层状硅质岩沉积环境研究的一种新方法（酸溶蚀法）──兼论武昌地区孤峰组沉积环境

武昌地区孤峰组硅质岩主要包括放射虫岩、海绵骨针岩和微晶硅质岩。将这些岩石样品浸入氢氟酸（５—１０％）中１２—２４ｈ，可见清楚的沉积构造。孤峰组上部具丰富的放射虫化石，发育块状层理、条带状层理和三分层理，形成于深水盆地环境；下部具丰富的海绵骨针，发育滑塌构造、粒序层理、水平层理、波状层理，形成于较深水斜坡环境。

A NEW RESEARCH METHOD OF SEDIMENTARY ENVIRONMENTS OF BEDDED SILICEOUS ROCKS,WITH DISCUSSIONS ON SEDIMENTARY ENVIRONMENTS OF THE GUFENG FORMATION IN THE WUCHANG AREA,HUBEI

The siliceous rocks in the Gufeng Formation in the Wuchang area,Hubei consist mainly of radiolarite,sponge-spicule rocks and microcrystalline siliceous rocks. A new research method,i.e.,the corrosion of hydrofluoric acid has been proposed in the study for the purpose of the analysis of sedimentary environments of the siliceous rocks in the study area.Some representative samples of these siliceous rocks were selected to be immersed in a dilute hydrofluoric acid (5 10%)for 12 24 hours,and then the distinct sedimentary structures could be recognized on the surfaces of the samples. The upper Gufeng Formation is characterized by abundant fossil radiolarias, massive bedding, striped bedding,triple-layered bedding,indicating a deep-water basin environment,while the lower Gufeng Formation by abundant sponge spicules, slump structure, graded bedding, horizontal bedding,wavy bedding,suggesting a deeper-water slope environment.