排序方式: 共有2条查询结果,搜索用时 0 毫秒
1
1.
The garnet megacrysts from Yingfengling basalts are characterized by high FeO (>20%), CaO (7.02% –8.16%) and low MgO (5.88%–10.87%).
Significant composition variations are observed in these megacrysts, of which Ni, V, Sc, Co, and HREE are positively correlated
with their Mg#, and Zr, Hf, Ga, Y, Sr, Nb, Zn and LREE-MREE are negatively correlated with Mg#. Megacryst parent magma is a highly evolved residual melt with strongl depletion in Ti, Sr, Hf, Nb and HREE. This parental
magma was generated by more than 60% of crystallization fractionation of clinopyroxene, garnet, plagioclase and ilmenite from
quartz tholeiitic magma. It has not erupted to the surface, but stayed at the upper mantle and formed the megacrystic cumulate.
Megacrysts and their host basalt are in disequilibrium. 相似文献
2.
Trace-element of Tuoyun clinopyroxene: Implication for the deep processes of lithospheric mantle beneath the southwest Tianshan, West China 总被引:1,自引:0,他引:1
Based on the LAM-ICPMS analytic results on the trace elements of clinopyroxenes in peridotitic xenoliths occurring in early-Cretaceous
basalts from western Xinjiang, the properties and the deep processes, including partial melting and mantle metasomatism, of
the subcontinental lithospheric mantle beneath the Tuoyun Basin are analyzed. In the northern edge of the Tarim Basin (southwest
Tianshan), the Mesozoic subcontinental lithosphere which has experienced the effect of partial melting (<10%) and intricate
mantle metasomatism is characterized by Phanerozoic ‘ocean-type’ mantle. The superposed influence of SiO2-unsaturated silicate melt and carbonate melt probably results in the metasomatic medium which resembles the hydrous silicated
carbonate melt in some aspects. By comparing Tuoyun mantle with Cenozoic main mantle beneath eastern China, the properties
are similar, while the former shows finer grain and higher diopside content of the peridotites and more conspicuous modal
metasomatism. 相似文献
1