Plate tectonics, like crustal evolution, provides a basis for understanding the distribution and origin of mineral and energy deposits. Different types of ores are characterized by distinct geological environment and tectonic settings.

1. 1
DEPARTMENT OF APPLIED GEOLOGY
SCHOOL OF ENGINEERING AND TECHNOLOGY
DR. HARISINGH GOUR VISHWAVIDYALAYA (A CENTRAL UNIVERSITY)
PRESENTATION ON: Ore Deposits and Plate Tectonics.
GUIDED BY PRESENTED BY
PROF R.K. TRIVEDI GOURAV RAJAK
Course Co-Ordinator M. TECH 3rd SEM

2. Contents.
1. Plate tectonic and Ore deposits.
• Intracratonic Basins.
• Domes, Rifts and Aulacogens.
• Hotspot Associated Mineralization.
• Continental Rifting.
2. Interior Basins and Intracratonic rifts and Aulacogens
• Cyprus type deposits
3. Ocean Basins and Rises
4. Passive Continental Margins
• Island Arcs
• Continental Margin Arcs
5. Subduction related settings
6. Strike Slip Settings
• I type Granite
• S type Granite
7. Collision Related Settings
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3. Plate Tectonic and Ore Deposits
• Plates or Lithospheric plates are rigid but thin (100-150 km) plates sliding
over partially molten plastic layer called the Asthenosphere.
• Plates = Oceanic Crust + Continental Crust.
• These plates are made up of plate boundaries and are classified based on
their mutual interface such as
i) constructive type, ii) destructive type, and iii) conservative type.
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4. • Plate tectonics, like crustal evolution, provides a basis for understanding the
distribution and origin of mineral and energy deposits. The relationship of
plate tectonics and mineral deposits is significant on three counts:
1. Geological processes operating due to energy released at plate
boundaries control the process of mineral deposition.
2. Mineral deposits form in particular tectonic settings which are governed
by plate tectonics.
3. Reconstruction of fragmented continents can provide a useful basis for
exploration of new mineral deposits.
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5. T
ectonicSettings
According to Mitchell & Reading(1986), six tectonic settings
will be discussed here:-
1. Interior Basins and Intracratonic rifts and Aulacogens
2. Oceanic basins and rises
3. Passive continental margins
4. Subduction – related settings
5. Strike- slip settings
6. Collision- related settings.
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6. 1. Interior Basins and Intracratonic Rifts & Aulacogen
Continental Interior Basins (Intracratonic Basins)
Intracratonic sedimentary basins occur in the middle of stable continental or
cratonic blocks.
• May contain entirely of continent sediments, deposited in larger lakes eg
Chad Basin of Africa.
• Archaean Basins:- Dominion Reef and Witwatersrand Supergroup of South
Africa were laid down containing important Gold mineralization.
• Proterozoic Basins:- Hurronion Supergroup with Uraniferous
Conglomerates
• Phanerozoic Basins:- Important for their evaporite deposits, such as the
Permian Zechstein evaporates of central Europe.
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7. Indian Examples:
• There are three large intracratonic basins (Vindhyan, Cuddapah and
Chattisgarh) and several smaller basins (Kaladgi, Bhima, Pakhal,
Penganga, Indravati, Khariar, Sabari and Kolhan).
• Cuddapah :- Uranium resource and Pb–Zn sulphide mineralization.
• Bhima and Kaladgi basin:- Uranium mineralization.
• Penganga basin:- Manganese.
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8. Fig 2. Intracratonic Witwatersrand Basin situated in Kaapvaal craton.
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9. Domes, Rifts and Aulacogens.
• These are initiated by the doming of continental areas which, due to
stretching, develop three rift valleys that meet at a 120° triple junction.
• Two of the rift valleys may combine to form a divergent plate boundary
leading through graben development to ocean spreading, whilst the third
arm may show only partial development.
• The third arm is called failed arm or Aulacogen.
• Examples:- Kutch rift and Cambay rift.
• Aulacogens are characterized by the presence of fluorite, barite,
carbonatites (with Nb, P, REE, U, Th etc) and Sn-bearing granites.
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Doming Stretching Rifting Divergence

10. Hotspot associated Mineralisation.
• Plumes may cause melting of the continental crust forming granitic
intrusions, e.g., the Cabo Granite of Brazil
• Tin provinces in Nigeria, Brazil, Saudi Arabia and Sudan are often associated
with sodic granites in ring complexes.
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Fig 3. Sketch map showing the locations of the Benue
Trough, the Amazon Rift Zone and the lead
mineralization within these aulacogens. (After Burke &
Dewey 1973 and Mitchell & Garson 1976.)

