occurence of Eucairite & Klockmannite

Hello friends

anybody can explain and describe which are the geologically occurence of the Cu selenides, especially Eucairite and Klockmannite?

How about nature of this deposits?
Which forming-type rock may be found in such deposits & environment?

Skarn iron ore, Diorites, others?

Are Diorites related to genesis of copper selenides, as Eucairite and Klockmannite?

Beside, how is the mineraligical asociation of Cu selenides in other deposits?

actinolite,epidote,clorite are accesory minerals?.

Perhaps I have made some confusion with my bad english, but I hope you might understand what I am trying to know!!!

thanks
Maurizio Dini

Hi! Selenides occur mainly in some kinds of hydrothermal (telethermal) deposits. These deposits are indeed often connected with the ore mineralization of some skarns, but its not a '100% rule'. So there's no strict/close relation between diorites and selenides. In the hydrothermal deposits selenides often co-occur with uranium minerals (like in Czech, Polish, German, ... deposits). Calcite (possibly also barite and fluorite) is very often companion of selenides. If in skarns (as usual), the selenide-bearing veins are surrounded by typical skarn silicate minerals: pyroxenes (diopside and hedenbergite, in general), garnets (often with grossular composition), vesuviane, sometimes indeed secondary chlorites and epidote.

Greetings!

Hello Maurizio,
Interesting details of a selenide deposit at Hope's Nose, UK can be found in a paper that can be downloaded from:

[www.minersoc.org]

starting page 485.

Regards
Chris S

Thanks Lucasz and Chris:

your contribution was really helpfull!


Lukasz, just a question;

Which geochemical process makes the differences among Telethermal and Hydrotermal deposits?

In Chile there are no relationship among Uranium mineral and Cu selenides!

There seems to be a strong correlations in the genesis of some Cu-Au deposits in arid conditions (especially in the Morado-Flamenco area-Atacama desert), and presence of Fe solutions (hematite, magnetite, specularite).

Maurizio Dini