MINEBK00806

• County: Pitkin
• Volume: 8
• Document: Inspectr
• Suffix: A

GEOLOGY. ,
3
}sere is n good geological survey of the district made by Spurr of the
i
U.S.C.S.
Tho ore bodies occur in the'Cnrhninferoun~fnrrmtinn principally in the
contact bstt:eon the hro:vn line nr Lendville dolor.3lteCctndathefb>bue}lime.
The are tfodies of the Durant-Anpenr&.nre found on the east limb of the
;Aspen Lit.synclinerwhich becor.~e.^. very steep n little below surfacerturn-
ling dovrn so as to become vertical rand even overturning locally ao as
to dip to the eant.After t$is steepening the beds recover and assume a
iflattor dip to the rreat.Iiear change of dip the Aspen fault in developed
vertical vrith a alight throw. Piest of the ltnpen fault another fault be-
',longing to name systera in developed called the Schiller,
:The ore in c}:iefly found in .a narrow vertical zone batvreon the aspen and
', Contact fnultn..blany other minor faults }wove. been developed which also
!~}tave afforded favorable placer for the deposition of large pro bodies .
The ore is nearly always found in t}:n dolomite nt the intersection of
one or more of these fnultn vrith tar Contact fault. r
T}te ore.n in' the Durant varyrhotF, in coraponitiott and quality. A large
amount of oxidized arc. has been taY.en out from cror}an,;s near surface,
the srtme changing to sulp}:ides •rrith dept}t,though Home oxidized ores
are to be found in ]saver eror}:in};n, i7te ore is chiefly an argentiferous
I galonarwhich har, re}ilnced tho dolomite and limestone to a greater or
I
j less extent. In some of the ores the silver occurs in the form of
arKehtite ar nulpi'.idc. There in also considerable sulp}tide and car-
~ borate of zinc.
TA.e Schiller workings lie vrest of the Durant and consequently the
ore horizon is lntver dovrn.
The A.J.workingn are a] no run on th (:orttact fault betwer+rt the dolomite
and blue limerporphyry and shale are to be seen same being due to
crown faulting.
~ GoinF; crust on Aspen bit. we find the Sara Jane and, Saddle Pock faults
along whic~re is-found and being on the went limb of the Aapen'Lit.
synoline. An intrusive porphyryrcoc~anly known an quartz porphyry i2