IDEAN   23403
INSTITUTO DE ESTUDIOS ANDINOS "DON PABLO GROEBER"
Unidad Ejecutora - UE
artículos
Título:
Geochemical make-up of oceanic peridotites from NW Turkey and the multi-stage melting history of the Tethyan upper mantle
Autor/es:
IBRAHIM UYSAL; DUNDAR SEN; YALCIN ERSOY; YILDRIM DILEK; SAMET SAKA; FEDERICA ZACCARINI; MONICA P ESCAYOLA; ORHAN KARSLI
Revista:
MINERALOGY AND PETROLOGY
Editorial:
SPRINGER WIEN
Referencias:
Lugar: Viena; Año: 2014 vol. 108 p. 49 - 69
ISSN:
0930-0708
Resumen:
Abstract We present the whole-rock and the mineral chemical
data for upper mantle peridotites from the Harmancık region in
NW Turkey and discuss their petrogenetic?tectonic origin. These
peridotites are part of a Tethyan ophiolite belt occurring along
the İzmir-Ankara-Ercincan suture zone in northern Turkey, and
include depleted lherzolites and refractory harzburgites. The
Al2O3 contents in orthopyroxene and clinopyroxene from the
depleted lherzolite are high, and the Cr-number in the coexisting
spinel is low falling within the abyssal field. However, the
orthopyroxene and clinopyroxene in the harzburgites have lower
Al2O3 contents for a given Cr-number of spinel, and plot within
the lower end of the abyssal field. The whole-rock geochemical
and the mineral chemistry data imply that the Harmancık peridotites
formed by different degrees of partial melting (~%10?
27) of the mantle. The depleted lherzolite samples have higher
MREE and HREE abundances than the harzburgitic peridotites,
showing convex-downward patterns. These peridotites represent
up to ~16 % melting residue that formed during the initial
seafloor spreading stage of the Northern Neotethys. On the other
hand, the more refractory harzburgites represent residues after
~4?11 % hydrous partial melting of the previously depleted
MOR mantle, which was metasomatized by slab-derived
fluids during the early stages of subduction. The
Harmancık peridotites, hence, represent the fragments
of upper mantle rocks that formed during different
stages of the tectonic evolution of the Tethyan oceanic
lithosphere in Northern Neotethys. We infer that the
multi-stage melting history of the Harmancık peridotites
reflect the geochemically heterogeneous character of the
Tethyan oceanic lithosphere currently exposed along the
İzmir-Ankara-Erzincan suture zone.