The aim of this paper is to present a concept or model regarding a
particular geological environment where gold orebodies occur in the Pine
Creek Geosyncline and indeed in many other pans of the world. The name GIGIACS (an acronym for Gold In Greywacke In Anticlinal
CrestS) is proposed to label this concept or model. The name Saddle Reefs (which has been in use for many years)
is used for gold-bearing quartz veins which often occur in
conjunction with Gigiacs. Simple patterns formed by this type of mineralisation at the surface due
to different configurations are illustrated. Some examples of Gigiacs and associated saddle reefs are presented
from the Pine Creek Geosyncline together with examples from other parts
of the world. This concept has been used successfully as an exploration tool and five
examples are given. The terms Gicsiacs (for Gold In Carbonaceous Shale In Anticlinal
CrestS) and Giliacs (for Gold In Limestone In Anticlinal CrestS) are also
used.