THE METAMORPHISM AND THE RELATIONSHIP BETWEEN INFRA AND SUPRASTRUCTURES OF THE BİTLİS MASSIF - TURKEY
The infrastructure of the massife consists essentially of amphibolites, gneisses and micaschists intruded by a biotite granite and the successive hololeucocratic phase. The mantling rocks of the suprastructure comprise metapelitic rocks unconformably underlying metacarbonates dated as Middle Devonian- Mesozoic. The infra-suprastructure boundary is interpreted as a surface of transgressive overlap. The rocks of infra and suprastructure are involved in isoclinal folds with ductile deformation along most of the boundary conclusively suggesting in situ position of the suprastructure during the Alpine deformation. The shear planes are discontinous, en echelon and run independent of the infra-suprastructure boundary. A uniform sequence of Palaezoic rocks, which is not intruded by the granites of the infra-structure, together with the infra-suprastructure boundary being a sedimentary contact, are conclusive evidence for the existence of a Precambrian event. Eradication of Precambrian paragenesis occurs in the flanks of major folds where a complete Alpine zoning exists from very low grade to anatectic conditions as exemplified by the Kesandere section in contrast to the preservation of Precambrian parageneses in the unsheared competent rocks of the infrastructure of the hinge areas. There is no gap in physical conditions with regard to a single episode of deformation. The gap occurring between the infra and the suprastructure is due to different physical conditions of Precambrian and Alpine deformations. Retrograde effects are presumably due to an Alpine imprint on the Precambrian parageneses, whereas they are attributed to a continous process of deformation with conternparaneous uplift and progressive dimunition of physical conditions in the case of imprint on early Alpine parageneses. The interpretation herein presented in relation to nature of infra and suprastructure boundary and metamorphism of Bitlis massive is consistent, for all aspects, with the regional geologic data showing that it is the deformed Alpine passive margin of the Arabian plate.
Keywords:
-,
___
- Boray, A., 1973, The structure and metamorphism of the Bitlis area, southeast Turkey: University of Lon- don, Doctorate thesis, 233p, (unpublished).
- Çağlayan, M.A.; Dağer, Z..; Erkanol, D.; İnal, R.N.; Sevin, M. and Şengün, M., 1983, Bitlis masifinde Meso- zoyik yaşlı kaya birimleri ve GD Anadolu otokto- nu He deneştirilmesi: TJK, 37. Bilimsel ve Teknik Kongresi Bildiri Özetleri, 65.
- .; İnal, R.N.; Şengün, M. and Yurtsever, A., 1984, Structural setting of Bitlis massive: International symposium of the geology of the Taurus belt, MTA special publication, p. 245-254.
- Erdoğan, B. and Dora, Ö., 1983, Bitlis masifi apatitli demir yataklarının jeolojisi ve oluşumu: TJK Bull., 26, 133-144.
- Genç, S., 1987, Petrogenesis of metamorphics in the Çökekyazı-Gökay (Hizan-Bitlis) area of the Bitlis massive: Geological Congress of Turkey, Abs- tracts, p.33.
- GöncüoğIu, C.M. and Turhan, N., 1983, Bitlis masifinde yeni yaş, bulguları: MTA Bull., 95/96, 44-48.
- and , 1985, Bitlis metamorfik kuşağı orta bölümünün temel jeolojisi: MTA Rep., 7707 (un- published), Ankara.
- Hall, R., 1976, Ophiolite emplacement and the evolution of the Taurus suture zone, Southeastern Turkey: Geol. Soc. American Bull., 87, 1078-1088.
- Helvacı, C., 1983, Bitlis masifi Avnik (Bingöl) bölgesi me- tamorfik kayaçlarının petrojenezi: TJK Bull., 26, 117-132.
- Leake, B.E., 1978, Nomenclature of amphiboles: Amer. Min.,63, 1023-1050.
- Mason, R., 1975, Bitlis masifinin tektonik durumu: Cum- huriyetin 50. Yılı Yerbilimleri Kongresi, 31-41, An- kara, Turkey.
- McKenzie, D.P., 1972, Active tectonics of the Mediterra- nean region: Geophys. J.R. astr. Soc. 30, 109- 185.
- Özkaya, I., 1982, Marginal basin ophiolites at Oramar and Karadağ, SE Turkey: J. Geol. Soc. London, 139, 203-210.
- Storre, B. and Karrotke, E., 1971, Glimmerschiefern in Modellsystemmen: Fortschr. Mineral., 49, 56-58.
- Şengör, A.M.C. and Yılmaz, Y., 1981, Tethyan evolution of Turkey :a plate tectonic approach, Tectonophy- sics, 75,181-241.
- Şengün, M., 1984, Tatvan güneyinin (Bitlis masifi) jeolojik/ petrografik incelenmesi: Doktora tezi, 157p. (un- published).
- Tuttle, O.F. and Bowen, N.L., 1958, Origin of granite in the light of experimental studies in the system: Geol. Soc. Am. Mem., 74, 1-153.
- Winkler, H.G.F., 1976, Petrogenesis of metamorphic rocks: Springer Verlag, New York, 320p.
- Yazgan, E., 1984, Geodynamic evolution of Eastern Tau- rus: TJUS, Int. Symp., Proceeding, 199-208.
- Yılmaz, O., 1971, Etude petrographique et geochronologique de la region de Cacas: Univ. Grenoble, Doctorate theses (unpublished), 230p.
- ; Michel, R.; Vialette, Y. and Bonhomme, M.G., 1981, Reinterpretation des donnees isotopiques Rb-Sr obtenues sur les metamorphites de la partie meridionale du massif de Bitlis (Turquie): Sci. Geol. Bull.,34/1, 59-73.
- Yurtsever, A.; Aksoy, Ö.; Boztepe, Y.; Dağer, Z.; Konuk, O.; Şengün, M. and Yurtsever, G., 1983, Gevaş. (Van) dolayının jeolojisi: MTA Rep., (unpublished), Ankara, Turkey.
- ISSN: 0026-4563
- Yayın Aralığı: Yılda 3 Sayı
- Başlangıç: 1950
- Yayıncı: Cahit DÖNMEZ