11. Fig 4. Distribution of carbonatite
intrusions relative to the East
African Rift Valley
(After Mitchell & Garson 1976)
• Volcanism in the rifts is usually of alkaline type,
sometimes with the development of carbonate
lavas and intrusives and occasionally kimberlites.
• Erosion of these may lead to the formation of
soda deposits (e.g. Lakes Natron and Magadi in
East Africa) and the intrusive carbonatites may
carry a number of metals of economic interest as
well as being a source of phosphorus and lime.
Ambadongar, which is a famous carbonatite
Complex, Newania carbonatite complex (Apatite
and REE), Rajasthan,
Sevathur carbonatite (Vermiculite)complex,
Tamilnadu.
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Mineralization associated with continental rifting

12. 2. Ocean Basins and Rises
Volcanogenic Massive Sulphides.
• Massive sulphides deposits are currently forming in undersea locations
characterized by “Black Smokers”. These Black Smokers are plumes of
sulphide-rich fluids and represent the venting of hydrothermal fluids, rich in
base and precious metals, onto the ocean floor.
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• Eg- Base metal deposits of
Ambaji and Deri in Delhi Fold
Belt, Rajasthan.
Fig. 5 Diagram showing how sea water circulation through
oceanic crust might give rise to the formation of an
exhalative volcanic-associated massive sulphide deposit.

13. 13
Cyprus Type Massive Sulphide Deposit
• Cu-Fe rich associated with ophiolites and represent hydrothermal
deposits formed at ocean ridges.
• They are typically underlain by copper-rich "stringer-zones" composed
of anastomosing quartz-sulfide mineral veins in extensively chloritized
basalt
• Hydrothermal mineralization with the development of Cu, Zn, Ag and
Hg have been reported from oceanic ridges in the Atlantic and Indian
Oceans by Dmitriev et al. (1971)

14. 3. Passive Continental Margins
• Passive continental margins develop along coastlines that are not
tectonically active.
• Passive continental margins that have suffered marine transgressions are
important for phosphorite deposits.
• Coastlines marked by considerable upwelling are favourable sites for
phosphogenesis e.g., Miocene phosphate deposits of south – eastern
continental margin of USA.
• Important beach placer deposits are developed along the trailing edges
(passive continental margins).
• Placer deposits include: diamond placers of the Namibian coast, the rutile-
zircon-monazite-ilmenite deposits of the eastern and western coasts of
Australia.
• Eg- Beach Placer Deposits of Western Coast of India
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15. (a) Nutrient rich, deep ocean water floods
on to the continental shelf and low grade
phosphorite deposits form
(b) A sea level rise leads to a major marine
transgression resulting in a reworking of
phosphorite shelf sediments and the
shoreward transport of phosphatic grains to
form major deposits in the coastal zone and
in marginal embayements. (After Cook
1984)
Possible model for phosphorite formation beside an upwelling site initiated in a deep ocean.
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Fig 7

16. 4. Subduction-Related Settings
Subduction is a geological process in which the oceanic lithosphere and some
continental lithosphere is recycled into the Earth's mantle at convergent
boundaries.
Subduction can produce Island arc or continental margin arc.
Mineralization in Island arcs
• Ocean lithosphere is subducted beneath an overlying plate composed of
oceanic lithosphere produce an island arc
• Series of volcanoes that lies on the continental side of an oceanic trench of
a lithospheric plate. 2 types of deposits
i. Allochthonous Deposits
ii. Autochthonous Deposits
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17. Allochthonous Deposits
• Rocks and Minerals deposits initially formed at the Mid Oceanic Ridge will
ultimately reach the subduction zone.
• Some of the material will get subducted some, however, is obducted to
form accreted terrain.
• Cyprus-type massive sulfide ore bodies thrust into a mélange, occur in
north western California.
• Podiform chromites are the most important magmatic deposits in the
allochthonous peridotites. The chromites are cumulates that originated in
the upper mantle, often at mid-oceanic ridges.
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18. 18
Fig 8 Ore deposits associated with island-arc and adjacent regions. (Source: Evans, 2009)

19. Autochthonous Deposits
• 3 Stages
1) Initial or tholeiitic stage :- Considerable sedimentation and subaerial
volcanicity may have occurred during the tholeiitic stage. No major Ore
deposits.
2) Main calc-alkaline stage.:- main island arc building and plutonic igneous
activity belong to this stage.
• Volcanic massive sulphide, stockwork, skarn and vein deposits are formed
in this stage. Conformable sulphide ore bodies of Besshi-type develop at
this stage in back-arc basins.
• Sillitoe (1972a) suggested that the solutions which deposited some of
these massive sulphide deposits might have come directly from subducted
sulphide bodies
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20. 3) Waning calc-alkaline stage:- The massive sulphide deposits of Kuroko-type
probably belong to the later stages of development of island arcs.
• They are associated with the more felsic stages of calc-alkaline magmatism.
• Kuroko-type ores in ancient island arcs include the Paleozoic deposits of
Captain's Flat, New South Wales; Buchans, Newfoundland; Parys Mountain,
Wales; and Avoca, Iceland.
• Present opinion is that these deposits too are wholly or mainly developed
in back-arc settings
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21. (a) Ocean-ocean convergence
producing island arc volcanoes and
backarc basins.
(b) Ocean—continent convergence
producing continental volcanic arcs.
(Courtesy of the US Geological
Survey.)
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Fig 9

