GEOCHEMISTRY AND TECTONIC SETTING OF ECLOGITE PROTOLITHS FROM KECHROS COMPLEX IN EAST RHODOPE (N.E. GREECE)

PDF (English)
Publiée : Jan 1, 2010
DOI : https://doi.org/10.12681/bgsg.11659
I. Baziotis
E. Mposkos
Résumé

Eclogites and partially amphibolitized eclogites from the metamorphic Kechros complex in East Rhodope are studied in order to provide the geodynamic framework for the origin of their protoliths. Geochemical evidence from whole rock major and trace element concentrations shows two distinct protolith groups. The low-Fe-Ti eclogites (Charakoma locality) have low-TiO2 content (<0.67 wt%), negative Nb anomalies, positive Sr anomalies, small negative Zr and Hf anomalies and variable enrichments in LILE (e.g. Rb and Ba). The REE patterns are characterized by strong LREE enrichment (LaN/YbN=5.45-5.81), HREE depletion (GdN/YbN=1.60-1.63) and HREE abundance within the range
of 9-10 × chondrite. The high-Fe-Ti eclogites (Kovalo and Virsini locality) have variable Sr contents, small to moderate LILE enrichment, HREE`s similar to MORB values and absence of Nb anomalies. The REE patterns of the Kovalo and Virsini eclogites are characterized by LREE depletion and relative flat MREE HREE patterns at approximately 20-30 × chondrite concentrations. Our results suggest that the protoliths of the Low-Ti eclogites show a continental rifting tectonic environment. In contrast, the protoliths of the High-Ti eclogites indicate formation of their protoliths by partial melting in an extensional oceanic environment.

Article Details
  • Rubrique
  • Petrology and Mineralogy
Creative Commons License

Ce travail est disponible sous licence Creative Commons Attribution - Pas d’Utilisation Commerciale 4.0 International.

Authors who publish with this journal agree to the following terms:

Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution Non-Commercial License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.

Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g. post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal. Authors are permitted and encouraged to post their work online (preferably in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work.

