Volcanic Massive Sulphide Mineral Deposits - VMS

Summary

This video explains volcanic massive sulfide (VMS) deposits, formed by underwater volcanic eruptions at rifts caused by extension faulting in the Earth's crust. Magma rises through faults, creating eruptions that deposit metals like copper, gold, zinc, and silver. These metals settle in volcanic piles near the eruptions, forming VMS deposits over thousands of years. Periods of volcanic activity alternate with sedimentation, forming layers of deposits. Uplifting and erosion expose these deposits, which are essential for mining operations, as seen in the Flin Flon VMS belt in Canada.

Takeaways

• 🌋 Volcanic massive sulfide (VMS) deposits form from underwater volcanic eruptions along rift or spreading centers caused by extension faulting.
• 🌊 Extension faulting is driven by magmatic vortices in Earth's liquid outer core, which stress the crust, leading to separation.
• 🌋 Magma from the Earth's interior exploits these faults, oozing out onto the seafloor and creating volcanic eruptions.
• 🏔️ These eruptions form volcanic piles made of ash and rock, which settle at the seafloor and can extend tens of kilometers from the volcanic center.
• 💦 Seawater is drawn through muds and rocks around the volcano, dissolving minerals and forming hydrothermal fluids rich in copper, gold, lead, zinc, and sulfur.
• 🔥 Hydrothermal fluids, heated by magma, rise through cracks in the volcanic pile, depositing metals like copper, gold, lead, zinc, and silver as they cool.
• ⚒️ The deposition of metals forms zonation: copper and gold settle near the vent, while lead, zinc, and silver are found higher up and farther away.
• ⏳ These processes occur over tens to hundreds of thousands of years, with layers of volcanic and sedimentary material building up over time.
• 🏞️ Continental uplift and collision bring these deposits closer to the surface, where they can be exposed by erosion and eventually recycled back into the ocean.
• 📍 A real-world example of VMS deposits is the Flin Flon VMS belt in Saskatchewan, which has been mined for nearly a century by the Hudson Bay Mining and Smelting Company.

Q & A

What are Volcanic Massive Sulfide (VMS) deposits?

VMS deposits are mineral deposits formed as a result of underwater volcanic eruptions. They occur primarily along rift zones or spreading centers where the seafloor is extended and faulted, allowing magma to ooze out and form deposits of metals such as copper, gold, lead, zinc, and silver.

What geological process leads to the formation of VMS deposits?

VMS deposits form due to underwater volcanic eruptions that occur along rift zones or spreading centers caused by extension faulting of the seafloor. Magma from Earth’s interior reaches the surface, and the resulting eruptions create volcanic piles that are rich in minerals.

How does extension faulting contribute to VMS formation?

Extension faulting, caused by magmatic vortices in Earth’s liquid outer core, exerts stress on the rocks making up the seafloor, causing them to separate. This allows magma to rise to the surface, where it plays a key role in the formation of VMS deposits through underwater volcanic eruptions.

What happens when magma erupts onto the seafloor?

When magma erupts onto the seafloor, it creates violent volcanic eruptions that form a volcanic pile of ash and rock. This pile can extend for kilometers and becomes the foundation for the deposition of metals through hydrothermal processes.

What role do hydrothermal fluids play in the formation of VMS deposits?

Hydrothermal fluids, formed when seawater is drawn through rocks and volcanic materials, dissolve minerals like copper, gold, lead, zinc, and sulfur. These fluids are heated by magma and deposit the dissolved metals as they cool, creating layers of mineral deposits in the volcanic pile.

How do metals like copper and gold get deposited within a VMS deposit?

As hydrothermal fluids rise and cool within the volcanic pile, metals like copper and gold are deposited first because they precipitate out at higher temperatures. These metals are often found deeper in the pile or closer to the volcanic vent.

What is the zonation of metals in a VMS deposit?

Zonation in VMS deposits refers to the arrangement of metals based on their temperature of deposition. Copper and gold are deposited closer to the vent and deeper in the pile, while metals like lead, zinc, and silver are deposited higher up and further away from the vent as the fluids continue to cool.

