The best worldwide examples of obducted ophiolite sequences occur along the Alpine-Himalayan belt in Italy (Northern Apennines), in Cyprus (Troodos ophiolite) and in Oman (Semail ophiolite). Despite the fact that these Ophiolite sheets belong to the same orogenic belt, they were not so far compared. We propose to compare quantitatively for the first time these three areas concerning the following aspects: thickness of obducted ophiolite sheets; thermal evolution of sub-ophiolite rocks; structural level at which obduction processes occurred; tectonic structures that accommodated ophiolite obduction and unroofing of sub-ophiolite rocks; nature and temperature of fluids involved during faulting; timing and duration of obduction and exhumation processes.
To do this, we propose a multidisciplinary study based on stratigraphic and structural field geology, geochemical laboratory analyses (clumped isotopes), fluid inclusions on calcite veins, mixed layers illite-smectite (I-S) paleothermal indicators, paleomagnetic analyses and U-Pb datings.
The following research objectives will be pursued:
1) the lateral variation of the thickness of ophiolite sheets will be constrained by paleothermal analysis of sub-ophiolite rocks;
2) the structural level at which obduction processes occurred will be constrained via paleothermal analysis of sub-ophiolite rocks and via analysis (clumped isotopes and fluid inclusions on syn-kinematic calcite veins associated with faults) of fossil fluids which permeated fault zones;
3) the tectonic structures that accommodated ophiolite obduction and exhumation of sub-ophiolite rocks will be constrained by field and laboratory structural analyses and by paleomagnetic analysis on sub-ophiolite rocks;
4) the age and duration of obduction and exhumation processes will be constrained by U-Pb datings of syn-tectonic calcite veins;
5) we will finally propose evolutionary models for ophiolite obduction in the investigated areas.
