DOCUMENTING RARE EARTH AND TRACE ELEMENTS IN HYDROTHERMAL TOURMALINE: NEMAZGAH PLUTON, WESTERN TURKEY

The Nemazgah pluton, located in the Biga Peninsula of western Turkey, is a Miocene in age tourmaline bearing leucocratic porphyry formed in response to either subduction migration along the Hellenic arc or wide spread extension due to the closure of the Vardar Ocean. The Namazgah pluton is a high K–alkali, peraluminous, I type granitoid with a composition that varies from granite to quartz monzonite. Zoned tourmalines appear in acicular clusters and as larger columnar crystals with precipitated zircons in quartz rich veins. Zircon grains also appear hydrothermal with morphologies suggesting precipitation from a fluid phase. This study is aimed at providing a better understanding of timing the hydrothermal activity and physio-chemical conditions under which it occurred. Five rock samples were collected from an aplite from the Nemazgah pluton to analyze the textural properties of the host rock, zircon, and tourmaline. Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) was used to determine minor and trace element concentrations to characterize the fluid and previous host rock composition. Zircon grains were dated using Secondary Ion Mass Spectrometry (SIMS). Ages of Nemazagh zircons are Miocene, and preliminary trace element data from LA-ICP-MS exhibits LREE enrichment of tens of µg/g and element partitioning of Sn and V in the c-sector between core to rim zonation patterns.