GENERAL41483

• Permit No: M1995097
• IBM Index Class Name: General Documents
• Doc Name: BIBLIOGRAPHY WITH INTRODUCTION GLOSSARY OF TERMS AND LIST OF MINERALS
• Media Type: D
• Archive: No

S PURR MONOGRAPH
[Castle Butte] in the Aspen, Durant, Camp Bird, Justice
and other mines on Aspen mountain; and in places the
entire Leadville is mineralized, as in the Bonnybel mine
[Tourtellotte Park]. However, most ore throughout the
district occurs in the vicinity of the Weber [Belden]
shales, near its contact with underlying rocks, and in
turn most of it in this contact, which is the Silver
fault [breccia I ~ II in the Smuggler mine].
Process of mineralization, pp. 233-234. Ore occurs
along fractures and faults, extending into wall rocks
varying distances by the process of replacement,
commonly along micro-fractures. Replacement is also
proven by the presence of mineralized fossils. The only
other principal mechanism is the precipitation of
sulfides and other minerals in preexisting cavities.
Cause of ore precipitation, pp. 234-235. One important
factor is that orebodies are generally found at the
intersection of two faults, one dipping steeply [the
breccias] but the other much flatter [Della-Smuggler
system]. If the source was ascending hot springs, it
may be further supposed that these springs rose along
the steep to vertical fault." Spurr speculates that
different solutions were channeled by the flatter
faults, and that the mingling of these solutions
resulted in widespread sulfide mineralization at these
intersections. The most likely agent for ore
precipitation is hydrogen sulfide (HIS) resulting from
the decomposition of organic material in Weber [Belden]
shales.'I
Original source of metals, pp. 235-236. The deposition
of metals was but one of numerous changes resulting from
the uplift of rocks in a limited area, among the other
effects being faulting, with principal ore deposition
along these faults. The probable cause of this uplift
was a body of "eruptive" rock not now exposed." Surface
waters descended along fractures, came in contact with
heated rock, became heated itself, and dissolved metals
from the intrusive. Barium and most metals found in
Breccia. There is much discussion early in this section, pp. 206-
216, omitted here, regarding dolomitization, an initial stage of
mineralization, and specifically the Glenwood Springs hot springs, pp.
212-216.
'I HIS is a strong reducing agent.
'~ A major difference with the current terminology. Igneous rock
that does not reach the surface is now regarded as an intrusive rock;
"eruptive" or extrusive rocks are basalts and other volcanics.
Bruce A. Collins - 7 - BIBLIOGRAPHY