深海沉积物中的宇宙球粒

1978-1979年,我国海洋调查船“向阳红09号”从太平洋西部海底沉积物中发现了很多透明、半透明和不透明的细小球粒(直径<1mm),作者曾作过初步报道^1,2]。本文将报道对这些球粒的进一步研究结果。

COSMIC SPHERULES FROM DEEP-SEA SEDIMENTS

Three types of cosmic spherules(iron, silicate and glassy)collected from the Western central Pacific sea-floor sediments(depth about 4000-5000m)have been recognized in the light of their morphological features, mineralogy and chemical compositions by using SEM, PDF and EPMA.There are at least four types minerals, taenite(Fe-Ni-Co)magnetite(Fe₃O₄), wus-tite(FeO)and hematite(Y Fe₂O₃)in iron spherules.The silicate spherules are the dominant group. They are composed mainly of the olivine crystals, glass and fine mineral crystals. Grain size is variable for the olivine and the fine crystals. Olivine crystals range from about 1 to 40 m in diameter, while the fine mineral crystals range from submieron to only a few microns in diameter. These fine mineral crystals maybe are magnetite, taenite and pentlandite, etc. A mixtural spherules of olivine-pyroxene are also discovered in silicate spherules.The possible origin of these spherules are obtained in present paper:(1)The iron spherules are produced during ablation of iron and metal-rich silicate meteorites.(2)The silicate spherules are derived from ablation of stony meteorites.(3)The glassy spherules are probably derived from silicate or metal-rich silicate meteorites.(4)A few spherules are the primitive material without ablative parent meteorites.