Aluminous granulites from the Pulur complex, NE Turkey: A case of partial melting, efficient melt extraction and crystallisation

Gültekin Topuz, Rainer Altherr*, Angelika Kalt, Muharrem Satir, Olaf Werner, Winfried H. Schwarz

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

139 Citations (Scopus)

Abstract

In the Pulur complex, NE Turkey, a heterogeneous rock sequence ranging from quartz-rich mesocratic gneisses to silica- and alkali-deficient, Fe-, Mg- and Al-rich melanocratic rocks is characterized by granulite-facies assemblages involving garnet, cordierite, sillimanite, ilmenite, ±spinel, ±plagioclase, ±quartz, ±biotite, ±corundum, rutile and monazite. Textural evidence for partial melting in the aluminous granulites, particularly leucosomes, is largely absent or strongly obliterated by a late-stage hydrothermal overprint. However, inclusion relations, high peak P - T conditions, the refractory modes, bulk and biotite compositions of the melanocratic rocks strongly support a model of partial melting. The melt was almost completely removed from the melanocratic rocks and crystallised within the adjacent mesocratic gneisses which are silica-rich, bear evidence of former feldspar and show a large range in major element concentrations as well as a negative correlation of most elements with SiO2. Peak conditions are estimated to be ≥800 °C and 0.7-0.8 GPa. Subsequent near-isothermal decompression to ∼0.4-0.5 GPa at 800-730 °C is suggested by the formation of cordierite coronas and cordierite-spinel symplectites around garnet and in the matrix. Sm-Nd, Rb-Sr and 40Ar/39Ar isotope data indicate peak conditions at ∼330 Ma and cooling below 300 °C at ∼310 Ma.

Original languageEnglish
Pages (from-to)183-207
Number of pages25
JournalLithos
Volume72
Issue number3-4
DOIs
Publication statusPublished - Feb 2004
Externally publishedYes

Funding

This paper benefited from stimulating discussions with Alfons Berger. Careful and constructive reviews by Ian Scrimgeour and Kjell P. Skjerlie helped to clarify important aspects of the paper and to improve the style. Our thanks are especially due to Ilona Fin, Udo Geilenkirchen and Jürgen Mällich for preparing hundreds of high-quality thin sections. We also appreciate the assistance of Thomas Ludwig and Hans-Peter Meyer during microprobe and scanning electron microscope work. The help of Gisela Bartholomä and Marcella Schumann during mineral separation is greatly acknowledged. Rb–Sr and Sm–Nd isotope analyses were performed under the supervision of Ernst Hegner. The authors express their gratitude to M. Burhan Sadiklar for his logistic help and encouragement during each stage of the study. Our special thanks go to the friendly local residents for their hospitality. This study is part of the Dr. rer. nat. thesis of G.T. that was financially supported by the Deutsche Akademische Austauschdienst (DAAD) and the Deutsche Forschungsgemeinschaft (DFG-Graduiertenkolleg no. 273 at Heidelberg).

FundersFunder number
DFG-Graduiertenkolleg
Deutscher Akademischer Austauschdienst
Deutsche Forschungsgemeinschaft

    Keywords

    • Aluminous granulite
    • Dehydration melting
    • Isotopic dating
    • Melt extraction
    • Pulur
    • Turkey

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