Geomineralisation & Lucas Setijadji
In response to Lucas Setajadji's 4-Apr-2000 inquiry about
Carlin-type mineralization in the East Asian Region and in particular
Newmont's Mesel deposit in Sulawesi. I think you have to get back to
trying to better define exactly what you mean by "Carlin-type"
mineralization. If the backbone of your definition is relatively
low-temperature Au replacement systems in calcareous host rocks which
also show anomalous As, Sb, Hg, Tl etc. then there are numerous
occurrences around the world, Mesel being one of them and others
including the Bau District (Sarawak); El Hueso-Jeronimo (Portrillos
District, Chile), Barney's Canyon and Melco Deposits (Bingam Canyon
District, Utah); Star Pointer auriferous jasperoids (Ely or Robinson
District, NV), Puirsima-Concepcion (Yauricocha District, central Peru)
among numerous others that get lumped together with the bona-fide
classic systems and trends typical of the Late Eocene to Early Oligocene
tectonic development of north-central Nevada. As Eric Seedorf put so
well in his 1991 GSN Symposium Paper: there are "Carlin-type" deposits
and "Carlin-like" deposits. In other words, "Sediment-Hosted" and
"Carlin-type" are NOT NECESSARILY equivalent terms. Distinguishing
between them is critical in guiding your exploration.
I would take a harder look at comparing the tectonic settings to
make sure your "East Asian region" is indeed similar to this specific
period of tectonic evolution in Nevada. - (NOTE: It wasn't exactly a
volcanic arc if that helps). On the other hand, it is quite reasonable
to expect that typical low-sulfidation systems whose plumbing just
happened to intersect, or be dominated by, favorable stratigraphic
characteristics of local calcareous host rocks might end up as Carlin
facsimiles. Finally - the Mesel deposit (Ratatotok District, Sulawesi)
may also be referred to as a "Carlin-type" deposit (see Turner et al.,
1994, Jour. Geochem Explor. V50, p. 317-337), because Newmont's
management (and arbiters of exploration/development budgets) prefers
this terminology based on their extraordinarily successful Nevada
history. Simply put: "Carlin-type" is "music to their ears" and has
become a comfortable term everybody has heard before and even
accountants think they understand. It may just come down to semantics.
I hope this helps. Please contact me directly if you want to go into
this in greater detail.
Saludos,
---------------------------------------------------------
Carl A. "Tony" Kuehn -- IMDEX, Inc. -- IMDEX/Cascabel:
The "Un-Official Directory" of Mining Companies in Mexico
at http://www.imdex.com/ P.O. Box 65538, Tucson, AZ 85728
Tel (520) 797-1618 Fax (520) 797-3955 [log in to unmask]
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