灰泥灰岩中疑难的超微化石结构及其成因、结构分类

COMPLICATED STRUCTURE OF NANNOFOSSILS IN LIMEMUD LIMESTONE AND CLASSIFICATION OF THEIR ORIGIN AND STRUCTURE

黄杏珍

Huang Xingzheng

中国科学院兰州地质研究所

Lanzhou Institate of Geology, Academia Sinica

灰泥灰岩是由直径小于10微米的方解石颗粒组成、研究灰泥的组成与结构特别是超微生物化石结构,这是碳酸盐岩岩石学方面的一个棘手的问题。本文选取四川峨眉、纳溪),陕甘宁),塔里木,柴达木盆地等,寒武系至第三系不同沉积环境的灰泥灰岩样品118个,通过薄片矿物染色鉴定,扫描电镜观察与照像)等研究,初步认为:侏系系以前的灰泥灰岩中也存在有怀疑超微生物化石结构;灰泥除化学沉淀、机械破碎等成因外,更重要的是生物成因,表现为岩石具有超微生物化石结构及藻类、菌类成因的生物结构。

This paper deals with 118 samples of limemicrtescanning electron micro-scope (SEM) is mainly used on studying the structure of ultrafossils in limemicrete, the diameter of ultrafossils discovered in limemicrite is about 5-30μ the shapes can be described as walnut, regular round and ellipes, irregular round and ellipse, bottle, sowl, star, gear, whell, flower shape, etc.. In the last decade the ultrafossil plates were established from the period of Jurassic.This paper mainly studies on the old stratum prior to Jurassic.At present, however there is no standard fossil plate available for reference, so problematical ultrafossils are advanced for the discussion. In addition, the structures visible in the thin section and relative to the activity of algae life are analyseed. It is one of the basis by which the biogenie micrograin of limemicrite is ascertained. Three geneses of limemicrite can be observed under SEM., as follows:chemogenic, mechanogenic and biogenic. They are distinguished one from another according to their structures. It is suggested that a genetic prefix should be added to limemicrite, that means on the basis of the structure nomenclature of limemicrite/grain content to add a genetic nomenclature.

https://doi.org/10.11781/sysydz198501047