Metallogenic Epoch and Province
Metallogenetic Epochs
Metallogenetic epochs, as defined above, are specific periods characterised by formation of large number of mineral deposits. It does not mean that all the mineral deposits formed during a definite metallogenetic epochs. In India the chief metallogenetic epochs were:
1. Precambrian
2. Late Palaeozoic
3. Late Mesozoic to Early Tertiary
Boundary problems between :-
Precambrian/Cambrian
Permian/Triassic
Cretaceous/Tertiary
Neogene/Quaternary
Stratigraphic boundaries are determined by one or more of geological events such as volcanic activity, sedimentation, tectonism, paleo-environments & evolution of life.
Faunal records have played major role in determining the boundaries of the Phanerozoic units.
The other geological events are dated on the evidence of fossil records.
A presentation on Hydrothermal wall rock alteration with case studies on geophysical applications.
References : https://drive.google.com/drive/folders/16VSZMPMASMNVB47JdBUa_7udBk1qvK2U?usp=sharing
Boundary problems between :-
Precambrian/Cambrian
Permian/Triassic
Cretaceous/Tertiary
Neogene/Quaternary
Stratigraphic boundaries are determined by one or more of geological events such as volcanic activity, sedimentation, tectonism, paleo-environments & evolution of life.
Faunal records have played major role in determining the boundaries of the Phanerozoic units.
The other geological events are dated on the evidence of fossil records.
A presentation on Hydrothermal wall rock alteration with case studies on geophysical applications.
References : https://drive.google.com/drive/folders/16VSZMPMASMNVB47JdBUa_7udBk1qvK2U?usp=sharing
CLASSIFICATION OF ORE DEPOSITS
The Mixture of ore minerals are gangue minerals form an Ore deposit. The ore
deposits are generally found enclosed within the country rocks. The ore deposits
are formed in many different ways. Depending upon the process that may
operate to produce them, the ore deposits may be classified as follow:
Magmatic ore deposits.
Sublimation ore deposits.
Pegmatitic ore deposits.
Contact metasomatic ore deposits.
Hydrothermal ore deposits
Cavity filling deposits.
Replacement deposits.
Sedimentation ore deposits.
Evaporation ore deposits.
Residual and mechanical concentration deposits
Metamorphic ore deposits.
MAGMATIC ORE DEPOSITS:
The magmatic ore deposits are the magmatic products which crystallize from
magmas. The magmatic ore deposits are classified as follows:
o Early magmatic deposits
o Late magmatic deposits
Early magmatic deposits:
Early magmatic deposits are formed during the
early stage of the magmatic period. In this case the
ore minerals crystallize earlier than the rock
silicates. The Minerals of Nickel, Chromium, and
Platinum are usually found as early magmatic
deposits. The early magmatic deposits can be sub
divided into two groups:
o Dissemination deposits
o Segregation deposits
Dissemination deposits:
When magma crystallizes
conditions, a granular igneous rock is formed. In
such a rock early formed crystals of
may occur in dissemination.
Segregation deposits:
Magmatic segregation deposits are
formed as a result of gravitative
crystallization differentiation. In
case, the ore mineral which crystallize
early, get ocean-trated on a particular
part of igneous part. The ore deposits
thus formed are known as “Segregation
deposits”.
rly under seated
ore minerals
such
Late Magmatic Deposits:
The ore deposits which are formed to
called late magmatic deposits. The late magmatic deposits contain those ore
minerals which have crystallized at rather low temperature from the residual
magma. The magma which is left after crystallization of early for
is called residual magma. This magma frequently contains many ore minerals. The
late magmatic deposits include most of the magmatic deposits of iron and
titanium ores, these deposits are almost always associated with mafic igneous
rocks.
SUBLIMATION DEPOSITS:
Sublimation is a very minor process of formation of ore deposits. Sublimation
deposits contain only those minerals which have been volatilized by hear and
subsequently redeposit in the same form at low temperature and pressure. The
sublimation deposits are found associated with Volcanoes and Fumaroles. Sulfur
of this origin has been mined in Japan, Italy, and Mexico.
Minerals are formed by changes in chemical energy in systems which contain one fluid or vapor phase. In nature, minerals are formed by crystallisation or precipitation from concentrated solutions. These solutions are called as ore-bearing fluids. Ore-bearing fluids are characterised by high concentration of certain metallic or other elements.
Fluids are the most effective agents for the transport of material in the mantle and the Earth's crust.
