Ordovician reef-hosted Jiaodingshan Mn-Co deposit and Dawashan Mn deposit, Sichuan Province, China

	Ordovician reef-hosted Jiaodingshan Mn-Co deposit and Dawashan Mn deposit, Sichuan Province, China
	Fan, DL ; Hein, JR ; Ye, J
刊名	ORE GEOLOGY REVIEWS
	1999-10-01
卷号	15 期号:1-3 页码:135-151
关键词	Mn carbonate ore Ordovician carbonate reefs Dawashan and Jiaodingshan ores Co enrichments
ISSN号	0169-1368
文献子类	Review
英文摘要	The Jiaodingshan Mn-Co and Dawashan Mn deposits are located in the approximately 2-m thick Daduhe unit of the Wufengian strata of Late Ordovician (Ashgill) age. Paleogeographic reconstruction places the deposits at the time of their formation in a gulf between Chengdu submarine rise and the Kangdian continent. The Jiaodingshan and Dawashan deposits occur in algal-reef facies, the former in an atoll-like structure and the latter in a pinnacle reef. Ores are mainly composed of rhodochrosite, kutnahorite, hausmannite, braunite, manganosite, and bementite. Dark red, yellowish-pink, brown, green-gray, and black ores are massive, banded, laminated, spheroidal, and cryptalgal (oncolite, stromatolite, algal filaments) bound-stones. Blue, green, and red algal fossils show in situ growth positions. Samples of high-grade Jiaodingshan and Dawashan ores assay as much as 66.7% MnO. Jiaodingshan Mn carbonate ores have mean contents of Ba, Co, and Pb somewhat higher than in Dawashan ores. Cobalt is widely distributed and strongly enriched in all rock types as compared to its crustal mean content. Cobalt is correlated with Cu, Ni, and MgO in both deposits and additionally with Ba and Zn in the Dawashan deposit. The delta(13)C(PDB) values of Mn carbonate ores (-7.8 to -16.3 parts per thousand) indicate contributions of carbon from both seawater bicarbonate and the bacterial degradation of organic matter, the latter being 33% to 68%, assuming about -24 parts per thousand for the delta(13)C(PDB) of the organic matter. Host limestones derived carbon predominantly from seawater bicarbonate (delta(13)C(PDB) of +0.2 to -7 parts per thousand). NW-trending fault zones controlled development of lithofacies, whereas NE-trending fault zones provided pathways for movement of fluids. The source of Co, Ni, and Cu was mainly from weathering of mafic and ultramafic rocks on the Kangdian continent, whereas contemporaneous volcanic eruptions were of secondary importance. The reefs were likely mineralized during early diagenesis under shallow burial. The reefs were highly porous and acted as the locus for metasomatic replacement by Mn that combined with CO2 produced during oxidation of organic matter in the zone of sulfate reduction and seawater bicarbonate. That metasomatic replacement formed the rhodochrosite ores. (C) 1999 Elsevier Science B.V. All rights reserved.
WOS关键词	ENVIRONMENT ; MANGANESE
WOS研究方向	Geology ; Mineralogy ; Mining & Mineral Processing
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000083933600009
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/75236]
专题	中国科学院地质与地球物理研究所
通讯作者	Fan, DL
作者单位	1.Chinese Acad Sci, Inst Geol, Beijing 100029, Peoples R China 2.US Geol Survey, Menlo Park, CA 94025 USA
推荐引用方式 GB/T 7714	Fan, DL,Hein, JR,Ye, J. Ordovician reef-hosted Jiaodingshan Mn-Co deposit and Dawashan Mn deposit, Sichuan Province, China[J]. ORE GEOLOGY REVIEWS,1999,15(1-3):135-151.
APA	Fan, DL,Hein, JR,&Ye, J.(1999).Ordovician reef-hosted Jiaodingshan Mn-Co deposit and Dawashan Mn deposit, Sichuan Province, China.ORE GEOLOGY REVIEWS,15(1-3),135-151.
MLA	Fan, DL,et al."Ordovician reef-hosted Jiaodingshan Mn-Co deposit and Dawashan Mn deposit, Sichuan Province, China".ORE GEOLOGY REVIEWS 15.1-3(1999):135-151.