Hydrothermal Ore Deposits

Summary

This educational video explores hydrothermal deposits, which form from hot water solutions carrying metals from magma. It explains the formation of epigenetic deposits and classifies them into hypothermal, mesothermal, and epithermal based on depth and temperature. The script also discusses two types of hydrothermal deposits: cavity filling and replacement, with examples like Fisher veins and replacement loads. It covers various deposit types, their characteristics, and the metals they contain, providing a comprehensive look at the subject.

Takeaways

• 🌋 Hydrothermal deposits are formed from hot water solutions that carry metals from magma after magmatic differentiation.
• 🔥 The term 'epigenetic' refers to deposits formed after the formation of the host rock, and hydrothermal processes are key in their formation.
• 🏺 Common metals found in hydrothermal deposits include gold, silver, copper, lead, zinc, and mercury.
• 🌡️ Hydrothermal deposits are classified based on depth and temperature of deposition into hypothermal, mesothermal, and epithermal groups.
• 🏰 Hypothermal deposits form at great depths and high temperatures (300-500°C), and may contain native gold, sulfides, and oxides.
• 🏞️ Mesothermal deposits form at intermediate depths and temperatures (200-300°C), and are typically rich in copper, zinc, silver, and gold.
• 🌅 Epithermal deposits form at shallow depths and lower temperatures (50-200°C), and are often sources of silver, gold, and mercury.
• 🔩 Hydrothermal deposits can also be classified based on formation mode into captive filling deposits and replacement deposits.
• 🏰 Cavity filling deposits occur when hydrothermal solutions deposit minerals in openings within rocks, without involving replacement.
• 🔄 Replacement deposits form through chemical interaction between hydrothermal solutions and country rock, leading to the deposition of ore minerals.
• 📊 Types of cavity filling deposits include fissure veins, stockwork, saddle reefs, ladder veins, and gossan veins, each with distinct characteristics and settings.

Q & A

What does the term 'hydrothermal' mean in the context of mineral deposits?

In the context of mineral deposits, 'hydrothermal' refers to hot water with temperatures ranging from 50 to 500°C, which carries metals originally present in magma, resulting from magmatic differentiation.

What are epigenetic deposits?

Epigenetic deposits are those that are formed after the formation of the host rock, and deposits formed by hydrothermal solutions are called hydrothermal deposits.

List the common metals found in hydrothermal deposits.

Common metals found in hydrothermal deposits include gold, silver, copper, lead, zinc, and mercury.

What are the three groups of hydrothermal deposits based on depth and temperature of deposition?

The three groups of hydrothermal deposits based on depth and temperature of deposition are hypothermal, mesothermal, and epithermal deposits.

At what temperature range do hypothermal deposits form?

Hypothermal deposits form at great depths and high temperatures, with temperatures ranging from 300 to 500°C.

What are the characteristics of mesothermal deposits?

Mesothermal deposits form at intermediate depths and temperatures, with temperatures ranging from 200 to 300°C.

What is the temperature range for the formation of epithermal deposits?

Epithermal deposits form at shallow depths and relatively low temperatures, with temperatures ranging from 50 to 200°C.

What are the two classifications of hydrothermal deposits based on the mode of formation?

Hydrothermal deposits are classified into two groups based on the mode of formation: cavity filling deposits and replacement deposits.

How do cavity filling deposits form?

Cavity filling deposits form when hydrothermal solutions deposit their dissolved minerals in various types of openings present in the rock, without involving replacement.

What are some common types of cavity filling deposits?

Common types of cavity filling deposits include fissure veins, share zone deposits, stock work, saddle reefs, ladder veins, and gossan veins.

How do replacement deposits differ from cavity filling deposits?

Replacement deposits form due to chemical interaction between the hydrothermal solution and the country rock, where the original minerals are dissolved and replaced by ore minerals.

What are the three types of replacement deposits?

The three types of replacement deposits are massive deposits, replacement load, and disseminated deposits.

