Sr-Nd Isotopic Characteristics of Jurassic Granites in Northeastern Da Hinggan Mountains and Their Geological Implications
Sr-Nd isotopic data of the Jurassic granites in northeastern Da Hinggan Mountains show that Xing’an massif has relatively low initial Sr (0. 7048~0. 7065), high εNd (t) (+0. 23~+2. 54), and low TDM2 (0. 76~0. 95 Ga), suggesting that their source materials were mainly crustal materials derived from the depleted mantle during Phanerozoic. In contrast, Jurassic granites in Ergun massif have relatively high initial Sr (0.7057~0.7075), low εNd (t) (-2.47~-9.72), and high TDM2 (1.16~1.7 Ga), implying that their source materials were mainly crustal materials derived from the depleted mantle in Meso-Neo-Proterozoic. Different crustal accretion periods of Ergun and Xing’an massifs suggest they have different early crustal evolution histories.