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5 Ways Gold Deposits Are Formed - Roaring Camp Gold

09/11/2016  Gold ore is formed in the rocks of active volcanoes this way. Now, we can’t climb into an active volcano, but when those volcanoes go dormant or extinct, like much of the Sierra range, those deposits 09/11/2016  Gold ore is formed in the rocks of active volcanoes this way. Now, we can’t climb into an active volcano, but when those volcanoes go dormant or extinct, like much of the Sierra range, those deposits

Formation of gold deposits: Review and evaluation of the ...

01/05/2009  Gold deposit formation during regional metamorphism (metamorphic model), as an alternative genetic model to the continuum. There is little difference between the temperature of gold formation and peak metamorphism for the greenschist facies, but significant temperature differences for amphibolite and granulite facies examples.01/05/2009  Gold deposit formation during regional metamorphism (metamorphic model), as an alternative genetic model to the continuum. There is little difference between the temperature of gold formation and peak metamorphism for the greenschist facies, but significant temperature differences for amphibolite and granulite facies examples.

Gold Ore - an overview ScienceDirect Topics

The Mother Lode District of California may be the most famous of a class of lode gold-ore deposits that are found in metamorphic terranes associated with accretionary plate tectonics. They have also been called greenstone-belt and mesothermal lode ores (Figure 1). The discovery in 1848 of placer gold at Sutter's Mill, downstream from this district, led to the California Gold Rush of 1849, one of the most The Mother Lode District of California may be the most famous of a class of lode gold-ore deposits that are found in metamorphic terranes associated with accretionary plate tectonics. They have also been called greenstone-belt and mesothermal lode ores (Figure 1). The discovery in 1848 of placer gold at Sutter's Mill, downstream from this district, led to the California Gold Rush of 1849, one of the most

How Ore Deposits Are Formed? - Geology In

These fluids make their way up through the volcanic vent, which has already solidified into porphyritic rock. At a certain height, the metals precipitate from the ascending fluids. The ore deposit has a typical, well-defined shape that resembles the cap of a mushroom. Its “stem” is the volcanic vent, which has solidified into porphyry and then cracked to form numerous veins through which the fluid pushed its These fluids make their way up through the volcanic vent, which has already solidified into porphyritic rock. At a certain height, the metals precipitate from the ascending fluids. The ore deposit has a typical, well-defined shape that resembles the cap of a mushroom. Its “stem” is the volcanic vent, which has solidified into porphyry and then cracked to form numerous veins through which the fluid pushed its

Processes of Ore Formation - geol-amu.org

Hydrothermal Deposits: Hot aqueous solutions are responsible for the formation of many ore deposits. Fluid inclusion research indicates most ore forming fluids range in temperature from 50°C to 650°C. Analysis of the fluid in inclusions has shown that water is the most important phase and salinities are often much greater than those of seawater. The chemistry of ore fluids and the mechanism of deposition of ore Hydrothermal Deposits: Hot aqueous solutions are responsible for the formation of many ore deposits. Fluid inclusion research indicates most ore forming fluids range in temperature from 50°C to 650°C. Analysis of the fluid in inclusions has shown that water is the most important phase and salinities are often much greater than those of seawater. The chemistry of ore fluids and the mechanism of deposition of ore

How Is Gold Formed and Where Does it Come From?

18/05/2015  Of course, there are different kinds of accessible gold deposits. This precious metal has been found in streams, in the sides of rock outcroppings, and of course, under the earth. At different times in the earth’s history, hot fluids circulated through gold-bearing rocks and because of the weight and chemical properties of the gold, the gold may have been carried off to form a vein or a lode. In other instances, gold 18/05/2015  Of course, there are different kinds of accessible gold deposits. This precious metal has been found in streams, in the sides of rock outcroppings, and of course, under the earth. At different times in the earth’s history, hot fluids circulated through gold-bearing rocks and because of the weight and chemical properties of the gold, the gold may have been carried off to form a vein or a lode. In other instances, gold

Gold Deposits and Their Geological Classification

Classifications of ore deposits provide essential frameworks for designing exploration strategies, evaluating prospects, and performing resource assessments of selected areas. A rational geological classification of the commonly recognized lode gold deposits is feasible if it is based on the geological settings of the deposits, host rocks, nature of mineralization and geoche m-ical signature ...Classifications of ore deposits provide essential frameworks for designing exploration strategies, evaluating prospects, and performing resource assessments of selected areas. A rational geological classification of the commonly recognized lode gold deposits is feasible if it is based on the geological settings of the deposits, host rocks, nature of mineralization and geoche m-ical signature ...

