Abstract

The first study results on foraminifera from the Permian–Triassic boundary deposits in the southern Verkhoyansk region (the lower part of the Nekuchan Formation, Suol section located in the basin of Setorym River, a tributary of the East Khandyga River) are presented. The studied foraminifera constitute a novel group for this section and have not been used in paleontological-stratigraphic studies. The foraminiferal assemblage is represented exclusively by ammodiscids (Ammodiscus, Glomospira, and Glomospirella genera), among which Ammodiscus septentrionalis Gerke dominates. The distribution of foraminifera in the Suol section is compared to the previously constructed carbon isotope curve, which reflects global environmental changes. Three intervals are identified in the stratigraphic distribution of foraminifera. In the lower interval, foraminifera are relatively numerous and diverse. In the middle interval, foraminifera are not detected; the maximum negative values of δ¹³C_org isotope is also recorded here. This interval obviously corresponds to the main extinction episode in the Tethyan basins. In the upper interval, a gradual restoration of the abundance and structure of the foraminiferal complex occurs. A comparative analysis of the distribution and dynamics of taxonomic reorganization of the foraminiferal assemblages from the Permian–Triassic deposits within the Suol section and the assemblages from the Tethyan and Boreal sections has been carried out; as a result of this analysis, the common features and regularities are established. Brief descriptions of four foraminiferal species and a plate with their images are given.

中文翻译：

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Verkhoyansk南部地区二叠纪-三叠纪边界沉积物有孔虫的新发现和地层分布

摘要

提出了对南部Verkhoyansk地区（Nekuchan组的下部，位于Setorym河盆地的Suol段，东部Khandyga河的支流）的二叠纪-三叠纪边界沉积物有孔虫的首次研究结果。所研究的有孔虫在本节中构成了一个新的群体，尚未用于古生物学地层学研究中。有孔虫的组合只由弹药（Ammodiscus，Glomospira和Glomospirella属）代表，其中Ammodiscus septentrionalis盖克（Gerke）独领风骚。将Suol剖面中有孔虫的分布与先前绘制的碳同位素曲线进行比较，该曲线反映了全球环境的变化。在有孔虫的地层分布中确定了三个间隔。在较低的时间间隔中，有孔虫相对较多且种类繁多。在中间间隔内，未检测到有孔虫；δ的最大负值¹³ Ç_有机同位素也记录在这里。这个间隔显然对应于特提斯盆地的主要灭绝事件。在较高的区间，有孔虫复合物的丰度和结构逐渐恢复。对苏奥尔地区二叠纪-三叠纪沉积物中有孔虫组合和特提斯人和北方地区组合的有孔虫组合的分类和分类动力学进行了比较分析；分析的结果是建立了共同的特征和规律。简要描述了四个有孔虫物种和一个带有其图像的平板。