How do volcanic piles grow and change over time?

Volcanic piles grow through repeated eruptions. Coarser materials settle closer to the volcanic center, while finer materials drift further away. Over time, these piles are buried by sediments, and new volcanic piles may form on top during subsequent eruptions, creating a vertical and lateral accumulation of deposits.

What is the role of black smokers in VMS formation?

Black smokers are hydrothermal vents where some of the more energetic mineral-rich fluids escape from the volcanic pile and are expelled into the surrounding ocean. These vents contribute to the formation of metal deposits in the surrounding area.

What happens to VMS deposits over geological time periods?

Over time, VMS deposits may be uplifted due to continental collision, exposing them to erosion. The eroded material may then be transported back to the ocean and contribute to the cycle of sediment deposition and mineral formation.

What is an example of a region with prolific VMS deposits?

An example of a prolific area for VMS deposits is the Flin Flon VMS belt located in eastern Saskatchewan, Canada. This region has supplied metals for mining companies such as the Hudson Bay Mining and Smelting Company for nearly a century.

Outlines

00:00

🌍 Introduction to Geology Simply Explained

The video introduces its purpose: providing simple explanations for complex geological processes, focusing on how mineral deposits form. This episode centers on Volcanic Massive Sulfide (VMS) deposits, which result from underwater volcanic eruptions.

🌋 Formation of VMS Deposits

VMS deposits form through underwater volcanic eruptions that occur along rift or spreading centers, where extension faulting of the sea floor occurs. This extension is caused by stress from magmatic vortices in Earth's liquid outer core, which causes the sea floor to separate.

🧨 Magma and Eruption Cycles

Magma from Earth's interior moves through extension faults and flows onto the sea floor. Sometimes, a sudden surge of magma triggers massive eruption cycles. These eruptions lead to the formation of VMS deposits and have occurred since ancient times, continuing to form even today.

🏔 Formation of Volcanic Piles

As volcanic eruptions happen, ash and rock are expelled, settling to form a 'volcanic pile.' This pile can span tens of kilometers, with coarser material nearer to the volcanic center and finer material settling further away. The pile's thickness decreases as it extends away from the volcano.

💦 The Role of Hydrothermal Fluids

Volcanic eruptions create negative pressure, pulling seawater through surrounding muds and rocks. This water absorbs minerals like copper, gold, lead, zinc, silver, and sulfur as it moves toward the volcano. Heated by magma, these mineral-rich hydrothermal fluids are trapped in the volcanic pile or escape through vents known as black smokers.

⚙ Metal Zonation in VMS Deposits

As hydrothermal fluids cool and react with seawater and volcanic materials, they release dissolved metals in stages. Copper and gold are deposited first, followed by lead, zinc, and silver. This zonation places copper and gold deeper in the pile, while the other metals form higher up and farther from the volcanic vent.

🕰 Long-Term VMS Formation Process

VMS deposits form over tens of thousands of years. Once eruptions stop, sediments gradually cover the volcanic pile. Over time, additional volcanic eruptions create new piles, repeating the process. VMS deposits can accumulate both laterally along faults and vertically through layers of eruptions and sedimentation.

🌄 Uplift and Erosion of VMS Deposits

Over time, tectonic activity like continental collisions uplifts the rock containing VMS deposits, exposing them to erosion. Eroded materials return to the ocean as sediments, where they may be recycled in future geological processes. The cycle continues with new deposit formation.

📍 Example of a VMS-Rich Region

The Flin Flon VMS Belt in eastern Saskatchewan is highlighted as a key region for VMS deposits. These deposits supported the Hudson Bay Mining and Smelting Company for nearly a century. The search for new VMS deposits continues.

👍 Conclusion and Final Thoughts

The video concludes with a summary of the key points regarding VMS deposits and their formation. The creators express hope that viewers found the explanation helpful in understanding this complex geological process. The video ends with a thank-you message.

