Gezende Barajı (Gülnar) rezervuar alanının stratigrafisi ve mühendislik jeolojisi

Abstract

60 SUMMARY In this study, the stratigraphy of the Gezende Arch Dam Reservoir is investigated as a thesis of master which is located around Mut, Gülnar (îçel) and Ermenek (Konya) towns in the middle of the Mediterranean Region. The area was studied systematically according to its chronostratig- raphic and litostratigraphic properties and detailed p geological map about 120 km land area on a scale of 1/25000 has been prepared. During the study Silifke 030-d3 -d4- and Silifke P30-a2 topographic sheets were used. High mountains surround the Gezende Bam'. Re servo ir and the heights which limits both sides of the in vestigated area varies between 1500 to 1800 m., and the elongation of them are northwest to southeast direction. Though the area is located in a transitional zone between Mediterranean and semiarid climates, it is 'under the effect of Mediterranean climate. The ma^or stream is the Ermenek River. This study was carried out in three stages : 1. preliminary studies, 2. field works and 3 o laboratory works. During the field works, collection of samples, measuring of stratigraphic sections and geological mapping were made. In the laboratory thin sections determinations were being made. According to its chrono stratigraphic properties Mesozoic and Cenozoic aged sedimentary sequences were mapped in the investigated area and the allocthonous and autochtonous units were differentiated. The upper Cretaceous aged Ermenek melange is located to the region alloc thonously. Eocene aged Gezende formation consists of conglomerate and shale interbedded limestone. Marine conditions changed during the Oligocene-Lower Miocene time and under the lacustrine conditions Yenimahalle formation deposited. Terrestrial Gildirli formation deposited during61 the same time has a thickness of 0 - 350 m.Gildirli formation consists of red coloured conglomerate, sandstone, silt stone and mudstone alternations. This formation is overlain by the Lower Miocene aged Kaplankaya formation which has a shallow marine - beach character consisting of sandy-silty limestone and the upper part of this formation transits to Karaisalı formation. Karaisalı formation has a reefoidal character and includes a lot of algea,corall and foraminif eras. The Lower - Middle Miocene aged Karaisalı formation has a thickness of 250-750 metres in a regional scale. Investigated area shows a great complexity because of the tectonic movements. Many faults developed by the situation of Ermenek melange and uplifting of the area. Some of them have become effective for the basement. The drainage systems were developed under the tectonic condi tions. Hard consolidated limestones of Karaisalı formation forms the highest points and detritic units form mildly sloping flanks with bad lands topography. From the view point of engineering geology, though the Gezende Dam Site and Reservoir comprises impermeable: units, the grouting works are made for supplying a curtain and preventing the dam leaking. On the. other hand, in some parts of the reservoir, especially where Yenimahalle formation outcrops, some little landslides are wide spread. The aggregates which are supplied from the limestone blocks in the melange and from the collections of the Ermenek River are used in the dam construction. There is not any mineralization of economic significance in the area. In the investigated area, inside the Mesozoic basement and Oenozoic units, petrolium may be trapped in structural and stratigraphic traps and rocks may be potential for hydrocarbon reservoir.

60 SUMMARY In this study, the stratigraphy of the Gezende Arch Dam Reservoir is investigated as a thesis of master which is located around Mut, Gülnar (îçel) and Ermenek (Konya) towns in the middle of the Mediterranean Region. The area was studied systematically according to its chronostratig- raphic and litostratigraphic properties and detailed p geological map about 120 km land area on a scale of 1/25000 has been prepared. During the study Silifke 030-d3 -d4- and Silifke P30-a2 topographic sheets were used. High mountains surround the Gezende Bam'. Re servo ir and the heights which limits both sides of the in vestigated area varies between 1500 to 1800 m., and the elongation of them are northwest to southeast direction. Though the area is located in a transitional zone between Mediterranean and semiarid climates, it is 'under the effect of Mediterranean climate. The ma^or stream is the Ermenek River. This study was carried out in three stages : 1. preliminary studies, 2. field works and 3 o laboratory works. During the field works, collection of samples, measuring of stratigraphic sections and geological mapping were made. In the laboratory thin sections determinations were being made. According to its chrono stratigraphic properties Mesozoic and Cenozoic aged sedimentary sequences were mapped in the investigated area and the allocthonous and autochtonous units were differentiated. The upper Cretaceous aged Ermenek melange is located to the region alloc thonously. Eocene aged Gezende formation consists of conglomerate and shale interbedded limestone. Marine conditions changed during the Oligocene-Lower Miocene time and under the lacustrine conditions Yenimahalle formation deposited. Terrestrial Gildirli formation deposited during61 the same time has a thickness of 0 - 350 m.Gildirli formation consists of red coloured conglomerate, sandstone, silt stone and mudstone alternations. This formation is overlain by the Lower Miocene aged Kaplankaya formation which has a shallow marine - beach character consisting of sandy-silty limestone and the upper part of this formation transits to Karaisalı formation. Karaisalı formation has a reefoidal character and includes a lot of algea,corall and foraminif eras. The Lower - Middle Miocene aged Karaisalı formation has a thickness of 250-750 metres in a regional scale. Investigated area shows a great complexity because of the tectonic movements. Many faults developed by the situation of Ermenek melange and uplifting of the area. Some of them have become effective for the basement. The drainage systems were developed under the tectonic condi tions. Hard consolidated limestones of Karaisalı formation forms the highest points and detritic units form mildly sloping flanks with bad lands topography. From the view point of engineering geology, though the Gezende Dam Site and Reservoir comprises impermeable: units, the grouting works are made for supplying a curtain and preventing the dam leaking. On the. other hand, in some parts of the reservoir, especially where Yenimahalle formation outcrops, some little landslides are wide spread. The aggregates which are supplied from the limestone blocks in the melange and from the collections of the Ermenek River are used in the dam construction. There is not any mineralization of economic significance in the area. In the investigated area, inside the Mesozoic basement and Oenozoic units, petrolium may be trapped in structural and stratigraphic traps and rocks may be potential for hydrocarbon reservoir.