Kırıkkale-Çorum yöresinin metalojenezi ve baz-kıymetli metal potansiyeli
Thesis Type: Doctorate
Institution Of The Thesis: Hacettepe Üniversitesi, Fen Bilimleri Enstitüsü, Jeoloji Mühendisliği A.B.D., Turkey
Approval Date: 2010
Thesis Language: Turkish
Student: ERCAN KUŞCU
Principal Supervisor (For Co-Supervisor Theses): YURDAL GENÇ
Open Archive Collection: AVESIS Open Access Collection
Abstract:Middle-Upper Triassic Devecidağ and Upper Cretaceous Artova ophiolitic complexes constitute the basement rocks in the study area having different continental blocks (Sakarya Block and Kırşehir Massif). The basement rocks are unconformably overlain by Lower-Middle Eocene Alacahöyük formation comprising intercalations of pebblestone-sandstone-siltstone-shale-marn. Middle-Upper Eocene (?) Bayat formation, which conformably overlays the Alacahöyük formation, consists of volcanic-volcanoclastic Bayat volcanites and locally Çatkara member (pebblestone-sandstone-limestone-marn-mudstone).Bayat volcanites are represented by four different stages. First three stages of these volcanites range from basaltic trachyandesite to dacite-rhyolite and they are accompanied by pyroclastic rocks. The last stage volcanite is basaltic trachyandesite and basaltic andesite in composition. Plutonic rocks (Dededağ granitoid) accompanying volcanic rocks, are composed of gabbro, syeno-diorite, diorite-porphyry, granite-porphyry, aplite and quartz veins.Volcanic and plutonic rocks, forming a magmatic complex, are both related to the same magmatic system. Both volcanic and plutonic rocks of this magmatic complex are mostly alkaline with lesser subalkaline in character.Pre-Eocene and Eocene units are unconformably overlain by sedimentary succession including Miocene age Kızılırmak, Dodurga and Bozkır formationsVein type mineralisations in the study are restricted to magmatic complex and their generation is related to quartz veins. Veins include copper-lead-zinc, gold, antimony and arsen.Şaphane and Mehmetdedesi gold mineralizations are in the quartz veins with massive and vuggy structure. Alteration minerals such as kaolinite, amorph silica and lesser amount alunite, illite, natroalunite, mica/illite, illite/smectite, smectite (montmorillonite), jarosite, cristobalite and pyrophyllite are also present associated with the gold mineralizations. In the quartz veins in places tourmaline is observed. The alteration mineral paragenesis developed around the quatz veins have been classified as argillic and advanced argillic alterations. Native gold, limonite-hematite, pyrite, trace amount of chalcopyrite, malachite and azurite are also have been observed in the quartz veins. Veins with arsenopyrite have pyrite, arsenopyrite and malachite with colloform texture. Presence of both pyrite and marcasite in the veins, indicates that the temperature of the system forming veins is less than 400oC.The Soğucak and Salur Cu-Pb-Zn mineralizatios are located in the deeper levels according to the gold bearing quartz veins. In the veins, calcite is present along with quartz. In the Soğucak Cu-Pb-Zn vein, while high temperature minerals like chalcopyrite are observing in the deeper parts, in the upper parts relatively low temperature minerals like chalcosite are found.Mehmetdede Obruğu antimony mineralization consists of antimonite minerals related to the quartz-calcite vein.When mineralogic-petrographic features and alteration paragenesis of the mineralizations present in the area are taken into consideration, it is suggested that veins were generated from magmatic-hydrothermal system affected by both magmatic and meteoric waters on the upper part of a shallow setting intrusion.It is thought that vein type mineralizations in the study area are situated in the same belt together with Bakırçay porphyry Cu-Mo (Merzifon/Amasya) and Gümüş (Gümüşhacıköy/Amasya) vein type Pb-Zn-Ag-Au mineralization. Porphyry type Cu-Mo mineralizations representing deeper parts, Şaphane and Mehmetdede Tekkesi gold mineralizations forming upper top part of the magmatic-hydrothermal system.In the region red bed type copper mineralizations present in Oligo-Miocene aged red coloured terrestrial sedimentary succession have resulted from the circulations of the oxidized, almost neutral (pH=6-8), Cl rich solutions generated from the evaporitc units. During the circulation of these solutions in the red coloured terrestrial succession, the trace amount of copper present in the rocks dissoves and precipitates in the reducing environments (pyrite, H2S or organic matter bearing environment). It is thought that the sources of Cu enrichment in the evaporitic units are basement rocks (basic volcanic and ofiolitic rokcs) bearing high Cu and their mineralizations.