Abstract

The Hudson Platform embraces an area of 375,000 square miles of which the greater part (235,000 square miles) is covered by water of Hudson and James Bays. It is represented onshore in the south by the Hudson Bay Lowlands (125,000 square miles) and in the north by the Southampton Plain (15,000 square miles).

Two Phanerozoic sedimentary basins are present within the Hudson Platform: the Moose River Basin in the southern part of the Hudson Bay Lowlands, and the Hudson Bay Basin of which only a small part is exposed in the northern Lowlands and on Southampton, Coats and Mansel Islands. The two basins are separated by a northeast trending positive area, the Cape Henrietta Maria Arch, where Archean and Proterozoic rocks are exposed in several inliers which are surrounded by a thin veneer of Silurian rocks.

In the Moose River Basin, Ordovician, Silurian, Devonian and Lower Cretaceous rocks are present and these have a total thickness of about 2,500 feet in the central part of the basin. In the Hudson Bay Basin rocks of Ordovician, Silurian and Devonian ages are represented in the Hudson Bay Lowlands, and rocks of Ordovician and Silurian ages are present on Southampton, Coats and Mansel Islands. The total succession in the water-covered central part of the latter basin is estimated by geophysical studies to be about 6,000 feet thick.

Ordovician rocks within the Hudson Platform underlie an area of about 360,000 square miles and have a volume of about 55,000 cubic miles. Three types of exploration targets are worthy of consideration: (1) unconformity traps, (2) fault traps, and (3) biohermal structures. Estimated possible potential of these rocks is 550 million barrels of oil and 3.3 trillion cubic feet of gas, assuming a yield of 10,000 barrels per cubic mile of sedimentary rocks.

Silurian rocks underlie an area of about 331,000 square miles and have a volume of 98,000 cubic miles. Biohermal structures in the Attawapiskat Formation are the main target both in the onshore and offshore regions. Assuming an arbitrary yield of 15,000 barrels of oil per cubic mile of sediment, Silurian rocks have a potential of 1.4 billion barrels of oil and 8.4 trillion cubic feet of gas.

Devonian rocks underlie an area of about 90,000 square miles and have a volume of 16,000 cubic miles. The more promising of these rocks are the Moose River, Murray Island and Williams Island Formations which are coeval and lithologically similar to producing carbonate reservoirs in the Michigan Basin. Estimated possible potential is 320 million barrels of oil and 1.9 trillion cubic feet of gas, assuming an arbitrary yield of 20,000 barrels of oil per cubic mile of sedimentary rocks.

The two basins of the Hudson Platform are compared with the productive Michigan Basin, pointing out gross similarities and differences. In addition, the more promising as well as the adverse geological factors affecting the petroleum possibilities of the Hudson Platform are discussed.