22. Continental Margins
• Continent – ocean convergent margins, where continental margin volcanic
arcs develop on the overlying continental lithosphere.
• Partial melting of a thick overlying wedge containing continental lithosphere
produces the calc - alkaline series that include andesitic, dacitic, basaltic
and rhyolitic rocks.
• Ore Deposits here are associated with volcanic arc magmatism.
• These deposits are caused due to progressive liberation of metals from the
descending slab.
Example-
Along the Circum-Pacific Belt major metallic deposits occur in western North
and South America, Japan, Philippines, New Zealand and Indonesia
Porphyry Copper Deposits of Malajhkhand, India( ?)
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23. 23
In the Andes, going from west to east, the various zones encountered are:
a) Contact metasomatic Fe-deposits;
b) Cu-Ag and Ag veins;
c) Porphyry Cu-Mo deposits;
d) Pb-Zn-Ag veins and contact metasomatic deposits; and
e) Sn deposits.
Fig 10

24. .
• Relatively narrow and sub vertical wrench zones along which two adjacent
blocks move sideways, horizontally, parallel to the strike of the fault zone.
• Transform faults are, however, loci of higher heat flow and could well be
channel-ways for hydrothermal solutions, as certainly appears to be the
case in the Red Sea.
• Donnybrook-Bridgetown Shear Zone of western Australia, which is
considered to be analogous to the San Andreas Fault System, hosts the
Greenbushes pegmatite group (Sn-Ta- Li producer) which is potentially the
largest rare metal resources in the world.
• Gold deposits in Archaean Abitibi Greenstone belt of Ontario-Quebec
(Canada) exhibit close connection with regional fault zones.
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5. Strike Slip Settings

25. 6. Collision Related Settings
• When a continent on the subducting plate meets either a continental
margin or island arc on overriding plate.
• Subduction can then lead to melting in the heated continental slab and the
production of S-type granites or I type granite.
I - type granites are generated by the melting of an igneous protolith from
either the downgoing oceanic lithosphere or the overlying mantle wedge.
• Porphyry copper, tungsten and molybdenum deposits are associated with I
- type granites.
Eg:- Permian volcanic-plutonic arc with a porphyry copper deposit at Loei.
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26. S - type granites are produced by the melting of sedimentary crustal rocks in
collision zones.
• Tin deposits are associated with S - type granites.
• Uranium deposits, particularly vein type, may be associated with S-type
granites as in the Hercynides and Damarides (Rossing uranium deposit,
Namibia).
• Eg- In the foreland molasse basins, uranium mineralization is
reported from the Siwaliks in India and Pakistan.
• Tin Tungsten deposit of Chhendapathar, West Bengal.
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27. Fig 11 (a) Two continents on a collision course as oceanic crust between them is
subducted. Here we have the Andean-type situation of Fig. 23.5 in which I-type
granites are generated along the Benioff Zone. Some of these granites may host
porphyry copper deposits.
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28. Fig 11 b) Collision has taken place and the leading section of the underriding plate has
been blanketed with thick thrust slices of sediment and mélange. Temperatures rise
sufficiently in this continental crust to permit partial melting and the formation of S-type
granites. If the crustal material contained above average amounts of tin, tungsten, etc.,
then these granites may have associated, epigenetic deposits of these metals. The I-type
and S-type granites, with their associated mineralization, may occur in parallel belts as in
Thailand and Malaysia. (After Beckinsale 1979.)
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29. Conclusion
• Ore deposits are formed in various environments.
• These environments in some way or other are related to plate
tectonics.
• Predication and Correlation of various ore deposits can be done
using Plate Tectonics.
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30. References
1. Evans, A. M. (1992): Ore geology and Industrial Minerals, Blackwell Science.
2. Hefferan, K and O’Brien, J (2010): Earth Materials, Wiley Blackwell.
3. https://www.degruyter.com/document/doi/10.1515/geo-2020-0007/html.
4. https://epgp.inflibnet.ac.in/epgpdata/uploads/epgp_content/S000448GO/P00
0596/M018265/ET/1482317225MAINTEXT.pdf
5. https://epgp.inflibnet.ac.in/epgpdata/uploads/epgp_content/S000448GO/P00
0596/M018266/ET/1482317287MAINTEXT.pdf
6. https://egyankosh.ac.in/bitstream/123456789/58973/3/Block-4.pdf
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31. Thank You
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