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The sedimentary appearance of the thin laminations led to early interpretations that the deposits formed exclusively or mainly by exhalative processes onto the seafloor, hence the term SEDEX. However, recent study of numerous deposits indicates that shallow subsurface replacement is also an important process, in several deposits the predominant ...
Sedimentary exhalative (SEDEX) deposits account for 40% of total world zinc production, 60% of lead and a significant proportion of silver. Despite their economic importance however, sedex deposits are relatively rare. A worldwide compilation of sedex deposits indicates that about 70 are known, of which 24 have been or are being mined.
For example, sedimentary exhalative deposits (SEDEX), are a class of ore deposit formed on the sea floor (sedimentary) by exhalation of brines into seawater (exhalative), causing chemical precipitation of ore minerals when the brine cools, mixes with sea water, and loses its metal carrying capacity.
Marine sediment, or ocean sediment, or seafloor sediment, are deposits of insoluble particles that have accumulated on the seafloor.These particles either have their origins in soil and rocks and have been transported from the land to the sea, mainly by rivers but also by dust carried by wind and by the flow of glaciers into the sea, or they are biogenic deposits from marine organisms or from ...
VMS deposits are a major source of zinc (Zn), copper (Cu), lead (Pb), silver (Ag), and gold (Au). [33] Gold ore (size: 7.5 × 6.1 × 4.1 cm) Sedimentary exhalative sulphide deposits (SEDEX) are a copper sulphide ore which form in the same manor as VMS from metal rich brine but are hosted within sedimentary rocks and are not directly related to ...
A diagram of various depositional environments. In geology, depositional environment or sedimentary environment describes the combination of physical, chemical, and biological processes associated with the deposition of a particular type of sediment and, therefore, the rock types that will be formed after lithification, if the sediment is preserved in the rock record.
VMS deposits have a wide variety of morphologies, with mound shaped and bowl shaped deposits most typical. The bowl-shaped formations formed due to venting of hydrothermal solutions into submarine depressions - in many cases, this type of deposit can be confused with sedimentary exhalative deposits. The mound-shaped deposits formed in a way ...
The key criteria for BHT ore deposits are; [11] Association with major sedimentary packages of sandstone and siltstone protoliths sequences in highly disturbed metamorphic terranes. A Proterozoic age is considered important, as no other major SEDEX lead-zinc deposits of this style are known from the Phanerozoic or Archean.