Keywords

💡Volcanic Massive Sulfide (VMS) deposits

VMS deposits are mineral-rich formations created by underwater volcanic eruptions. They result from the interaction between magma, seawater, and surrounding rocks, producing valuable metals like copper, gold, zinc, and silver. In the video, VMS deposits are highlighted as the outcome of geological processes along underwater rifts or spreading centers, making them important for mining.

💡Underwater volcanic eruptions

These eruptions occur beneath the ocean, often along rift zones where the Earth's crust is pulling apart. Magma oozes out from the Earth's interior and interacts with seawater, leading to the formation of VMS deposits. The video explains how these eruptions along faults create volcanic piles and influence mineral deposition.

💡Rift or spreading center

A rift or spreading center is a region where tectonic plates are moving apart, causing the seafloor to stretch and crack. Magma from the Earth's mantle can rise through these cracks, leading to volcanic activity. In the video, rifts are the main zones where VMS deposits form as volcanic activity leads to mineral deposition on the ocean floor.

💡Extension faulting

Extension faulting refers to the process where the Earth's crust is stretched, leading to the creation of faults or cracks. In the video, these faults allow magma to rise to the seafloor, triggering underwater eruptions that eventually form VMS deposits. It’s a key process that creates the setting for volcanic and mineral-rich activity.

💡Volcanic pile

A volcanic pile is a layered accumulation of ash and rock that settles on the seafloor following volcanic eruptions. The material is thicker near the volcanic center and thinner further away. The video discusses how this pile serves as a reservoir for mineral-rich hydrothermal fluids that eventually form VMS deposits.

💡Hydrothermal fluids

These are hot, mineral-rich fluids that circulate through cracks in the Earth's crust near volcanic activity. They dissolve metals like copper, gold, and zinc from surrounding rocks and deposit them within the volcanic pile. The video describes how hydrothermal fluids are crucial in transporting and concentrating minerals to form VMS deposits.

💡Black smokers

Black smokers are underwater vents that release hot, mineral-rich water, often found near volcanic or tectonic activity. In the video, they are described as the escape points for energetic hydrothermal fluids, which deposit metals like copper and gold, contributing to the formation of VMS deposits.

💡Zonation of metals

Zonation refers to the spatial distribution of different metals within a VMS deposit. As hydrothermal fluids cool, metals like copper and gold precipitate first, followed by lead, zinc, and silver. The video explains that this leads to the formation of distinct zones within the volcanic pile, with certain metals concentrated closer to the volcanic vent and others further away.

💡Continental collision

Continental collision occurs when tectonic plates carrying landmasses converge, causing uplift of the Earth's crust. This process eventually exposes VMS deposits to erosion, as described in the video. Over time, the metals are eroded and recycled back into the ocean, continuing the geological cycle.

💡Flin Flon VMS Belt

The Flin Flon VMS Belt is a region in eastern Saskatchewan, Canada, known for its rich deposits of VMS minerals. The video mentions it as an example of a prolific mining area that has supported the Hudson Bay Mining and Smelting Company. It illustrates the importance of VMS deposits for economic and industrial purposes.

Highlights

Introduction to the video series aimed at simplifying complex geological processes like the formation of mineral deposits.

Explanation of Volcanic Massive Sulfide (VMS) deposits and their formation due to underwater volcanic eruptions.

VMS deposits occur along rift or spreading centers caused by extension faulting in the sea floor.

Extension faulting is driven by magmatic vortices in Earth's liquid outer core, creating stress that separates the Earth's crust.

Magma from Earth's interior exploits extension faults and emerges on the sea floor.

Sudden magma influxes lead to massive volcanic eruption cycles, forming VMS deposits.

Ancient seas have witnessed the formation of VMS deposits for billions of years, and this process continues today.

Volcanic eruptions create volcanic piles, consisting of ash and rock, which can extend tens of kilometers from the eruption center.

Seawater drawn into volcanic systems dissolves metals like copper, gold, lead, zinc, silver, and sulfur, forming mineral-rich hydrothermal fluids.

