scholarly journals The role of metamorphic fluids in the formation of ore deposits

2013 ◽  
Vol 393 (1) ◽  
pp. 117-134 ◽  
Author(s):  
Bruce W. D. Yardley ◽  
James S. Cleverley
Keyword(s):  
Ore Deposits ◽  
Metamorphic Fluids

The Role of Magmatic Sulfur in the Formation of Ore Deposits

2011 ◽  
Vol 73 (1) ◽  
pp. 513-578 ◽  
Author(s):  
A. C. Simon ◽  
E. M. Ripley
Keyword(s):  
Ore Deposits

Metamorphic Fluids in Orogenic Settings

Elements ◽  
2020 ◽  
Vol 16 (6) ◽  
pp. 381-387 ◽  
Author(s):  
Katy A. Evans ◽  
Andrew G. Tomkins
Keyword(s):  
Phase Equilibria ◽  
Melting Temperature ◽  
Fluid Inclusions ◽  
Indirect Evidence ◽  
Ore Deposits ◽  
Variable Composition ◽  
Future Research ◽  
Temperature Cycle ◽  
Thermodynamic Models ◽  
Metamorphic Fluids

Metamorphic reactions within the Earth’s crust produce fluids of variable composition that play a major role in the evolution of continents. Metamorphic fluids facilitate reactions that alter crustal rheology, reduce melting temperature, cycle elements between geological reservoirs and form ore deposits. These fluids are relatively inaccessible, other than by study of fluid inclusions, so most studies rely on a combination of indirect evidence and predictive thermodynamic models to determine the characteristics and roles of the fluids. In this article, the origins, compositions, controlling phase equilibria, and roles of metamorphic fluids are reviewed, followed by a discussion of selected areas of current and future research.

Introduction

1994 ◽  
Author(s):  
Václav Nēmec
Keyword(s):  
Ad Hoc ◽  
International Association ◽  
The United States ◽  
Ore Deposits ◽  
Western World ◽  
Mathematical Geology ◽  
25Th Anniversary ◽  
European Universities ◽  
The World

Friends and associates of Daniel F. Merriam have prepared this volume in Dan's honor to commemorate his 65th birthday and mark the 25th anniversary of the International Association for Mathematical Geology. This compendium is in the tradition of the Festschriften issued by European universities and scholarly organizations to honor an individual who has bequeathed an exceptional legacy to his students, associates, and his discipline. Certainly Dan has made such an impact on geology, and particularly mathematical geology. It is a great privilege for rne to write the introduction to this Festschrift. The editors are to be congratulated for their idea to collect and to publish so many representative scientific articles written by famous authors of several generations. Dan Merriam is the most famous mathematical geologist, in the world. This statement will probably provoke some criticism against an over-glorification of Dan. Some readers will have their own candidates (including themselves) for such a top position. I would like to bring a testimony that the statement is correct and far from an ad hoc judgment only for this solemn occasion. It may be of interest to describe how I became acquainted with Dan. In my opinion this will show how thin and delicate was the original tissue of invisible ties which helped to build up the first contacts among Western and Eastern colleagues in the completely new discipline of mathematical geology. The role of Dan Merriam in opening and increasing these contacts has been very active indeed. In the Fall 1964 I was on a family visit in the United States. This was— after the coup of Prague in 1948—my first travel to the free Western world. With some experience in computerized evaluation of ore deposits, I was curious to see the application of computers in geology and to meet colleagues who had experience with introducing statistical methods into regular estimation of ore reserves. I had very useful contacts in Colorado and in Arizona. In Tucson I visited the real birthplace of the APCOM symposia.

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.

