The Timpa delle Murge ophiolitic gabbros, southern Apennines: insights from petrology and geochemistry and consequences to the geodynamic setting

Authors

  • Giovanna Rizzo <p>Dipartimento di Scienze, Universit&agrave; degli Studi della Basilicata, Potenza</p>
  • Salvatore Laurita Dipartimento di Scienze, Universit&agrave; degli Studi della Basilicata, Potenza
  • Uwe Altenberger Institute of Earth and Environmental Science, University of Potsdam

DOI:

https://doi.org/10.2451/2018PM741

Keywords:

Southern Apennines, Liguride Complex, North Calabrian Unit, ophiolite, gabbros.

Abstract

Abstract

The Timpa delle Murge ophiolite in the North Calabrian Unit is part of the Liguride Complex (southern Apennines). The study is concentrated on the gabbroic part of the ophiolite of the Pollino area. They preserve the high-grade ocean floor metamorphic and locally developed flaser textures under ocean floor conditions. The primary magmatic assamblages are clinopyroxene, plagioclase, and opaques. Brown hornblende is a late magmatic phase. Green hornblende, actinolite, albite, chlorite and epidote display metamorphic recrystallization under lower amphibolite facies conditions, followed by greenschist facies.
The gabbros show subalkaline near to alkaline character with a tendency to a more calkalkaline trend. The normalization to primitive mantle and mid-ocean ridge basalt (N-MORB) compositions indicates a considerable depletion in Nb, P, Zr and Ti and an enrichment in Ba, Rb, K, Sr and Eu. This points to a mantle source, which is not compatible with a “normal” mid-ocean ridge situation. Rather, the gabbros are generated from a N-MORB-like melt with a strong crustal component, which was influenced by subduction related fluids and episodic melting during mid-ocean-ridge processes.
Plausible geodynamic settings of the Timpa delle Murge gabbros are oceanic back-arc positions with embryonic MORB-activities. Similar slab contaminated magmatism is also known from the early stage of island arc formation in supra-subduction zone environments like the Izu-Bonin-Mariana island arc.

 

Author Biographies

Giovanna Rizzo, <p>Dipartimento di Scienze, Universit&agrave; degli Studi della Basilicata, Potenza</p>

Department of Science

Salvatore Laurita, Dipartimento di Scienze, Universit&agrave; degli Studi della Basilicata, Potenza

Department of Sciences

Uwe Altenberger, Institute of Earth and Environmental Science, University of Potsdam

Institute of Earth and Environmental Science

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Published

2018-04-03

Issue

Section

PETROLOGY