GEOLOGICAL THERMOMETERS
DEFINITION AND CLASSIFICATION
Proper understanding of origin of mineral deposits and their classification requires the knowledge of formation-temperatures of these deposits. Certain minerals, present over there, give information’s with regard to temperatures of their formations and of the enclosing deposits and they are known as geological thermometers. These geological thermometers may be classed chiefly into the following groups based on their preciseness:
1. The thermometers that record fairly accurately the specific temperature condition of formation of deposits.
2. The thermometers that provide an upper or a lower temperature, above or below which the deposits do not form
3. The thermometers that provide a range of temperature within which the deposits form; and
4. The thermometers that serve as rough indications of temperatures of formation of mineral deposits.
The presence of two or more of less precise geological thermometers in a deposit narrows the range of temperature of formation for the deposits
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
CLASSIFICATION OF ORE DEPOSITS
The Mixture of ore minerals are gangue minerals form an Ore deposit. The ore
deposits are generally found enclosed within the country rocks. The ore deposits
are formed in many different ways. Depending upon the process that may
operate to produce them, the ore deposits may be classified as follow:
Magmatic ore deposits.
Sublimation ore deposits.
Pegmatitic ore deposits.
Contact metasomatic ore deposits.
Hydrothermal ore deposits
Cavity filling deposits.
Replacement deposits.
Sedimentation ore deposits.
Evaporation ore deposits.
Residual and mechanical concentration deposits
Metamorphic ore deposits.
MAGMATIC ORE DEPOSITS:
The magmatic ore deposits are the magmatic products which crystallize from
magmas. The magmatic ore deposits are classified as follows:
o Early magmatic deposits
o Late magmatic deposits
Early magmatic deposits:
Early magmatic deposits are formed during the
early stage of the magmatic period. In this case the
ore minerals crystallize earlier than the rock
silicates. The Minerals of Nickel, Chromium, and
Platinum are usually found as early magmatic
deposits. The early magmatic deposits can be sub
divided into two groups:
o Dissemination deposits
o Segregation deposits
Dissemination deposits:
When magma crystallizes
conditions, a granular igneous rock is formed. In
such a rock early formed crystals of
may occur in dissemination.
Segregation deposits:
Magmatic segregation deposits are
formed as a result of gravitative
crystallization differentiation. In
case, the ore mineral which crystallize
early, get ocean-trated on a particular
part of igneous part. The ore deposits
thus formed are known as “Segregation
deposits”.
rly under seated
ore minerals
such
Late Magmatic Deposits:
The ore deposits which are formed to
called late magmatic deposits. The late magmatic deposits contain those ore
minerals which have crystallized at rather low temperature from the residual
magma. The magma which is left after crystallization of early for
is called residual magma. This magma frequently contains many ore minerals. The
late magmatic deposits include most of the magmatic deposits of iron and
titanium ores, these deposits are almost always associated with mafic igneous
rocks.
SUBLIMATION DEPOSITS:
Sublimation is a very minor process of formation of ore deposits. Sublimation
deposits contain only those minerals which have been volatilized by hear and
subsequently redeposit in the same form at low temperature and pressure. The
sublimation deposits are found associated with Volcanoes and Fumaroles. Sulfur
of this origin has been mined in Japan, Italy, and Mexico.
Minerals are formed by changes in chemical energy in systems which contain one fluid or vapor phase. In nature, minerals are formed by crystallisation or precipitation from concentrated solutions. These solutions are called as ore-bearing fluids. Ore-bearing fluids are characterised by high concentration of certain metallic or other elements.
Fluids are the most effective agents for the transport of material in the mantle and the Earth's crust.
GEOLOGICAL THERMOMETERS
DEFINITION AND CLASSIFICATION
Proper understanding of origin of mineral deposits and their classification requires the knowledge of formation-temperatures of these deposits. Certain minerals, present over there, give information’s with regard to temperatures of their formations and of the enclosing deposits and they are known as geological thermometers. These geological thermometers may be classed chiefly into the following groups based on their preciseness:
1. The thermometers that record fairly accurately the specific temperature condition of formation of deposits.
2. The thermometers that provide an upper or a lower temperature, above or below which the deposits do not form
3. The thermometers that provide a range of temperature within which the deposits form; and
4. The thermometers that serve as rough indications of temperatures of formation of mineral deposits.
The presence of two or more of less precise geological thermometers in a deposit narrows the range of temperature of formation for the deposits
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Dissertation on surda mines jharkhand under MECL-2014BKUMAR39
Copper deposit of Surda lies on the Survey of India toposheet no. 73 J/6; latitude of 220 33’ 7’and longitude of 860 26’40’’. The area lies in the south west of Ghatsila
A Petrographical Approach to Study Mineral Phases Paragenesis of Gold Bearing...Premier Publishers
India hosts several world class gold prospects like Kolar Gold Fields (KGF), Hutti Gold Fields (HGF) and Gadag Gold Fields (GGF). Karnataka is the prime state for gold production since all of these gold deposits are located within. Apart from these world class gold deposits, several other gold prospects in India were identified and exploration activities are under progress. The present study aims to characterize the mineral assemblage and paragenetic phases of gold bearing Precambrian rocks around Hosur village in Gadag Schist Belt through detailed examination by Ore Microscopy. Gadag Schist Belt (GSB) is known by its significance of gold deposits for centuries. Gold mineralization in GSB is associated with tholeiitic meta-andesite, quartz porphyries and argillite greywacke assemblage. The Gadag Gold Field (GGF) constitutes one of the most important auriferous zones of the Archaean Greenstone terrains in Southern India. All known mineralization is in the form of structurally controlled vein systems. The occurrence of the gold is intimately associated with arsenopyrite. Representative samples were studied under polarizing reflected-light microscope to identify and to characterize the mineral phases of gold occurrences and its textural relationships. It has been observed that there are five phases of mineralization only in the third phase gold has formed along with arsenopyrite. Surface morphology of gold and sulphide mineralization was examined under SEM; whereas the elemental analysis of selected sample was carried out using EDS.The present work reveals the clear perception of gold occurrence and mineral phases paragenesis using ore microscopic approach.
Gold is a transitional metal. In its purest form have reddish yellow color, soft, malleable, and ductile metal.
Atomic number : 79
Atomic mass : 196.9 u
Density : 19.32 g/cm3
Melting point : 1,064 °C
Boiling point : 2,700 °C
Founded in different form associated with different rock type in different tectonic setting.
Discovered from earlier time and used for multi purposes.
Formation of gold
The saying among prospectors that "gold is where you find it" suggests its occurrence is unpredictable, but there is some certain geological environments for the formation.
Because gold is very stable over a range of conditions, it is very widespread in the earth’s crust.
Gold dissolved in warm to hot salty water, the fluids are generated in huge volumes deep in the Earth’s crust as water-bearing minerals dehydrate during metamorphism.
Any gold present in the rocks being heated and squeezed is sweated out and goes into solution as complex ions.
In this form, dissolved gold, along with other elements such as silicon, iron and sulphur, migrates wherever fractures in the rocks allow the fluids to pass.
The direction is generally upwards, to cooler regions at lower pressures nearer the Earth’s surface.
Gold eventually becomes insoluble and begins to crystallize, most often enveloped by quartz.
The association of gold and quartz vein forms one of the most common types of "primary gold deposits".
India
In India, gold mineralization of economic importance is mainly restricted to Archean greenstone terranes of the Dharwar Craton (DC).
The eastern block of the DC has a high favorability for hosting major gold deposits such as Kolar, Hutti, and Ramagiri, whereas the western block hosts only a few smaller deposits such as Gadag, Ajjahanahalli, and Kempinkote.
Gold also discoverrd by GSI in the Singbhum Craton, Aravalli Craton, Bastar Craton and Southern Granulite Terrain (SGT).
India is the second-largest consumer of gold after China.
India currently holds about 558 tones of gold, representing 6.6% of its reserves, (World Gold Council, October 2016).
Kolar Gold Field, Hutti Gold Field and Ramgiri Gold Field are the most important gold fields.
Gold Demand and Use
The largest source of demand is the jewelry industry Gold’s workability, unique beauty, and universal appeal make this rare precious metal the favorite of jewelers all over the world.
Besides jewelry, gold has many applications in a variety of industries including aerospace, medicine, dentistry, and electronics for the manufacture of computers, telephones, televisions...
The third source of gold demand is governments and central banks that buy gold to increase their official reserves.
Private investors there are private investors. Depending upon market circumstances, the investment component of demand can vary substantially from year to year.
