Dating of Lakhshak intrusive assemblage through the U-Pb method on zircon and titanite, East Iran

The Lakhshak intrusive assemblage consisting of a granodiorite pluton and monzodiorite and dacite dykes are parts of Zahedan-Saravan granitoid belt which cover about 90.5 km2.. Dykes are parallel with NE-SW trends and comprise about 20-30 percent of the pluton. The granodiorite plutonis granular in texture and comprises mainly consists of plagioclase, K-feldspar, quartz, green hornblende, and biotite. The accessory minerals are zircon, titanite, apatite, allanite and Fe-oxides. The monzodiorite dykes are fine-grained and mainly consist of plagioclase and brown hornblende, while dacite dykes show porphyritic texture and consist of plagioclase, sanidine, quartz, biotite and hornblende (few percent). The best zircons and titanite minerals were selected from the study rocks for U-Pb dating. The results of U and Pb isotopic ratios determined by Mass spectrometer showed that the granodiorite rocks from the Lakhshak pluton were crystallized at 29.80 ± 0.048Ma ago; and then microdiorite and dacite dykes were cut the pluton at 28.9 ± 0.11 and 28.11± 0.69 Ma ago, respectively.