Evidence for Pan-African basement in Ghalghachi Leucogranite (west the Urmia Lake) with using U-Pb zircon dating and whole-rock Sm-Nd and Rb-Sr isotopic analyses

The Ghalghachi leucogranite intrussion with approximately 2 Km2 is located in west Urmia Lake and 70 Km north of Urmia city. This intrussion in form of small stock has intruded into Precambrian metamorphic rocks including gneiss, schist and amphibolite. This area is part of the Sanandaj-Sirjan zone in northwestern of Iran. This is the first time that age of leucogranite was determined by LA-ICP-MS zircon grains 558.6 ± 3.8 Ma that indicates acidic magmatic activity and the presence of Pan-African basement similar to the central Iran. The presence of older cores in some of zircon grains with age between 900 to 2500 Ma suggest the presence of older rocks in the study area. The rock show negative initial eNd (t) values of -4.3 with TDM 1.61 that are consistent with partial melting of a primary crust (with Paleoprotrozoic age) that was formed during the Neoproterozoic the same as Arabian Shield. The 87Sr/86Sr and εNd of whole rock and Th/U values in zircons show the involvement of more crustal and less mantle components, during the opening of Paleotethys Ocean.