The prospecting and mining of base metal in India
dates back to 3000 B.C. All the base metal deposit of India has
surface manifestations in various forms. From 19th century to the
middle of the present century, certain European companies
started a modern phase of base metal exploration and
development. Earlier, the search for base metal was confined to
the close study of surface features. In 1940 ground geophysical
survey work has been introduced in order to search the mineral
deposits. The total world production of lead and zinc metals are
about 3.9 and 11.4 million tonnes respectively in 2009. The
leading producing countries for lead is China (41% of world
production), followed by Australia (15%), USA (10%), Peru (8%)
and Mexico (4%). The Indian production of lead and zinc ore is
7.10 million tonnes in the year 2009-10, it includes 136095 tonnes
of lead concentrate and 1224077 tonnes zinc concentrate. In
India, the Western Indian Craton (Rajasthan) is the main
provider of base metal to the country. It contributes nearly 85%
of the estimated lead and zinc. In Western India Craton, the main
metallotect of lead and zinc from an elongated NE – SW trending
polygon, this covers an area of about 20000 sq. km. It comprises
three metalliferous belts mainly, the Pur-Banera belt, the
Rajpura-Dariba- Bethumni belt, and the Sawar belt and two
metalliferous enclaves namely; the Agucha and the Kayar
enclave.
The 20 km. long crescent shaped, Rajpura-Dariba-Bethumni
belt striking N-S to NNE-SSW. The ancient mining and smelting
activities have been noticed at both ends of the belts. Towards the
southernmost part of the belt, the typical gossan is exposed in the
form of hill. B.C. Gupta, Geological survey of India (G.S.I) first
reported Dariba – Bethumni belt, in the year 1934. The
systematic exploration of the belt was initiated by G.S.I in 1962
and continuing till present. In the Rajpura-Dariba-Bethumni belt
Rajpura and Dariba blocks are under active production since
1983, whereas in the Sindesar Khurd block the production was
started in 2007, under the ownership of Hindustan Zinc Limited
of Vedanta Group. Recently the exploration activity is going on in
the Sonariya Khera block, Chittor block and Bethumni block
under the possession of Hindustan Zinc Limited.
Concept 1. The same physical processes and laws that operate today operated throughout geologic time, although not necessarily always with the same intensity as now.
Concept 2. Geologic structure is a dominant control factor in the evolution of land forms and is reflected in them.
Nothing can entirely replace careful field observations in the study of a geomorphic problem, but numerous aid can add to their effectiveness s, reduce the amount of field work for many problems, make possible a more effective planning of the field program, and add support to the conclusions drawn. These aids are what may be called the "tools" of the geomorphologist, although their use is by no means restricted to him. Topographic maps, geologic maps, block diagrams, aerial photographs, soil map, and climatic data are the most commonly used tools in geomorphic studies.
Name: Probably used in the mineralogical sense by 1706 and originally "smicka" and from the Latin micare - to flash or glisten in allusion to the material's appearance. Isinglass predates the use of mica as a mineral term and known from at least 1535, but isinglass also referred to the matter from the sturgeon fish that also had pearly flakes from the scales.
Mica is widely distributed and occurs in igneous, metamorphic and sedimentary regimes. Mica group represents 34 phyllosilicate minerals that exhibits a layered or platy structure. Commercially important mica minerals are muscovite (potash or white mica) and phlogopite (magnesium or amber mica). Granitic pegmatites are the source of muscovite sheet, while phlogopite is found in areas of metamorphosed sedimentary rocks into which pegmatite rich granite rocks have been intruded. It possesses highly perfect basal cleavage due to which it can easily and accurately split into very thin sheets or films of any specified thickness. It has a unique combination of elasticity, toughness, flexibility and transparency. It possesses resistance to heat and sudden change in temperature and high dielectric strength. It is chemically inert, stable and does not absorb water.
Iron is the most vital metal in human use. It constitutes 5.05% of the crust material and holds third position in abundance after silicon and aluminium. It is rarely found in native condition except in meteorites and some eruptive rocks. It enters into large number of rocks forming silicates and is widely available as oxides. The mineral containing iron must be mineable at profit in order to be called an 'iron-ore.' The total world production of iron-ore in 1990 was about 1,008 million tonnes (Economic Geology - Umeshwar Prasad) to which India's contribution was about 55.5 million tonnes (contributing 5.5%) with 6th position in the world production.
Boiling Point: 5182°F (2862°C) Atomic Symbol: Fe
Melting Point: 2800°F (1538°C) Atomic Number: 26
silicate mineral. The physical properties, besides asbestos is a group of six naturally occurring fibrous character, such as, fineness, flexibility, tensile strength & length of fibres, infusibility, low heat conductivity and high resistance to electricity & sound as also to corrosion by acids, make asbestos commercially important. Commercial asbestos is classified into two main mineralogical groups: serpentine asbestos or chrysotile asbestos and amphibole asbestos. The latter includes asbestos minerals, such as, tremolite, actinolite, anthophyllite, amosite and crocidolite. Commercially, chrysotile asbestos is far superior in physical properties and hence more valuable than amphibole asbestos.
