论文部分内容阅读
对阿尔泰造山带南缘喀拉通克和锡泊渡两个杂岩体的Sr-Nd-O同位素研究表明,两个杂岩体的同位素特征相似,均具有低的(87Sr/86Sr)t和高的εNd(t)值(6.3~9.1),表明其来源于亏损的软流圈地幔,但是其δ18O值(‰)大多大于6(5.4~10.2),表明有地壳物质的加入。Sr和O同位素表明,这种地壳物质的混入主要是源区的混入。根据Nd同位素模式年龄以及区域构造演化特征,可能是混入有早期俯冲的洋壳(可能是早古生代)的亏损地幔熔融的结果。然而,与锡泊渡杂岩体不同的是,喀拉通克杂岩体局部还经历了上部地壳的混染作用。此外,额尔齐斯深大断裂南北两侧镁铁质-超镁铁质杂岩体源区特征的相似性可能暗示了该断裂可能不是阿尔泰造山带和准噶尔造山带的分界线。
The Sr-Nd-O isotope studies of the two complex bodies of Kalatongk and Xipudu on the southern margin of the Altay orogen show that the two complexes have similar isotopic characteristics with low (87Sr / 86Sr) t and The high εNd (t) values (6.3-9.1) indicate that they originate from depleted asthenosphere mantle, but their δ18O values (‰) are mostly larger than 6 (5.4-10.2), indicating the addition of crustal material. Sr and O isotopes indicate that this crustal material incorporates mainly the source region. Based on Nd isotope pattern age and regional tectonic evolution, it may be the result of a depleted mantle melting mixed with early subducted oceanic crust (probably of the Early Paleozoic). However, unlike the Xipudu complex, the karatat complex complex locally undergoes the contamination of the upper crust. In addition, similarities in the source regions of the mafic-ultramafic complex on the north and south sides of the Erqis Deep Fault may suggest that the fault may not be the demarcation line between the Altay or Junggar orogen.