ON THE RELATIVELY COMPOSITIONAL HOMOGENEITY OF ALBANIAN EASTERN OPHIOLITIC BELT

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Published: Jul 28, 2016
DOI: https://doi.org/10.12681/bgsg.14106
Keywords:
Chromite ophiolite section SSZ-type
Α. Çina
Institute of Geosciences, Energy, Water and Environment, Polytechnic University of Tirana
Abstract

Ophiolitic formation of Albanides, named as Mirdita zone, represents a compact
segment of oceanic lithosphere of Middle-Upper Jurassic. Based on petrographic,
geochemical and metalogenical features two types of belts are distinguished: western
MORB and eastern SSZ types. In fact, structural and geological units as well as many
other elements have shed light on lack of a sharp separation between the two belts.
Recent investigations have evidenced that different ultramafic massifs of western
ophiolitic formation, represent an evident variation of their composition from
harzburgite to lherzolitic -types. This composition reflects a different grade of partial
melting of upper mantle. Peridotites show a high variability, from 0.3 - 3.8 wt.%
Al2O3, varying from small to highly extreme depleted peridotite.
On the contrary, Albanian eastern belt, it seems to be formed by a more homogeneous
hartzburgitic mantle.
Detailed petrologic and metallogenic investigations have evidenced that this belt
changes also from one massif to another, naturally at a smaller level, therefore it is
easier to be named relatively homogeneous. It is distinguished by a higher melting
degree, chiefly of hartzburgitic-type, characterized by whole and thick ultramafic
section, as well as by metalogenic variety, mostly of metallurgic-type of chromite
mineralization. It is supposed that rock-forming and mineraluzation processes have
been developed not uniformly along the ophiolitic belt.

Article Details
  • Section
  • Petrology and Mineralogy
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