India's asbestos requirement is mainly met through imports from Russia, Kazakhstan, Brazil and China. India uses an estimated 350,000 tons of asbestos annually, trailing behind China.
Asbestos – white to greenish and brownish in color with fibrous form. H – 2.5-3, classifies into Long fibre and short fibre.
Classification
Kingdom Animalia
Sub kingdom Invertibrata
Phylum Mollusca
Class Cephalopoda
Order Nautiloidea
Genus Nautilus
Morphological characters –
Shell is Globular and involute coiling
Few whorls with large body chamber, Aperture is oval and rarely semilunar
Umbilicus may be occluded with callus.
Central siphuncle is present with septal neck-retrosiphonate.
Shows simple nauitiloid suture line, thin growth lines and simple ribs.
Geological Age – Triassic to recent
The term "trap" has been used in geology since 1785–95 for rock formations. It is derived from the Swedish word for stairs (trapp , trappa) and refers to the step-like hills forming the landscape of the region.
The plateau: also called a high plain or tableland, is an area of highland, usually consisting of relatively flat terrain. A plateau is an elevated land. It is a flat-topped table standing above the surrounding area. A plateau may have one or more sides with steep slopes.
LIP – Large Igneous provinces. (Province = Area / Region)
DVP - The Deccan Volcanic Province is one of the Earth’s giant continental flood basalts and has a total exposed area of about half a million square kilometers in Maharashtra, Madhya Pradesh, Gujrat and some part of Andhra Pradesh. Deccan trap has maximum thickness 3400m in western ghat and its thickness goes decrease toward east side. At Amrakantat on east its thickness is just 160m. Geographical distribution is between latitudes 16° - 24° N and longitudes 70° - 77° E.
THE DISTRIBUTION OF IGNEOUS ROCKS IN SPACE AND TIME
CONSANGUINITY-The term consanguinity (Iddings) is used to indicate the fact that certain groups of igneous rocks, the members of which are associated in space and time, possess a community of character or family likeness which is expressed in their chemical, mineralogical, textural, and geological features. While in chemical composition consanguineous series or suites may range from acid to ultrabasic types, some mineral and chemical characters are constant, i.e. are common to practically all members; while other characters are serial, that is to say, they show regular variation throughout the series. Thus, in some suites, a constant character is oversaturation with silica, which causes free silica to appear in quite basic members. A serial character may be afforded by the regular variation of the alkalis, or of ferrous iron oxide and magnesia throughout the suite. Some series may be characterised throughout by a peculiar mineralogical feature, such as the occurrence of anorthoclase, as in certain Norwegian, East Mrican, and Antarctic suites. Consanguinity in an igneous series leads to the hypothesis that the assemblage has been derived by some process of differentiation from a common initial magma, from a number of closely related magmas.
How to Split Bills in the Odoo 17 POS ModuleCeline George
Bills have a main role in point of sale procedure. It will help to track sales, handling payments and giving receipts to customers. Bill splitting also has an important role in POS. For example, If some friends come together for dinner and if they want to divide the bill then it is possible by POS bill splitting. This slide will show how to split bills in odoo 17 POS.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
The Art Pastor's Guide to Sabbath | Steve ThomasonSteve Thomason
What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
1. Investigations have shown that metallogeny is by no means a series of isolated phenomena in the
history of the evolution of the earth’s crust. It constitutes characteristic events in the evolution of
mobile belts and platforms. Such mineral deposits are related in time and place to periods of
crustal evolution and igneous activity that have taken place at definite periods in the earth’s
history. For this period of mineralisation Lindgren used the term Metallogenetic Epochs,
emphasing the timing of certain kinds of mineralisation, such as Precambrian iron-ore deposits of
Bihar, Orissa and Madhya Pradesh. The areas which are characterised by preponderance of
deposits of some particular type, such as gold; copper or iron, are called Metallogenetic
Province. These minerals may have formed by various geological processes besides igneous
activities like sedimentation, metamorphism, weathering etc
The metallogenetic epochs and provinces, in the India context, are described below:
❖ Metallogenetic Epochs
Metallogenetic epochs, as defined above, are specific periods characterised by formation of large
number of mineral deposits. It does not mean that all the mineral deposits formed during a
definite metallogenetic epochs. In India the chief metallogenetic epochs were:
1. Precambrian
2. Late Palaeozoic
3. Late Mesozoic to Early Tertiary
▪ Precambrian Epoch
The Precambrian epoch is the most important the world over because of the great length
of time involved and presence of large and varied mineral deposits. The huge sequence of
Precambrian metasediments and associated granitoids, gneisses etc. are supposed to have
a different Metallogenic history in which post consolidated events of magmatism and ,
metallogeny are important. The endogenic deposits have been broadly correlated to
ultrabasic, basic, acid-intermediate and post-orogenic acidic phases of magmatism, while
exogenic deposits, like iron and manganese, are related to sedimentary, metamorphic and
other processes.