Hydrothermal fluids, rich in minerals, are heated by magma and deposit metals as they cool in the volcanic pile.

Metal zonation occurs with copper and gold deposits forming deeper, while lead, zinc, and silver are deposited higher up.

VMS deposits form over tens to hundreds of thousands of years and are buried by sediment after volcanic eruptions cease.

Repeated eruptions create new volcanic piles on top of previous ones, leading to vertical and lateral VMS deposit formation.

Continental collision uplifts VMS deposits, exposing them to erosion and initiating the recycling of these materials.

The Flin Flon VMS belt in Saskatchewan is an example of a prolific area for VMS deposition, supporting long-standing mining operations.

Transcripts

welcome to geology simply explained the

purpose of this video series is to

provide very simple explanations of very

complicated geological processes that

form mineral deposits

in this one we're going to discuss

volcanic massive sulfide deposits

otherwise known as vms deposits

vms deposits occur as the result of

underwater volcanic eruptions

these eruptions occur along a rift or

spreading center that is created by

extension faulting of the rocks that

make up the sea floor

extension faulting is caused by magmatic

vortices in earth's liquid outer core

that put an enormous amount of stress on

the rock that make up the earth's crust

causing it to separate

let's zoom in closer to the earth's

crust located below the sea where this

extension folding is taking place

magma from earth's interior exploits the

extension faults and oozes out onto the

sea floor

[Music]

occasionally a sudden influx of magma

into chambers below the surface caused

massive eruption cycles to develop along

this fault

it's these eruptions that create

volcanic massive sulfide deposits this

type of deposition occurred in ancient

seas since the dawn of time billions of

years ago and continued to form to this

day

as these violent eruptions occur the

ejected material of ash and rock settle

to the bottom creating what is known as

a volcanic pile

this pile can extend tens of kilometers

from the volcanic center the coarser

material is located closest to the

volcano while the finer material drifts

further away

the pile grows less thick as it extends

further from the eruption center

these eruptions create negative pressure

causing sea water to be drawn through

the surrounding muds and underlying

rocks as it makes its way toward the

base of the volcano along the way this

water dissolves minerals within these

muds rocks and magma becoming a

mineral-rich hydrothermal fluid

the dissolved metals include copper gold

lead zinc silver and other elements such

as sulfur

these mineral-rich fluids are heated as

they are drawn near the magma deep below

the volcano as they rise upward they

encounter the volcanic pile getting

trapped in cracks and voids within it

some of the more energetic fluids escape

the pile and form vents known as black

smokers while other fluid is ejected

from the volcano

as the hydrothermal fluids cool and

encounter changes in chemistry within

the volcanic pile and in the sea water

they begin to drop out the dissolved

metals

copper and gold are the first then lead

zinc and silver as the fluids continue

to cool

this creates zonation of the metals

copper and gold deposits are located

deeper in the pile or closer to the vent

while the other metals are deposited

higher up in the pile and further from

the vent these deposits form over tens

to hundreds of thousands of years

once the eruptions cease and we return

to a much less violent period of magma

oozing from the extension faults onto

the sea floor sediments have time to

accumulate and bury the volcanic pile

after some time we may have another

period of violent volcanic eruption

caused by another sudden influx of magma

this creates a new volcanic pile above

the previous one and the process repeats

until the extension faulting ceases in

that area

as a result vms deposits can occur

laterally along the length of the

extension faulting and also vertically

as subsequent eruptions occur on top of

the sedimentary sequence

uplifting due to continental collision

eventually move the rock containing

these deposits upward exposing it to the

forces of erosion once eroded it will be

transported back to the ocean in the

form of the sediments that will

eventually be scavenged to repeat the

cycle once again

an example of a prolific area for vms

deposition is the flinfland vms belt

located in eastern saskatchewan

these deposits provided the metals for

the hudson bay mining and smelting

company that operated for almost a

century in that area

the search goes on for other vms

deposits

we hope you enjoyed this video and that

it helps you to understand the processes

that form volcanic massive sulfide

deposits

thanks for watching

[Music]

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