Models and Exploration Methods for Major Gold Deposit Types

new gold deposits. The objectives of this paper are to provide an update on gold deposit models, and what new approaches and techniques can now be used to find gold deposits. Gold occurs in a wide range of deposit types and settings, but this paper is concerned with deposits in which gold forms the main economic commodity or a co-product. Deposits in which gold occurs onlynew gold deposits. The objectives of this paper are to provide an update on gold deposit models, and what new approaches and techniques can now be used to find gold deposits. Gold occurs in a wide range of deposit types and settings, but this paper is concerned with deposits in which gold forms the main economic commodity or a co-product. Deposits in which gold occurs only

5 Ways Gold Deposits Are Formed - Roaring Camp Gold

09/11/2016  Gold ore is formed in the rocks of active volcanoes this way. Now, we can’t climb into an active volcano, but when those volcanoes go dormant or extinct, like much of the Sierra range, those deposits still remain. Given so many of our mountains were 09/11/2016  Gold ore is formed in the rocks of active volcanoes this way. Now, we can’t climb into an active volcano, but when those volcanoes go dormant or extinct, like much of the Sierra range, those deposits still remain. Given so many of our mountains were

Formation of gold deposits: a metamorphic

01/07/2010  Gold deposition is accompanied by carbonation, sulphidation and muscovite/biotite alteration where the host rock is of suitable bulk composition. The correlation of major gold deposits with rock type, even when the gold is primarily in veins, argues for rock-dominated depositional systems, not fluid-dominated ones. As a consequence, a general ...01/07/2010  Gold deposition is accompanied by carbonation, sulphidation and muscovite/biotite alteration where the host rock is of suitable bulk composition. The correlation of major gold deposits with rock type, even when the gold is primarily in veins, argues for rock-dominated depositional systems, not fluid-dominated ones. As a consequence, a general ...

Mesothermal and Greenstone Gold Deposits AKA

23/11/2016  Mesothermal gold deposits form half way up through the rise of the melt from the deep crust to the surface usually at a depth of less than 10 km but greater than 1 km. temperatures at these depths are generally somewhere between 450 degrees and 250 degrees Celsius. The term mesothermal veins is really a sack term, referring simply to the depth formation. It pays little attention to the origin ...23/11/2016  Mesothermal gold deposits form half way up through the rise of the melt from the deep crust to the surface usually at a depth of less than 10 km but greater than 1 km. temperatures at these depths are generally somewhere between 450 degrees and 250 degrees Celsius. The term mesothermal veins is really a sack term, referring simply to the depth formation. It pays little attention to the origin ...

The Formation of Gold deposits in South Africa

In 1852, the English prospector J.H. Davis discovered the first gold in the Witwatersrand, leading to the South African gold rush and the discovery of much more gold deposits within the basin. Although the Witwatersrand has been subject for decades of research, the genesis of gold and uranium ore In 1852, the English prospector J.H. Davis discovered the first gold in the Witwatersrand, leading to the South African gold rush and the discovery of much more gold deposits within the basin. Although the Witwatersrand has been subject for decades of research, the genesis of gold and uranium ore

Models and Exploration Methods for Major Gold Deposit Types

Ore Deposits and Exploration Technology _____ Paper 48 _____ ... environments of formation. Minor types of gold deposits are not discussed in this paper. As proposed by Robert et al. (1997) and Poulsen et al. (2000), many of these gold deposit types can be grouped into clans, i.e. families of deposits that either formed by related processes or that are distinct products of large scale ...Ore Deposits and Exploration Technology _____ Paper 48 _____ ... environments of formation. Minor types of gold deposits are not discussed in this paper. As proposed by Robert et al. (1997) and Poulsen et al. (2000), many of these gold deposit types can be grouped into clans, i.e. families of deposits that either formed by related processes or that are distinct products of large scale ...

