Cyanobacterial fossils in terminal Paleoproterozoic ferric microbialites (Xuanlong type iron formation) in Hebei, China

中国河北古元古代末长城系串岭沟组铁质微生物岩宣龙式铁矿中发现丝状蓝细菌胶鞘化石

Hong-Xia Jiang (姜红霞)¹, Zhuo-Fei Sha (沙卓菲)^*1, Ao-Ran Liu (刘傲然)¹

¹ Hebei International Joint Research Center for Paleoanthropology, College of Earth Science,

Hebei GEO University, Shijiazhuang 050000, China. (河北省古人类形态与演化国际联合研究中心，河北地质大学地球科学学院，石家庄，050000)

*Corresponding author: Zhuo-Fei Sha. Email: jianghx@hgu.edu.cn; shazhuofei@163.com

Abstract

The stratiform iron formation in the terminal Paleoproterozoic Chuanlinggou Formation (1650-1640 Ma) in Xuanhua-Longguan area of Hebei Province, China, i.e., the Xuanlong-type iron formation, is one of the important iron ore types in China. Some researchers considered it had a microbial origin, but did not gi​ve convincing evidence. In this study, rich filamentous fossils were found from an iron bed. The filaments are 3.9~26.7 μm in diameter. Based on their shape and size, the fossils are identified as sheath fossils of cyanobacteria. The presence of the fossils indicates that the Xuanlong-type iron formation formed in the marine euphotic zone, and cyanobacteria may have provided oxygen for the formation of the iron ore.

Key words: Xuanlong-type iron formation; iron formation; iron oolite; ferr​ic ooid; iron stromatolite; ferric oolite; ferric stromatolite; sheath fossil; cyanobacteria; Paleoproterozoic; Changchengian System; Chuanlinggou Formation  

Funding:  This study was supported by the National Natural Science Foundation of China (Grant No. 41972320) to Ya-Sheng Wu.

Cite it as:  Jiang, H.X., Sha, Z.F., Liu, O.R. 2024.Cyanobacterial fossils in the terminal Paleoproterozoic ferric microbialites (Xuanlong type iron formation) in Hebei, China.  Biopetrology, 4(1): 10-22. https://biopetrology.com/cfitpf