Outlines

00:00

🌋 Hydrothermal Deposits: Formation and Classification

The script introduces hydrothermal deposits, which are formed by hot water resulting from magmatic differentiation carrying metals originally present in magma. These deposits are categorized based on depth and temperature into hypothermal (300-500°C), mesothermal (200-300°C), and epithermal (50-200°C) deposits. Hypothermal deposits are found at great depths with minerals like native gold and sulfides, while mesothermal deposits form at intermediate depths with minerals such as native gold and various sulfides. Epithermal deposits form at shallow depths and are sources of silver, gold, and mercury. Additionally, hydrothermal deposits are classified into cavity filling and replacement deposits, with cavity filling deposits occurring in various openings like veins and stockworks.

05:07

🏭 Cavity Filling Deposits: Types and Characteristics

This paragraph delves into cavity filling deposits, which are formed when hydrothermal solutions deposit dissolved minerals in openings within rocks. These deposits come in various sizes and shapes, with common types including fissure veins, stockwork, saddle reefs, ladder veins, and gossan veins. Fissure veins are tabular bodies within rock fissures, with simple fissure veins having straight and parallel walls, while chambered veins have irregular and branched walls. Stockwork forms through hydrothermal solutions percolating through vertical zones of fracturing in igneous intrusions. Saddle reefs are deposits formed along openings between rock beds at the crest of anticlines, and ladder veins are mineralized vertical solution joints in carbonate rocks, often containing valuable metal deposits.

10:16

🔄 Replacement Deposits: Formation and Types

The script explains replacement deposits, which form due to chemical interactions between hydrothermal solutions and country rock, leading to the deposition of ore minerals in place of the original rock. This process can occur simultaneously with the filling of rock openings. Replacement deposits are common sources of iron, lead, zinc, copper, silver, and many non-metallic minerals. They are subdivided into massive deposits, replacement load, and disseminated deposits. Massive deposits are large ore bodies found in limestone, replacement load deposits form along thin beds or fissures, and disseminated deposits consist of scattered ore mineral grains throughout the host rock.

Keywords

💡Hydrothermal deposits

Hydrothermal deposits are mineral deposits formed from hot water solutions that circulate through the Earth's crust. These solutions, often a result of magmatic differentiation, carry metals originally present in magma. In the video, hydrothermal deposits are the central theme, with a focus on how they form and the types of metals they contain, such as gold, silver, copper, lead, zinc, and mercury.

💡Epigenetic deposits

Epigenetic deposits are those that form after the formation of the host rock. They are not directly related to the original rock but are instead formed by secondary processes, such as hydrothermal activity. The video explains that hydrothermal deposits are a type of epigenetic deposit, highlighting their formation after the host rock has been established.

💡Hypothermal deposits

Hypothermal deposits are a type of hydrothermal deposit formed at great depths and high temperatures and pressures, typically ranging from 300 to 500°C. The video describes these deposits as containing minerals such as native gold, sulfides, and oxides, and are a source of metals like copper, tin, tungsten, gold, and lead.

💡Mesothermal deposits

Mesothermal deposits form at intermediate depths and temperatures, with temperatures ranging from 200 to 300°C. These deposits are characterized by the presence of native gold and sulfides like galena, sphalerite, and pyrite. The video mentions that metals mined from mesothermal deposits include copper, zinc, silver, gold, and lead.

💡Epithermal deposits

Epithermal deposits are formed at shallow depths and relatively low temperatures and pressures, with temperatures ranging from 50 to 200°C. The video notes that these deposits are a source of silver, gold, and mercury, and they often form in areas of high heat flow, such as near volcanic activity.

💡Cavity filling deposits

Cavity filling deposits are formed when hydrothermal solutions deposit their dissolved minerals in openings present in the rock. This type of deposition does not involve replacement of the rock but rather filling of existing spaces. The video provides examples such as fissure veins, stockwork, and gossan veins, which are all types of cavity filling deposits.

💡Fissure veins

Fissure veins are a type of cavity filling deposit that fills fractures or fissures in the rock. The video explains that these veins can be simple, chambered, or complex, with simple veins having straight and parallel walls, while chambered veins have irregular and branched walls.

💡Stockwork

Stockwork refers to a network of small, vein-like fractures that have been filled with minerals by hydrothermal solutions. The video describes stockwork as a mass of rock traversed by a network of small ore-bearing veins, often formed in areas of vertical fracturing within igneous intrusions.