On the source of orogenic gold Geology

Gold has historically been a key strategic commodity, and the study of gold deposit formation has long been investigated. Debate on the genesis of so-called “orogenic gold deposits” (>75% of gold recovered through history; Phillips, 2013), continues largely because it is difficult to reliably identify the source of gold.In this issue of Geology, Gaboury.Gold has historically been a key strategic commodity, and the study of gold deposit formation has long been investigated. Debate on the genesis of so-called “orogenic gold deposits” (>75% of gold recovered through history; Phillips, 2013), continues largely because it is difficult to reliably identify the source of gold.In this issue of Geology, Gaboury.

Formation Environments of Metasomatites and Ores of the ...

10/11/2020  These deposit are characterized by the combination of ore mineralization with preore metasomatites in a wide range of acidity (рН) and oxidation (fO 2).In subsurface conditions, when the ore-controlling faults reach the Earth’s surface, the heterogenization (unmixing) of fluids in an open system at low pressure results in a gas phase enriched in acid components in the upper part of the ...10/11/2020  These deposit are characterized by the combination of ore mineralization with preore metasomatites in a wide range of acidity (рН) and oxidation (fO 2).In subsurface conditions, when the ore-controlling faults reach the Earth’s surface, the heterogenization (unmixing) of fluids in an open system at low pressure results in a gas phase enriched in acid components in the upper part of the ...

Ore deposits formed by oxidation and supergene

Ore Deposits Formed by Oxidation and Supergene Enrichment When ore deposits are exposed to the oxidation zone they are weathered and altered with the country rocks. The surface waters oxidize many ore minerals and yield solvents that dissolve other minerals. An orebody thus becomes oxidized and generally leached of many of its valuable materials down to the groundwater table, or to ...Ore Deposits Formed by Oxidation and Supergene Enrichment When ore deposits are exposed to the oxidation zone they are weathered and altered with the country rocks. The surface waters oxidize many ore minerals and yield solvents that dissolve other minerals. An orebody thus becomes oxidized and generally leached of many of its valuable materials down to the groundwater table, or to ...

The Source of Gold - Its Ores and Minerals

While historically speaking vein deposits were the most productive, these disseminated deposits currently yield much of the worlds gold ore. Within gold ores, the element itself occurs in nature chiefly in the form of native gold, which is by far the most common gold bearing mineral. In various gold ores, the native gold commonly occurs as tiny particles contained within sulfide minerals such ...While historically speaking vein deposits were the most productive, these disseminated deposits currently yield much of the worlds gold ore. Within gold ores, the element itself occurs in nature chiefly in the form of native gold, which is by far the most common gold bearing mineral. In various gold ores, the native gold commonly occurs as tiny particles contained within sulfide minerals such ...

17 - Flotation of Gold Ores - Aalto

copper ore, gold antimony ores, etc.), because the flotation methods used for the recovery of gold from different ores is vastly different. 17.2 GEOLOGY AND GENERAL MINERALOGY OF GOLD-BEARING ORES The geology of the deposit and the mineralogy of the ore play a decisive role in the selection of the best treatment method for a particular gold ore. Geology of the gold deposits [3] varies ...copper ore, gold antimony ores, etc.), because the flotation methods used for the recovery of gold from different ores is vastly different. 17.2 GEOLOGY AND GENERAL MINERALOGY OF GOLD-BEARING ORES The geology of the deposit and the mineralogy of the ore play a decisive role in the selection of the best treatment method for a particular gold ore. Geology of the gold deposits [3] varies ...

5 Ways Gold Deposits Are Formed - Roaring Camp Gold

09/11/2016  Gold ore is formed in the rocks of active volcanoes this way. Now, we can’t climb into an active volcano, but when those volcanoes go dormant or extinct, like much of the Sierra range, those deposits still remain. Given so many of our mountains were 09/11/2016  Gold ore is formed in the rocks of active volcanoes this way. Now, we can’t climb into an active volcano, but when those volcanoes go dormant or extinct, like much of the Sierra range, those deposits still remain. Given so many of our mountains were

Formation of gold deposits: a metamorphic

01/07/2010  Gold deposition is accompanied by carbonation, sulphidation and muscovite/biotite alteration where the host rock is of suitable bulk composition. The correlation of major gold deposits with rock type, even when the gold is primarily in veins, argues for rock-dominated depositional systems, not fluid-dominated ones. As a consequence, a general ...01/07/2010  Gold deposition is accompanied by carbonation, sulphidation and muscovite/biotite alteration where the host rock is of suitable bulk composition. The correlation of major gold deposits with rock type, even when the gold is primarily in veins, argues for rock-dominated depositional systems, not fluid-dominated ones. As a consequence, a general ...

