The story of
Leduc emerged in large part due to the Alberta marine environment some 400
million years ago. Alberta was once covered by ancient shallow seas which were
ideal for the growth of reefs during the late Devonian period. These warm
tropical waters supported a myriad of organisms that are now preserved as
fossils. As these shallow seas covered large parts of the continent that are now
dry lands, they became a breeding ground for coral reefs to grow. Specifically,
Leduc would become the location of a great coral reef containing oil.
often found in the sediments laid down in ancient seas, in sedimentary rocks.
Within and around the Devonian Reefs, oil began in the remains of various plants
and animals that lived in the sea or washed down into it with mud from streams
and rivers. This organic residue settled to the bottom of the ancient seas and
accumulated, layer upon layer. As these layers accumulated over millions of
years, the organic materials were forced into adjacent porous coral reefs. As a
result, porous rock growth decreased and the organic materials transformed into
oil and natural gas due to pressure, heat and other geological factors. These
layers managed to seal the corals (due to the porous rock's tiny holes) into
large pockets of pressurized oil and natural gas waiting to be tapped.
reefs would lead to Imperial Oil's discovery in 1947 of petroleum in a buried
reef at Leduc, triggering an intense search for Devonian Reefs in the subsurface
of Western Canada.