This epoch in India is defined by the presence of iron-ore, chromite, manganese ore,
gold, copper, lead, sillimanite, gypsum, kyanite. gemstones etc.
Examples of iron-ore deposits are in: southern Singhbhum (Bihar), Keonjhar, Mayurbhanj and
Sundargarh (Orissa), Bastar and Durg (Madhya Pradesh), Chanda and Ratnagiri (Maharashtra),
Dharwar, Bellary, Sendur, Shimoga and Chikmangalur (Karnataka), Goa and other places;
Chromite in Singhbhum (Bihar), Dhenkanal, Cuttack and Keonjhar (Orissa), Mysore and
Hassan (Karnataka) and Bhandara and Ratnagiri (Maharashtra);
Gold in Kolar, Hutti and Gadag (Karnataka), Ramgiri and Anantapur (Andhra Pradesh), Wynad
(Tamil Nadu) and Kondrakocha (Bihar);
Copper in Singhbhum (Bihar), Khetri and Pur-Banera-Bhindar (Rajasthan), Malanjkhand
(Madhya Pradesh), Mailaram, Gani and Agnigundala (Ar.dhra Pradesh), Ingaldaiur and , Kalvadi
(Karnataka);
lead and zinc in Zawar, Rajpura Dariba, Deri, Rampur Agucha (Rajasthan), Sargipalli,
Kesarpur, Karmali (Orissa), Banaskantha and Vadodara (Gujarat) and other places; and
Manganese-ore in Balaghat (MP), Bhandara and Nagpur (Maharashtra), Bellary, Chitradurga,
Uttar Kannad, Dharwar, Shimoga and Tumkar (Karnataka), Panch Mahal and Vadodara
(Gujarat) and other places. There are many more examples of ; similar deposits.
GL-Aug-2019 Economic Geology
Q U A R T Z – E C I E S Nikhil V. Sherekar M.Sc. Geology
8390377801 (SET+PET+CSIR-UGC-NET-JRF AIR-28)
Metallogenic Epoch & Province
2. ▪ Permo Carboniferous (Late Palaeozoic) Epoch
Towards the upper Carboniferous (Late Palaeozoic) the Hercynian: movement Introduced great
changes on the surface of the globe and this is marked by mountain building and initiation of
sedimentary era. In India the epoch is known by rich coal deposits of Lower Gondwana, like
those of Jharia, Bokaro, Karanpura, Giridih, Ramgarh, Hutar, Daulatganj, Deoghar and Rajmahal
of Bihar; Raniganj Barjora and Darjeeling of West Bengal, Singrauli, Korba, Chirimiri,-
Sohagpur, Umaria, Johilia/ Bisrampur, Jhilmili etc. of MP and Godavari valley of Andhra
Pradesh and at many other places. A large number of hypabyssal basic, intrusive-dolerites and
basalts, and mica-rich ultrabasic rock, mica-peridotite, traverse these coal fields. Other important
mineral deposits of this epoch are fireclay, iron stone and ochre, which occur within the
Gondwana formation.
▪ Late Mesozoic to Early Tertiary Epoch
This epoch is dominated by fissure eruptions of basalt lava flow (Deccan Trap) which now
occupy over 500,000 sq.km, area in western and central India with semi-precious stones like
rock crystal, amethyst, agate, carnelian, onyx and other varieties of chalcedony. Rare copper
mineralisation is noted in the trap rocks.
Considerable igneous activities of this epoch marked by granites, granodiorite, basic and
ultrabasic rocks occur in extra peninsular regions, comprising main Himalayan ranges,
Manipur-Meghalaya and Andaman Nicobar Islands. These are associated with occurrences of
fluorite, copper, lead, zinc, chromite, magnesite, clay asbestos etc. in Ladakh area of Indus
ophiolite belt; magnetite, nickel chromite, asbestos, magnesite and talc occurrences in
Manipur-Nagaland and base metals, nickel and chromite in Andaman-Nicobar areas.