💡Saddle reefs

Saddle reefs are deposits formed along openings between rock beds at the crest of an anticline. The video mentions that these deposits are formed during folding, where the opening allows for mineralization, creating a type of hydrothermal deposit.

💡Ladder veins

Ladder veins are mineral deposits that form as a result of transverse cracks in dykes, which are often subject to mineralization. The video describes these as forming due to the cooling and contraction of the dyke masses, leading to the formation of mineral deposits known as ladder veins.

💡Replacement deposits

Replacement deposits are formed due to chemical interaction between the hydrothermal solution and the country rock, where the original minerals are replaced by ore minerals. The video explains that this process can lead to the formation of massive deposits, replacement load, and disseminated deposits, which are characterized by the presence of ore minerals scattered throughout the host rock.

Highlights

Hydrothermal deposits are formed from hot water solutions resulting from magmatic differentiation.

Epigenetic deposits are those formed after the formation of the host rock.

Common metals in hydrothermal deposits include gold, silver, copper, lead, zinc, and mercury.

Hydrothermal deposits are classified into hypothermal, mesothermal, and epithermal based on depth and temperature.

Hypothermal deposits form at great depths with temperatures ranging from 300 to 500°C.

Mesothermal deposits form at intermediate depths with temperatures between 200 to 300°C.

Epithermal deposits form at shallow depths with temperatures ranging from 50 to 200°C.

Hydrothermal deposits are also classified as cavity filling or replacement deposits based on formation mode.

Cavity filling deposits form when hydrothermal solutions deposit minerals in openings in rocks.

Fissure veins are a type of cavity filling deposit, filling with ore within fissures.

Fissure veins are important for metals like gold, silver, copper, lead, zinc, and mercury.

Types of fissure veins include simple veins, chamber veins, sheet veins, and composite veins.

Replacement deposits form through chemical interaction between hydrothermal solutions and country rock.

Replacement deposits are dominated by higher temperatures and pressures.

Types of replacement deposits include massive deposits, replacement load, and disseminated deposits.

Massive deposits are characterized by great variation in size and irregular form.

Disseminated replacement deposits consist of low-grade ores scattered throughout the host rock.

