南京地区栖霞阶早期环境

<正> 南京地区栖霞组臭灰岩段在含Misellina claudiae带之下,船山组Pseucloschwagerina带之上,广泛分布一层厚0.5—2.5m的页岩夹石灰岩层(以下简称为页岩层)。内含丰富的介形类、苔藓虫、双壳类、腕足类、有孔虫、珊瑚以及藻类等化石。笔者拟从沉积物中的生物标志、物理标志二方面阐明其环境意义。 代表剖面出露在南京城东20km的孔山北坡公路壁,自上而下层序如下:(图1)

Environments of the early Chihsia Stage of the Nanjing region

Based on physical and biological sings in sediments, the writer analysed environments of the Lower Chihsia Stage (Lower Permian) of the Nanjing region. During the early age Chihsia scawater advanced from Southwest China. In the Nanjing region, the sea was shallow, a few meters in depth, indicating a sublittoral environment with low energy. Its salinity was normal and temperature was high. All of these were of great advantage to the growth of the ostracodes, bilvalves, foraminifers, bryozoans, bra-chiopods, corals and Dasycladales.