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太古宙登封绿岩带中变基性火山岩(2.5Ga)的ε_(Nd)~i=+2.16,经计算表明,具此值的岩石遭受了ε_(Nd)=-5的大陆地壳的混染,混染量约为16％,而正常的、无混染的幔源岩浆在2.5Ga前的ε_(Nd)~i值应为+3.7。据此推断,登封绿岩带是在有陆壳基底存在的裂谷盆地中发育起来的,同时,前登封绿岩基底是以长英质为主而且下部经历了麻粒岩相变质作用的陆壳,这一陆壳的年龄在2.9Ga以上(据锆石pb-pb年龄)。由于古老地壳麻粒岩相变质作用的影响,造成混染的绿岩带基性火山岩过低的~(87)Sr/~(86)Sr初始值以及该值与ε_(Nd)~i值相关性的破坏。
The ε Nd Nd of i = 2.16 for the Archean volcanic rocks in the Archean Endeavor Green Belt shows that the rocks with this value suffer from the continental crust of ε Nd = - 5 Dyeing and mixing were about 16%, while normal and uncontaminated mantle magma should have ε_ (Nd) i value of +3.7 before 2.5Ga. Therefore, it is inferred that the Dengfeng greenstone belt was developed in rift basins with continental basement. At the same time, the basement of the former Dengfeng Greenstone was dominated by Chang-Ying and the lower part experienced granulite facies metamorphism The continental crust, this continental crust is over 2.9 Ga (according to zircon pb-pb age). The initial value of ~ (87) Sr / ~ (86) Sr, which is too low in the mafic greenstone-hosted volcanic rocks, and the value of ε_ (Nd) ~ i are related to the metamorphism of the granulite facies in the ancient crust Sexual destruction.