SUMMARY
 

Geological features suggest that Gillies Limit township is an extremely good candidate to host silver-arsenide vein deposits and to a lesser degree base metal sulphide mineralization.

WABANA EXPLORATIONS Inc. holds a group of 29 claims amounting to 170 units in the northern part of Gillies Limit township. The strata and geotectonic setting underlying the property is similar to the Cobalt Mining Camp which is situated a short distance to the north. Given this similarity, there is a high potential of silver-arsenide veins occurring near to or in the extensive Nipissing diabase sill that underlies the property. In addition there exits potential, as in the Cobalt camp, for base metal deposits associated with the Archean metavolcanics.

INTRODUCTION

In 1996 WABANA EXPLORATIONS Inc. of Waterloo, Ontario entered into a number of option agreements to conduct mineral exploration on properties in the Temagami and Cobalt areas of northern Ontario.

This portion covers the Gillies Limit property lies just south of the "Cobalt Camp" where silver was first discovered in 1904. This discovery led to over 60 years of exploration work in the area. Due to the Temagami Land Caution, the area has received little attention over the past 25 years. The opening of the caution in stages over the past 3 years has led to renewed interest and in September 1996 led to one of the largest staking rushes in recent memory.

WABANA'S 1996/97 EXPLORATION PROGRAM

During late 1996 and early 1997 WABANA EXPLORATIONS, Inc. completed an airborne magnetometer and electromagnetic survey over their Gillies Limit property. A total of 400 line kilometers were flown with a 100 m line spacing. The survey lines were oriented east-west. 

The magnetic relief on the property is controlled by a series of northwest-southeast formations which alternate between strongly and weakly magnetic. These are more evident in the southern half of the coverage area and are attributed to the occurrence of diabase sills.

There is a strong correlation between linear magnetic features. The Montreal River clearly coincides with the axis of a northwest-southeast magnetic depletion (Lambert 1997).

It is proposed that the narrow and sharp linear magnetic contrasts and depletions in the magnetic relief are related to major faults contacts, whereas the wider areas of magnetic quiescence are more likely due to sediments. The linear breaks generally strike northwest-southeast, north-northwest, south-southeast and north-south. 

A number of strong EM conductors were outlined, predominantly in the northern half of the coverage area, north of the Montreal River. These conductors lie at depths of less than 75 m (Lambert 1997).

A number of these strong conductors may be attributable to man-made causes and ground checks are pending. However the conductors designated Gl-1, Gl-2, Gl-6, Gl-8, Gl-9, Gl-10, to Gl-11, and Gl-12 are thought in part to be associated with sulphide mineralization. Strong conductors Gl-3, Gl-4, Gl-5, Gl-6, Gl-7 all underlie the property. In addition a number of weaker conductors also exist.

DISCUSSION

The Early Proterozoic Nipissing diabase sills of the Cobalt area are considered to be a favorable host for fractures and veins filled by post-Nipissing silver mineralization. Reactivation of regional scale faults during tectonic activity, before, during and after these intrusions, resulted in the use of the structures as fluid pathways. Most veins are carbonate rich and occur within a vertical distance of 200 m from the sill. The deposits are located at or near the Archean-Huronian unconformity. Associated low pressure temperature (propylitic) alteration in the wall rock surrounding the veins is indicative of highly alkaline fluids (Andrews et. al. 1986). The vein constituents are thought to be introduced with the these fluids.

Abundant base metal sulphides hosted in the underlying Archean volcanics are a probable source of the silver and cobalt mineralization in the area (Patterson 1979).

In the Coleman member most of the rocks contain disseminated sulphides. These occur both as vein related and as detrital sulphides (Patterson 1979). The vein related sulphides may be controlled by the sulphides in the underlying Archean volcanics while the detrital sulphides are probably controlled by paleovalleys in the Archean basement (Patterson 1979).

Copper, cobalt and silver minerals are hosted in carbonate rich veins that may contain various amounts of quartz and other minerals such as; smaltite cobaltite, gersdorffite, erythrite, annabergite, pyrite, chalcopyrite, bismuth, argentite, nicolite and galena. Others such as native silver and numerous sulpharsenides occur, but are rare (Born and Hitch 1990).

In general three vein types exist within the area. These are dilatant, shear and replacement types with mineralization being typically discontinuous along their length. Higher grade areas may occur in the vicinity of the vein intersection with, shallow-dipping shear zones, lithologic contacts and abrupt fault controlled changes in the configuration of the Archean basement (Andrews et. al. 1986).

The occurrences of copper, cobalt, silver, gold, zinc, lead and nickel in the Cobalt and surrounding area can be subdivided into four groups based on lithological and mineral assemblage characteristics (Boyle and Dass 1971, Andrews et al 1986). 

