Ontario Geological Survey
Permanent Link to this Record:
MDI000000000197
| Record Name(s) | Best - 1986 |
|---|---|
| Related Record Type | |
| Related Record(s) | |
| Record Status | Occurrence |
| Date Created | 2006-Dec-19 |
| Date Last Modified | 2022-Oct-11 |
| Created By | |
| Revised By |
Primary Commodities: Gold
Township or Area: Connell
Latitude: 51° 31' 41.62" Longitude: -90° 4' 29.32"
UTM Zone: 15 Easting: 702900 Northing: 5712625 UTM Datum: NAD83
Resident Geologist District: Thunder Bay North
NTS Grid: 52O09SE
Point Location Description: Location obtained from assessment file map in AFRO# 2.32421.
Location Method: Data Compilation
| Office File Number | Online Assessment File Identifier | Online Assessment File Directory |
|---|---|---|
| 2.32421 | 20000001524 | 20000001524 |
| 52O09SE0059 | 52O09SE0050 | 52O09SE0050 |
Province: Superior
Subprovince: Uchi
Terrane: North Caribou
Domain: Uchi
Belt: Pickle Lake
Geological Age: Mesoarchean
Dec 19, 2006 (Mark Puumala) - The Tarp Lake area gold prospects and occurrences are located in the northern portion of the Pickle Lake Greenstone Belt. These occurrences are found within a mafic metavolcanic rock dominated supracrustal sequence identified by Young (2003) as being part of the > 2860 Ma Pickle Crow Assemblage. According to Young (2003), the Pickle Crow assemblage is dominated by massive and pillowed mafic metavolcanic flows with subordinate (likely synvolcanic) gabbroic sills. MacTavish (2006) describes the mafic metavolcanic flows as being commonly well-foliated to schistose, amphibolitized, and often finely-amygdaloidal. In addition, MacTavish (2006) indicates that the mafic metavolcanics include units of pillow and hyaloclastite breccia. The gabbroic sills are described by MacTavish (2006) as fine- to coarse-grained gabbro, melagabro and ferrogabbro sills up to 200 m thick. The mafic metavolcanics are intercalated with thin, laterally continuous banded iron formation and small, discontinuous lenses of intermediate to felsic metavolcanics. A significant 90 to 125 m thick northeast-trending unit of felsic to intermediate tuff breccia to pyroclastic breccia has been reported in this area by MacTavish. Relatively thin units (up to 70 m thick) of clastic metasedimentary rocks have also been reported by MacTavish (2006). All lithologies are intruded by semi-concordant feldspar porphyry dikes. These dikes are reported by MacTavish (2006) to vary widely in thickness and lateral continuity. MacTavish (2006) also indicates that all lithologies are crosscut by late biotite lamprophyre dikes that are up to 5 m in thickness. One of these dikes is reported to contain ultramafic and country rock xenoliths, red garnets and greenish diopside. Stratigraphy in the Tarp Lake area generally faces toward the northwest, except where asymmetric folding (mainly further to the southeast in the Pickle Crow mine area) has caused reversals in the younging direction (Young 2003). The dominant geological structure in the Tarp Lake area is the Tarp Lake Shear Zone. This structure strikes northeast and forms a wide, diffuse and anastamosing deformation zone that is poorly exposed and characterized (MacTavish 2006). The mafic metavolcanic rocks affected by this shear zone are characterized by moderate to intense carbonatization, sericitization and local silicification (MacTavish 2006). This alteration zone hosts the numerous gold occurrences throughout the area. Many of the more significant gold prospects appear to be located where the Tarp Lake Shear Zone is intersected by splays and/or later fault/shear zones, or relatively competent lithological units such as porphyry intrusions, gabbro and iron formation. The cross-cutting deformation zones are most commonly reported to strike approximately northwest, east-west and north-northeast. Similar complex faulting/shearing patterns have been noted nearby by MacQueen (1987) in the vicinity of the Pickle Crow gold mine, and by McAuley and Winter (1990) in the vicinity of a number of gold occurrences in the July Falls area.
| Rock Type | Rank | Composition | Texture | Relationship | Mafic lava flow-unsubdivided | 1 | Contains |
|---|
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Sulphides | Economic | Ore | ||||
| Silica | Alteration | Silicification | 1 | ||||
| Carbonate | Alteration | Carbonatization | 2 |
Dec 19, 2006 (Mark Puumala) - The Best occurrence is described by Goodwin (1986) as brecciated chlorite-rich rock with interstitial quartz-carbonate material containing minor sulphides. The host rock is further described by MacTavish (2006) as mafic metavolcanic. The mineralized structure is reported by Goodwin (1986) to be at least 0.5 m wide. Grab samples collected from this outcrop by Billiton in 1985 assayed as high as 1035 ppb Au (Goodwin 1986).
| Rank | Classification |
|---|---|
| 1 | Lode (Gold) |
| Rank | Characteristic |
|---|---|
| 1 | Breccia |
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