Structural geometry of orogenic gold deposits ...

of formation of gold deposits are most robust if they involve an understanding of tectonic and structural evolution within a geochronological frameworkwhich involves robust isotopic agesof the gold mineralization itself. Goldfarb et al. (1988) demonstrated that gold mineralization was essentially a single widespread event late in tectonic evolution, related to a shift in tectonic regime from ...of formation of gold deposits are most robust if they involve an understanding of tectonic and structural evolution within a geochronological frameworkwhich involves robust isotopic agesof the gold mineralization itself. Goldfarb et al. (1988) demonstrated that gold mineralization was essentially a single widespread event late in tectonic evolution, related to a shift in tectonic regime from ...

Major Gold Deposit Types and Exploration process

of gold deposits are presently recognized, each with its own well-defined characteristics and environments of formation. Minor types of gold deposits are not discussed in this paper. As proposed by Robert et al. (1997) and Poulsen et al. (2000), many of these gold deposit types can be grouped into clans, i.e. families ofof gold deposits are presently recognized, each with its own well-defined characteristics and environments of formation. Minor types of gold deposits are not discussed in this paper. As proposed by Robert et al. (1997) and Poulsen et al. (2000), many of these gold deposit types can be grouped into clans, i.e. families of

Formation Environments of Metasomatites and Ores of the ...

10/11/2020  These deposit are characterized by the combination of ore mineralization with preore metasomatites in a wide range of acidity (рН) and oxidation (fO 2).In subsurface conditions, when the ore-controlling faults reach the Earth’s surface, the heterogenization (unmixing) of fluids in an open system at low pressure results in a gas phase enriched in acid components in the upper part of the ...10/11/2020  These deposit are characterized by the combination of ore mineralization with preore metasomatites in a wide range of acidity (рН) and oxidation (fO 2).In subsurface conditions, when the ore-controlling faults reach the Earth’s surface, the heterogenization (unmixing) of fluids in an open system at low pressure results in a gas phase enriched in acid components in the upper part of the ...

Geology of Gold Properties, Mining, and Formation of ...

20/06/2021  Identifying authentic gold ore is easier said than done. Even early prospectors often suffered a learning curve trying to differentiate gold ore from other copycat minerals like silica, mica, and pyrite. To identify real gold, you can start by spotting rock with distinct copper tones, particularly if the geographic area of your search has yielded previous gold finds.20/06/2021  Identifying authentic gold ore is easier said than done. Even early prospectors often suffered a learning curve trying to differentiate gold ore from other copycat minerals like silica, mica, and pyrite. To identify real gold, you can start by spotting rock with distinct copper tones, particularly if the geographic area of your search has yielded previous gold finds.

Metallogenic problems of hydrothermal gold deposit ...

gold-ore deposit formation were proposed at the turn of 21st century. Probable metal and fluid sources could be granite and/or basalt magma reservoirs (according to magmagene hypothesis); rocks in dynamo-zonal metamorphism areas of hydration and dehydration (according to metamorphogene hypothesis); and/or as numerous sources having been subjected to regional metamorphism , such as gold-ore deposit formation were proposed at the turn of 21st century. Probable metal and fluid sources could be granite and/or basalt magma reservoirs (according to magmagene hypothesis); rocks in dynamo-zonal metamorphism areas of hydration and dehydration (according to metamorphogene hypothesis); and/or as numerous sources having been subjected to regional metamorphism , such as

Ore deposits formed by oxidation and supergene

Ore Deposits Formed by Oxidation and Supergene Enrichment When ore deposits are exposed to the oxidation zone they are weathered and altered with the country rocks. The surface waters oxidize many ore minerals and yield solvents that dissolve other minerals. An orebody thus becomes oxidized and generally leached of many of its valuable materials down to the groundwater table, or to ...Ore Deposits Formed by Oxidation and Supergene Enrichment When ore deposits are exposed to the oxidation zone they are weathered and altered with the country rocks. The surface waters oxidize many ore minerals and yield solvents that dissolve other minerals. An orebody thus becomes oxidized and generally leached of many of its valuable materials down to the groundwater table, or to ...

