Zirconolite, baddeleite, zircon and thorite of island arc quartz gabbro-norite-dolerites of Ayu-Dag intrusion (Mountain Crimea)
Journal: Moscow University Bulletin Series 4 Geology
Year: 2018

Early Bajocian island arc quartz gabbro-norite-dolerites of Ayu-Dag contain syngenetic zirconolite and baddeleite. Zirconolite presents as Ca-dominant and uncommon Y-dominant (Y, Ca, Th, REE)2FeZr2Ti3O14. Two genetic types of zircon and thorite are developed. Predominant xenogenic zircon-I with thorite inclusions and a mass of lacunes — traces of reflow, is enriched with Hf, Th, Y, P (up to 6 wt.% HfO2, 5% ThO2, 6% Y2O3, 3% Р2О5). Thorite contains 7–9% UO2. Zircon and thorite of such composition