Téléchargements
Les données relatives au téléchargement ne sont pas encore disponibles.
Références
Bauer, C., Rubatto, D., Krenn, K., Proyer, A. and Hoinkes, G. 2007. A zircon study from the Rhodope
metamorphic complex, N-Greece: Time record of a multistage evolution. Lithos, 99, 207-228.
Baziotis, I., Mposkos, E. and Asimow, P.D. 2008. Petrogenesis of ultramafic rocks from the ultrahigh-pressure
metamorphic Kimi Complex in Eastern Rhodope (NE Greece). Journal of Petrology, 49, 5, 885-909.
Becker, H., Jochum, K.P. and Carlson, R.W. 2000. Trace element fractionation during dehydration of
eclogites from high-pressure terranes and the implications for element fluxes in subduction zones.
Chemical Geology, 163, 65-99.
Burg, J.P., Ricou, L.E., Ivanov, Z., Godfriaux, I., Dimov, D. and Klain, L. 1996. Syn-metamorphic nappe
complex in the Rhodope Massif: structure and kinematics. Terra Nova, 8, 6-15.
Cornelius, N.K., 2008. UHP metamorphic rocks of the Eastern Rhodope Massif, NE Greece: new constraints
from petrology, geochemistry and zircon ages. PhD Thesis, Johannes-Gutenberg Universität, Mainz.
Elliott, T., Plank, T., Zindler, A., White, W. and Bourdon, B. 1997. Element transport from slab to volcanic
front at the Mariana arc. Journal of Geophysical Research, 102 (B7), 14991-15019.
Ernst,W.G. and Liou, J.G., 1995. Contrasting plate-tectonic styles of the Qinling–Dabie–Sulu and Franciscan
metamorphics. Geology 23, 353–356.
XLIII, No 5 – 2530
Foley, S.F., Tiepolo, M. and Vannucci, R. 2002. Growth of continental crust controlled by melting of amphibolite,
not eclogite. Nature, 417, 837-840.
Hebert, L.B., Asimow, P.D. and Antoshechkina, P. 2009. Fluid source-based modeling of melt initiation
within the subduction zone mantle wedge: Implications for geochemical trends in arc lavas. Chemical
Geology, 266, 306-319.Jacob, D.E. and Foley, S.F. 1999. Evidence for Archean ocean crust with
low high field strength element signature from diamondiferous eclogite xenoliths. Lithos, 48, 317-336.
Jacob, D.E., Jagoutz, E., Lowry, D., Mattey, D. and Kudrjavtseva, G. 1994. Diamondiferous eclogites
from Siberia: remnants of Archean oceanic crust. Geochimica et Cosmochimica Acta, 58, 5191-5207.
Jacob, D.E. and Foley, S.F., 1999. Evidence for Archean ocean crust with low high field strength element
signature from diamondiferous eclogite xenoliths. Lithos, 48, 317-336.
Krohe, A. and Mposkos, E., 2002. Multiple generations of extensional detachments in the Rhodope Mountains
(N.Greece): evidence of episodic exhumation of high-P rocks. In: Blundell, D.J., Neubauer, G.
and Von Quant, A. (eds.): The timing and location of major ore deposits in an evolving orogen. Geological
Society of London, Special Publication, 204, 151-178.
Liati, A., 2005. Identification of repeated Alpine (ultra) high-pressure metamorphic events by U–pb
SHRIMP geochronology and REE geochemistry of zircon: the Rhodope zone of Northern Greece,
Contributions to Mineralogy and Petrology 150, 608–630.
Liati, A. and Mposkos, E., 1990. Evolution of the eclogites in the Rhodope Zone of northern Greece,
Lithos, 25, 89–99.
Lips, A.L.W., White, S.H. and Wijbrans, J.R. 2000. Middle–Late Alpine thermotectonic evolution of the
southern Rhodope Massif, Greece. Geodinamica Acta, 13, 281–292.
Martin, R.F., 1998. Symbols of the rock-forming minerals. The Nomenclature of minerals: A compilation
of IMA reports. IMA`98 Toronto, 148-149.
Mposkos, E., 1989. High-pressure metamorphism in gneisses and pelitic schists in the Eat Rhodope Zone
(N. Greece). Mineralogy and Petrology, 41, 25-39.
Mposkos, E. and Krohe, A., 2000. Petrological and structural evolution of continental high pressure (HP)
metamorphic rocks in the Alpine Rhodope domain (N.Greece). Proceedings of the 3rd International
Conference on the Geology of the Eastern Mediterranean, 221-232.
Mposkos, E. and Kostopoulos, D., 2001. Diamond, former coesite and supersilicic garnet in metasedimentary
rocks from the Greek Rhodope: a new ultrahigh-pressure metamorphic province established.
Earth and Planetary Science Letters, 192, 497-506.
Mposkos, E. and Liati, A., 1993. Metamorphic evolution of metapelites in the high-pressure terrane oft
he Rhodope zone, Northern Greece. Canadian Mineralogist, 31, 401-424.
Mposkos, E. andWawrzenitz, N., 1995. Metapegmatites and pegmatites bracketing the time of HP-metamorphism
in polymetamorphic rocks of the E-Rhodope: Petrological and geochronological constraints.
Geological Society of Greece, Special Publication 2(4), 602-608.
Stalder, R., Foley, S.F., Brey, G.P. and Horn, I. 1998. Mineral-aqueous fluid partitioning of trace elements
at 900-12000C and 3.0-5.7 GPa: new experimental data for garnet, clinopyroxene, and rutile, and implications
for mantle metasomatism. Geochimica et Cosmochimica Acta, 62, 1781-1801.
Sun, S.S. and McDonough, W.F., 1989. Chemical and isotopic systematics of oceanic basalts: implications
for mantle composition and process. In: Saunders, A.D. & Norry, J.M. (eds) Magmatism in
Ocean Basins. Geological Society of London, Special Publications 42, 313-345.
Wawrzenitz, N. and Mposkos, E., 1997. First evidence for lower Cretaceous HP / HT-metamorphism in
the Eastern Rhodope, North Aegean Region, North-East Greece. European Journal of Mineralogy,
, 659-664.
Articles les plus lus par le même auteur ou la même autrice