Ferruginous microbialite blooms of the Miaolingian (Cambrian) in the southern North China Craton: a response to the volc
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ORIGINAL ARTICLE
Ferruginous microbialite blooms of the Miaolingian (Cambrian) in the southern North China Craton: a response to the volcanic event? Xiyang Zhang1,2 · Yong’an Qi1 · Yue Li3 · Mingyue Dai1 · Min Wang1 Accepted: 29 August 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Ferruginous microbialites of the Mantou Formation (Miaolingian, Cambrian) in the southern North China Craton are available for investigation of their formation mechanisms. The ferruginous microbial structures are existing in a deepening upwards sequence with occurrences of the oolitic limestone, oncolite, stromatolite, and thrombolite in ascending order. The ooids larger than 2 mm in diameter are made up of repeated alternations of bright coarse-grained calcites and homogeneously ferruginous fine-grained calcites. Oncoids and stromatolites comprise alternations of coarse-grained calcite and Girvanella-laminae. Thrombolites consist of massive Girvanella-clots and micritic interstitial sediments. Several filaments with ferruginous sheathes in the laminae/clots are interpreted as the remains of iron-oxidizing bacteria. Mineral components of ferruginous microbialites are mainly calcite, quartz, plagioclase, microcline, clay minerals, and some iron minerals. The sharp increases of ferruginous volcanogenic materials in the strata are ascribed to the contemporaneous ash fall. The elevated nutrient concentration dramatically spurred the cyanobacterial bloom and then caused an extensive eutrophication. Microaerophilic iron-oxidizing bacteria then thrived therein promoting oxidize ferrous solution into iron oxide/oxyhydroxide. The widespread Miaolingian ferruginous microbialites indicated the proliferation of microbial communities in the aftermath of contemporaneous volcanism in the southern North China Craton. Keywords Ferruginous microbialite · Volcanism · Mantou formation · Cambrian miaolingian · Southern North China Craton
Introduction Ironstones with conspicuous red color (Taylor et al. 2002) were distinctive sedimentary rocks especially occurred in two Phanerozoic episodes of the Ordovician–Devonian and Jurassic–Palaeogene (Van Houten and Arthur 1989; Young 1989; Sturesson et al. 2000; Mamet and Préat 2006; Taylor
* Yong’an Qi [email protected] 1
School of Resources and Environment, Henan Polytechnic University, Shiji Road 2001, Jiaozuo 454000, China
2
CAS Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, West Xin’gang Road 164, Guangzhou 510301, China
3
CAS Key Laboratory of Economic Stratigraphy and Palaeogeography, Nanjing Institute of Geology and Paleontology, East Beijing Road 39, Nanjing 210008, China
and Konhauser 2011; Baioumy et al. 2017; Todd et al. 2019). Unlike the Proterozoic analogue–banded iron formation, non-banded and non-cherty structures are considered as essential features of the Phanerozoic ironstones. The Phanerozoic ironstones are recorded from diverse carbonates such as coated grains of ooids, pisoids
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