Foraminiferal sequence of the middle–upper Viséan (Mississippian) of the Sikasya River Valley in the South Urals and correlation with the Belgian standard
Foraminiferal sequence of the middle–upper Viséan (Mississippian) of the Sikasya River Valley in the South Urals and correlation with the Belgian standard
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DOI：
10.1007/s12542-021-00556-9
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发表时间：
2021-07
期刊：
影响因子：
1.8
通讯作者：
E. Kulagina
中科院分区：
文献类型：
--
作者：
E. Kulagina
本文研究了南乌拉尔Sikasya（Sikaza）河谷一剖面的晚维森期有孔虫组合，为南乌拉尔西坡维森-谢尔普霍夫期界线层的地层学和对比提供了可靠的框架。Sikasya河上的中上部Viséan沉积物由具有丰富有孔虫、珊瑚和腕足动物的浅陆棚碳酸盐组成，并以四个区域亚阶段为代表：Tulian、Aleksinian、Mikhailovian和Venevian。这一部分被称为“Sikaza部分”。上维塞期矿床被主要由钙钛矿组成的谢尔普霍夫层覆盖。图利安和阿列克斯的层序由生物碎屑岩和有孔虫杂砂岩和杂砂岩组成。在米哈伊洛瓦阶，有一套含生物碎屑颗粒灰岩至碎屑岩夹层的碎屑岩，其中含有有孔虫。Venevian以生物碎屑岩、有孔虫颗粒灰岩和碎屑岩为代表。讨论了以下有孔虫单位：维塞安中部：（1）Paraarchaediscus koktjubensis-Endothyranopsis compressa;维塞安上部：（2）Ikensieformis proikensis-Archaediscus gigas，（3）Vissarionovella层（对应于Ikensieformis ikensis带），和（4）Ikensieformis tenebrosa; Serpukhovian以（5）Eostaffellina decurta层为代表。
Late Viséan foraminiferal assemblages from a section in the Sikasya (Sikaza) River Valley (South Urals) are studied to provide a reliable framework for stratigraphy and correlation of the Viséan-Serpukhovian boundary beds on the western slope of the South Urals. The middle–upper Viséan deposits on the Sikasya River are composed of shallow shelf carbonates with abundant foraminifers, corals, and brachiopods, and are represented by four regional substages: Tulian, Aleksinian, Mikhailovian, and Venevian. This section is known as the “Sikaza Section”. The upper Viséan deposits are overlain by Serpukhovian beds composed mainly of dolomites. The Tulian and Aleksinian successions consist of bioclastic and foraminiferal wackestone and packstone. In the Mikhailovian, there are packages of dolomites with interbeds of bioclastic grainstone to packstone, containing foraminifers. The Venevian is represented by bioclastic and foraminiferal grainstone and packstone. The following foraminiferal units are discussed: in the middle Viséan: (1)Paraarchaediscus koktjubensis–Endothyranopsis compressa;in the upper Viséan: (2)Ikensieformis proikensis–Archaediscus gigas, (3) beds withVissarionovella(corresponding to theIkensieformis ikensisZone), and (4)Ikensieformis tenebrosa; the Serpukhovian is represented by (5) beds withEostaffellina decurta.