❖ Metallogenetic Provinces
The metallogenetic province is known by the name of dominant and specific mineral, such as
Gold Province, Copper Province, Iron-Ore Province or Manganese Ore Province. It may
comprise mineralisation of more than one epoch, each superimposed upon the other, but
essentially of the same type.
India affords many examples of metallogenetic provinces. A few important ones are enumerated
below:
1. Gold Province of Karnataka - Andhra Pradesh - Tamil Nadu (Hutti Kolar-Anantapur- Godag- Wynad
Gold Province).
2. Copper Province of Singhbhum.
3. Copper Province of Khetri-Pur Banera-Bhinder.
4. Lead-Zinc Province of Hesatu-Belbathan.
5. Iron-Ore Province of Southern Singhbhum-Keonjhar-Sundargarh Mayurbhanj.
6. Iron Ore Province of Drug-Bastar-Chanda-Ratnagiri.
7. Iron Ore Province of Karnataka-Goa.
8. Manganese Province of Balaghat-Bhandara-Nagpur.
• Gold Province of Karnataka-Andhra Pradesh-Tamil Nadu
It covers gold fields of Kolar, Hutti and Gadag of Karnataka, Ramgiri, Gcoty, Bisanatham and
Gavanikonda of Andhra Pradesh and Wynad, Cherambadi and Bensibetta of Tamil Nadu. By
far the greatest part of the Province is occupied by Dharwars, represented by metamorphosed
mafic volcanic rocks altered to schistose, massive, granular and fibrous amphibolites.
The other rock types are muscovite-biotite-schist, quartzites and granulites, with Peninsular
gneisses and granites. All these rocks and the auiferous reefs are intruded by dolerite dykes,
and the final phase of igneous activity is marked by a few pegmatites.
The structural metallogenic zones of the Province are characterised by mineralisations of the
intermediate-late-final stages of development of the mobile belt [Au, (As, Fe, Cu, Pb, W), Pb,
(Ag, Zn, Cu, Fe) and may be defined principally as :
(i) Gadag-Chitaldrug-Mysore zone.
(ii) Ramgiri-East Bangalore zone.
(iii) Hutti-Kolar-Mamandur-Vellore-Terupati zone.
3. The gold is associated mostly with quartz-loads of quartz-veins and sulphide bearing reefs
within schist and belongs to high temperature (hypothermal) hydrothermal class.
• Copper Province of Singhbhum
The Copper Province of Singhbhum is localised in the shear zone, which extends from
Duarpuram in the west to Barahagora in southeast for over 128 km with a width ranging upto
5 km and is moulded along the northern and the noth-eastern margin of Singhbhum granite
massif. The copper ores of Singhbhum seems to be related to tongues of granite which intrude
the schists. The ores occur as veins in the granite and the neighbouring mica-schists,
quartz-schists, and hornblende-schist or epidiorite. These veins are well developed along a
zone of overthrust, where they form well defined lodes. This province [Cu, Au, (Fe, Ni, 0)];
Pb, (Cu, Au, Fe, Zn); U, Th, Ce, (La, Pr, Nd, Sm, Be)] indicates intermediate-late final stages
of development of the mobile belt.
The Province represents hydrothermal and pegmatitic mineralisation in refolded synforms and
dislocated antiforms of predominantly metamorphosed sedimentary of the greywacke suite are
associated melavolcanics
• Copper Province of Khetri-Pur-Banera-Binder
There are two main zones of copper mineralisation in the Province, namely Khetri zone and
Pur-Banera-Bhinder zone. They run for about 80 kin in the northeast and 135 km in the
southeast part respectively of the state. The potential areas for copper are in Madhan Kudan,
Kalihan and Chanmari in the Khetri zone and Dariba in Pur-Banera-Bhinder zone.
Pre-Aravalli, Aravalii and Delhi groups of rocks are found in the area and the copper
mineralisation are along favourable structural zones related to different orogenic
movements. The Province shows, basic volcanics of the earlier stage of development of the
mobile belt and an acidic magmatism of the intermediate-late stage. The mineralisation
associated with earlier stage are not very predominant, while the mineralisation of the late
stage have givenn rise to the following important structural Metallogenic zones; namely :
(i) Singhana-Khetri-Babai zone [Cu, (Fe, As, Co)]..
(ii) Anjari-Dariba-Bairat-Jadawas zone [Cu, (Fe, Ni, Co), Pb, (Zn, Sb)].
(iii ) Kishangarh-Ajitgarh-Ambamara zone [(Pb, Cu, Ti), Cu],
All these zones occupy highly contorted and refolded synforms, flanked by granites and
gneisses.
