贵州剑河寒武系第二统第四阶“清虚洞组”主要是一套下部和顶部为碳酸盐岩, 中上部为泥岩、泥质灰岩不等厚互层的岩性组合。本文主要通过酸蚀法对剑河松山剖面“清虚洞组”碳酸盐岩层进行系统的化石采集和处理, 对丰度和分异度均较高的微型腕足动物进行了系统古生物学研究。系统鉴定了剑河寒武系“清虚洞组”微型腕足动物5属6种, 包括乳孔贝超科的Eohadrotreta zhenbaensis、Hadrotreta primaea, 乳房贝超科的Schizopholis napuru、Schizopholis yorkensis和舌形贝超科的Palaeobolus sp.、Eoobolus sp.。数量上以E. zhenbaensis为主, 约占80%。其中E. zhenbaensis, S. yorkensis在研究区内为首次发现。对剑河“清虚洞组”碳酸盐岩中的微型腕足动物组合面貌碎屑岩中的腕足动物组合进行对比研究, 发现碳酸盐岩中是以Eohadrotreta为主的微型腕足动物群, 而碎屑岩中则保存大量Nisusia及少量Diandongia、Kutorgina等未见于碳酸盐岩中的腕足动物。该组合面貌的不同可能是由于埋藏条件的差异导致的变化, 也可能是相对海平面变化以及环境底质导致的腕足动物与环境共演化的结果。本研究丰富了“清虚洞组”腕足动物的组合面貌, 也为了解寒武纪时期腕足动物的组成情况及其与环境之间的联系提供了信息。

The ‘Tsinghsutung Formation’ (Cambrian Series 2 Stage 4) in Jianhe County, Guizhou is mainly composed of a lithological assemblage featuring carbonate rocks at the lower and top parts, with interbedded mudstones and argilla-ceous limestones with various thickness at the middle and upper sections. The carbonate layers of the Cambrian ‘Tsinghsutung Formation’ at the Songshan section were systematically sampled and processed using acid etching method, allowing for the study of the highly abundant and diverse micro-brachiopods. Five genera and six species of micro-brachiopods from the ‘Tsinghsutung Formation’ are identified, including Eohadrotreta zhenbaensis and Hadrotreta primaea of the Acrotretoidea; Schizopholis napuru and Schizopholis yorkensis of the superfamily Acrotretacea; and Palaeobolus sp. and Eoobolus sp. of the superfamily Linguloidea. Eohadrotreta zhenbaensis is dominant, accounting for approximately 80% of the assemblage. Notably, E. zhenbaensis and S. yorkensis are discovered for the first time in the study area. A comparison of characters of the micro-brachiopod assemblage from the carbonate rocks of the ‘Tsinghsutung Formation’ with those of macro-brachiopods in clastic rocks, as reported by previous researchers from Jianhe, reveals a micro-brachiopod fauna dominated by Eohadrotreta in the carbonate rocks. In contrast, a large number of macro-brachiopod Nisusia, along with smaller amounts of Diandongia and Kutorgina, are uniquely preserved in the clastic rocks. This difference between these assemblages may be resulted from variations in burial conditions or changes in relative sea level and environmental substrates. This study not only enriches our understanding of the characteristics of the brachiopod assemblage from the ‘Tsinghsutung Formation’, but also provides more information for a comprehensive understanding of the brachiopod composition in Cambrian Stage 4 and their evolutionary adaptations to environmental changes.

国家自然科学基金项目(42262003, 42262002)和贵州省科技计划项目(黔科合基础-ZK[2025]重点100, 黔科合平台ZSYS[2024]002)联合资助