Volcanic Massive Sulphide Mineral Deposits - VMS
Summary
TLDRThis 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
- π Volcanic massive sulfide (VMS) deposits form from underwater volcanic eruptions along rift or spreading centers caused by extension faulting.
- π Extension faulting is driven by magmatic vortices in Earth's liquid outer core, which stress the crust, leading to separation.
- π Magma from the Earth's interior exploits these faults, oozing out onto the seafloor and creating volcanic eruptions.
- ποΈ 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.
- π¦ Seawater is drawn through muds and rocks around the volcano, dissolving minerals and forming hydrothermal fluids rich in copper, gold, lead, zinc, and sulfur.
- π₯ Hydrothermal fluids, heated by magma, rise through cracks in the volcanic pile, depositing metals like copper, gold, lead, zinc, and silver as they cool.
- βοΈ 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.
- β³ These processes occur over tens to hundreds of thousands of years, with layers of volcanic and sedimentary material building up over time.
- ποΈ 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.
- π 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 Earthβs 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 Earthβs 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
π 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.
π 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.
𧨠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.
π 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.
π¦ 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.
β 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.
π° 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.
π 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.
π 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.
π 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.
Mindmap
Keywords
π‘Volcanic Massive Sulfide (VMS) deposits
π‘Underwater volcanic eruptions
π‘Rift or spreading center
π‘Extension faulting
π‘Volcanic pile
π‘Hydrothermal fluids
π‘Black smokers
π‘Zonation of metals
π‘Continental collision
π‘Flin Flon VMS Belt
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]
you
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