Abstract
This study examines the fluid-rock interaction and thermal evolution along a thrust that juxtaposes calcite-rich marbles of high P-T metamorphic unit of the Attic-Cycladic Massif (Greece) on top of a lower-grade dolomite marble unit. The Tertiary thrust represents a major phase of tectonic movement related to the decompression of the Alpine orogen in the Hellenides. The stable isotope signatures of the thrust plane and adjacent sections of the footwall and hanging wall rocks are characterized by significant carbon and oxygen isotope depletions. The depletion is most pronounced in calcite, but is almost entirely missing in coexisting dolomite. The isotopic patterns in the thrust zone can be explained by the infiltration of an externally derived water-rich H2O-CO2-CH4 fluid [X(C) (=X(CO)(2) + X(CH)(4) < 0.05] at water-rock ratios on the order of 0.1 to 0.5 by weight. The fluid-induced calcite recrystallization is viewed as an important rheological control during thrusting. The temperature evolution of the footwall, hanging wall and mylonitic tectonic contact was determined by calcite-dolomite solvus thermometry. Histograms of calcite-dolomite temperatures are interpreted as indicating a heating of the footwall dolomite marble during the thrusting of the hotter upper plate. Conversely, the hanging wall marble unit was cooled during the thrusting. The calcite-dolomite thermometry of the thrust plane gives temperatures intermediate between the initial temperatures of the lower and upper marble units, and this leads to the conclusion that conductive heat transfer rather than fluid infiltration controlled the thermal evolution during thrusting.
| Original language | English |
|---|---|
| Pages (from-to) | 212-224 |
| Number of pages | 13 |
| Journal | Contributions to Mineralogy and Petrology |
| Volume | 135 |
| Issue number | 2-3 |
| DOIs | |
| State | Published - May 1999 |
Bibliographical note
Funding Information:Acknowledgements The authors are indebted to Dr Rainer Abart for his extremely perceptive comments, which have lead to considerable improvement and revision of the manuscript. Dr. Avner Ayalon, Avi Bosaglou-Yoresh and Ran Yogev are thanked for help with the analyses. Dr. Benita Putlitz kindly performed the laser fluorination analyses. Discussions with Dr. Judy Baker on the modelling and presentation of the data are very much appreciated. The research was supported by a grant from the Israeli Ministry of Sciences in cooperation with the European Economic Community. Construction of the laser probe fluorination system was in part supported by a grant from the Israel Science Foundation funded by the Israel Academy of Sciences and Humanities.