摘要
本文报道了四川重庆中梁山P/T界线粘土层中的非粘土组分及其研究成果,包括具似文象结构的铁质微球粒,硅质、石质微球粒以及各种碎屑矿物。认为除了具似文象结构的铁质微球粒可能属地外成因外,其他微球粒和碎属矿物均为火山作用产物。
Several clay rock beds ware found near the Permian-Triassic interface of Southern China, and there is a large mass of extinction. There are two opinions on the cause of the extinction, i. e. , outer-space crash event and volcanism of the earth. The author, after analyzed the non - clay components the mentioned clay beds in Zhongliangshan of Chongqing, found some microspherulitic and clastic minerals that featured by the following characters.
1. Microspherulitic material, with the diameters of 30-150μm and composed by (1) ferruginous, (2) siliceous and (3) lithical components. Division 1 is very round (nearly standard globular) with smooth surface or decorated by modular bulges. The most outstanding feature is their graphic texture on the surface, which made of dendritic, small bulges, holes of eruption and fusion crust. EDX analysis shows that the elemental components are Fe (avrage in 85. 0%), Si (12. 3% in average), some Al, Ni, Cr, Mg and Mn, distribute inhomogenously. The highest concentration of Fe is found in the eruption holes and on the crust around the holes, Al and Si concentrated on the surface of the spherulitic balls, especially on the noduler bulges. concentrated on the noduler bulges, while Ni, Cr and Mn only found inside the eruption holes and Mg only on the surface of the spherule. No obvious diffence between the dendritic bulges and the depressed parts in the distribution of Fe and Si. Division 2 and 3. siliceous and lithical microspherulitic matters, are global or pear - like, mostly with a simple smooth surface. and a few have eruption holes. EDX analysis revealed that the component of silicer-ous one is Si (75. 2%). Al (15. 0%), some Ti and Fe, and for lithical ones, are mainly lithophile elements, i.e. , Si, Al, K, Fe, Zn, Ti and Mg.
2. Clastic Minerals Include zircon, magnetite, hexagonxl dipyramid quartz and mtile. Most of them
are excellent euhedral crystals with few trace of abrasion, and in the size of 30-300μm.
The crystal form of quartz is frequen
出处
《沉积学报》
CAS
CSCD
北大核心
1993年第3期105-113,共9页
Acta Sedimentologica Sinica
基金
国家自然科学基金(48970116)