These are described as follows:

Type 1: Cu, Co, Ag +_ Au and Ni mineralization hosted in narrow (70-140m) Nipissing diabase dikes. Deposits of this type are not common in the Cobalt camp but occur to the south in Gillies Limit (Born and Hitch 1990).

Type 2: Cu, Co, Ag+_ Au and Ni mineralization related to the upper margin of the Nipissing diabase sill. In the Cobalt camp no significant mineralization was discovered in the adjacent rocks above the upper margin of the sill (Born and Hitch 1990).

Type 3: Cu, Co, Ag+_ Au and Ni mineralization is hosted in the lower margin of the Nipissing diabase sill at or near the contacts between the diabase and sedimentary rocks of the Cobalt Group. There are many examples of this type in the Cobalt camp (Born and Hitch 1990).

Type 4: Cu, Co, Ag+_ Au Ni mineralization hosted within Archean volcanics and interflow sediments and sediments of the Gowganda formation adjacent to Nipissing diabase sills. The mineralization in adjacent rocks is spatially related and is linked to the diabase. Ore grades are highest in the host volcanics and generally disappear rapidly in the diabase (Andrews et. al. 1986). 

Ruzicka and Thorpe (1996) suggests a similar subdivision based on three principal mineral assemblages. These are:

1. minor base metal sulphide assemblage in the Archean basement

2. arsenite silver-cobalt veins, which occur principally at or near the contacts between the Nipissing diabase and Gowganda formation sediments

3. a late stage sulphide assemblage which in part is distributed along the margins of arsenide-rich veins that have been reopened 

The age of the arsenide silver-cobalt veins (Type 3) has been established from geological evidence and age dating of the associated diabase, but are displaced by postore reverse faults which are contemporaneous with the intrusion of the quartz diabase dikes. The deposition of the ore must therefore have taken place after the intrusion of the diabase sills. Andrews et. al. (1986) state that the bulk of the ore was emplaced very soon after the intrusion of the diabase.

An association exists between the distribution of the silver-cobalt veins in the Cobalt camp and the contact between the Nipissing diabase and Gowganda formation. These veins occur within the diabase and in sedimentary rocks within 200 m of the diabase. They dip steeply and may extend horizontally for as much as 1000 m and vertically as much as 120 m (Ruzicka and Thorpe 1996) .

In addition there exist a number of minor sulphide occurrences in central and southern Gillies Limit township that do not fit the above subdivisions (Born and Hitch 1990). These are hosted in Archean metavolcanics but are not spatially associated with the Nipissing diabase sills. Born and hitch (1990) believe that they represent either primary Archean volcanogenic sulphide mineralization or Archean shear related and remobilized sulphides hosted within these rocks.

The arsenide-silver vein deposits in the Cobalt area are localized in areas affected by basinal subsidence and rifting and are spatially related to regional fault systems and closely associated with intrusions of mafic rocks (Ruzicka and Thorpe 1996). The application of this relationship in the Gillies Limit area is hampered by the lack of exploration during the land caution. However it would seem that the claims overlie an anticlinal depression, west of a north-south bedrock high located west of Cobalt.

Distribution of the arsenide silver-cobalt veins seems to be structurally controlled by regional fault systems and by the contact zones between Nipissing diabase sills and Huronian sediments and less commonly with Nipissing diabase and Archean rocks (Ruzicka and Thorpe 1996). The veins tend to dip steeply and have a strike extent of <100 m. Alteration zones are developed in the wall rock along the veins as narrow, (10cm), zones of calcite, chlorite, K-feldspar, muscovite, and anatase. Chlotite often occurs as spots, 1-5 mm in diameter (Ruzicka and Thorpe 1996).

The Gillies limit claims have high potential for silver-arsenide mineralization near to or up to 200 m below the Nipissing diabase sills. A large diabase sill is exposed on the property west of the Montreal river and extends northerly from the vicinity of Hound Chute Lake. Thomson (1965) and Born and Hitch (1990) indicate that the dips in the Huronian strata are steep (9-15o SW) in the vicinity of block 19 (one block north of Hound Chute Lake). Therefore initial exploration should be concentrated in the northwest of the property in the vicinity of the diabase-sediment contact with the hope of identifying shallower targets.

Evidence of proximal vent facies rocks, as interpreted by Born and Hitch (1990) , in the vicinity of Borden Lake (east of property) suggest the possibility of massive sulphide mineralization in Gillies Limit township. These rocks contain primary sulphide fragments and are hydrothermally altered. Similar rocks also occur, although to a much lesser extent, in the northern part of the township, in the vicinity of block 9, north or the Montreal river. This area is in part covered by the property but seems to have sparse outcrop.