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利用常规BrF5法和激光探针技术对中国东部有代表性的中生代碾子山A型花岗岩全岩、石英、碱性长石、磁铁矿以及锆石进行了系统的氧同位素分析. 与造岩矿物δ18O值变化范围相对较大(<3.0‰)形成鲜明对照的是, 锆石样品δ18O值的分布相对较为集中(3.12‰<4.19‰)并明显偏低, 表明该岩体曾先后经历过两阶段的水-岩相互作用. 早期与海水发生过高温同位素交换的下部洋壳通过板块俯冲发生低程度部分熔融衍生出低δ18O值的A型花岗岩浆. 在岩浆期后高温亚固态条件下花岗岩与大气降水之间发生第2次同位素交换. 第1阶段的水-岩交换导致碾子山A型花岗岩源岩δ18O值明显低于正常地幔氧同位素组成变化范围, 第2次水-岩相互作用则造成锆石与造岩矿物之间不平衡的氧同位素分馏.
Systematic oxygen isotope analysis of the whole rock, quartz, alkaline feldspar, magnetite and zircon from the Mesozoic Nianzishan A-type granites in eastern China was performed by using conventional BrF5 and laser probe techniques. In sharp contrast, the δ18O values of zircon samples are relatively concentrated (3.12 ‰ <4.19 ‰) and relatively low, indicating that the rock mass has experienced two stages successively The lower oceanic crust, which had been subjected to high temperature isotope exchange with seawater, derived A-type granite magma with low δ18O value by partial subduction of plate subduction.At the end of the magma period, The second isotope exchange occurred during the precipitation.The water-rock exchange in the first stage resulted in the δ18O value of the Nianzijishan A-type granite source rock obviously lower than that of the normal mantle oxygen isotope composition, and the second water-rock interaction resulted in the formation of zirconium Unbalanced Oxygen Isotope Fractionation Between Stones and Rock-forming Minerals.