Scandium: Ore deposits, the pivotal role of magmatic enrichment and future exploration

2021 ◽  
Vol 128 ◽  
pp. 103906
Author(s):  
Zhenchao Wang ◽  
Martin Yan Hei Li ◽  
Ze-Rui Ray Liu ◽  
Mei-Fu Zhou
Keyword(s):  
Ore Deposits ◽  
Pivotal Role

Ore deposits and the role of the lithospheric mantle

Lithos ◽  
2013 ◽  
Vol 164-167 ◽  
pp. 1
Author(s):  
Sisir K. Mondal ◽  
William L. Griffin ◽  
Wolfgang Maier
Keyword(s):  
Lithospheric Mantle ◽  
Ore Deposits

Role of rheological heterogeneities in vein-ore localization

1993 ◽  
Vol 30 (1) ◽  
pp. 113-123 ◽  
Author(s):  
C. Castaing ◽  
D. Cassard ◽  
Y. Gros ◽  
M. Moisy ◽  
J. C. Chabod
Keyword(s):  
Lower Order ◽  
Shear Zones ◽  
Ore Deposits ◽  
Second Order ◽  
Massif Central ◽  
First Order ◽  
Ore Localization ◽  
Ore Minerals ◽  
Partial Destruction

Structural studies of the Saint-Salvy zinc deposit and other Hercynian, veinhosted ore deposits in the French Massif Central and Pyrénées reveal a fourstage evolution of mineralized structures under rheological control: (i) localization of potential mineralized areas, guided by the presence of first-order lithological or structural heterogeneities that caused stress and strain perturbations; (ii) creation of second-order heterogeneities, corresponding to indurated shear zones that acted as rheological discontinuities; (iii) tectonic activation of these second-order heterogeneities, opening voids that allowed circulation of hydrothermal fluids and periodic trapping of ore minerals; (iv) reworking and partial destruction of the mineralized structures, caused by the reactivation of anisotropic surfaces acting as zones of weakness. The interaction between preexisting, first-order heterogeneities and regional shear strain caused instability, which in turn produced second-order and then lower-order heterogeneities. Such progressively smaller heterogeneities induced an increasingly focused, centripetal localization of structural disturbances that enabled hydrothermal fluid channelling. This is the reason that lower-order and late structures preferentially bear economic mineralization.

scholarly journals On the concept of in-situ metal leaching

2021 ◽  
Vol 5 (4) ◽  
pp. 349-357
Author(s):  
O. Z. Gabaraev ◽  
A. O. Gabaraeva ◽  
N. T. Dedegkaeva ◽  
Zh. Bolotbekov
Keyword(s):  
Process Intensification ◽  
Ore Deposits ◽  
Metal Extraction ◽  
Metal Leaching ◽  
Metal Mining ◽  
Traditional Methods ◽  
The North ◽  
Mining Methods

The information on history of in-situ metal leaching method (ISL) was given. The role of Russian scientists and research organizations in research into ISL processes was shown. Examples of ISL application at the mines of the USSR, the CIS and nonCIS countries with the implementation features were given. The main disadvantages of ISL were formulated: low rate of metal production and difficulty in monitoring the completeness of metal recovery into pregnant solution. It was noted that underground leaching of even well-crushed ores lasts for many years. This, under otherwise equal conditions, decreases attractiveness of ISL in comparison with traditional methods of metal mining. Well-known and new promising methods of the leaching process intensification for increasing the rate of metal extraction into solution were described. As illustrated by the North Caucasian deposits of the Sadon group, the expediency of ISL use for extracting the residual reserves, which would not be extracted by the traditional methods, was shown. The role of Professor I.A. Ostroushko in development and implementation of methods for extracting metals remained in the mined-out space of mines, in particular, by extracting metals from the Sadon deposits wastewater. Information on the current state of ISL application was given. The conclusion was made about insufficient use of this promising method in mining in some regions. For the first time, the details of the ISL general concept were clarified: the feasibility of ISL use not only in favorable conditions, but also at non-continuous geology and mineralization; ISL applicability for not only substandard ores (non-extractable by traditional mining methods), but also for balance reserves; ISL (block leaching) was proposed as an alternative to traditional mining methods in specific conditions, for example, at the North Caucasian complex ore deposits.

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