Petrographical and geochemical investigation of the magmatic and contact metasomatic rocks in the vicinity of Çakmak village

ABSTRACT (Masters Thesis) PETROGRAPHICAL AND GEOCHEMICAL INVESTIGATION OF THE MAGMATIC AND CONTACT METASOMATIC ROCKS IN THE VICINITY OF ÇAKMAK VILLAGE (NW ELAZI?) Melek URAL Fuat University Graduate School of Science and Technology Department of Geological Engineering 2005, Page: 100 The studied area is situated at the northwest of Elazığ, between Çakmak and Koruk villages and covers approximately 250 sq km. The studied area is surrounded by Anatolian Plate (Keban, Malatya Metamorphics) from the North and Elazığ Magmatics from the South and plays an important role in reflecting geodynamic evolution of Eastern Taurus region. The studied area consists of the following units from the oldest to the youngest Permo- Triassic Keban Metamorphics, Upper Cretaceous Elazığ Magmatics, Middle Paleocene-Lower Eocene Seske Formation, Middle Eocene-Upper Oligocene Kırkgeçit Formation, Upper Miocene-Lower Pliocene Karabakir Formation and Quaternary Alluvion. The Keban Metamorphics, which are mostly carbonate and pelitic origin were metamorphosed in the lower P/T subfacies of the green schist facies at Jurassic-Lower Creataceous time. However, in some places of the studied area, existence of ortoamfibolites points out the degree of the metamorphism, risen up to amphibolites facies. Elazığ Magmatics which is one of the main subjects of this study is composed of plutonic rocks of various kinds such as gabbro, diorite, tonalite, granite and granodiorite; subvolcanic rocks of microgranite, microdiorite, microgabbro, diabase, aplite and lamprophyr XI(generally which cut diorite and tonalite) volcanic rocks of basalt, dacite, rhyolite, lathe and quartz lathe in the study area. Kırkgeçit Formation mostly consists of sandstone, limestone and sandy limestone in the study area. Karabakir Formation starts with aglomerates and lava flows at the base and grades upwards into basalt, basaltic andeshe and tuff. There are endoskarn and exoskarn formations along the contact zone between Elazığ Magmatics and Keban Metamorphics. The fractures in Keban Metamorfics and Elazığ Magmatics served as channel for skarnization. In these skarn zones, there are garnets with grossular, andradhe composition; pyroxene with diopside-hedenbergite-piegonite composition and amphiboles with tremolite-actinolite (which formed resvit of the uralization of the pyroxene), arfvedsonite, magnesioriebeckite composition; epidote, quartz, titanite as add to these minerals. Ore mineralization is composed of magnetite, hematite, pyrite, calcophyrite, specularite, limonite, ilmenhe, pyrrhotine and covelline/calcozine. The field, mineralogical and petrographycal data indicate that these rocks are mainly composed of epidote skarn, garnet skarn, garnet pyroxene skarn, pyroxene skarn, pyroxene- epidot skarn. Contact metasomatic rocks are composed of hornblend-hornfels fades at the zones of diorite, granite, and gabbroic compositions of magmatic rocks which intruded in to Keban Metamorfites at the last Upper Cretaseous. The existence of the garnet pyroxene minerals together in the contact zone indicates that h has been reached until pyroxene hornblend fades in the progressive metamorphism conditions. The field observations indicate that Elazığ Magmatics consist of three phases. The first phase is the basic and intermediate compositions of plutonic and volcanic rocks. The second phase is acidic plutonic and volcanic rocks. The third phase is aplites and lamprophyrs which are derived from residual magma. The chemical analyses of 12 samples indicate that the magmatics and skarn rocks belong to subalkaline and low-K tholehe. Key words: Keban Metamorphics, Elazığ Magmatics, skarn, endoskarn, exoskarn, XRD, ore mineralization, intrusion, metasomatism, contact metasomatic rocks, garnet, pyroxene, epidote, tremolite/actinolite, calcite, dolomite, limestone. xn