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Ontario Geological Survey
Permanent Link to this Record:
MDI42E04NW00007
| Record Name(s) | Dello Lake Occurrence - 1983, R. Michon & P. Nevins - 1991, Dello Lake - 1991, R. Michon and P. Nevins - 1983 |
|---|---|
| Related Record Type | Simple |
| Related Record(s) | |
| Record Status | Occurrence |
| Date Created | 1991-Apr-01 |
| Date Last Modified | 2022-May-12 |
| Created By | |
| Revised By |
Primary Commodities: Lead, Zinc
Secondary Commodities: Silver
Township or Area: Cosgrave Lake Area
Latitude: 49° 14' 16.13" Longitude: -87° 49' 4.95"
UTM Zone: 16 Easting: 440452.006 Northing: 5454214.894 UTM Datum: NAD83
Resident Geologist District: Thunder Bay South
NTS Grid: 42E04NW
Point Location Description: Pit
Location Method: Conversion from MDI
Access Description: The occurrence is located on the south side of a small outcrop near the northwest corner of a pond, which is about 1.2 km east of Dello Lake and 6.4 km east of Cosgrave Lake. Dello Lake lies approximately 40 km northwest of Nipigon (claim TB768335, claim map G-25, Cosgrave Lake). Access to the showing may be gained via the Little Bear Quarry (Camp 81) Road which extends north from Highway 17 at a point approximately 15 km east of Nipigon. 26 km along the road there is a northerly branch towards Cosgrave Lake. A logging road branches off at a point 3.2 km from the turn-off and it extends 4.7 km to a point where the occurrence is 1.6 km north overland.
1950-1970: The occurrence was staked as part of claim groups of the nearby Barker, Miron occurrence and Potter prospect (copper showing). Prospectors looking for gold excavated a pit on a quartz vein that exposed zinc mineralization. 1983-1984: The occurrence was staked by R. Michon as part of a 12 claim group (TB 768334 to 768337 inclusive, 786090 to 786097 inclusive). Prospecting and sampling was conducted. Noranda Exploration Company Ltd. conducted VLF and Mag surveys. 1985: P. Nevins staked 4 claims.
Province: Superior
Geological Age: Archean
Dec 07, 2005 (B Nelson) - Kusins (1983) described the Dello Lake showing: The showing occurs within metasediments of the Quetico Metasedimentary Belt. A hand steeled pit in a low lying area adjacent to a small pond in the central portion of the claim group has exposed a one foot section (true thickness) of zinc mineralization. A check of the government mapping (Pye, 1965) shows the area to be underlain by granite, although during the visit a number of metasedimentary outcrops were observed. The granites appear to be capping the metasediments with granite commonly found along the tops of hills, while the metasediments typically outcrop the lower lying areas. The host rocks of this occurrence consist of metasedimentary rocks of biotite-quartz schist or gneiss and wacke which strike east-west. A distinct foliation has been imparted to the host rocks due to the parallel to sub-parallel alignment of biotite crystals. This foliation is also parallel to bedding. In the immediate vicinity of the showing, the metasedimentary rocks have been silicified, perhaps partially due to the intrusion of a vertically dipping quartz vein striking north and cutting the mineralized zone. The quartz vein is about 1 m wide in maximum thickness and does not appear to carry mineralization. The lead-zinc mineralization has been exposed in a trench about 9.1 m long, 0.75 m deep and 1 to 1.2 m wide. Individual beds in the vicinity of the trench range in thickness from less than 2.54 cm up to 12 to 15 cm. Since the deposit dips to the north at an angle of 25 to 45 degrees (into the side of a hill), the thickness of the mineralized zone could not be determined.
| Rock Type | Rank | Composition | Texture | Relationship | Schist-Unsubdivided | 1 | Biotite-Quartz | Host |
|---|---|---|---|---|
| Gneiss-Unsubdivided | 2 | Host | ||
| Sandstone | 3 | Wacke | Host |
| Rank | Mineral Name | Class | Economic Mineral Type | Alteration Mineral Type | Alteration Ranking | Alteration Intensity | Alteration Style |
|---|---|---|---|---|---|---|---|
| 1 | Chalcopyrite | Economic | Ore | ||||
| 2 | Galena | Economic | Ore | ||||
| 3 | Pyrite | Economic | Ore | ||||
| 4 | Sphalerite | Economic | Ore | ||||
| Quartz | Alteration | Silicification | 1 | Unknown | Disseminated |
Dec 07, 2005 (B Nelson) - The mineralization consists of semi-massive to disseminated sp and gn with minor cp and py. Near the walls of the quartz vein, the major minerals, sp and gn, appear to have been remobilized, concentrating in blebs and clots in the host rocks. The sp mineralization in particular occurs as massive to semi-massive beds or layers separated by highly silicified sediments. This banding appears to be parallel to the bedding and therefore appears to be stratiform (stratabound). Campbell (1984) suggests that the Dello Lake zinc occurrence is not a vein deposit, but a stratabound deposit. Kusins (1985) noted that the best chip sample (length unknown) collected at the time of the (1983) visit returned 3.53% zinc and 0.38% lead with negligible amounts of copper, silver and gold. Sampling by Kusins (1983) and Resident Geologist's office personnel report assays including the following: Sample 13804: 0.02% Cu, 3.53% Zn, 0.38% Pb, 0.08 oz/ton Ag (from mineralized metasediments). Sample 21306: 0.06% Cu, 3.25% Zn, 0.35% Pb, 0.23 oz/ton Ag (grab sample). 84-BBM-1: 162 ppm Cu, 2.64% Zn, 820 ppm Pb, 0.10 oz/ton Ag, <0.01 oz/ton Au. 84-BBM-2: 203 ppm Cu, 15% Zn, 3720 ppm Pb, 0.26 oz/ton Ag, <0.01 oz/ton Au. 84-BBM-3: 157 ppm Cu, 8.5% Zn, 1880 ppm Pb, 0.14 oz/ton Ag, <0.01 oz/ton Au. 84-BBM-4: 31 ppm Cu, 3380 ppm Zn, 2260 ppm Pb, 0.10 oz/ton Ag, <0.01 oz/ton Au.
Date: Feb 26, 1997
Geologist: B Nelson
Notes: Resident Geologist personnel visited the occurrence August 11, 1984.
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:
MonoMap - Geology and lithium deposits of Georgia Lake area, District of Thunder Bay
Publication Number: R031 Date: 1997
Author: Pye E.G.
Publisher Name: Ontario Dept. of Mines
Location:
File - Resident Geologist mineral deposit files
Publication Number: Min Dep Date:
Author:
Publisher Name:
Location: Thunder Bay RGP
Map - Georgia Lake area, Thunder Bay District
Publication Number: M2056 Scale: 1:63,360 Date: 1997
Author: Pye E.G.
Publisher Name: Ontario Dept. of Mines
Location:
Mono - Mineral Occurrences in the Nipigon-Marathon Area, Volumes 1 and 2.
Publication Number: OFR5951 Date: 1996
Author: Schnieders B.R., Smyk M.C., Speed A.A., McKay D.B.
Publisher Name: Ontario Geological Survey
Location:
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For detailed information regarding this mineral record please contact the Thunder Bay South Resident Geologist District Office