Sm - Nd monazite isochron age for bastnaesite and riebeckite is 1200 to 1300 Ma , .
Th - Pb and Sm - Nd age of Ba - REE - F carbonates and aeschynite is 474 to 402 Ma .
Sm - Nd monazite isochron age for bastnaesite and riebeckite is 1200 to 1300 Ma , whereas Th - Pb and Sm - Nd age of Ba - REE - F carbonates and aeschynite is 474 to 402 Ma .