Where are VMS deposits found?

The geological processes that form VMS deposits occur at the depths of the ocean and are associated with volcanic and/or sedimentary rocks. At sections where the Earth’s crust is thin due to faulting or separation of tectonic plates, the magma heats up the ocean floor.

What is the difference between VMS and Sedex deposits?

VMS deposits are typically massive lens-shaped bodies, underlain by discordant vein mineralization and altered volcanic rocks. SEDEX deposits are finely layered massive sulfides interbedded with shale, siltstone, or sandstone, typical of deep marine turbidites.

What are VMS minerals?

Volcanogenic massive sulfide ore deposits, also known as VMS ore deposits, are a type of metal sulfide ore deposit, mainly copper-zinc which are associated with and created by volcanic-associated hydrothermal events in submarine environments.

What is Kuroko type deposits?

Synopsis. The Kuroko deposits of Japan are predominantly massive, stratiform sulphide ores with associated underlying stockwork ores of Miocene age in the Green Tuff volcanic sequences.

What is a VMS discovery?

These VMS deposits occur worldwide, often formed in clusters around tectonic plate boundaries in areas with ancient underwater volcanic activity that can date back to around 3 billion years. These deposits are usually underlain by mineralized vein or stringer sulfide footwall stockwork and hydrothermal alteration.

How are VMS mined?

Black and white smokers expel this seawater back to the surface. Black and white smokers exhale a mineral rich-plume that spreads out over the ocean floor. As it moves farther and farther away from its heat source, the plume precipitates minerals onto the ocean floor.

How is VMS formed?

VMS deposits form at or near the seafloor in submarine volcanic environments containing metal-enriched fluids associated with seafloor hydrothermal convection related to spreading centers.

What is VMS geology?

Volcanogenic massive sulfide (VMS) and sedimentary-exhalative (SEDEX) ore deposits are stratiform or stratabound accumulations of sulfide minerals that were precipitated on or near the seafloor at submarine hydrothermal vents. From: Encyclopedia of Geology (Second Edition), 2021.

What is Kuroko type of deposit How did this deposit form?

Kuroko deposits (Model 28a; Singer, 1986b) are typically developed in intermediate to felsic volcanic rock and are generally interpreted to have formed in extensional environments associated with arc volcanism. They are commonly high grade and can be very large.

How are VMS formed?

VMS deposits commonly form along submarine tectonic plate boundaries such as mid-ocean ridges and subduction-relating settings such as ▶volcanic arcs and ▶back-arc basins.

How do Sedex deposits form?

SEDEX deposits most likely formed from oxidized and therefore H2S-poor fluids generated in geopressured hydrothermal reservoirs within syn-rift clastic (and evaporitic) sediments sealed by fine-grained marine sediments.

What is stratiform deposit?

In mineral deposit: Stratiform deposits. A final class of hydrothermal deposit is called stratiform because the ore minerals are always confined within specific strata and are distributed in a manner that resembles particles in a sedimentary rock.

Can Platinum be found in a skarn deposit?

The occurrence of platinum group elements is reported in some skarns (e.g. Knopf, 1942). These deposits have not been well documented in the literature and most appear to represent metasomatism of ultramafic rocks (e.g. Yu, 1985).

How is skarn deposit formed?

Skarn-type deposits are formed in a similar process to porphyry orebodies. Skarn deposits are developed due to replacement, alteration, and contact metasomatism of the surrounding country rocks by ore-bearing hydrothermal solution adjacent to a mafic, ultramafic, felsic, or granitic intrusive body.

What is the difference between stratiform and stratabound?

The terms stratiform orebody and stratabound orebody are defined and it is suggested that stratiform orebodies are a particular form of stratabound orebodies. The former may be subdivided into sedimentary, volcanic, hypabyssal, vein, re- placement and metamorphic types.

What is the most precious mineral found below the ground?

Diamonds were known in India 2300 years ago. Diamonds formed between 120-200 kms or 75-120 miles below the Earth’s surface.

What is Greisen deposit?

Greisen deposits consist of disseminated cassiterite and cassiterite-bearing veinlets, stockworks, lenses, pipes, and breccia (fig. 3) in gangue composed of quartz, mica, fluorite, and topaz.

What is Scarn deposit?

The skarn deposits that are considered economically important for containing valuable metals are a result of large-scale metasomatism, where the composition of fluid controls the skarn and its ore mineralogy. They are relatively coarser grained and do not reflect the composition of protolith or surrounding rocks.