• Lead and Zinc Province of Hesatu-Belbathan, Bihar
The Province extends in WNW-ESE for about 250 km from Hesatu (Hazaribagh district) in
the west to Belbathan (Godda district) in the east and has a width of about 50 km. There are
over four dozen occurrences showing evidences of lead-zinc, copper mineralisation,
covering the whole Province, some of the important occurrences are at Baraganda, Chandio,
Jhalakdiha, Ganganpur, Damgi, Toolsitanr, Bagjrmari and other places. The mineralisation
is associated mostly with Precambrian tremoliteactinolite schist, amphibolite and
calc-granulite which occur as pockets within Chotanagpur granite-gneisses.
• Iron Ore Province of South Singhbhum-Keonjhar-Sundargarh - Mayurbhanj
About 15 to 20 million tonnr.es of annual Iron-Ore production is from this Province.
Deformed and folded belts of Precambrian metasediments (flysch and volcanics) along with
gneisses and granites of at least two generations (Chotanagpur gneiss and Singhbhum
granite) cover a major part of the area and indicate the development of interior areas of a
mobile belt. The Province embraces iron-ore deposits of Noamundi, Notoburu, * ' Jamda,
Gua, Jhilingburu and Pansiraouda and others of $outh Singhbhum Bihar) and Thakurani,
Rolana. Joda , Malanteli etc. of Keonjhar, Baliapahar, Barsua, Bonai etc. of Sundargarh,
Gorumahisani, Salaipat, Badampahar and Simlipal hill of Mayurbhanj; Daitari, Tamka and
Kansa of Cuttack, and Hirapur and llmarkot of Koraput (Orissa). The banded Iron-Ore
formation with very good hematite iron-deposits are found. The important structural metallic
zones delineated in the area are given below :
4. ( i ) Cuttack-Keonjhar-Singhbhum-Mayurbhanj Zone [Cr, (Fe, Ni, Co); Fe, (Va, Ti); Pb]
(ii ) Singhbhum-Keonjhar zone (Fe, Mn)
(iii ) Mayurbhanj-Sarnbalpur-Koraput-Sundargarh zone (Fe, Mn)
The above are structural Metallogenic zones of the sedimentary metamorphic deposits of
iron and manganese. Titano-vanadiferous iron ore type, recognised in south-east Singhbhum
and Mayurbhanj is classed as liquid magmatic deposit and have formed during early
crystallization of basic plutonic rocks.
• Iron-Ore Province of Chanda-Drug-Bastar
This iron-ore Province embraces important iron-ore deposits of Lohara, Pipalgaon, A.sola
and Dewalgaon (Chanda district); Dhalli and Rajhara (Drug); and Rawghat, Parrekaro and
Bailadila (Bastar district) and produces about 12 to 15 million tonnes ore annually! This
represents metamorphosed flysch type of association with exogenic mineralisation m
Banded-Hematite-Quartzite of the early stage of development of mobile belt. The following
structural metallogenic zones have been recognised in the Province :
(i ) Pipalgaon-Lohara-Asola-Dewalgaon zone.
(ii) Dhalli-Rajhara-ParrerkaO zone.
(iii) Bailadila-Kandpai-Parotwada-Taki zone.
• Iron-Ore Province of Karnataka-Goa
This is another iron-ore province which produces altogether 46% of Indian production i.e.
annually about 25 million tonnes of iron-ore. This represents structural metallogenic zones
of sedimentary metamorphic deposits, considered to be corresponding to the early stage of
development of mobile bells - iron-ores in greywacke association Banded iron-ore formation
with good hematite iron-ore deposits is prevalent Magnetite rron-ore (Titano- venadiferous)
is found in Tumkur district and may be classed as magmatic deposit, formed during early
crystallisation of basic plutonic rocks. Bellary-Hospet, Shimoga, Chitradurga, Chikmaglur,
Kudramukh and Bababudan hills are the important iron-ore deposits found in the Province.
• Manganese Province of Balaghat-Bhandara-Nagpur
This Province falls in Madhya Pradesh and Maharashtra states and together produces about
40 per cent of manganese-ore annually out of total Indian output. They represent Gondite
type of deposits associated with metamorphosed Dharwar rocks which are characterised by
predominantly quartzite-carbonate associations with subordinate gneisses and granites of at
least two generations. The exogenic deposits of Mn in the Province are associated with an
early phase of sedimentation and as such may also be largely pre-orogenic.