Transcripts

okay friends today our topic is

hydrothermal or

deposits the term hydrothermal means hot

water with possible temperature of 50 to

500° Centigrade the fluid resulting as

an end product of magmatic

differentiation constitute hydrothermal

solution which carries metal originally

present in the

magma this process is

responsible for the formation of the

epigenetic

deposits actually the epigenetic deposit

are those deposit which are formed after

the formation of the host

strog the epigenetic deposit formed by

hydrothermal solution are

called hydrothermal or

deposit the or deposits which are

commonly formed by the hydrothermal

process are gold silver copper lead zinc

and

Mercury now what is the classification

of the O

deposits on the basis of the depth and

the temperature of the

deposition lrin has classified the

hydrothermal deposit into three groups

number one is hypothermal

deposits

second

mmal or

deposits and third epithermal or

deposits now what is hypothermal O

deposits okay we'll

see hypothermal deposits are formed at

Great depths and high temperatures and

pressures temperature May range from 300

to 500° C during the formation of which

during the formation of such

deposits or mineral found may include

native gold sulfide Galina chopy pyite

Mite bismi

knite and arop pyite the

oxide urite cerite

magnetite and the tong State

vulite and

slite metals which may be extracted from

hypothermal deposit consist of copper

M tin tungsten gold and

Lead second is

mesothermal mesothermal deposits form at

at intermediate depth temperature and

pressure temperature May range from 200

to

300° Celsius during the formation of

such

deposits or mineral which may be found

include native gold and the sulfide

Galina seerite Chalopy pyite borite

arsenopyrite and tetrah

hydrite metal which are mined consist of

copper zinc silver gold and

lead the third type is epithermal

deposit these deposit are formed at

shallow depth and relatively low

temperature and pressure temperature

during formation May range from 50 to

200° C Metals which are mined from

epithermal deposits

include silver gold and

Mercury now the second classification is

based on the mode of the formation and

the Genesis of the

deposits hydrothermal deposit have been

classified into two groups number one is

captive filling deposit and second is

replacement deposit what what is cavity

filling deposit these deposits are

formed when hydrothermal solution

deposits their disol mineral in the

various type of opening present in the

Rock in this deposition no replacement

is

involved such a deposition take place by

change of temperature and pressure of

the hydrothermal

solution most of

a epithermal deposits are cavity filling

deposits type of cavity filling

deposits depending upon the nature of

the opening the cavity filling deposits

occur in a variety of size and shape the

common type of the cavity filling

deposits are Fisher Vin share Zone

deposits stock work saddle Reef ladder

veins and C deposit and gosh

veins now what are Fisher deposits

actually these Fisher deposits filled

with when fishes are filled with ore is

called Fisher veins it is tabular or

body which occupy one or more fish F

within a

rock Fisher

Vans deposits are the most important of

all the cavity filling

deposits they are the chief source of

most of the metal like gold silver

copper lead zinc and

Mercury the common type of the fish

deposit are as follow simple Fisher

Vans and chamber van

what is simple

Fisher acidic R which occupies a single

Fisher whose walls are nearly straight

and parallel is called Simple Fisher

wind chambered veins are those vein

whose walls are irregular and

brated are called chamber

Vin such Vin branch and join

as shown in

figure in this figure figure a this a

chamber

vs second is a lantic V and third is a

sheet

V dilation are lenticular vein generally

in shist which is a metamorphic rock

several discon disconnected lens of the

or occur together such lens are called

dations

when their weth range from a few cm to

tens of

meter sheet

veins a group of closely spaced parallel

veins are called sheet vein in this case

all the vein together farm and

load composite

veins a composite vein is a wide zone of

nearly parallel Fisher the weth of such

vein is measured in many tens of meter

shared Zone deposits shared Zone

deposits

of thin and closely spaced

fracture here as opening are minute The

Opening space deposition is minor

however the large specific surface of

the opening make the Shar Zone very

susceptible to

replacement hence many Lodge and

valuable or deposit are

formed in this she

Zone stock

work stock work is nothing but it is a

mass of rock traversed by a network of

small or

bearing

veins stock work are

formed when the hydrothermal Solutions

percolate through vertical zone of 10 10

shuttering which occur in certain ignas

intrusion as shown in figure

three this is stock work this is the

stock this is a stock

work now what are saddle reefs during

folding opening are formed between rocks

bed at the crust of the

anticline all

deposits formed along such opening are

called saddle Reef as shown in figure

four

[Music]

ladder

V

transverse crack in dyes forming as a

result of cooling and contraction of the

ous masses are due to movement of the

wall Rock are often subject to

mineralization

giving rise to mineral deposit known as

the lad

wind this is the ladder V dies these are

the transfers cracks form in a

d

goshin gsh vins are mineralized vertical

solution joints in carbonate country Ro

and contain valuable deposits of

metals metallic and non-metallic

minerals mineralization along opening in

brated and vesiculated rock has led to

development of copper lead zinc and

silver

ore this is

a carbonate rock and these black spots

are your gosh

vs replacement

deposit these deposit are formed due to

chemical interaction between the

hydrothermal solution and The quantry

Rock the or minerals are

deposed from a mineral bearing

solution in place of country rock the L

being dissolved and removed in

solution The Filling of the rock opening

by precipitation and the replacement of

their walls may occur

simultaneously replacement dominate

under condition of higher temperature

and pressure where whereas C filling

dominate under condition of low

temperature and

pressure the replacement deposit C

commonly contain ore of iron lead zinc

copper silver and many non-metallic

minerals type of replacement

deposit the O deposit form by

replacement can be subdivided into three

groups number one massive deposits

replacement load and disseminated

deposit

massu

deposits are the O deposit commonly

occur in

Limestone the O terminate abruptly

against the H Str and characterize by

great variation in size and extremely

irregular

form replacement load the load deposits

are formed when the replacement is

localized along thin beds or Fisher in

this case the Fisher walls are replaced

by the

or the load dep deposits resemble Fisher

vein in form however they are wider than

Fisher winds and their walls are wavy

and irregular as shown in figure

7

disseminated replacement deposits these

are low grade or

deposit where grains of or minerals are

found scattered throughout the host

truck thank you