Page 51 - Handbook of Gold Exploration and Evaluation

32 Handbook of gold exploration and evaluation

· Economic minerals, including gold, of the various lode formations may not
be located in sufficient quantity in a common drainage basin to form a viable
placer deposit.
· The incidence of indicator minerals such as rock forming silicates in a placer
is no guarantee that economic quantities of gold will be found in the alluvial
or primary lode system.
· Placer geometry changes continuously due to structural alterations that occur
as the result of changing rates of precipitation and run-off in the short term
and by tectonic uplift, fluctuating base levels and climatic cyclicity and
change in the long term.

1.2 Gold through the ages

In tracing the growth of scientific thought from its beginnings to present-day
levels of understanding, it is important to note how many modern scientific
concepts had already been foreshadowed and argued by ancient philosophers.
Throughout history there have always been people who have sought explana-
tions for how the Universe was formed, how it works and man's place in it. The
Ancient Greeks were amongst the first to investigate the evolution and structure
of the Earth. More factual than the Greeks, the Romans were probably the first
to organise gold mining and exploration in a systematic fashion. Asian and
Eastern scientists were in many ways more inventive than other world scientists
were. Many significant scientific discoveries were made in China centuries or
even millennia before they were made in the West. Important observations in
physics, mathematics and medicine were made in India and clearly, scientific
progress has never been impeded by genetic constraints; black, white, yellow
and all races regardless of colour have made major scientific discoveries.
Historically, only the religions, regardless of creed have imposed barriers to
progress, either rejecting harshly or accepting only slowly and with great
reluctance any ideas contrary to their particular religious dogma.

1.2.1 Gold in ancient times

Stone-Age people fashioned their tools and weapons from natural materials until
about 10,000 years ago when atmospheric warming at the end of the last great
ice age gave rise to melting of the ice caps and the widespread concentration of
alluvial gold in streambeds of the day. Prehistoric man relied heavily upon meat
and followed migrating reindeer as the ice sheets retreated more or less simul-
taneously in the Middle East, Orient and the Americas. Stone-Age implements
were gradually replaced by tools made of native metals, (mainly copper and
meteoric iron) which could be hammered into desired shapes. Gold was
probably gathered for ornamental purposes because of its unique colour, and a
few nuggets have been found in some later-period graves (Smirnov, 1962). The