Deseret evening news. [volume] (Great Salt Lake City [Utah]) 1867-1920, 1904-12-24
SPURR'S REPORT
ON GOLDFIELD.
eminent Government GeOIoeiSt
Presents Some interesting Facts
About New District
VISITED CAMP IN LAST MONTH.
A. ColdGeld Aurierous Deposits Oc-
cur 10 RhyOlites and Audesltes--
Other Geological Conditions.


The new camp OF Gold0eld In Ne
voda was revisited IN November Of
me year By Mr. j. ~ Spur, OF the
UNITED states geological survey TINS
district lies about 23la miles south OF
1onopah. and was located late IN the
tpring OF 1908 shortly after the dis
ooyery Of gold In this district it was
visited by Mr.. spur A little work was
then in progress on what is now known
AZ Columbia mountain, but up to that
time no good strikes had been made
In January and February, 1904 how
ever rich finds were made M cerlAlh
snots south Of Columbia mountain Inc
district has now an approximate popu,
iatlon OF 5000. The town OF Goldheld
hns eprung NJ, and number OF small
er adjacent camps have been eslhb-
llshed' II is estimated that up to the
nresont time about S2,0OOO00 worth OF
ore has been shipped from the district
Most OF these shipments nave peell
made In the last FIVE months.
The district Is bounded on the west
IN part by a lava capped mesa, inc
erosion II which has laid bare the IN
derlylng gold-beerlng rock, The aurll-
erous region Is characterized by numer-
GUS low, irregular ridges standing out
from the lower and more nearly Level
surface. These ridges owe their origin
10 hard reefs OF quartz which form
their crests. Their resistance TO ero-
sion has left them protrudlny thus
above the general elevation and In
these quarts roofs the Nuriferous de-
posits are found,
Columbia mountain Is the most prom
inent OF these ridges, and some notes
on Its geology were made public by
Mr. Spur last year. I'm bulletin 223
published by the United States geo
logical survey Near the south end Of
the ridge the rock is largely alaskite
ian igneous rock consisting Of quartz
and feldmar), which Is sometimes Of
granite structure, and sometimes very
fine-gslined even resembling quart
Elte. White mica or muscovlte Is
sometimes present, and pure quartz
veins or dlkes, OF similar origin, also
occur. These alaskitic rocks are intru-
sive into a dark slliceous rock Jas-
popld) which Is probably the result
OF the slllclncatlon OF an original lime
stone. One may suspect that this
limestone was paloo2oic, and that the
alaskite IL also OF ancient geological
age on the north end OF the noun
tain the rock Is n very much altered
rhyollte, IN this rhyollto are broad
masses Of white TO purplish and red
dish shorty quartz, which extend ir-
regularly IN q northerly direction This
quartz Is simply q highly slicihed
rhyollte The silclfed areas have III
defined walls, and the highly mineral
iIed portions which they enclose are
very irregular.
INVESTIGATED LARGE AREA.
on his last visit Mr. Spurr took notes
over an extended area, and made in
teresting additions TO his knowledge Of
the geology Of tho district. The area
OF known ore bodies has spread since
last year 80 far beyond Columbia
mountain that values are now found
over an urea about six miles square.
The most productive area measures
two TO two aud 0ne-half miles I'm either
direction. The chief mines mt the pres
ent time are the Jumbo, the Combna-
ton the January. and the Florence all
grouped together about a mile south
OF the southeast end OF Columbia
mountain Some nine miles southeast Of
Columbia mountain Is the Diamondheld
group, including the Vernal, the Quart
zlte, and Black Butte, from which ship
ments have also been made. Other ore
deposits have been developed IN various
parts OF the field,
ROCKS OF VOLCANIC ORIGIN,
The rocks IN that part OF the field
visited by Mr. Spur on his last trip
1.-THE region Of Columbia mountain, Dlg-
mondfeld, and the Jumbo group Of
mines) we found to be almost
entirely volcanic, consisting Of rhyo-
lites, rhyolIte tuns, andosltes and ba-
salts, ell probably Of Tortlary age The
alaskite and jasperoid Of Columbia
mountain are hardly represented In the
surrounding district although at the
Tonopah Club (mlne) patch OF prob
able jasperoid (sllIctied shaly lime
Bt0ne), I'm this case constituting the ore,
was seen, The predominant rocks are
abundant rhyOlltes and andcsItes, while
basalt is rare. One andeslte examined
mcroscoplcany from near the Tonopah
Club is a hornblonde andeste, resem-
bling the early andesite al Tonopah, a
patch OF basalt from near the Florence
IL an augite basalt, Ike the hasalt OF
Slebert mountain at Touopah. The
rhyollte resembles the rhyolite OF the
Gold Mountain district, which lies about
four miles south OF Tonopah ON the
road between Tonopah and GoldGeld.
and this Gold Mountain rhyolte. again,
resembles closely some OF the phases Of
the earlier (dacitic) rhyolite at Tono,
pah. The relative age OF the rocks At
Goldhelds has not been determined. but
It probably corresponds TO that OF SINH
lar rocks at Tonopah,
RHYOLITES AND ANDESITES.
At Goldhed the ores occur In both
rhyolites and andesites, showing that
naturalization occurred subsequent 20
the eruption Of both lavas. At Gold
Mountain the deposition Of the ores evil
IDENTIFY followed the eruption Of the
rhyolltes, and az Tonopah the eruption
OF the earlier (dacitic) rhyolItes was
succeeded by a period Of naturalization
which produced Irregular veins that
frequently carry larger proportion of
sold than the locally more important
veins formed after the eruption OF the
early andesite. There is therefore the
possibility that the Goldheld deposits
are Identical In origin with the later
series OF veins az T0nopah. Indeed
there are al Tonopah, IN one place al
least, mineralzed quartz reefs IN rhyo-
lite tufts that have the same peculiar
characteristics as the tufts OF the Cold
Geld reefs; and assays OF these Tono-
pah deposits, as was known 20 Mr.
spurr two years ago, have shown a
moderate amount Of gold and silver.
NO DEFINITE VEINS.
AZ Goldheld there are no definite
veins. The outcrops OF the quartz bod.
ies are Irregular struggling branching