Petrographical and petrological features of magnetic rocks in the vicinity of piran village (Keban)

The Studied area covers an area of 270 sq. km.s in the vicinity of Piran village (Keban) which is situated in 30 km.s NW of Elazığ. The units of the studied area (from the oldest to the youngest); Permo - Triassic Keban Metamorphics, Upper Cretaceous Yüksekova Complex, Upper Paleocene - Lower Eocene Seske Formation and Middle Eocene - Upper Oiigocene Kırkgeçit Formation. Keban Metamorphics are composed of marble and calcphyllite. The contact between the marbles of Keban Metamorphics and diorite group rocks of Yüksekova Complex, is intrusive type and along the contact endo and exo skarn formations are present. The Calcphyllite Formation forms the uppermost parts of Keban Metamorphics and thrusts over Yüksekova Complex. In the study area Yüksekova Complex, which is the main subject of this study, is represented by plutonic rocks of gabbro, diorite, tonalit and granodiorite, subvolcanic rocks of microtonalite, aplite and lamporphyr, volcanic rocks of basalt, basaltic andesite, andesite and dacite and flysch type volcano sedimentary rocks. IllThe field investigations indicate a 3 - phase magmatic activity. The products of initial phase are basic volcanics and plutonics, of intermediate phase are acidic volcanics and plutonics and of final phase are aplites and lamporphyres. 42 Samples of Yüksekova magmatics were analysed for major and minor elements in order to; classify these rocks, establish original relationships among rocks and discuss geotectonic evolution. The evaluation of the analysis data indicate that the magmatic rocks of the studied area are low - K tholeiitic products of island arc magmatism. On the basis of Si02 content the magmatics can be diveded into two groups; low SiÖ2 group (SiO2<60 %) and high Si02 group (SiO^O %) Absence of rocks whose Si02 contents are between these limits indicate that the rocks of two groups have different parent magmas. However, all types of magmatics rocks have close values of Na20 and K20 and some incomptible elements (Rb,Ba,Sr,Zr and REE). Thus, the rocks of these two groups are thought to be the products of magmas what have the same origin but have different partial melting degrees and phases. The subvolcanic rocks with aplitic and lamporphyric compositions were formed after the emplacement of tonalitic intrusives and as a magmatic segregation products of tonalites. The relatively higher values of K20 and Rb which compatible with K, lower values of Sr, Ba for aplitic and lamporphyric rocks indicate an advanced degree of segregation. Gabro, diorite, tonalite and granodiorite of the studied area have characteristics of granitoids of arc magmatism products what are belong to tholeiitic series and gives CAFEM magma type and called I - Type and Magnetite Series by some researchers. The volcano - sedimentary rocks of Yüksekova Complex are in normal flysch character at lower levels and upper levels bear gabro, piroksenite and serpantinite blocks and are of wild - flysch character. IV