The origin of the Popiel peridotite (Western Sudetes, SW Poland): metamorphism of the island arc tholeiitic cumulate

Anna Kukula, Jacek Puziewicz, Theodoros Ntaflos

Veröffentlichungen: Beitrag in FachzeitschriftArtikelPeer Reviewed

Abstract

A small (280 × 140 m) outcrop of peridotite occurs on Popiel Hill (Sudetes, SW Poland) within the low-grade metabasic rocks of the Rudawy Janowickie Complex, which form the eastern and northeastern cover of the Variscan Karkonosze granite. The peridotite is situated on the Intra-Sudetic Fault, one of the major Variscan dislocations in the region. The rock consists of strongly tectonised olivine (Fo84-88) and orthopyroxene (Mg# 0.84-0.88) aggregates, overgrown by tremolite-magnesiohornblende, locally forming large crystals, embedded in serpentine. Spinel and magnetite are subordinate; ilmenite, Fe-sulfide, and apatite are accessories. The bulk-rock chemical composition suggests a lherzolitic composition and the occurrence of primary clinopyroxene, now completely replaced by tremolite and magnesiohornblende. Rare Earth Element patterns are flat, slightly enriched relatively to primitive mantle, as is typical of island arc tholeiites. Olivine, orthopyroxene, and spinel were the first to crystallize, and they represent relics of a primary igneous assemblage. They were followed by tremolite and serpentine, formed during uplift and related metamorphism. The last mineral to crystallise was magnesio-hornblende, which originated due to contact metamorphism by the Karkonosze granite magma. The Popiel peridotite probably represents a small slice of lherzolitic cumulate, which originated in a tholeiitic magma chamber at the roots of a supra-subduction volcanic arc.

OriginalspracheEnglisch
Seiten (von - bis)239-247
Seitenumfang9
FachzeitschriftGeological Quarterly
Jahrgang59
Ausgabenummer2
DOIs
PublikationsstatusVeröffentlicht - 2015

ÖFOS 2012

  • 105120 Petrologie

Zitationsweisen