Tectonometamorphic Nappe Evolution in the Zillertal Area

Research project P 14571 Tektonemetamorphic Nappe Evolution in the Zillertal Area Peter W. MIRWALD 27.11.2000 Tectonometamorphic Evolution of the Austroalpine Nappes in the Zillertal Area: Investigations along the Seismic OEKORP Profile between the Tauern Window and the Inntal Fault This project is closely related to the international geophysical OEKORP project which provides a continuous seismic reflection profile through the Eastern Alps along the transect Bad T61z (D) Venice (1). In the frame of the OEKORP project, this proposal addresses the problem of the tectonometamorphic evolution of the Austroalpine nappes in the Zillertal Area. The two units to be studied in the course of this project are the "Innsbrucker Quarzphyllit" and the "Schwazer Augengneis", which form a tectonic contact in this area. The former is part of the lower Austroalpine units and the latter of debated origin, since it has been attributed over the years to either the lower-or the middle Austroalpine units. Most importantly, both units lack modem petrological investigations, to determine their P-T-t-d path. The detailed tectonometamorphic investigation of both units and their tectonic contacts, provides an important key to the understanding of the paleogeographic reconstructions of this part of the Eastern Alps. The aims of this project are: (1.) Detailed field mapping and structural investigations within the two units as well as along selected cross sections across their contact. (2.) Petrological (thermobarometry) and thermochronological investigations (radiogenic dating, fission track dating) will provide a P-T data set on a large regional scale of this part of the Eastern Alps and help to unravel the tectonometamorphic evolution (P-T-t-d path) of the two units, as well as investigate the relations of the Schwazer Augengneis to the adjacent 6tztal-Stubai Crystalline Complex. (3.) Furthermore the project focusses on tectonic contact between the two units to constrain kinematics, amounts of offset and possibly the time of activity. Methodologically, the project is based on field work, petrological, microstructural studies and thermochronological (radiogenic and fission track) studies. The latter will be carried out in close connection with Rb/Sr and Ar/Ar- dating by Dr. M. Rockenschaub (FWF-Project: P 11771 -Geo).

1. Scientific success of the project: Rating: 80-60 Contribution and importance of the work to the further development of the scientific discipline, any importance for related disciplines (transdisciplinary questions and methods), quality of the dissemination of the scientific results (publications, activities at conferences and so on) 2. Development of human resources in the course of the project Rating: 80-60 Improvement of the project leader`s standing in the relevant scientific community; involvement of young scientists in the project work; development of international contacts Comments On the condition that the collected data are published in international journals I think that the Project leader`s improvement into the scientific community will be certain. The project team, although composed of two senior researcher and of two students, worked very well but at a rather local level, as the list 3 of collaborations, all limited to austrian colleagues, may indicate. 3. effects of the project beyond the scientific field Rating: 60-40 (Section 3 of the report): Comments (I did not find any section 3 of the report regarding this question) The project is quite specific and of high technical content, so that important impacts on social or economic effects beyond the scientific field can not be envisaged. 4. Project performance (in the sense of efficient use of Available resources): Rating: 80-60 Were the goals achieved? Were changes to the original research plan sensible? What is the relation between the results obtained , the duration of the project and the resources available? Comments During the project some technical problems arose about the achievment of the prefixed goals, but the leader solved these problems collecting geochemical and other different data. The obtained results are in agreement with the project duration and with the available resources. 5. Future perspectives of the research work: Rating: 60-40 Should the topic be pursued or should the scientists involved be advised to switch their attention to a different area? What goals does the referee feel should be set for future work? Comments The study area has been analysed in detail and the project leader does not indicate any further possible development. Some more detail on the strctural evolution would be interesting as well as some consideration about the implication that these data bring to the geodynamical evolution of the study sector.