气候变化领域集成服务门户(CCPortal): Microaerophilic Fe-oxidizing micro-organisms in Middle Jurassic ferruginous stromatolites and the paleoenvironmental context of their formation (Southern Carpathians, Romania)

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DOI	10.1111/gbi.12376
	Microaerophilic Fe-oxidizing micro-organisms in Middle Jurassic ferruginous stromatolites and the paleoenvironmental context of their formation (Southern Carpathians, Romania)
	Grădinaru M.; Lazăr I.; Ducea M.N.; Petrescu L.
发表日期	2020
ISSN	14724677
起始页码	366
结束页码	393
卷号	18 期号:3
英文摘要	Ferruginous stromatolites occur associated with Middle Jurassic condensed deposits in several Tethyan and peri-Tethyan areas. The studied ferruginous stromatolites occurring in the Middle Jurassic condensed deposits of Southern Carpathians (Romania) preserve morphological, geochemical, and mineralogical data that suggest microbial iron oxidation. Based on their macrofabrics and accretion patterns, we classified stromatolites: (1) Ferruginous microstromatolites associated with hardground surfaces and forming the cortex of the macro-oncoids and (2) Domical ferruginous stromatolites developed within the Ammonitico Rosso-type succession disposed above the ferruginous microstromatolites (type 1). Petrographic and scanning electron microscope (SEM) examinations reveal that different types of filamentous micro-organisms were the significant framework builders of the ferruginous stromatolitic laminae. The studied stromatolites yield a large range of δ56Fe values, from −0.75‰ to +0.66‰ with predominantly positive values indicating the prevalence of partial ferrous iron oxidation. The lowest negative δ56Fe values (up to −0.75‰) are present only in domical ferruginous stromatolites samples and point to initial iron mobilization where the Fe(II) was produced by dissimilatory Fe(III) reduction of ferric oxides by Fe(III)-reducing bacteria. Rare-earth elements and yttrium (REE + Y) are used to decipher the nature of the seawater during the formation of the ferruginous stromatolites. Cerium anomalies display moderate to small negative values for the ferruginous microstromatolites, indicating weakly oxygenated conditions compatible with slowly reducing environments, in contrast to the domical ferruginous stromatolites that show moderate positive Ce anomalies suggesting that they formed in deeper, anoxic–suboxic waters. The positive Eu anomalies from the studied samples suggest a diffuse hydrothermal input on the seawater during the Middle Jurassic on the sites of ferruginous stromatolite accretion. This study presents the first interpretation of REE + Y in the Middle Jurassic ferruginous stromatolites of Southern Carpathians, Romania. © 2020 John Wiley & Sons Ltd
关键词	accretion cerium data interpretation geochemistry iron iron-reducing bacterium Jurassic microbial activity mineralogy mobilization morphology oxidation oxide group Paratethys rare earth element reduction seawater stromatolite Tethys yttrium Carpathians Romania
语种	英语
来源机构	Geobiology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/133189
推荐引用方式 GB/T 7714	Grădinaru M.,Lazăr I.,Ducea M.N.,et al. Microaerophilic Fe-oxidizing micro-organisms in Middle Jurassic ferruginous stromatolites and the paleoenvironmental context of their formation (Southern Carpathians, Romania)[J]. Geobiology,2020,18(3).
APA	Grădinaru M.,Lazăr I.,Ducea M.N.,&Petrescu L..(2020).Microaerophilic Fe-oxidizing micro-organisms in Middle Jurassic ferruginous stromatolites and the paleoenvironmental context of their formation (Southern Carpathians, Romania).,18(3).
MLA	Grădinaru M.,et al."Microaerophilic Fe-oxidizing micro-organisms in Middle Jurassic ferruginous stromatolites and the paleoenvironmental context of their formation (Southern Carpathians, Romania)".18.3(2020).