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引言江西西部的笔石地层是在近几年才发现的。1961年,江西省地质局区测三分队首次在宁冈县棋子石的前泥盆纪“演吉岭系”浅变质岩系中发现了奥陶纪笔石。1962年,我队地层组先后在永新、宁冈及井冈山等地(图1)详细测制剖面,系统采集化石。此次采获的化石很多,全属笔石。这里仅就上述地区的笔石地层剖面予以介绍,提供参考。江西西部奥陶纪笔石地层,过去尚无报导。因此,这些材料的研究,对本区奥陶纪地层的分组建带工作都很有帮助。值得提出的是,我国南方很多地区中奥陶统上部(如砚瓦山组或宝塔组)多为介壳相的碳酸盐岩沉积,笔石极为少见,但本区则全为笔石碎屑岩相。因之,江西西部笔石地层的研究及与邻区对比,对了解我国古地史发展特征,提供了重要材料。
Introduction Petrophysical formations in western Jiangxi Province were discovered in recent years. In 1961, for the first time, the third unit of the Geological Bureau of Jiangxi Province discovered Ordovician penoliths in the former Devonian “Yanjiling” shallow metamorphic rocks of Paizishi, Ninggang County. In 1962, the formation team of our team conducted a detailed survey of the sections in Yongxin, Ninggang and Jinggangshan (Figure 1) to collect fossils systematically. The acquisition of many fossils, all are pen and stone. Here only for the above-mentioned area of pen litholithography profile to provide a reference. Ordovician petrographic strata in western Jiangxi Province have not been reported in the past. Therefore, the research of these materials is very helpful to the sub-formation of Ordovician strata in this area. It is worth mentioning that most of the Upper Ordovician (such as the Yan Wanshan Formation or the Pagoda Formation) in many parts of southern China are mostly carbonate rocks with lithic shell facies. The penoliths are extremely rare, but the area is entirely composed of pen-stone detritus Lithofacies. Therefore, the study on the Penxi stratum in western Jiangxi Province and its comparison with its neighboring areas provide important materials for understanding the developmental characteristics of ancient Chinese history.