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Ontario Geological Survey
Permanent Link to this Record:
MDI42D15SW00068
| Record Name(s) | Observation Point Occurrence - 1880, Jackfish Bay Tunnel - 9999 |
|---|---|
| Related Record Type | Simple |
| Related Record(s) | |
| Record Status | Occurrence |
| Date Created | 1997-Feb-21 |
| Date Last Modified | 2022-May-09 |
| Created By | |
| Revised By |
Primary Commodities: Gold
Secondary Commodities: Molybdenum
Township or Area: Syine
Latitude: 48° 48' 27.58" Longitude: -86° 58' 30.68"
UTM Zone: 16 Easting: 501821.76 Northing: 5406074.88 UTM Datum: NAD83
Resident Geologist District: Thunder Bay South
NTS Grid: 42D15SW
Point Location Description: Outcrop
Location Method: Field Visit
Access Description: The Observation Point occurrence is located just east of Observation Point towards Tunnel Bay, within Jackfish Bay of Lake Superior. The occurrence is located approximately 15 km east of Terrace Bay. The occurrence lies just below the Canadian Pacific Railway, approximately 15 m from the shore of Lake Superior, at a point 1370 m along the tracks west of the railway tunnel on Jackfish Bay.
ca. 1880: Unspecified sampling; McKellar brothers. 1983: Highmark Resources Ltd. and MacMillan Energy Ltd. in a joint venture carried out sampling. 1988: Trenching and sampling; J. and A. Ferguson. Property examination and lithogeochemical sampling; OGS Resident Geologist staff.
| Office File Number | Online Assessment File Identifier | Online Assessment File Directory |
|---|---|---|
| 2..8192 | 42D15SW0113 | 42D15SW0113 |
Province: Superior
Subprovince: Wawa
Terrane: Wawa-Abitibi
Geological Age: Archean
Dec 07, 2005 (D McKay) - The occurrence is hosted by locally quartz-phyric granite and quartz diorite that comprise the southern margin of the Terrace Bay batholith. The contact with the enclosing mafic metavolcanic rocks lies approximately 1.3 km to the east. Lineaments trend east, northwest and northeast and represent faults and fracture zones commonly occupied by diabase dikes. The occurrence consists of subparallel quartz vein sets that usually occupy northeast-striking, west-dipping joints in the granite. The veins range in width up to 30 cm and are cut in some places by narrow lamprophyre dikes.
| Rock Type | Rank | Composition | Texture | Relationship | Vein | 1 | Quartz | Host |
|---|---|---|---|---|
| Granite | 2 | Host | ||
| Diabase | 3 | Diabase Dikes | Near | |
| Quartz Diorite | 5 | Host |
Dec 07, 2005 (D McKay) - The occurrence is hosted by locally quartz-phyric granite and quartz diorite that comprise the southern margin of the Terrace Bay batholith.
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Pyrite | Economic | Ore | ||||
| 2 | Molybdenite | Economic | Ore | ||||
| 3 | Galena | Economic | Ore | ||||
| 1 | Quartz | Economic | Gangue | ||||
| Quartz | Alteration | Hydrothermal | 1 | Unknown | Veins |
Dec 07, 2005 (D McKay) - The quartz vein on which the pit has been sunk is exposed in a south-facing pit wall. It is irregular on surface and strikes approximately north-northeast; it dips 25 to 30 west. the vein system consists of a main, bull-white section, 30 cm wide, plus parallel quartz stringers, irregular veins and rusty, fissile fracture zones which occupy a zone over 1 m wide. The quartz is largely barren of sulphides. Pyrite occurs in patches and narrow bands with molybdenite, parallel to vein margins. the pyrite- and molybdenite-rich portions of the vein returned the best gold values. No visible gold was noted in samples, nor in panning of crushed quartz vein material. Grab samples collected from the occurrence by OGS Resident geologist staff in 1988 returned assay values which varied from 0.07 to 0.18 opt Au and <0.10 to 0.48 opt Ag.
May 29, 2018 (Therese Pettigrew) - The showing on Observation Point consists of a quartz vein about 0.5 m wide which has been traced over a strike length of 10 m. The hangingwall and footwall are both massive hornblende granodiorite with some hematite-chlorite alteration. An old trench which exposes the vein shows minor disseminated pyrite and traces of galena, molybdenite, and calcite. Samples returned assays of up to 0.025 opt Au (0.857 gpt Au), 3 ppm Ag, and 106 ppm Mo (AFRI 42D15SW0113). Grab samples collected by RGP personnel from mineralized sections of the vein returned assays of up to 0.18 opt Au (6.17 gpt Au) (Schnieders et al., 1996).
| Rank | Classification |
|---|---|
| 1 | Vein |
| Rank | Characteristic |
|---|---|
| 1 | Vein |
Map - Nipigon-Schreiber, geological compilation series, Thunder Bay District
Publication Number: M2232 Scale: 1:253,440 Date: 1973
Author: Carter M.W., McIlwaine W.H., Wisbey P.A.
Publisher Name: Ontario Division of Mines
Location:
Mono - Mineral Occurrences in the Nipigon-Marathon Area, Volumes 1 and 2.
Publication Number: OFR5951 Page: 736-67 Date: 1996
Author: Schnieders B.R., Smyk M.C., Speed A.A., McKay D.B.
Publisher Name: Ontario Geological Survey
Location:
File - Schreiber-Hemlo Resident Geologist Mineral Deposit Files
Publication Number: Min Dep Date:
Author:
Publisher Name:
Location: Thunder Bay RGP
Map - Jackfish-Middleton area, Thunder Bay District
Publication Number: M2107 Date: 1967
Author: Walker J.W.R.
Publisher Name: Ontario Dept. of Mines
Location:
Part - Schreiber-Duck Lake area
Publication Number: ARV30-04.001 Date: 1998
Author: Hopkins P.E.
Publisher Name: Ontario Dept. of Mines
Location:
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For detailed information regarding this mineral record please contact the Thunder Bay South Resident Geologist District Office