Tectono-magmatic division of the Late Ordovician (Sandbian) volcanism at the south-western margin of Baltica using immobile trace elements: Relations to the plate movements in the Iapetus Palaeo-Ocean

Tarmo Kiipli, Rutt Hints, Toivo Kallaste, Arne T. Nielsen, Siim Pajusaar, Niels H. Schovsbo

Publikation: Bidrag til tidsskriftArtikelForskningpeer review

5 Citationer (Scopus)

Abstrakt

Immobile trace elements in K-bentonites indicate three volcanic stages during the Sandbian Stage of the Late Ordovician: Early Grefsen is characterised by high-Ti source magmas alternating with a few high-Zr layers. Middle Grefsen is characterised by overall low-Ti source magmas with multiple high-Zr layers alternating with less frequent low-Zr layers. Late Grefsen to Early Katian is characterised by a low content of all studied immobile trace elements (Ti, Zr, Nb, and Th). In all K-bentonites, the Nb/Al2O3 ratio indicates subalkaline volcanism dominated by rhyolites. In the Early Grefsen stage, andesites and dacites occur. The TiO2/Al2O3 versus Zr/Al2O3 discrimination diagram suggests low- and high-temperature magmatism. Low-temperature magmatism may have occurred during subduction of water-rich oceanic sediments in the frontal arc of Avalonia and high-temperature magmatism during the overriding of a mid-ocean ridge or hot spot. The coeval end of the volcanic record in Avalonia and Baltica may indicate the collision of Avalonia with a hypothetical continental crust within the Iapetus Ocean.

OriginalsprogEngelsk
Sider (fra-til)5155-5165
Antal sider11
TidsskriftGeological Journal
Vol/bind55
Udgave nummer7
DOI
StatusUdgivet - 1 jul. 2020

Programområde

  • Programområde 3: Energiressourcer

Fingeraftryk

Dyk ned i forskningsemnerne om 'Tectono-magmatic division of the Late Ordovician (Sandbian) volcanism at the south-western margin of Baltica using immobile trace elements: Relations to the plate movements in the Iapetus Palaeo-Ocean'. Sammen danner de et unikt fingeraftryk.

Citationsformater