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Geological Survey of Canada





















Gold placers on the northeast Newfoundland inner shelf

In the early 1900s the Canada-Newfoundland Co-operation Agreement on Mineral Development funded a program of surveys on the northeast Newfoundland Shelf. The research focus was the inner shelf between White Bay and Cape Freels. The surveys, onshore and offshore, took place from 1990-1993. The conclusions were contained in GSC Bulletin 595.

Northeast Newfoundland inner shelf

Marine Gold Placers on the northeast Newfoundland Inner Shelf

GSC Bulletin 595

J. Shaw, D.L. Forbes, and K. A. Edwardson

Abstract The inner Northeast Newfoundland Shelf and coast were mapped to determine the potential of the region to host marine placer minerals, particularly gold.  Five units were mapped:  Unit 1 - bedrock;  Unit 2 - glacial diamicton;  Unit 3 - glacial-marine mud;  Unit 4 - postglacial mud;  and Unit 5 - postglacial sand and gravel.  These units occur in five zones defined by depth:  (1)  deep offshore basins contain thick deposits of glacial-marine gravelly sandy mud overlain by postglacial mud;  (2)  in shallower water, sediments have been winnowed by currents;  (3)  above 200 m depth the seabed has been furrowed and pitted by grounded icebergs;  (4)  above 70 m the seabed is highly mobile;  (5) the intertidal /supratidal zone is narrow and rocky, except along the Straight Shore.  Relative sea level has been falling throughout postglacial time in the west, but in the east it dropped to -20 m about 8.7 ka before rising again.  Fiords contain thick deposits of glacial-marine mud, capped by thin postglacial mud deposits.  Shallow, outer-fiord areas are heavily imprinted by iceberg furrows and pits.  In zone 4, which has the highest potential to host marine placers, extensive gravel and sand deposits occur on the wide, shallow inner shelf between Cape Freels and Hamilton Sound, but no gold has been found in samples, likely due to a lack of gold mineralisation onshore.  Some gold was found at Deer Cove in Baie Verte, although the volume is small and the grades low.
 
Comments The northeast Newfoundland inner shelf continues to be imprinted by icebergs that drift south in the Labrador current. The bergs disturb the sea floor, creating intersecting furrows. However, there is also a population of ancient furrows. In some coastal areas, the icebergs become grounded for long periods, creating circular and oval iceberg pits. The potential for gold in marine placers is limited to a few shallow, wave-dominated areas with sandy sea floors. The conceptual models shown here are from GSC Bulletin 595 and describe parts of the shelf that are narrow (top) and wide (bottom).