J.S.
Mason - Central Wales
Orefield: Chalcopyrite Disease
|
|
Chalcopyrite-disease is a
controversial texture. Some have attributed it to exsolution, others to
diffusion. In these samples, from Erglodd mine, dark grey early
sphalerite is crowded with orientated chalcopyrite needles and also
rows of siegenite grains (L, unusual). At Erglodd, the argument for
diffusion/ replacement stands strong. The texture is not ubiquitous,
but is restricted to sphalerite adjacent to later chalcopyrite veins
(R).
Chalcopyrite-disease
is restricted to the early, complex polymetallic
mineralisation. Later sphalerites are squeaky-clean in contrast.
|
BACK
TO CENTRAL WALES MENU
|