The Source of Gold - Its Ores and Minerals

While historically speaking vein deposits were the most productive, these disseminated deposits currently yield much of the worlds gold ore. Within gold ores, the element itself occurs in nature chiefly in the form of native gold, which is by far the most common gold bearing mineral. In various gold ores, the native gold commonly occurs as tiny particles contained within sulfide minerals such ...While historically speaking vein deposits were the most productive, these disseminated deposits currently yield much of the worlds gold ore. Within gold ores, the element itself occurs in nature chiefly in the form of native gold, which is by far the most common gold bearing mineral. In various gold ores, the native gold commonly occurs as tiny particles contained within sulfide minerals such ...

17 - Flotation of Gold Ores - Aalto

copper ore, gold antimony ores, etc.), because the flotation methods used for the recovery of gold from different ores is vastly different. 17.2 GEOLOGY AND GENERAL MINERALOGY OF GOLD-BEARING ORES The geology of the deposit and the mineralogy of the ore play a decisive role in the selection of the best treatment method for a particular gold ore. Geology of the gold deposits [3] varies ...copper ore, gold antimony ores, etc.), because the flotation methods used for the recovery of gold from different ores is vastly different. 17.2 GEOLOGY AND GENERAL MINERALOGY OF GOLD-BEARING ORES The geology of the deposit and the mineralogy of the ore play a decisive role in the selection of the best treatment method for a particular gold ore. Geology of the gold deposits [3] varies ...

Major Gold Deposit Types and Exploration process

of gold deposits are presently recognized, each with its own well-defined characteristics and environments of formation. Minor types of gold deposits are not discussed in this paper. As proposed by Robert et al. (1997) and Poulsen et al. (2000), many of these gold deposit types can be grouped into clans, i.e. families ofof gold deposits are presently recognized, each with its own well-defined characteristics and environments of formation. Minor types of gold deposits are not discussed in this paper. As proposed by Robert et al. (1997) and Poulsen et al. (2000), many of these gold deposit types can be grouped into clans, i.e. families of

Structural geometry of orogenic gold deposits ...

of formation of gold deposits are most robust if they involve an understanding of tectonic and structural evolution within a geochronological frameworkwhich involves robust isotopic agesof the gold mineralization itself. Goldfarb et al. (1988) demonstrated that gold mineralization was essentially a single widespread event late in tectonic evolution, related to a shift in tectonic regime from ...of formation of gold deposits are most robust if they involve an understanding of tectonic and structural evolution within a geochronological frameworkwhich involves robust isotopic agesof the gold mineralization itself. Goldfarb et al. (1988) demonstrated that gold mineralization was essentially a single widespread event late in tectonic evolution, related to a shift in tectonic regime from ...

Establishing thE ProcEss MinEralogy of gold orEs

Some metallurgical implications to these gold ore types are summarised below: Placers, quartz vein gold ores and oxidized ores: Generally, placers, quartz vein gold ores and oxidized ores are free-milling and gold can be recovered by gravity and/or direct cyanide leaching. Some epithermal deposits may be free-milling (such as the oxidized portion) but more commonly contain significant amounts ...Some metallurgical implications to these gold ore types are summarised below: Placers, quartz vein gold ores and oxidized ores: Generally, placers, quartz vein gold ores and oxidized ores are free-milling and gold can be recovered by gravity and/or direct cyanide leaching. Some epithermal deposits may be free-milling (such as the oxidized portion) but more commonly contain significant amounts ...

Geology of Gold Properties, Mining, and Formation of ...

20/06/2021  Identifying authentic gold ore is easier said than done. Even early prospectors often suffered a learning curve trying to differentiate gold ore from other copycat minerals like silica, mica, and pyrite. To identify real gold, you can start by spotting rock with distinct copper tones, particularly if the geographic area of your search has yielded previous gold finds.20/06/2021  Identifying authentic gold ore is easier said than done. Even early prospectors often suffered a learning curve trying to differentiate gold ore from other copycat minerals like silica, mica, and pyrite. To identify real gold, you can start by spotting rock with distinct copper tones, particularly if the geographic area of your search has yielded previous gold finds.

