotian), i.e., the complex formed during rifting for
  about 20 Myr.
metadata.lang: en_GB
metadata.name: dc.language.iso
metadata.value: en
metadata.lang: en_GB
metadata.name: dc.title
metadata.value: The Early Cambrian bimodal magmatism in the northeastern Siberian Craton
metadata.lang: en_GB
metadata.name: dc.type
metadata.value: Article
metadata.lang: en_GB
resources.filename: Prokopiev-et-al-2016-GG.pdf
resources.url: https://dspace.spbu.ru/bitstream/11701/19263/1/Prokopiev-et-al-2016-GG.pdf
resources.format: Adobe PDF
resources.size: 7,03 MB