Universidad Complutense de Madrid
E-Prints Complutense

Late Cambrian magmatic arc activity in peri-Gondwana: geochemical evidence from metagranitoid rocks of the Basal Allochthonous Units of NW Iberia

Impacto

Downloads

Downloads per month over past year

Andonaegui Moreno, Pilar and Abati Gómez, Jacobo and Díez Fernández, Rubén (2017) Late Cambrian magmatic arc activity in peri-Gondwana: geochemical evidence from metagranitoid rocks of the Basal Allochthonous Units of NW Iberia. Geologica Acta, 15 (4). pp. 305-321. ISSN 1695-6133

[img]
Preview
PDF
Creative Commons Attribution Share Alike.

3MB

Official URL: http://revistes.ub.edu/index.php/GEOACTA/article/view/GeologicaActa2017.15.4.4


URLURL Type
http://www.ub.edu/web/ub/ca/Organisation


Abstract

The North African section of the Gondwana margin was the site of voluminous, arc-related magmatism during the Late Neoproterozoic (Avalonian–Cadomian orogen). The lower (and older) metasedimentary sequence that constitutes the Basal Units of the Allochthonous Complexes of NW Iberia was deposited in that setting. In these units, sedimentation was followed by the intrusion of tonalites and granodiorites in the late Cambrian (ca. 493–489Ma). In the Late Paleozoic, the collision of Gondwana and Laurussia (Variscan orogeny) deformed and metamorphosed the whole ensemble. New whole rock geochemical analysis performed in seven samples of metatonalites and fourteen samples of metagranodiorites are characterized by: i) slight enrichment in incompatible elements (Rb, Ba, Th, U), ii) negative anomalies in Nb, Ta, P, and Ti, and iii) negative anomalies in Eu. These chemical features are in agreement with a subduction-related setting for the genesis of both types of magma, which is also supported by chemical discrimination using tectonic setting diagrams. Positive anomalies of Pb suggest a crustal component. The new geochemical data reveal that the convergent orogen that ruled the paleogeography of the Gondwana periphery during the Neoproterozoic (Cadomian orogen) remained active beyond the Neoproterozoic-Cambrian transition, up to at least late Cambrian times.


Item Type:Article
Uncontrolled Keywords:Convergent margin, Subduction, Magmatism, Whole rock geochemistry, NW Iberian Massif
Subjects:Sciences > Geology > Geochemistry
Sciences > Geology > Petrology
ID Code:47610
Deposited On:06 Jul 2020 08:20
Last Modified:13 Jul 2020 09:18

Origin of downloads

Repository Staff Only: item control page