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该岩样系太平洋东北部胡安·德·富卡洋中脊上底拖所取得的岩石样品,其表面具有黑色玻璃质,由表面向下逐渐过渡为晶质。 对该岩样的化学成分做了较全面的(化学、X光、红外光谱、电镜等)分析。其化学成分虽与大洋拉斑玄武岩的平均值相近似,但Ca、Mg略高于大洋拉斑玄武岩的平均值;而Si,K含量又稍低于大洋拉斑玄武岩。表明该岩石系地幔岩浆分异早期溢出而成的。其主要矿物成分是拉长石和普通辉石,其中拉长石占斑晶的70—80％左右。 镜下研究表明该岩石从顶面到底部可被划分成若干层次,并具有气孔的存在,表明该岩石系水下溢出而生成的。 电子探针分析发现Cu、Co、Ni三元素在冷却玻璃质部份的含量较结晶主体部份的含量为高,而Rb、Sr、Cs三元素在岩石冷却边部份与结晶主体中的含量上没有什么显著的差别。 根据扫描电镜和电子探针的微区元素分析研究,结晶表明铁镁硅酸盐先结晶,随后结晶的为基性斜长石。
The rock sample obtained from the bottom dragging of Juan de Fuca ocean ridge in the northeastern Pacific Ocean has a black glassy surface with gradual transition from the surface to the crystalline phase. The chemical composition of the rock sample to do a more comprehensive (chemical, X-ray, infrared spectroscopy, electron microscopy, etc.) analysis. Although its chemical composition is similar to that of oceanic basalt, the content of Ca and Mg is slightly higher than that of oceanic basalt and the content of Si and K is slightly lower than that of oceanic basalt. It shows that the rocks were formed by mantle magmatic differentiation early spillover. Its main mineral components are labradorite and pyroxene, of which labialite accounts for about 70-80% of the phenocrysts. Microscopic studies have shown that the rock can be divided into several levels from the top to the bottom and has the presence of stomata, indicating that the rock was spilled underwater. Electron probe analysis showed that the contents of Cu, Co and Ni in the cooled vitreous part were higher than those in the crystalline part, whereas the content of the three elements Rb, Sr and Cs in the cooling side part and the crystalline body There is no significant difference. According to the microanalysis of SEM and electron probe, the crystal shows that ferromagnesium silicate is crystallized first, then the crystal is basic plagioclase.