The indicator., 1897-08-14


'Thc placer gold deposits OF the
Klondyke and Yukon river BASIN gen
orally, are similar in origin. in the con
ditions under which the gold is found
and in largcneSs of yield, to the placers
which have been mined in the AMOR
and Lena river basins in Sibcria for
fifty and more years past. In all, eN-
cept as TO the perpetually frozen con
dition of the aurifcrous sands and bar
reii overburden. these Arctic placcrs
are similar to the Australian placers.
are similar to the Idaho and Montana
placers such MS the famous Alder
Gulch, near Helena and to some of
the gulch and ravinc placcrs of Cali
fornin-for example, Rich Gulch. in
talaveras county: Auburn tnvine. in
Placer county. and Grcenhorn and
Humbng creeks, in Siskiyou county.
Everywhere the origin of the placer
gold is the same. 1t is gold liberated
by the erosive agencies of fros, AMI
running water from It's rock matl'i. IL
the lodes. principally quartz. winch
have been formed by the chemical ac-
ton of mineral-ladrn water ascending
from the heated interior of the earth
through assures and fractured zones
of the outer crust. The action of frost
Is principally in breaking the lodes in
place into fragments. which are then
moved away by running water, thus
exposing fresh rock surfaces To the
frost. In running water in the stream
channels the grinding together of the
rock fragments gradually wears away
and liberates the gold. In accomplish
ing this, the brttlcness of the rock
matriN. the toughness of the gold re-
slsting abra sion. and the surfaces Of
= IL t,., y.,lI
and rock come together all facilitate
the freeing of the gold. which. once
freed. works its way downward to-
ward the underlying rock. and. once
there. stops at the first Inequality in
the surface. Its movement then is
very little. for very small PARTICLES of
gold cannot he moved by quite strong
currents of water over the slightest
obstruction. 1t only moves and
changes position, always downward rs
the bedrock of the stream channel
wears slowly deeper ill it reaches n
level where il 10 longer cuts the rock
deeper. hut spends It's crosivc energy
In widening the channel portion of its
basin Thus are made Hat valleys of
erosion many times wider than the
flowing stream. Gold does not flow or
float. excepting only very thin. light
gold. Even these will settle in such
moderately strong currents as will
wash coarse sand away. Gold grains
and nuggets are only moved by run
ming water while they are portions of
comparatively large rock Fragments
pebbles or bouldcrs, Just MS soon as
the rock fragment becomes so dimn-
ished in volume by abrasion thar its
normal specific gravity becomes in
creased by the higher specific gravity
of the attached gold particle, its nove-
ment by the running wafer becomes
more and more retarded, until the gold
particle, finally liberated, stops and
Joins the slowly growing accumulation
At the bottom of the stream cilunri
While its once matrix is swept Onward
~ sand to the sea.
"Glaciers have comparatively little
10 do with the liberation of gold from
its rock malriN. The glacial epoch in
all the noted placer gold localities takes
in but an insignificant fraction of the
Tine that has been occupied in the for
nation of the placcrs from the lOdcs. In
California the evidence of the placcrs
themselves is conclusive as to their al
most exclusive formation by frost and
stream erosion alone. The California
placers commenced to form us early as
what biologists term the crctnceous
period and their formation was con
tlnuous through the enormous intervals
of time represented by the Eoceuc, Mi
occnc, Pliocene. and throughout the
much shorter interval elapSing since
the close of the Plioccne down to and
including the present time. Of all these
enormous time intervals of gold accu-
mutation, glacial action has only GOV
cred Il small fraction Of the last and
shortest-the Postplioccnc period Ii
only covered n small portion of the ter
ritory of the placers. contributing pos
slbly an insignificant fraction of the
gold that has since been mined ont.
Siberia and Alaska represent precisely
the same relative glacial phenomena.
The placers We're all practically form.
ed before the age of glacial action pre-.
ciscly as the California placers were
formed by the action of frost and run
ning water. The glacial age has follow
ed this enormously long period of
placer formation. and holding oil in
both countries. but more particularly
Alaskn down into the present time. has
merely acted TO conserve the already
formed placers in maltcred form,
structurally and geographically. Gln-
cial action has added no more TO them
than ii did in California. The beginning
of the glacial epoch in all three locali-
lies was in the age of The mastodon and
mammoth. MS may very surely be infer
rcd from the perfect frozen bodies of
the latter which have been discovered
in siberia during the last century.
These locked up In the lee at the he
ginning of the epoch only now gratlu-
ally rcappear with the slow retreat of
the ice sheet nOrthward. The period of
Siberia and Alaska with The beginning
of the glacial epoch in age of the mas
todon and mammoth. for we find the
fossil bones of these animals in the
placers which frozen then are only now
being thawcd out in mining operations.
In California we find fossil remains of
the mastodon in the placer deposits of
The old buried rivers. but the long-ago
northern retreat of the lee has given
the time period during which the liv-
ing rivers and streams have made adj
ditlonal pacers. both indirectly from
portions of the old buried river placcrs
and directly from the breaking down
of fresh portions OF the collaborating
lodcs.
"'rhere is nothing phenomenal in the
yield of the Klondykc plnccrs. Cali
fornin. Australia. Montana, Idaho and
Silprin have all had MS extensive and
rich placers as the llondyke In
fact, there have been numbers of rich
or ones. These. long since worked out,
excepting in Siberia. are for the mo-
Inent being forgotten in the hopes and
anticipation from the one, hitherto
unknown. now in public view. II does
not require any heretofore unknown
sources of gold to have made the Klon-
dyke placers. II does not require any
heretofore unknown richness of known
sources to have made them. Just MS
everywhere else. lode deposits of gold
ores, prObnbly ltInriZ no ricller than