Late Mesozoic crust-mantle interaction in southeastern Fujian
Late Mesozoic crust-mantle interaction in southeastern Fujian
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DOI：
10.1007/bf02882602
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发表时间：
1997-03
影响因子：
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通讯作者：
C. Dong;Xinmin Zhou;Hui-ming Li;S. Ren;Xin-hua Zhou
中科院分区：
文献类型：
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作者：
C. Dong;Xinmin Zhou;Hui-ming Li;S. Ren;Xin-hua Zhou
3讨论通过与漳州二长花岗岩和辉长岩、泉州辉长岩（与花岗岩共生）以及永泰流纹岩和玄武岩的年龄和Sm-Nd同位素数据（表3）的对比，发现它们具有几乎相同的年龄值ε Nd（T）和Is值。证明了中晚白垩世幔源玄武质岩浆与壳源花岗质岩浆的同位素组成在更大范围内发生了充分交换。其原因是两种不同成分的岩浆长期共存于同一储层中时，沿着界面会发生热扩散、同位素交换和化学混合等边界效应。两种熔体之间的同位素交换比主元素的化学均一化进行得快得多。这一事实可以解释伴生的基性岩和硅质岩（辉长岩-花岗岩和流纹岩-玄武岩）同位素组成的一致性，也正是壳幔相互作用的地球化学标志。因此，机械混合（混合）之间的两个不同的。发生岩浆作用，岩浆上升侵位形成火成杂岩或复合熔岩。
3 DiscussionIn comparison with the ages and Sm-Nd isotopic data of the Zhangzhou monzogranite and gabbronorite, the Quanzhou gabbro (associated with granite) as well as the Yongtai rhyolite and basalt (table 3), it is found that they have almost identical ages,€ Nd (T) and Is, values. It is proved that the isotopic compositions between mantle-derived basaltic and crust-derived granitic magmas have taken fully exchange in a wider region in the mid-and late-Cretaceous times. The cause is that some boundary effects, such as thermal diffusion, isotopic exchange and chemical mixing, will take place along the boundary surface when two different compositional magmas coexist in a reservoir over a long period of time. The isotopic exchange between two melts proceeds much more quickly than the chemical homogenization of major'elements doe~[~-~ I. This fact may interpret the identity of isotopic composition for associated basic and silic rocks (gabbro-granite and rhyolite-basalt), and it just is a geochemical indicator for crustmantle interaction. Consequently, the mechanical mixing (mingling) between two different. magmas takes place, and igneous complex or composite lava forms during the ascent and emplacement of magmas.