论文部分内容阅读
东南极格罗夫山变质基性岩的地球化学研究表明,该区存在两类玄武岩,即洋岛型玄武岩(OIB)和洋中脊型玄武岩(MORB)。OIB型具有大体类似的地球化学性质,它们均富集Ti(TiO2-2.68％)、REE(=202μg/g)、LREE[(La/Yb)N=4.8]、Ti/Y(=343)、Zr/Y(=3.1),具洋岛玄武岩的特征,推测岩浆来源于富集地幔源区(EM)。而MORB型以低Ti(TiO2=1.1％～1.31％),明显低于OIB的P的含量(P2O5=0.1％～0.2％),低REE(47～93μg/g)、LREE/HREE(2.27～2.54)、(La/Yb)N(=1.30～1.62)为特征,具洋中脊玄武岩的特征。MORB和OIB组合的出现说明在泛非期该区可能存在过洋盆。
Geochemical studies of the Grove Mountains metamorphic basement rocks in the East Antarctic show that there are two types of basalts in this area: OIB and MORB. The OIBs have similar geochemical characteristics and all of them are rich in Ti (TiO2-2.68%), REE (= 202μg / g), LREE [(La / Yb) N = 4.8] Zr / Y (= 3.1), with the features of oceanic island basalts, suggesting that the magma is derived from the enriched mantle source region (EM). However, the MORB type was significantly lower than that of OIB (P2O5 = 0.1% ~ 0.2%), low REE (47 ~ 93μg / g) and LREE / HREE (2.27 ~ 2.54), (La / Yb) N (= 1.30-1.62), with characteristics of mid-oceanic basalts. The emergence of a combination of MORB and OIB suggests that there may be oceanic basins in the pan-African period.