干旱区生态环境知识资源中心(Arid): The paleoenvironmental implications of pre-Great Oxidation Event manganese deposition in the Mesoarchean Ijzermijn Iron Formation Bed, Mozaan Group, Pongola Supergroup, South Africa

Arid

DOI	10.1016/j.precamres.2022.106922
	The paleoenvironmental implications of pre-Great Oxidation Event manganese deposition in the Mesoarchean Ijzermijn Iron Formation Bed, Mozaan Group, Pongola Supergroup, South Africa
	Smith, Albertus J. B.; Beukes, Nicolas J.
通讯作者	Smith, AJB
来源期刊	PRECAMBRIAN RESEARCH
ISSN	0301-9268
EISSN	1872-7433
出版年	2023
卷号	384
英文摘要	The Ijzermijn Iron Formation Bed occurs in the Vlakhoek Member of the basal Sinqeni Formation of the Mes-oarchean Mozaan Group of the Pongola Supergroup of southern Africa. It represents the oldest known supra-cratonic Superior-type iron formation that has significant manganese enrichments. Lithostratigraphic correlation between the Mozaan Group and the Witwatersrand Supergroup indicates that there was a larger Witwatersrand-Mozaan depositional basin on the Kaapvaal Craton during the Mesoarchean. Detailed stratigraphy, mineralogy, petrography, carbonate mineral chemistry, major and trace element geochemistry and carbonate oxygen and carbon isotopes are presented for two drill cores intersecting the Ijzermijn Iron Formation Bed. Drill core PMH 24, which represents a more coast-distal depositional setting, is characterized by manganese-rich siderite, higher Fe2O3 and lower MnO and Al2O3 contents, more prominent europium anomalies, lower GdSN/YbSN values and less depleted 813CPDB values. Drill core DDN 1, which represents a more coast-proximal depositional setting, is characterized by iron-rich rhodochrosite, lower Fe2O3 and higher MnO and Al2O3 contents, less prominent europium anomalies, higher GdSN/YbSN values and more depleted 813CPDB values. The presence of early diagenetic magnetite, hematite and 13C-depleted carbonates indicate the iron and manganese, which were sourced from hydrothermal plumes, were deposited by oxidation, with subsequent diagenetic reduction by organic carbon. The most efficient oxidative mechanism would have been biological oxidation. The increase in manganese contents towards the paleocoastline further supports manganese oxidation as it was redox buffered by Fe2+ in the water column and could only be deposited and preserved once Fe2+ had been removed through oxidation further away from the distal hydrothermal plume source. This is supported by previously published iron isotope data, where 856/54Fe values are more depleted closer to the paleocoastline. Deposition of iron and manganese was restricted to below the photic zone. This implies that microaerophilic chemolithoautotrophs were responsible for iron and manganese oxidation. This requirement of free oxygen in the Ijzermijn Iron For-mation Bed has been supported by earlier molybdenum isotope studies. The presented work therefore further supports the idea of pre-Great Oxidation Event marine oxygen oases that did not lead to any appreciable build-up of oxygen in the atmosphere.
英文关键词	Iron formation Manganese deposition Mesoarchean Free oxygen
类型	Article
语种	英语
开放获取类型	Bronze
收录类别	SCI-E
WOS记录号	WOS:000990798200001
WOS关键词	PROTEROZOIC TRANSVAAL SUPERGROUP ; RARE-EARTH-ELEMENTS ; WITWATERSRAND SUPERGROUP ; FACIES TRANSITION ; SINQENI FORMATION ; ISOTOPE EVIDENCE ; GEOCHEMISTRY ; OXYGENATION ; SEAWATER ; RISE
WOS类目	Geosciences, Multidisciplinary
WOS研究方向	Geology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/398161
推荐引用方式 GB/T 7714	Smith, Albertus J. B.,Beukes, Nicolas J.. The paleoenvironmental implications of pre-Great Oxidation Event manganese deposition in the Mesoarchean Ijzermijn Iron Formation Bed, Mozaan Group, Pongola Supergroup, South Africa[J],2023,384.
APA	Smith, Albertus J. B.,&Beukes, Nicolas J..(2023).The paleoenvironmental implications of pre-Great Oxidation Event manganese deposition in the Mesoarchean Ijzermijn Iron Formation Bed, Mozaan Group, Pongola Supergroup, South Africa.PRECAMBRIAN RESEARCH,384.
MLA	Smith, Albertus J. B.,et al."The paleoenvironmental implications of pre-Great Oxidation Event manganese deposition in the Mesoarchean Ijzermijn Iron Formation Bed, Mozaan Group, Pongola Supergroup, South Africa".PRECAMBRIAN RESEARCH 384(2023).