志留纪初全球发生了大规模海侵和缺氧事件, 无论高纬度还是低纬度地区, 黑色含笔石页岩均广泛发育。与华南同期广布的龙马溪组黑色页岩不同, 塔里木盆地西北缘志留纪初沉积了一套以灰绿色粉砂质泥岩、泥质粉砂岩和粉砂岩为特征的柯坪塔格组, 序列发育良好, 出露较为齐全。本项研究主要聚焦新疆喀什地区伽师县西克尔镇北剖面柯坪塔格组底部的笔石动物群, 识别出Korenograptus lungmaensis (Sun)、K. jerini (Koren’ and Melchin)、Metabolograptus parvulus (Lapworth)、M. wangjiawanensis (Mu and Lin)、Normalograptus skeliphrus Koren’ and Melchin、N. mirnyensis (Obut and Sobolevskaya)、N. cf. ajjeri (Legrand)和Akidograptus? sp., 共4属8种, 指示地层时代为志留纪兰多维列世鲁丹早期(Akidograptus ascensus—Parakidograptus acuminatus带)。同时, 通过岩相、生物相和地球化学分析, 识别出研究区志留纪早期沉积环境演变的阶段性特征; 在此基础上开展了与华南同期地层的对比研究, 并探讨了不同阶段的主控因素。

At the beginning of the Silurian, black shales were widely deposited across various latitudes, likely driven by large-scale global marine transgressions and extensive anoxic events. However, in contrast to the widespread black shales of the Lungmachi Formation in South China, the early Silurian Kalpintag Formation on the northwestern margin of the Tarim Basin consists predominantly of green-yellow silty mudstone, muddy siltstone, and siltstone. Although the formation is well developed and well exposed, it remains poorly documented. This study focuses on the basal part of the Kalpintag Formation at the Xike’er North section, approximately 1.5 km north of the Xike’erkule Town, Jiashi County, Kashi (Kashgar) Prefecture, Xinjiang. The basal part of the Kalpintag Formation at this section is characterized by greenish grey mudstone and yields a graptolite fauna with a total of eight species in four genera, including Korenograptus lungmaensis (Sun), K. jerini (Koren’ and Melchin), Metabolograptus parvulus (Lapworth), M. wangjiawanensis (Mu and Lin), Normalograptus skeliphrus Koren’ and Melchin, N. mirnyensis (Obut and Sobolevskaya), N. cf. ajjeri (Legrand), and Akidograptus? sp. This fauna indicates an early Rhuddanian age (Silurian), corresponding to the Akidograptus ascensus-Parakidograptus acuminatus Zone. In addition, we investigate the early Silurian sedimentary environments through integrated lithofacies, biofacies, and geochemical analyses, and further explore the dominant factors controlling the development of environmental phases based on stratigraphic correlation to the contemporaneous strata in South China.

科技部国家重点研发计划(2023YFF0803701)、江苏省国际科技合作计划(BZ2023068)、国家自然科学基金(42172174)、古生物学与油气地层应用国家重点实验室(20232102)和四川省科技计划(2024NSFTD0004)联合资助