Oroclines of the Iberian Variscan beltpaleocurrent analysis, U-Pb detrital zircon age dating, and paleogeographic implications

  1. J. Shaw 1
  2. S.T. Johnston 1
  3. G. Gutiérrez-Alonso 2
  4. A.B. Weil 3
  1. 1 University of Victoria
    info
    University of Victoria

    Victoria, Canadá

    ROR https://ror.org/04s5mat29

    Geographic location of the organization University of Victoria
  2. 2 Universidad de Salamanca
    info
    Universidad de Salamanca

    Salamanca, España

    ROR https://ror.org/02f40zc51

    Geographic location of the organization Universidad de Salamanca
  3. 3 Bryn Mawr College
    info
    Bryn Mawr College

    Bryn Mawr, Estados Unidos

    ROR https://ror.org/05sjwtp51

    Geographic location of the organization Bryn Mawr College
Journal:
Geotemas (Madrid)

ISSN: 1576-5172

Year of publication: 2012

Issue Title: VIII Congreso Geológico de España, Oviedo, 17-19 de julio, 2012.

Issue: 13

Pages: 453-456

Type: Article

More publications in: Geotemas (Madrid)

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Abstract

Paleocurrent and U-Pb detrital zircon age data from the Lower Ordovician Armorican Quartzite of the Cantabrian, West Asturian-Leonese and Central Iberian zones define the geometry and paleogeography of the Iberian Variscan belt. Paleoflow directions oriented at high angles to structural strike reveal the Cantabrian Orocline of northwest Iberia to be continuous with a second, the Central Iberian Orocline. The two oroclines form an s-shaped fold pair of continental scale. Palinspastic restoration to a paleomagnetically constrained Late Variscan (Carboniferous) N-S trend yields a linear orogenic ribbon (The Cantabrian – Central Iberian Ribbon) >1500 km long characterized by passive margin strata (presumably Gondwanan) that display an offshore paleoflow towards a westerly oceanic domain (presumably the Rheic). Detrital zircons suggests that the Cantabrian-Central Iberian ribbon formed part of the L. Paleozoic Gondwanan margin that stretched east-west along the northern limits of the Saharan Metacraton and Arabian-Nubian Shield. A 90° counterclockwise rotation is required to reorient the ribbon to an Early Variscan N-S trend, suggesting post-Lower Ordovician, pre-Variscan separation from Gondwana.