Baddeleyite U-Pb Geochronology of Rare Metal Mineralized Carbonatite and Peridotite in Dagele Area of East Kunlun Orogen and Its Prospecting Significance
The rare-metal and rare-earth mineralized alkaline-carbonatite complex was first discovered in the Dagele area of East Kunlun orogen.This discovery indicates that the East Kunlun orogen has great prospects for rare-metal mineralization.Related studies are vital for understanding the geological processes and searching for rare-metal deposits in East Kunlun orogen.This study reports the geochemistry and geochronology of baddeleyites from peridotite and carbonatite within the Dagele alkaline complex.Baddeleyites from peridotite mainly contain ZrO2(96.48%-97.21%)with minor HfO2(0.83%-1.17%)and Nb2O5(0.61%-0.93%).After common Pb correction using measured 207Pb,they yield weighted average ages of 381.0±2.3 Ma and 417.5±3.4 Ma with low intercept ages of 381.1±2.3 Ma and 417.7±3.4 Ma,respectively.Baddeleyites from carbonatite are mainly composed of ZrO2(91.1%),followed by HfO2(4.3%),Nb2O5(1.22%),and FeO(2.31%).They yield weighted average ages of 381.5±2.5 Ma and 416.5±4.5 Ma with low intercept ages of 381.8±1.8 Ma and 416.7±4.5 Ma,respectively.It is inferred that the carbonatite and peridotite are formed at 381.8 Ma and 417.7 Ma,respectively.There are at least two stages of enrichment of Nb in the silica-unsaturated magma.Post-collisional and post-orogenic lithosphere extension and partial melting of mantle beneath the East Kunlun collisional orogen were considered as the geodynamic mechanism for its formation.Therefore,it is suggested that the Late Silurian-Devonian is an important period of rare-metal mineralization.The area between Dagela and Nuomuhong River is one of the important regions for prospecting of rare-metal mineralization.
East KunlunDageleperidotitecarbonatitebaddeleyiterare metalsgeochemistrypetrology