Metallogenic problems of hydrothermal gold deposit ...

gold-ore deposit formation were proposed at the turn of 21st century. Probable metal and fluid sources could be granite and/or basalt magma reservoirs (according to magmagene hypothesis); rocks in dynamo-zonal metamorphism areas of hydration and dehydration (according to metamorphogene hypothesis); and/or as numerous sources having been subjected to regional metamorphism , such as gold-ore deposit formation were proposed at the turn of 21st century. Probable metal and fluid sources could be granite and/or basalt magma reservoirs (according to magmagene hypothesis); rocks in dynamo-zonal metamorphism areas of hydration and dehydration (according to metamorphogene hypothesis); and/or as numerous sources having been subjected to regional metamorphism , such as

The formation of gold deposits in South Africa

20/04/2017  The formation of gold deposits in South Africa. April 20, 2017. Share on Facebook. Tweet on Twitter. tweet; The left picture shows uraninite (uranium ore) that surrounds gold. In the right picture, a computer programme was used the remove the uraninite to illustrate the large volume hidden in the uranium ore. Credit: S. Fuchs, GEOMAR. At a first glance, the Witwatersrand basin, the largest ...20/04/2017  The formation of gold deposits in South Africa. April 20, 2017. Share on Facebook. Tweet on Twitter. tweet; The left picture shows uraninite (uranium ore) that surrounds gold. In the right picture, a computer programme was used the remove the uraninite to illustrate the large volume hidden in the uranium ore. Credit: S. Fuchs, GEOMAR. At a first glance, the Witwatersrand basin, the largest ...

Mineral Ore Deposits: Meaning, Origin and Types

Magmatic deposits form major source of some important metals as gold, chromium, titanium and uranium. Concentration of the economic magmatic minerals may take place during the earlier or the later stages of the process of crystallisation. Accordingly, these are often distinguished as early or late magmatic crystallizations. Their stage of formation is easily revealed by their relationship with ...Magmatic deposits form major source of some important metals as gold, chromium, titanium and uranium. Concentration of the economic magmatic minerals may take place during the earlier or the later stages of the process of crystallisation. Accordingly, these are often distinguished as early or late magmatic crystallizations. Their stage of formation is easily revealed by their relationship with ...

Here Is The Correct Way To Effectively Recognize Gold Ore

07/12/2018  In the earth, during its molten formation stage, most of the native gold sunk into the core. Most of the gold at the crust and mantle layers was probably delivered via asteroid impact. Gold sometimes occurs as a lode deposit in small amounts in rock, known as gold ore. Gold can also be found in alluvial deposits known as placer deposits, as flakes, grains, or nuggets. Quick Navigation. 07/12/2018  In the earth, during its molten formation stage, most of the native gold sunk into the core. Most of the gold at the crust and mantle layers was probably delivered via asteroid impact. Gold sometimes occurs as a lode deposit in small amounts in rock, known as gold ore. Gold can also be found in alluvial deposits known as placer deposits, as flakes, grains, or nuggets. Quick Navigation.

Disseminated Ore - Mining Fundamentals

They are formed by a number of geologic processes and, in most cases, contain very large amounts of ore. Gold, copper, molybdenum, and several other valuable metals have been discovered and mined from disseminated deposits. The Carlin Trend in Nevada, USA, is a very good example of disseminated ore. In Australia, gold occurs in the following: Disseminated and stockwork gold-silver deposits in ...They are formed by a number of geologic processes and, in most cases, contain very large amounts of ore. Gold, copper, molybdenum, and several other valuable metals have been discovered and mined from disseminated deposits. The Carlin Trend in Nevada, USA, is a very good example of disseminated ore. In Australia, gold occurs in the following: Disseminated and stockwork gold-silver deposits in ...

The processes of formation of mineral deposits are

These are also called ‘hypogene-deposits’ Mineral deposits arising out of the processes of weathering, and activities of several geological agents are called ‘Secondary Mineral Deposits’. These are closely associated with the sedimentary pro­cesses of formation. Metamorphic mineral deposits are the out­come of metamorphic processes acting upon an earlier formed mineral deposits or rocks.These are also called ‘hypogene-deposits’ Mineral deposits arising out of the processes of weathering, and activities of several geological agents are called ‘Secondary Mineral Deposits’. These are closely associated with the sedimentary pro­cesses of formation. Metamorphic mineral deposits are the out­come of metamorphic processes acting upon an earlier formed mineral deposits or rocks.