Page Index
Base Metal Exploration 1972 - 1990
1955 Magnetic Kink
1959 Basic Sills
1969 Gravity Survey
1970 Mapping and Magnetic Survey
1970 Seismic Profiles
1972 Stream Sediment Sampling
1972 Seismic Survey
1973 Magnetic Anomaly
1980 Hydrocarbon Drill Holes
1991 Gravity Profiles
1993 Sill Sampling
1994 Anomaly Cause
Prior to 1994 the interest for exploration
development and production of base metals was non-existent in
this northern area. The emphasis was on gas and oil exploration
which legacy created the present regional infrastructure. There
is no record of ground exploration during this period other than
for gas and oil, except for an unpublished Mississippi Valley
type lead/zinc exploration program (1972) in part of the middle
Horton River drainage.
The only clue at that time to an anomalous
condition in the Darnley Bay area was a decided “kink” in the
declination of the earth’s magnetic field shown for navigation
purposes on the National Topographic maps of Canada.
International Nickel
Limited prospected in the area of the magnetic kink. It reported
on lignite coal seams and outcrops of basic sills.
The Geological Survey of Canada (GSC)
conducted a regional gravity survey in 1969 as part of its
national gravity coverage providing readings at 2.5 km (1.55
miles) to 20 km (12.4 miles) intervals over and surrounding the
area of Paulatuk; it discovered the gravity anomaly.
Ref: Bouger Gravity Map 119
The Dominion Observatory published the Inuvik-Horton River map
sheet. Northgate Exploration Limited flew a helicopter-borne
magnetic survey over the most intensive part of the gravity
anomaly and detected a coincident magnetic anomaly.
A number of seismic profiles were
surveyed in the early 1970’s on the western portion of the AMI,
most of these are located on the western sedimentary platform.
They identified a deep 6-800 metres trough (NW) along the west
margin of the dyke swarm, the significance of which is still
unknown.
The exploration discovery and
development of the Pine Point Pb/Zn deposits led to the
search for other Mississippi Valley type deposits in the
same lithology as in the Darnley Bay area. Cordilleran
Engineering Ltd. carried out a sampling program south of
the Paulatuk area in search of Mississippi Valley type
Pb, Zn deposits. A total of 837 samples were analyzed.
Arjay Kirker Resources Limited shot a short
seismic line over the west side of the anomaly for petroleum
exploration purposes.
The GSC undertook an aeromagnetic
survey over the positive gravity anomaly. The survey was
flown along north-south oriented flight lines spaced 2
km apart, at a constant height of 610 metres (2,000
feet) above sea level. It defined the positive magnetic
anomaly (detected by Northgate in 1970) at 1200 nT
amplitude, coincident with the gravity anomaly.
Ref: Riddihough and Hainer 1972
The Geological Survey of Canada
Memoir 430 report includes a list of the widespread hydrocarbon
holes drilled in the regional area of the gravity anomaly for
oil and gas.
In 1980 a regional correlation network was established based
upon radioactivity well logs (or electric logs in the case of
older wells) and examination of all available drill cuttings.
All 79 wells are listed in Appendix 3 of the Memoir 430, long
with basic geological data.
The GSC surveyed two gravity profiles
over the anomaly.
The GSC collected samples from a number of
basic sills east of the anomaly that contained minor amounts of
nickel, copper, platinum, gold, silver and cobalt. These rocks
and metallics may be genetically associated with the anomaly.
The GSC suggests that the cause of
the anomaly (130mGal) may be an igneous intrusive
similar to that in the Sudbury Basin, Ontario (30 mGals),
Norilsk in Russia (25 mGals), and the Bushveld Complex
in South Africa (65 mGals).
Ref: GSC Open File Report 2789 |
