Geochemical Characteristics and Genetic Significance of Datangpo‐Type Manganese Ore Deposits during the Cryogenian Period

2018 ◽  
Vol 69 (3) ◽  
pp. 227-248
Author(s):  
Jiafei Xiao ◽  
Jingyang He ◽  
Haiying Yang ◽  
Chengquan Wu ◽  
Jianbin Xu ◽  
...  
Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 408
Author(s):  
Brenton J. Fairey ◽  
Martin J. Timmerman ◽  
Masafumi Sudo ◽  
Harilaos Tsikos

The Postmasburg Manganese Field (PMF), Northern Cape Province, South Africa, once represented one of the largest sources of manganese ore worldwide. Two belts of manganese ore deposits have been distinguished in the PMF, namely the Western Belt of ferruginous manganese ores and the Eastern Belt of siliceous manganese ores. Prevailing models of ore formation in these two belts invoke karstification of manganese-rich dolomites and residual accumulation of manganese wad which later underwent diagenetic and low-grade metamorphic processes. For the most part, the role of hydrothermal processes and metasomatic alteration towards ore formation has not been adequately discussed. Here we report an abundance of common and some rare Al-, Na-, K- and Ba-bearing minerals, particularly aegirine, albite, microcline, banalsite, sérandite-pectolite, paragonite and natrolite in Mn ores of the PMF, indicative of hydrothermal influence. Enrichments in Na, K and/or Ba in the ores are generally on a percentage level for most samples analysed through bulk-rock techniques. The presence of As-rich tokyoite also suggests the presence of As and V in the hydrothermal fluid. The fluid was likely oxidized and alkaline in nature, akin to a mature basinal brine. Various replacement textures, particularly of Na- and K- rich minerals by Ba-bearing phases, suggest sequential deposition of gangue as well as ore-minerals from the hydrothermal fluid, with Ba phases being deposited at a later stage. The stratigraphic variability of the studied ores and their deviation from the strict classification of ferruginous and siliceous ores in the literature, suggests that a re-evaluation of genetic models is warranted. New Ar-Ar ages for K-feldspars suggest a late Neoproterozoic timing for hydrothermal activity. This corroborates previous geochronological evidence for regional hydrothermal activity that affected Mn ores at the PMF but also, possibly, the high-grade Mn ores of the Kalahari Manganese Field to the north. A revised, all-encompassing model for the development of the manganese deposits of the PMF is then proposed, whereby the source of metals is attributed to underlying carbonate rocks beyond the Reivilo Formation of the Campbellrand Subgroup. The main process by which metals are primarily accumulated is attributed to karstification of the dolomitic substrate. The overlying Asbestos Hills Subgroup banded iron formation (BIF) is suggested as a potential source of alkali metals, which also provides a mechanism for leaching of these BIFs to form high-grade residual iron ore deposits.


Author(s):  
G. F. Herbert Smith ◽  
G. T. Prior

Analyses of Indian manganese-ores generally show the presence of small amounts of arsenic. The form in which this constituent occurs was discovered by Dr. L. Leigh Fermor in the course of his investigations of these well-known deposits. At two different localities crystalline arsenates were found. One of these occurrences is at the Sitapar deposit in the Chhindwara district, Central Provinces. The pinkish-white to white arsenate found there is the new mineral to which we have given the name fermorite. The other locality at which an arsenate was found is Kajlidongri, Jhabua State, Central India. The pale-green arsenate, somewhat resembling apatite in appearance, which occurs at this locality has been found by us to be identical with the tilasite from Sweden described by Sjögren.


2016 ◽  
Vol 34 (4) ◽  
pp. 309-316 ◽  
Author(s):  
S. Mohanty ◽  
S. Ghosh ◽  
S. Nayak ◽  
A. P. Das
Keyword(s):  

Nature ◽  
1910 ◽  
Vol 84 (2135) ◽  
pp. 406-406 ◽  
Author(s):  
H. L.
Keyword(s):  

2013 ◽  
Vol 807-809 ◽  
pp. 2129-2132
Author(s):  
Jiao Jiao Chen ◽  
Ying Shu Li ◽  
Da Qing He ◽  
Dong Ming Yang ◽  
Yi Ke Zhang

Pangjiagou gold polymetallic deposit is located in bending parts of the north east direction of the Yanshan arc structural belt in Hebei province, which has a good regional metallogenic background. According to the collection of samples and tests of eight elements for the samples of the mining area, we studied the geochemical anomaly characteristics of the soil secondary halos of the ore deposit. By means of researching on geochemical characteristics of the ore deposit, it worked out that the ore deposit possesses the characteristics of multiphase ore-forming hydrothermal activity, which is divided into the Sb-Zn mineralization period and Cu-Au mineralization period. The important prospecting of the ore deposits in the area consist of the surface oxidation, the wall rock alteration and the geochemical characteristics.


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