Geology and ore genesis of the manganese ore deposits of the Postmasburg manganese-field, South Africa

1995 ◽  
Vol 30 (3-4) ◽  
pp. 257-267 ◽  
Author(s):  
E. von Plehwe-Leisen ◽  
D. D. Klemm
Keyword(s):  
South Africa ◽  
Ore Deposits ◽  
Manganese Ore ◽  
Ore Genesis

scholarly journals Rare elements — setting markers of the formation of the manganese and iron ore deposits of Kalahari and Postmasburg areas (South Africa). Communication 2. Iron- and manganese ore of Postmasburg area

2019 ◽  
pp. 466-485
Author(s):  
I. M. Varentsov ◽  
V. N. Kuleshov
Keyword(s):  
South Africa ◽  
Hydrothermal Activity ◽  
Ore Deposits ◽  
Manganese Ore ◽  
Iron Ores ◽  
Ore Formation ◽  
Rare Elements ◽  
Iron Ore Deposits ◽  
Marine Basin ◽  
Iron And Manganese

In the world resources of manganese and iron ores, a significant place belongs to the Postmasburg ore field (South Africa), enclosed in rocks of the Transvaal Supegroup. Ore deposits have the nature of karst residual accumulations. A number of elements (B, Cr, Ni, Zn, Ge, As, Se, Mo, Ag, Cd, Sb, Te, W, Pb, REE) form a characteristic association that sheds light on the geochemistry of the ore formation processes. Of these, the most representative elements are: Mo, As, Ag and REE. Molybdenum is distinguished by the chemisorption incorporation nature of accumulation in the ores under consideration, often with the formation of epic growths of ferri molybdate-type minerals. Arsenic leached from substrate rocks and accumulated in karstic Mn-Fe- and Fe-ores reflects the total effect of the dominant iron oxide minerals on its mobility. The behavior of silver is controlled by the processes of hypergenic change of Archean-Early Proterozoic carbonate rocks and banded iron ores (BIF). Comparison of the distribution of REE in karst Fe-, Mn-Fe- and Mn-ores and in banded iron ores shows that they are characterized by similar values of cerium (C/Ce*) and europium (Eu/Eu*) anomalies, but differ in the fractionation of heavy and light REE (typical values: Ce/Ce* = 0.7‒1.0; Eu/Eu* = 0.8‒1.1). Strip iron ores and associated manganese ore deposits accumulated in the marginal anoxide-disoxide marine basin, which was limited to continental land. Anoxide and disoxide conditions were the result of intense hydrothermal activity.

scholarly journals The Role of Hydrothermal Activity in the Formation of Karst-Hosted Manganese Deposits of the Postmasburg Mn Field, Northern Cape Province, South Africa

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 408
Author(s):  
Brenton J. Fairey ◽  
Martin J. Timmerman ◽  
Masafumi Sudo ◽  
Harilaos Tsikos
Keyword(s):  
Hydrothermal Fluid ◽  
Hydrothermal Activity ◽  
Ore Deposits ◽  
Manganese Ore ◽  
High Grade ◽  
Ore Formation ◽  
Manganese Ores ◽  
Manganese Deposits ◽  
Northern Cape

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.

On Fermorite, a new arsenate and Phosphate of lime and strontia, and Tilasite, from the manganese-ore deposits of India

1911 ◽  
Vol 16 (74) ◽  
pp. 84-96 ◽  
Author(s):  
G. F. Herbert Smith ◽  
G. T. Prior
Keyword(s):  
Central India ◽  
Ore Deposits ◽  
The Other ◽  
New Mineral ◽  
Manganese Ore ◽  
Manganese Ores ◽  
Pale Green

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.

Isolation, Identification and Screening of Manganese Solubilizing Fungi From Low-Grade Manganese Ore Deposits

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

The Ore Deposits of South Africa. Part ii

1910 ◽  
Vol 35 (2) ◽  
pp. 188
Author(s):  
J. P. Johnson
Keyword(s):  
South Africa ◽  
Ore Deposits

scholarly journals (1) The Ore Deposits of South Africa (2) The Geology of Ore Deposits

Nature ◽  
1910 ◽  
Vol 84 (2132) ◽  
pp. 293-293
Author(s):  
J. W. G.
Keyword(s):  
South Africa ◽  
Ore Deposits

scholarly journals Manganese Ore Deposits

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

scholarly journals Elevated magma fluxes deliver high-Cu magmas to the upper crust

Geology ◽  
2020 ◽  
Vol 48 (10) ◽  
pp. 957-960
Author(s):  
Daniel Cox ◽  
Sebastian F.L. Watt ◽  
Frances E. Jenner ◽  
Alan R. Hastie ◽  
Samantha J. Hammond ◽  
...  
Keyword(s):  
Small Proportion ◽  
Ore Deposits ◽  
Crustal Evolution ◽  
Upper Crust ◽  
Convergent Margins ◽  
Ore Genesis ◽  
Porphyry Cu ◽  
Show Evidence ◽  
Lower Crustal ◽  
Garnet Fractionation

Abstract Porphyry Cu-Au ore deposits are globally associated with convergent margins. However, controls on the processing and distribution of the chalcophile elements (e.g., Cu) during convergent margin magmatism remain disputed. Here, we show that magmas feeding many Chilean stratovolcanoes fractionate sulfides with a high-Cu/Ag ratio early in their crustal evolution. These magmas show evidence of lower-crustal garnet and amphibole crystallization, and their degree of sulfide fractionation and Cu depletion increase with both crustal thickness and the extent of garnet fractionation. However, samples from a small proportion of volcanoes with elevated eruptive fluxes depart from this Cu-depleting trend, instead erupting Cu-rich magmas. This implies that at these atypical sites, elevated magma productivity and crustal throughput, potentially facilitated by “pathways” exploiting major crustal fault systems, enable rapid magma transit, avoiding lower-crustal Cu-depleting sulfide fractionation and potentially playing an important role in porphyry ore genesis.

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