Characteristics of Volcanogenic Massive Sulphide Deposits

Volcanic connected massive sulphide or VMS deposits take place all around the world and during the geological time column in nearly all the tectonic areas that contain submarine volcanic rocks as an essential component. Volcanogenic massive sulphide deposits are main sources of Cu and Zn and have important amounts of Au, Ag, Pb, Se, Cd, Bi, Sn as well as small quantities of other metals.

As a group, volcanogenic massive sulphide deposits are made up of very big buildups of sulphide minerals, which are over 60 percent in sulphide minerals, which take place in lens like or tabular bodies parallel to the volcanic bedding.

They are by and large underlain by a footwall stock work of vein and stringer sulphide mineralization and hydrothermal modification. They might take place in any rock type, but the major hosts are volcanic rocks and fine grained, rich in clay sediments. The deposits are made up of ubiquitous iron sulphide such as pyrite and pyrrhotite, along with chalcopyrite, sphalerite, and galena as the most important economic minerals. Barite and cherty silica are ordinary gangue accessory minerals.

Volcanogenic massive sulphide deposits are inclined to occurring in districts. Up to a couple dozen deposits may be bunched in an area of a few tens of square kilometers. Known volcanogenic massive sulphide districts are fine hunting grounds for fresh findings. Deposits that are in a specific district are inclined to having comparable metal percentages and a rather fine range in composition. In any given area, deposits haven a tendency of ranging in sizes from under one million tonnes to some tens of millions of tonnes and nearly all the deposits at the small end of the range and only a small amount of bigger deposits.